The total_bytes_pinned counter is completely broken when accounting
delayed refs:
- If two drops for the same extent are merged, we will decrement
total_bytes_pinned twice but only increment it once.
- If an add is merged into a drop or vice versa, we will decrement the
total_bytes_pinned counter but never increment it.
- If multiple references to an extent are dropped, we will account it
multiple times, potentially vastly over-estimating the number of bytes
that will be freed by a commit and doing unnecessary work when we're
close to ENOSPC.
The last issue is relatively minor, but the first two make the
total_bytes_pinned counter leak or underflow very often. These
accounting issues were introduced in b150a4f10d ("Btrfs: use a percpu
to keep track of possibly pinned bytes"), but they were papered over by
zeroing out the counter on every commit until d288db5dc0 ("Btrfs: fix
race of using total_bytes_pinned").
We need to make sure that an extent is accounted as pinned exactly once
if and only if we will drop references to it when when the transaction
is committed. Ideally we would only add to total_bytes_pinned when the
*last* reference is dropped, but this information isn't readily
available for data extents. Again, this over-estimation can lead to
extra commits when we're close to ENOSPC, but it's not as bad as before.
The fix implemented here is to increment total_bytes_pinned when the
total refmod count for an extent goes negative and decrement it if the
refmod count goes back to non-negative or after we've run all of the
delayed refs for that extent.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We need this to decide when to account pinned bytes.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, we only increment total_bytes_pinned in
btrfs_free_tree_block() when dropping the last reference on the block.
However, when the delayed ref is run later, we will decrement
total_bytes_pinned regardless of whether it was the last reference or
not. This causes the counter to underflow when the reference we dropped
was not the last reference. Fix it by incrementing the counter
unconditionally, which is what btrfs_free_extent() does. This makes
total_bytes_pinned an overestimate when references to shared extents are
dropped, but in the worst case this will just make us try to commit the
transaction to try to free up space and find we didn't free enough.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The extents marked in pin_down_extent() will be unpinned later in
unpin_extent_range(), which decrements total_bytes_pinned.
pin_down_extent() must increment the counter to avoid underflowing it.
Also adjust btrfs_free_tree_block() to avoid accounting for the same
extent twice.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The value of flags is one of DATA/METADATA/SYSTEM, they must exist at
when add_pinned_bytes is called.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ added changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
There are a few places where we pass in a negative num_bytes, so make it
signed for clarity. Also move it up in the file since later patches will
need it there.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Following the factoring out of the creation code udpate_space_info can
only be called for already-existing space_info structs. As such it
cannot fail. Remove superfluous error handling and make the function
return void.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently the struct space_info creation code is intermixed in the
udpate_space_info function. There are well-defined points at which the
we actually want to create brand-new space_info structs (e.g. during
mount of the filesystem as well as sometimes when adding/initialising
new chunks). In such cases update_space_info is called with 0 as the
bytes parameter. All of this makes for spaghetti code.
Fix it by factoring out the creation code in a separate
create_space_info structure. This also allows to simplify the internals.
Also remove BUG_ON from do_alloc_chunk since the callers handle errors.
Furthermore it will make the update_space_info function not fail,
allowing us to remove error handling in callers. This will come in a
follow up patch.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We commit transaction in order to reclaim space from pinned bytes because
it could process delayed refs, and in may_commit_transaction(), we check
first if pinned bytes are enough for the required space, we then check if
that plus bytes reserved for delayed insert are enough for the required
space.
This changes the code to the above logic.
Fixes: b150a4f10d ("Btrfs: use a percpu to keep track of possibly pinned bytes")
Tested-by: Nikolay Borisov <nborisov@suse.com>
Reported-by: Nikolay Borisov <nborisov@suse.com>
Reviewed-by: Nikolay Borisov <nborisov@suse.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
can_overcommit using the root to determine the allocation profile
is the only use of a root in the call graph below reserve_metadata_bytes.
It turns out that we only need to know whether the allocation is for
the chunk root or not -- and we can pass that around as a bool instead.
This allows us to pull root usage out of the reservation path all the
way up to reserve_metadata_bytes itself, which uses it only to compare
against fs_info->chunk_root to set the bool. In turn, this eliminates
a bunch of races where we use a particular root too early in the mount
process.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are two places where we don't already know what kind of alloc
profile we need before calling btrfs_get_alloc_profile, but we need
access to a root everywhere we call it.
This patch adds helpers for btrfs_{data,metadata,system}_alloc_profile()
and relegates btrfs_system_alloc_profile to a static for use in those
two cases. The next patch will eliminate one of those.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The ->free_chunk_space variable is used to track the unallocated space
and access to it is protected by a spinlock, which is not used for
anything else. Make the code a bit self-explanatory by switching the
variable to an atomic64_t type and kill the spinlock.
Signed-off-by: Nikolay Borisov <nborisov@suse.com>
[ not a performance critical code, use of atomic type is ok ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we have to recover relocation during mount, we'll ultimately have to
evict the orphan inode. That goes through the reservation dance, where
priority_reclaim_metadata_space and flush_space expect fs_info->fs_root
to be valid. That's the next thing to be set up during mount, so we
crash, almost always in flush_space trying to join the transaction
but priority_reclaim_metadata_space is possible as well. This call
path has been problematic in the past WRT whether ->fs_root is valid
yet. Commit 957780eb27 (Btrfs: introduce ticketed enospc
infrastructure) added new users that are called in the direct path
instead of the async path that had already been worked around.
The thing is that we don't actually need the fs_root, specifically, for
anything. We either use it to determine whether the root is the
chunk_root for use in choosing an allocation profile or as a root to pass
btrfs_join_transaction before immediately committing it. Anything that
isn't the chunk root works in the former case and any root works in
the latter.
A simple fix is to use a root we know will always be there: the
extent_root.
Cc: <stable@vger.kernel.org> # v4.8+
Fixes: 957780eb27 (Btrfs: introduce ticketed enospc infrastructure)
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If we fail to add the space_info kobject, we'll leak the memory
for the percpu counter.
Fixes: 6ab0a2029c (btrfs: publish allocation data in sysfs)
Cc: <stable@vger.kernel.org> # v3.14+
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Unlike mirror based profiles, RAID5/6 recovery needs to read out the
whole full stripe.
And if we don't do proper protection, it can easily cause race condition.
Introduce 2 new functions: lock_full_stripe() and unlock_full_stripe()
for RAID5/6.
Which store a rb_tree of mutexes for full stripes, so scrub callers can
use them to lock a full stripe to avoid race.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ minor comment adjustments ]
Signed-off-by: David Sterba <dsterba@suse.com>
The members have been effectively unused since "Btrfs: rework qgroup
accounting" (fcebe4562d), there's no substitute for
assert_qgroups_uptodate so it's removed as well.
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We also don't bother to flush free space cache while with free space
tree.
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull sched.h split-up from Ingo Molnar:
"The point of these changes is to significantly reduce the
<linux/sched.h> header footprint, to speed up the kernel build and to
have a cleaner header structure.
After these changes the new <linux/sched.h>'s typical preprocessed
size goes down from a previous ~0.68 MB (~22K lines) to ~0.45 MB (~15K
lines), which is around 40% faster to build on typical configs.
Not much changed from the last version (-v2) posted three weeks ago: I
eliminated quirks, backmerged fixes plus I rebased it to an upstream
SHA1 from yesterday that includes most changes queued up in -next plus
all sched.h changes that were pending from Andrew.
I've re-tested the series both on x86 and on cross-arch defconfigs,
and did a bisectability test at a number of random points.
I tried to test as many build configurations as possible, but some
build breakage is probably still left - but it should be mostly
limited to architectures that have no cross-compiler binaries
available on kernel.org, and non-default configurations"
* 'WIP.sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (146 commits)
sched/headers: Clean up <linux/sched.h>
sched/headers: Remove #ifdefs from <linux/sched.h>
sched/headers: Remove the <linux/topology.h> include from <linux/sched.h>
sched/headers, hrtimer: Remove the <linux/wait.h> include from <linux/hrtimer.h>
sched/headers, x86/apic: Remove the <linux/pm.h> header inclusion from <asm/apic.h>
sched/headers, timers: Remove the <linux/sysctl.h> include from <linux/timer.h>
sched/headers: Remove <linux/magic.h> from <linux/sched/task_stack.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/init.h>
sched/core: Remove unused prefetch_stack()
sched/headers: Remove <linux/rculist.h> from <linux/sched.h>
sched/headers: Remove the 'init_pid_ns' prototype from <linux/sched.h>
sched/headers: Remove <linux/signal.h> from <linux/sched.h>
sched/headers: Remove <linux/rwsem.h> from <linux/sched.h>
sched/headers: Remove the runqueue_is_locked() prototype
sched/headers: Remove <linux/sched.h> from <linux/sched/hotplug.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/debug.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/nohz.h>
sched/headers: Remove <linux/sched.h> from <linux/sched/stat.h>
sched/headers: Remove the <linux/gfp.h> include from <linux/sched.h>
sched/headers: Remove <linux/rtmutex.h> from <linux/sched.h>
...
Instead of including the full <linux/signal.h>, we are going to include the
types-only <linux/signal_types.h> header in <linux/sched.h>, to further
decouple the scheduler header from the signal headers.
This means that various files which relied on the full <linux/signal.h> need
to be updated to gain an explicit dependency on it.
Update the code that relies on sched.h's inclusion of the <linux/signal.h> header.
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
The free space cache APIs accept a root but always use the tree root.
Also, btrfs_truncate_free_space_cache accepts a root AND an inode but
the inode always points to the root anyway, so let's just pass the inode.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_inc_block_group_ro is either passed the extent root or the dev
root, but it doesn't do anything with the dev tree. Let's convert
to passing an fs_info and using the extent root.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We don't need to pass a root to flush_space since it always uses
the fs_root.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Outside of interactions with qgroups, the roots passed in extent-tree.c
are usually passed to ensure that we don't do refcounts on log trees or
to get the allocation profile for an allocation request. Otherwise, it
operates on the extent root. This patch converts some more routines in
extent-tree.c that are always called with the extent root to accept
an fs_info instead.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Unused since qgroup refactoring that split data and metadata accounting,
the btrfs_qgroup_free helper.
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This uses a helper instead of open code around used byte of space_info
everywhere.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We don't need to take the lock if the block group has not been cached.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
run_delalloc_nocow has used trans in two places where they don't
actually need @trans.
For btrfs_lookup_file_extent, we search for file extents without COWing
anything, and for btrfs_cross_ref_exist, the only place where we need
@trans is deferencing it in order to get running_transaction which we
could easily get from the global fs_info.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
All we need is @delayed_refs, all callers have get it ahead of calling
btrfs_find_delayed_ref_head since lock needs to be acquired firstly,
there is no reason to deference it again inside the function.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Once a qgroup limit is exceeded, it's impossible to restore normal
operation to the subvolume without modifying the limit or removing
the subvolume. This is a surprising situation for many users used
to the typical workflow with quotas on other file systems where it's
possible to remove files until the used space is back under the limit.
When we go to unlink a file and start the transaction, we'll hit
the qgroup limit while trying to reserve space for the items we'll
modify while removing the file. We discussed last month how best
to handle this situation and agreed that there is no perfect solution.
The best principle-of-least-surprise solution is to handle it similarly
to how we already handle ENOSPC when unlinking, which is to allow
the operation to succeed with the expectation that it will ultimately
release space under most circumstances.
This patch modifies the transaction start path to select whether to
honor the qgroups limits. btrfs_start_transaction_fallback_global_rsv
is the only caller that skips enforcement. The reservation and tracking
still happens normally -- it just skips the enforcement step.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In a lot of places, it's unclear when it's safe to reuse a struct
btrfs_key after it has been passed to a helper function. Constify these
arguments wherever possible to make it obvious.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently btrfs_ino takes a struct inode and this causes a lot of
internal btrfs functions which consume this ino to take a VFS inode,
rather than btrfs' own struct btrfs_inode. In order to fix this "leak"
of VFS structs into the internals of btrfs first it's necessary to
eliminate all uses of struct inode for the purpose of inode. This patch
does that by using BTRFS_I to convert an inode to btrfs_inode. With
this problem eliminated subsequent patches will start eliminating the
passing of struct inode altogether, eventually resulting in a lot cleaner
code.
Signed-off-by: Nikolay Borisov <n.borisov.lkml@gmail.com>
[ fix btrfs_get_extent tracepoint prototype ]
Signed-off-by: David Sterba <dsterba@suse.com>
The expression is open-coded in several places, this asks for a wrapper.
As we know the MAX_EXTENT fits to u32, we can use the appropirate
division helper. This cascades to the result type updates.
Compiler is clever enough to use shift instead of integer division, so
there's no change in the generated assembly.
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_add_delayed_data_ref is always called with a NULL extent_op,
so let's drop the argument.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
If @block_group is not @used_bg, it'll try to get @used_bg's lock without
droping @block_group 's lock and lockdep has throwed a scary deadlock warning
about it.
Fix it by using down_read_nested.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In __btrfs_run_delayed_refs, when we put back a delayed ref that's too
new, we have already dropped the lock on locked_ref when we set
->processing = 0.
This patch keeps the lock to cover that assignment.
Fixes: d7df2c796d (Btrfs: attach delayed ref updates to delayed ref heads)
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In __btrfs_run_delayed_refs, the error path when run_delayed_extent_op
fails sets locked_ref->processing = 0 but doesn't re-increment
delayed_refs->num_heads_ready. As a result, we end up triggering
the WARN_ON in btrfs_select_ref_head.
Fixes: d7df2c796d (Btrfs: attach delayed ref updates to delayed ref heads)
Reported-by: Jon Nelson <jnelson-suse@jamponi.net>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now we only use the root parameter to print the root objectid in
a tracepoint. We can use the root parameter from the transaction
handle for that. It's also used to join the transaction with
async commits, so we remove the comment that it's just for checking.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are loads of functions in btrfs that accept a root parameter
but only use it to obtain an fs_info pointer. Let's convert those to
just accept an fs_info pointer directly.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With the exception of the one case where btrfs_wait_cache_io is called
without a block group, it's called with the same arguments. The root
argument is only used in the special case, so let's factor out the core
and simplify the call in the normal case to require a trans, block group,
and path.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The extent-tree tracepoints all operate on the extent root, regardless of
which root is passed in. Let's just use the extent root objectid instead.
If it turns out that nobody is depending on the format of this tracepoint,
we can drop the root printing entirely.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In routines where someptr->fs_info is referenced multiple times, we
introduce a convenience variable. This makes the code considerably
more readable.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We track the node sizes per-root, but they never vary from the values
in the superblock. This patch messes with the 80-column style a bit,
but subsequent patches to factor out root->fs_info into a convenience
variable fix it up again.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Even though a separate root is passed in, we're still operating on the
extent root. Let's use that for the trace point.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are many functions that are always called with the same root
argument. Rather than passing the same root every time, we can
pass an fs_info pointer instead and have the function get the root
pointer itself.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are 11 functions that accept a root parameter and immediately
overwrite it. We can pass those an fs_info pointer instead.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This issue was found when I tried to delete a heavily reflinked file,
when deleting such files, other transaction operation will not have a
chance to make progress, for example, start_transaction() will blocked
in wait_current_trans(root) for long time, sometimes it even triggers
soft lockups, and the time taken to delete such heavily reflinked file
is also very large, often hundreds of seconds. Using perf top, it reports
that:
PerfTop: 7416 irqs/sec kernel:99.8% exact: 0.0% [4000Hz cpu-clock], (all, 4 CPUs)
---------------------------------------------------------------------------------------
84.37% [btrfs] [k] __btrfs_run_delayed_refs.constprop.80
11.02% [kernel] [k] delay_tsc
0.79% [kernel] [k] _raw_spin_unlock_irq
0.78% [kernel] [k] _raw_spin_unlock_irqrestore
0.45% [kernel] [k] do_raw_spin_lock
0.18% [kernel] [k] __slab_alloc
It seems __btrfs_run_delayed_refs() took most cpu time, after some debug
work, I found it's select_delayed_ref() causing this issue, for a delayed
head, in our case, it'll be full of BTRFS_DROP_DELAYED_REF nodes, but
select_delayed_ref() will firstly try to iterate node list to find
BTRFS_ADD_DELAYED_REF nodes, obviously it's a disaster in this case, and
waste much time.
To fix this issue, we introduce a new ref_add_list in struct btrfs_delayed_ref_head,
then in select_delayed_ref(), if this list is not empty, we can directly use
nodes in this list. With this patch, it just took about 10~15 seconds to
delte the same file. Now using perf top, it reports that:
PerfTop: 2734 irqs/sec kernel:99.5% exact: 0.0% [4000Hz cpu-clock], (all, 4 CPUs)
----------------------------------------------------------------------------------------
20.74% [kernel] [k] _raw_spin_unlock_irqrestore
16.33% [kernel] [k] __slab_alloc
5.41% [kernel] [k] lock_acquired
4.42% [kernel] [k] lock_acquire
4.05% [kernel] [k] lock_release
3.37% [kernel] [k] _raw_spin_unlock_irq
For normal files, this patch also gives help, at least we do not need to
iterate whole list to found BTRFS_ADD_DELAYED_REF nodes.
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Tested-by: Holger Hoffstätte <holger@applied-asynchrony.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Move account_shared_subtree() to qgroup.c and rename it to
btrfs_qgroup_trace_subtree().
Do the same thing for account_leaf_items() and rename it to
btrfs_qgroup_trace_leaf_items().
Since all these functions are only for qgroup, move them to qgroup.c and
export them is more appropriate.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Rename btrfs_qgroup_insert_dirty_extent(_nolock) to
btrfs_qgroup_trace_extent(_nolock), according to the new
reserve/trace/account naming schema.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This fixes the WARN_ON on BTRFS_I(inode)->reserved_extents in
btrfs_destroy_inode and the WARN_ON on nonzero delalloc bytes on umount
with qgroups enabled.
I was able to reproduce this by setting up a small (~500kb) quota limit
and writing a file one byte at a time until I hit the limit. The warnings
would all hit on umount.
The root cause is that we would reserve a block-sized range in both
the reservation and the quota in btrfs_check_data_free_space, but if we
encountered a problem (like e.g. EDQUOT), we would only release the single
byte in the qgroup reservation. That caused an iotree state split, which
increased the number of outstanding extents, in turn disallowing releasing
the metadata reservation.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The only memset we do is to 0, so sink the parameter to the function and
simplify all calls. Rename the function to reflect the behaviour.
Signed-off-by: David Sterba <dsterba@suse.com>
During the time, the function has been shrunk to the point that it just
calls find_extent_buffer, just passing the parameters.
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_map_block supports different types of mappings, which to a large
extent resemble block layer operations. But they don't always do, and
currently btrfs dangerously overlays it's own flag over the block layer
flags. This is just asking for a conflict, so introduce a different
map flags enum inside of btrfs instead.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This issue was found when testing in-band dedupe enospc behaviour,
sometimes run_one_delayed_ref() may fail for enospc reason, then
__btrfs_run_delayed_refs（）will return, but forget to add num_heads_read
back, which will trigger "WARN_ON(delayed_refs->num_heads_ready == 0)" in
btrfs_select_ref_head().
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This reverts commit 5d8eb6fe51.
When we remove devices, we free the device structures. Delaying
btfs_remove_chunk() ends up hitting a use-after-free on them.
Signed-off-by: Chris Mason <clm@fb.com>
Really there's lots of things that can go wrong here, kill all the
BUG_ON()'s and replace the logic ones with ASSERT()'s and return EIO
instead.
Signed-off-by: Josef Bacik <jbacik@fb.com>
[ switched to btrfs_err, errors go to common label ]
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Code cleanup. count is already (unsgined long)-1. That is the reason
run_all was set. Do not reassign it (unsigned long)-1.
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The extent buffer 'next' needs to be free'd conditionally.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For many printks, we want to know which file system issued the message.
This patch converts most pr_* calls to use the btrfs_* versions instead.
In some cases, this means adding plumbing to allow call sites access to
an fs_info pointer.
fs/btrfs/check-integrity.c is left alone for another day.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This patch converts printk(KERN_* style messages to use the pr_* versions.
One side effect is that anything that was KERN_DEBUG is now automatically
a dynamic debug message.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
CodingStyle chapter 2:
"[...] never break user-visible strings such as printk messages,
because that breaks the ability to grep for them."
This patch unsplits user-visible strings.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In a corrupted btrfs image, we can come across this BUG_ON and
get an unreponsive system, but if we return errors instead,
its caller can handle everything gracefully by aborting the current
transaction.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We have a lot of random ints in btrfs_fs_info that can be put into flags. This
is mostly equivalent with the exception of how we deal with quota going on or
off, now instead we set a flag when we are turning it on or off and deal with
that appropriately, rather than just having a pending state that the current
quota_enabled gets set to. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Variable 'blocksize' in reada_walk_down() is not used since commit
d3e46fea1b ("btrfs: sink blocksize parameter to readahead_tree_block").
This patch simply removes this variable.
Signed-off-by: Luis Henriques <luis.henriques@canonical.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently, btrfs_relocate_chunk() is removing relocated BG by itself. But
the work can be done by btrfs_delete_unused_bgs() (and it's better since it
trim the BG). Let's dedupe the code.
While btrfs_delete_unused_bgs() is already hitting the relocated BG, it
skip the BG since the BG has "ro" flag set (to keep balancing BG intact).
On the other hand, btrfs cannot drop "ro" flag here to prevent additional
writes. So this patch make use of "removed" flag.
btrfs_delete_unused_bgs() now detect the flag to distinguish whether a
read-only BG is relocating or not.
Signed-off-by: Naohiro Aota <naohiro.aota@hgst.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Currently we allow inconsistence about mixed flag
(BTRFS_BLOCK_GROUP_METADATA | BTRFS_BLOCK_GROUP_DATA).
We'd get ENOSPC if block group has mixed flag and btrfs doesn't.
If that happens, we have one space_info with mixed flag and another
space_info only with BTRFS_BLOCK_GROUP_METADATA, and
global_block_rsv.space_info points to the latter one, but all bytes
from block_group contributes to the mixed space_info, thus all the
allocation will fail with ENOSPC.
This adds a check for the above case.
Reported-by: Vegard Nossum <vegard.nossum@oracle.com>
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
[ updated message ]
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
While processing delayed refs, we may update block group's statistics
and attach it to cur_trans->dirty_bgs, and later writing dirty block
groups will process the list, which happens during
btrfs_commit_transaction().
For whatever reason, the transaction is aborted and dirty_bgs
is not processed in cleanup_transaction(), we end up with memory leak
of these dirty block group cache.
Since btrfs_start_dirty_block_groups() doesn't make it go to the commit
critical section, this also adds the cleanup work inside it.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull btrfs fixes from Chris Mason:
"Josef fixed a problem when quotas are enabled with his latest ENOSPC
rework, and Jeff added more checks into the subvol ioctls to avoid
tripping up lookup_one_len"
* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
btrfs: ensure that file descriptor used with subvol ioctls is a dir
Btrfs: handle quota reserve failure properly
btrfs/022 was spitting a warning for the case that we exceed the quota. If we
fail to make our quota reservation we need to clean up our data space
reservation. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Tested-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Pull btrfs fixes from Chris Mason:
"I'm not proud of how long it took me to track down that one liner in
btrfs_sync_log(), but the good news is the patches I was trying to
blame for these problems were actually fine (sorry Filipe)"
* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
btrfs: introduce tickets_id to determine whether asynchronous metadata reclaim work makes progress
btrfs: remove root_log_ctx from ctx list before btrfs_sync_log returns
btrfs: do not decrease bytes_may_use when replaying extents
In btrfs_async_reclaim_metadata_space(), we use ticket's address to
determine whether asynchronous metadata reclaim work is making progress.
ticket = list_first_entry(&space_info->tickets,
struct reserve_ticket, list);
if (last_ticket == ticket) {
flush_state++;
} else {
last_ticket = ticket;
flush_state = FLUSH_DELAYED_ITEMS_NR;
if (commit_cycles)
commit_cycles--;
}
But indeed it's wrong, we should not rely on local variable's address to
do this check, because addresses may be same. In my test environment, I
dd one 168MB file in a 256MB fs, found that for this file, every time
wait_reserve_ticket() called, local variable ticket's address is same,
For above codes, assume a previous ticket's address is addrA, last_ticket
is addrA. Btrfs_async_reclaim_metadata_space() finished this ticket and
wake up it, then another ticket is added, but with the same address addrA,
now last_ticket will be same to current ticket, then current ticket's flush
work will start from current flush_state, not initial FLUSH_DELAYED_ITEMS_NR,
which may result in some enospc issues(I have seen this in my test machine).
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When replaying extents, there is no need to update bytes_may_use
in btrfs_alloc_logged_file_extent(), otherwise it'll trigger a
WARN_ON about bytes_may_use.
Fixes: ("btrfs: update btrfs_space_info's bytes_may_use timely")
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull btrfs fixes from Chris Mason:
"I'm still prepping a set of fixes for btrfs fsync, just nailing down a
hard to trigger memory corruption. For now, these are tested and ready."
* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
btrfs: fix one bug that process may endlessly wait for ticket in wait_reserve_ticket()
Btrfs: fix endless loop in balancing block groups
Btrfs: kill invalid ASSERT() in process_all_refs()
If can_overcommit() in btrfs_calc_reclaim_metadata_size() returns true,
btrfs_async_reclaim_metadata_space() will not reclaim metadata space, just
return directly and also forget to wake up process which are waiting for
their tickets, so these processes will wait endlessly.
Fstests case generic/172 with mount option "-o compress=lzo" have revealed
this bug in my test machine. Here if we have tickets to handle, we must
handle them first.
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pull btrfs fixes from Chris Mason:
"We've queued up a few different fixes in here. These range from
enospc corners to fsync and quota fixes, and a few targeted at error
handling for corrupt metadata/fuzzing"
* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: fix lockdep warning on deadlock against an inode's log mutex
Btrfs: detect corruption when non-root leaf has zero item
Btrfs: check btree node's nritems
btrfs: don't create or leak aliased root while cleaning up orphans
Btrfs: fix em leak in find_first_block_group
btrfs: do not background blkdev_put()
Btrfs: clarify do_chunk_alloc()'s return value
btrfs: fix fsfreeze hang caused by delayed iputs deal
btrfs: update btrfs_space_info's bytes_may_use timely
btrfs: divide btrfs_update_reserved_bytes() into two functions
btrfs: use correct offset for reloc_inode in prealloc_file_extent_cluster()
btrfs: qgroup: Fix qgroup incorrectness caused by log replay
btrfs: relocation: Fix leaking qgroups numbers on data extents
btrfs: qgroup: Refactor btrfs_qgroup_insert_dirty_extent()
btrfs: waiting on qgroup rescan should not always be interruptible
btrfs: properly track when rescan worker is running
btrfs: flush_space: treat return value of do_chunk_alloc properly
Btrfs: add ASSERT for block group's memory leak
btrfs: backref: Fix soft lockup in __merge_refs function
Btrfs: fix memory leak of reloc_root
We need to call free_extent_map() on the em we look up.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Function start_transaction() can return ERR_PTR(1) when flush is
BTRFS_RESERVE_FLUSH_LIMIT, so the call graph is
start_transaction (return ERR_PTR(1))
-> btrfs_block_rsv_add (return 1)
-> reserve_metadata_bytes (return 1)
-> flush_space (return 1)
-> do_chunk_alloc (return 1)
With BTRFS_RESERVE_FLUSH_LIMIT, if flush_space is already on the
flush_state of ALLOC_CHUNK and it successfully allocates a new
chunk, then instead of trying to reserve space again,
reserve_metadata_bytes returns 1 immediately.
Eventually the callers who call start_transaction() usually just
do the IS_ERR() check which ERR_PTR(1) can pass, then it'll get
a panic when dereferencing a pointer which is ERR_PTR(1).
The following patch fixes the above problem.
"btrfs: flush_space: treat return value of do_chunk_alloc properly"
https://patchwork.kernel.org/patch/7778651/
This add comments to clarify do_chunk_alloc()'s return value.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
This patch can fix some false ENOSPC errors, below test script can
reproduce one false ENOSPC error:
#!/bin/bash
dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128
dev=$(losetup --show -f fs.img)
mkfs.btrfs -f -M $dev
mkdir /tmp/mntpoint
mount $dev /tmp/mntpoint
cd /tmp/mntpoint
xfs_io -f -c "falloc 0 $((64*1024*1024))" testfile
Above script will fail for ENOSPC reason, but indeed fs still has free
space to satisfy this request. Please see call graph:
btrfs_fallocate()
|-> btrfs_alloc_data_chunk_ondemand()
| bytes_may_use += 64M
|-> btrfs_prealloc_file_range()
|-> btrfs_reserve_extent()
|-> btrfs_add_reserved_bytes()
| alloc_type is RESERVE_ALLOC_NO_ACCOUNT, so it does not
| change bytes_may_use, and bytes_reserved += 64M. Now
| bytes_may_use + bytes_reserved == 128M, which is greater
| than btrfs_space_info's total_bytes, false enospc occurs.
| Note, the bytes_may_use decrease operation will be done in
| end of btrfs_fallocate(), which is too late.
Here is another simple case for buffered write:
CPU 1 | CPU 2
|
|-> cow_file_range() |-> __btrfs_buffered_write()
|-> btrfs_reserve_extent() | |
| | |
| | |
| ..... | |-> btrfs_check_data_free_space()
| |
| |
|-> extent_clear_unlock_delalloc() |
In CPU 1, btrfs_reserve_extent()->find_free_extent()->
btrfs_add_reserved_bytes() do not decrease bytes_may_use, the decrease
operation will be delayed to be done in extent_clear_unlock_delalloc().
Assume in this case, btrfs_reserve_extent() reserved 128MB data, CPU2's
btrfs_check_data_free_space() tries to reserve 100MB data space.
If
100MB > data_sinfo->total_bytes - data_sinfo->bytes_used -
data_sinfo->bytes_reserved - data_sinfo->bytes_pinned -
data_sinfo->bytes_readonly - data_sinfo->bytes_may_use
btrfs_check_data_free_space() will try to allcate new data chunk or call
btrfs_start_delalloc_roots(), or commit current transaction in order to
reserve some free space, obviously a lot of work. But indeed it's not
necessary as long as decreasing bytes_may_use timely, we still have
free space, decreasing 128M from bytes_may_use.
To fix this issue, this patch chooses to update bytes_may_use for both
data and metadata in btrfs_add_reserved_bytes(). For compress path, real
extent length may not be equal to file content length, so introduce a
ram_bytes argument for btrfs_reserve_extent(), find_free_extent() and
btrfs_add_reserved_bytes(), it's becasue bytes_may_use is increased by
file content length. Then compress path can update bytes_may_use
correctly. Also now we can discard RESERVE_ALLOC_NO_ACCOUNT, RESERVE_ALLOC
and RESERVE_FREE.
As we know, usually EXTENT_DO_ACCOUNTING is used for error path. In
run_delalloc_nocow(), for inode marked as NODATACOW or extent marked as
PREALLOC, we also need to update bytes_may_use, but can not pass
EXTENT_DO_ACCOUNTING, because it also clears metadata reservation, so
here we introduce EXTENT_CLEAR_DATA_RESV flag to indicate btrfs_clear_bit_hook()
to update btrfs_space_info's bytes_may_use.
Meanwhile __btrfs_prealloc_file_range() will call
btrfs_free_reserved_data_space() internally for both sucessful and failed
path, btrfs_prealloc_file_range()'s callers does not need to call
btrfs_free_reserved_data_space() any more.
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
This patch divides btrfs_update_reserved_bytes() into
btrfs_add_reserved_bytes() and btrfs_free_reserved_bytes(), and
next patch will extend btrfs_add_reserved_bytes（）to fix some
false ENOSPC error, please see later patch for detailed info.
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Refactor btrfs_qgroup_insert_dirty_extent() function, to two functions:
1. btrfs_qgroup_insert_dirty_extent_nolock()
Almost the same with original code.
For delayed_ref usage, which has delayed refs locked.
Change the return value type to int, since caller never needs the
pointer, but only needs to know if they need to free the allocated
memory.
2. btrfs_qgroup_insert_dirty_extent()
The more encapsulated version.
Will do the delayed_refs lock, memory allocation, quota enabled check
and other things.
The original design is to keep exported functions to minimal, but since
more btrfs hacks exposed, like replacing path in balance, we need to
record dirty extents manually, so we have to add such functions.
Also, add comment for both functions, to info developers how to keep
qgroup correct when doing hacks.
Cc: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Reviewed-and-Tested-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
do_chunk_alloc returns 1 when it succeeds to allocate a new chunk.
But flush_space will not convert this to 0, and will also return 1.
As a result, reserve_metadata_bytes will think that flush_space failed,
and may potentially return this value "1" to the caller (depends how
reserve_metadata_bytes was called). The caller will also treat this as an error.
For example, btrfs_block_rsv_refill does:
int ret = -ENOSPC;
...
ret = reserve_metadata_bytes(root, block_rsv, num_bytes, flush);
if (!ret) {
block_rsv_add_bytes(block_rsv, num_bytes, 0);
return 0;
}
return ret;
So it will return -ENOSPC.
Signed-off-by: Alex Lyakas <alex@zadarastorage.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
This adds several ASSERT()' s to report memory leak of block group cache.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Pull more btrfs updates from Chris Mason:
"This is part two of my btrfs pull, which is some cleanups and a batch
of fixes.
Most of the code here is from Jeff Mahoney, making the pointers we
pass around internally more consistent and less confusing overall. I
noticed a small problem right before I sent this out yesterday, so I
fixed it up and re-tested overnight"
* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs: (40 commits)
Btrfs: fix __MAX_CSUM_ITEMS
btrfs: btrfs_abort_transaction, drop root parameter
btrfs: add btrfs_trans_handle->fs_info pointer
btrfs: btrfs_relocate_chunk pass extent_root to btrfs_end_transaction
btrfs: convert nodesize macros to static inlines
btrfs: introduce BTRFS_MAX_ITEM_SIZE
btrfs: cleanup, remove prototype for btrfs_find_root_ref
btrfs: copy_to_sk drop unused root parameter
btrfs: simpilify btrfs_subvol_inherit_props
btrfs: tests, use BTRFS_FS_STATE_DUMMY_FS_INFO instead of dummy root
btrfs: tests, require fs_info for root
btrfs: tests, move initialization into tests/
btrfs: btrfs_test_opt and friends should take a btrfs_fs_info
btrfs: prefix fsid to all trace events
btrfs: plumb fs_info into btrfs_work
btrfs: remove obsolete part of comment in statfs
btrfs: hide test-only member under ifdef
btrfs: Ratelimit "no csum found" info message
btrfs: Add ratelimit to btrfs printing
Btrfs: fix unexpected balance crash due to BUG_ON
...
Pull btrfs updates from Chris Mason:
"This pull is dedicated to Josef's enospc rework, which we've been
testing for a few releases now. It fixes some early enospc problems
and is dramatically faster.
This also includes an updated fix for the delalloc accounting that
happens after a fault in copy_from_user. My patch in v4.7 was almost
but not quite enough"
* 'for-linus-4.8' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: fix delalloc accounting after copy_from_user faults
Btrfs: avoid deadlocks during reservations in btrfs_truncate_block
Btrfs: use FLUSH_LIMIT for relocation in reserve_metadata_bytes
Btrfs: fill relocation block rsv after allocation
Btrfs: always use trans->block_rsv for orphans
Btrfs: change how we calculate the global block rsv
Btrfs: use root when checking need_async_flush
Btrfs: don't bother kicking async if there's nothing to reclaim
Btrfs: fix release reserved extents trace points
Btrfs: add fsid to some tracepoints
Btrfs: add tracepoints for flush events
Btrfs: fix delalloc reservation amount tracepoint
Btrfs: trace pinned extents
Btrfs: introduce ticketed enospc infrastructure
Btrfs: add tracepoint for adding block groups
Btrfs: warn_on for unaccounted spaces
Btrfs: change delayed reservation fallback behavior
Btrfs: always reserve metadata for delalloc extents
Btrfs: fix callers of btrfs_block_rsv_migrate
Btrfs: add bytes_readonly to the spaceinfo at once
Pull core block updates from Jens Axboe:
- the big change is the cleanup from Mike Christie, cleaning up our
uses of command types and modified flags. This is what will throw
some merge conflicts
- regression fix for the above for btrfs, from Vincent
- following up to the above, better packing of struct request from
Christoph
- a 2038 fix for blktrace from Arnd
- a few trivial/spelling fixes from Bart Van Assche
- a front merge check fix from Damien, which could cause issues on
SMR drives
- Atari partition fix from Gabriel
- convert cfq to highres timers, since jiffies isn't granular enough
for some devices these days. From Jan and Jeff
- CFQ priority boost fix idle classes, from me
- cleanup series from Ming, improving our bio/bvec iteration
- a direct issue fix for blk-mq from Omar
- fix for plug merging not involving the IO scheduler, like we do for
other types of merges. From Tahsin
- expose DAX type internally and through sysfs. From Toshi and Yigal
* 'for-4.8/core' of git://git.kernel.dk/linux-block: (76 commits)
block: Fix front merge check
block: do not merge requests without consulting with io scheduler
block: Fix spelling in a source code comment
block: expose QUEUE_FLAG_DAX in sysfs
block: add QUEUE_FLAG_DAX for devices to advertise their DAX support
Btrfs: fix comparison in __btrfs_map_block()
block: atari: Return early for unsupported sector size
Doc: block: Fix a typo in queue-sysfs.txt
cfq-iosched: Charge at least 1 jiffie instead of 1 ns
cfq-iosched: Fix regression in bonnie++ rewrite performance
cfq-iosched: Convert slice_resid from u64 to s64
block: Convert fifo_time from ulong to u64
blktrace: avoid using timespec
block/blk-cgroup.c: Declare local symbols static
block/bio-integrity.c: Add #include "blk.h"
block/partition-generic.c: Remove a set-but-not-used variable
block: bio: kill BIO_MAX_SIZE
cfq-iosched: temporarily boost queue priority for idle classes
block: drbd: avoid to use BIO_MAX_SIZE
block: bio: remove BIO_MAX_SECTORS
...
__btrfs_abort_transaction doesn't use its root parameter except to
obtain an fs_info pointer. We can obtain that from trans->root->fs_info
for now and from trans->fs_info in a later patch.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_trans_handle->root is documented as for use for confirming
that the root passed in to start the transaction is the same as the
one ending it. It's used in several places when an fs_info pointer
is needed, so let's just add an fs_info pointer directly. Eventually,
the root pointer can be removed.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We use BTRFS_LEAF_DATA_SIZE - sizeof(struct btrfs_item) in
several places. This introduces a BTRFS_MAX_ITEM_SIZE macro to do the
same.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Now that we have a dummy fs_info associated with each test that
uses a root, we don't need the DUMMY_ROOT bit anymore. This lets
us make choices without needing an actual root like in e.g.
btrfs_find_create_tree_block.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_test_opt and friends only use the root pointer to access
the fs_info. Let's pass the fs_info directly in preparation to
eliminate similar patterns all over btrfs.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When using trace events to debug a problem, it's impossible to determine
which file system generated a particular event. This patch adds a
macro to prefix standard information to the head of a trace event.
The extent_state alloc/free events are all that's left without an
fs_info available.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
In btrfs, btrfs_space_info's bytes_may_use is treated as fs used
space, as what we do in reserve_metadata_bytes() or
btrfs_alloc_data_chunk_ondemand(), so in dump_space_info(), when
calculating free space, we should also subtract btrfs_space_info's
bytes_may_use.
Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
With btrfs-corrupt-block, one can drop one chunk item and mounting
will end up with a panic in btrfs_full_stripe_len().
This doesn't not remove the BUG_ON, but instead checks it a bit
earlier when we find the block group item.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
The new enospc code makes it possible to deadlock if we don't use
FLUSH_LIMIT during reservations inside a transaction. This enforces
the correct flush type to avoid both deadlocks and assertions
Signed-off-by: Chris Mason <clm@fb.com>
Signed-off-by: Josef Bacik <jbacik@fb.com>
We used to allow you to set FLUSH_ALL and then just wouldn't do things like
commit transactions or wait on ordered extents if we noticed you were in a
transaction. However now that all the flushing for FLUSH_ALL is asynchronous
we've lost the ability to tell, and we could end up deadlocking. So instead use
FLUSH_LIMIT in reserve_metadata_bytes in relocation and then return -EAGAIN if
we error out to preserve the previous behavior. I've also added an ASSERT() to
catch anybody else who tries to do this. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
This is the case all the time anyway except for relocation which could be doing
a reloc root for a non ref counted root, in which case we'd end up with some
random block rsv rather than the one we have our reservation in. If there isn't
enough space in the block rsv we are trying to steal from we'll BUG() because we
expect there to be space for the orphan to make its reservation. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Traditionally we've calculated the global block rsv by guessing how much of the
metadata used amount was the extent tree, and then taking the data size and
figuring out how large the csum tree would have to be to hold that much data.
This is imprecise and falls down on MIXED file systems as we can't trust the
data used amount. This resulted in failures for xfstests generic/333 because it
creates lots of clones, which explodes out the extent tree. Our global reserve
calculations were woefully inaccurate in this case which meant we got into a
situation where we did not have enough reserved to do our work.
We know we only use the global block rsv for the extent, csum, and root trees,
so just get the bytes used for these trees and use that as the basis of our
global reserve. Since these are not reference counted trees the bytes_used
value will be accurate. This fixed the transaction aborts seen with
generic/333. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Instead of doing fs_info->fs_root in need_async_flush, which may not be set
during recovery when mounting, just pass the root itself in, which makes more
sense as thats what btrfs_calc_reclaim_metadata_size takes.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reported-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We do this check when we start the async reclaimer thread, might as well check
before we kick it off to save us some cycles. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We were doing trace_btrfs_release_reserved_extent() in pin_down_extent which
isn't quite right because we will go through and free that extent later when we
unpin, so it messes up apps that are accounting for the reservation space. We
were also unconditionally doing it in __btrfs_free_reserved_extent(), when we
only actually free the reservation instead of pinning the extent. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We want to track when we're triggering flushing from our reservation code and
what flushing is being done when we start flushing. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We can sometimes drop the reservation we had for our inode, so we need to remove
that amount from to_reserve so that our tracepoint reports a valid amount of
space.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Pinned extents are an important metric to keep track of for enospc.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Our enospc flushing sucks. It is born from a time where we were early
enospc'ing constantly because multiple threads would race in for the same
reservation and randomly starve other ones out. So I came up with this solution
to block any other reservations from happening while one guy tried to flush
stuff to satisfy his reservation. This gives us pretty good correctness, but
completely crap latency.
The solution I've come up with is ticketed reservations. Basically we try to
make our reservation, and if we can't we put a ticket on a list in order and
kick off an async flusher thread. This async flusher thread does the same old
flushing we always did, just asynchronously. As space is freed and added back
to the space_info it checks and sees if we have any tickets that need
satisfying, and adds space to the tickets and wakes up anything we've satisfied.
Once the flusher thread stops making progress it wakes up all the current
tickets and tells them to take a hike.
There is a priority list for things that can't flush, since the async flusher
could do anything we need to avoid deadlocks. These guys get priority for
having their reservation made, and will still do manual flushing themselves in
case the async flusher isn't running.
This patch gives us significantly better latencies. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I'm writing a tool to visualize the enospc system inside btrfs, I need this
tracepoint in order to keep track of the block groups in the system. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
These were hidden behind enospc_debug, which isn't helpful as they indicate
actual bugs, unlike the rest of the enospc_debug stuff which is really debug
information. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
There are a few races in the metadata reservation stuff. First we add the bytes
to the block_rsv well after we've set the bit on the inode saying that we have
space for it and after we've reserved the bytes. So use the normal
btrfs_block_rsv_add helper for this case. Secondly we can flush delalloc
extents when we try to reserve space for our write, which means that we could
have used up the space for the inode and we wouldn't know because we only check
before the reservation. So instead make sure we are always reserving space for
the inode update, and then if we don't need it release those bytes afterward.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
So btrfs_block_rsv_migrate just unconditionally calls block_rsv_migrate_bytes.
Not only this but it unconditionally changes the size of the block_rsv. This
isn't a bug strictly speaking, but it makes truncate block rsv's look funny
because every time we migrate bytes over its size grows, even though we only
want it to be a specific size. So collapse this into one function that takes an
update_size argument and make truncate and evict not update the size for
consistency sake. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
For some reason we're adding bytes_readonly to the space info after we update
the space info with the block group info. This creates a tiny race where we
could over-reserve space because we haven't yet taken out the bytes_readonly
bit. Since we already know this information at the time we call
update_space_info, just pass it along so it can be updated all at once. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
"Btrfs: track transid for delayed ref flushing" was deadlocking on
btrfs_attach_transaction because its not safe to call from the async
delayed ref start code. This commit brings back btrfs_join_transaction
instead and checks for a blocked commit.
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Using the offwakecputime bpf script I noticed most of our time was spent waiting
on the delayed ref throttling. This is what is supposed to happen, but
sometimes the transaction can commit and then we're waiting for throttling that
doesn't matter anymore. So change this stuff to be a little smarter by tracking
the transid we were in when we initiated the throttling. If the transaction we
get is different then we can just bail out. This resulted in a 50% speedup in
my fs_mark test, and reduced the amount of time spent throttling by 60 seconds
over the entire run (which is about 30 minutes). Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
The test for !trans->blocks_used in btrfs_abort_transaction is
insufficient to determine whether it's safe to drop the transaction
handle on the floor. btrfs_cow_block, informed by should_cow_block,
can return blocks that have already been CoW'd in the current
transaction. trans->blocks_used is only incremented for new block
allocations. If an operation overlaps the blocks in the current
transaction entirely and must abort the transaction, we'll happily
let it clean up the trans handle even though it may have modified
the blocks and will commit an incomplete operation.
In the long-term, I'd like to do closer tracking of when the fs
is actually modified so we can still recover as gracefully as possible,
but that approach will need some discussion. In the short term,
since this is the only code using trans->blocks_used, let's just
switch it to a bool indicating whether any blocks were used and set
it when should_cow_block returns false.
Cc: stable@vger.kernel.org # 3.4+
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Thanks to fuzz testing, we can pass an invalid bytenr to extent buffer
via alloc_extent_buffer(). An unaligned eb can have more pages than it
should have, which ends up extent buffer's leak or some corrupted content
in extent buffer.
This adds a warning to let us quickly know what was happening.
Now that alloc_extent_buffer() no more returns NULL, this changes its
caller and callers of its caller to match with the new error
handling.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We no longer pass in a bitmap of rq_flag_bits bits to __btrfs_map_block.
It will always be a REQ_OP, or the btrfs specific REQ_GET_READ_MIRRORS,
so this drops the bit tests.
Signed-off-by: Mike Christie <mchristi@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
While we are finishing a device replace operation, we can make a discard
operation (fs mounted with -o discard) do an invalid memory access like
the one reported by the following trace:
[ 3206.384654] general protection fault: 0000 [#1] PREEMPT SMP
[ 3206.387520] Modules linked in: dm_mod btrfs crc32c_generic xor raid6_pq acpi_cpufreq tpm_tis psmouse tpm ppdev sg parport_pc evdev i2c_piix4 parport
processor serio_raw i2c_core pcspkr button loop autofs4 ext4 crc16 jbd2 mbcache sr_mod cdrom ata_generic sd_mod virtio_scsi ata_piix libata virtio_pci
virtio_ring scsi_mod e1000 virtio floppy [last unloaded: btrfs]
[ 3206.388595] CPU: 14 PID: 29194 Comm: fsstress Not tainted 4.6.0-rc7-btrfs-next-29+ #1
[ 3206.388595] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 3206.388595] task: ffff88017ace0100 ti: ffff880171b98000 task.ti: ffff880171b98000
[ 3206.388595] RIP: 0010:[<ffffffff8124d233>] [<ffffffff8124d233>] blkdev_issue_discard+0x5c/0x2a7
[ 3206.388595] RSP: 0018:ffff880171b9bb80 EFLAGS: 00010246
[ 3206.388595] RAX: ffff880171b9bc28 RBX: 000000000090d000 RCX: 0000000000000000
[ 3206.388595] RDX: ffffffff82fa1b48 RSI: ffffffff8179f46c RDI: ffffffff82fa1b48
[ 3206.388595] RBP: ffff880171b9bcc0 R08: 0000000000000000 R09: 0000000000000001
[ 3206.388595] R10: ffff880171b9bce0 R11: 000000000090f000 R12: ffff880171b9bbe8
[ 3206.388595] R13: 0000000000000010 R14: 0000000000004868 R15: 6b6b6b6b6b6b6b6b
[ 3206.388595] FS: 00007f6182e4e700(0000) GS:ffff88023fdc0000(0000) knlGS:0000000000000000
[ 3206.388595] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3206.388595] CR2: 00007f617c2bbb18 CR3: 000000017ad9c000 CR4: 00000000000006e0
[ 3206.388595] Stack:
[ 3206.388595] 0000000000004878 0000000000000000 0000000002400040 0000000000000000
[ 3206.388595] 0000000000000000 ffff880171b9bbe8 ffff880171b9bbb0 ffff880171b9bbb0
[ 3206.388595] ffff880171b9bbc0 ffff880171b9bbc0 ffff880171b9bbd0 ffff880171b9bbd0
[ 3206.388595] Call Trace:
[ 3206.388595] [<ffffffffa042899e>] btrfs_issue_discard+0x12f/0x143 [btrfs]
[ 3206.388595] [<ffffffffa042899e>] ? btrfs_issue_discard+0x12f/0x143 [btrfs]
[ 3206.388595] [<ffffffffa042e862>] btrfs_discard_extent+0x87/0xde [btrfs]
[ 3206.388595] [<ffffffffa04303b5>] btrfs_finish_extent_commit+0xb2/0x1df [btrfs]
[ 3206.388595] [<ffffffff8149c246>] ? __mutex_unlock_slowpath+0x150/0x15b
[ 3206.388595] [<ffffffffa04464c4>] btrfs_commit_transaction+0x7fc/0x980 [btrfs]
[ 3206.388595] [<ffffffff8149c246>] ? __mutex_unlock_slowpath+0x150/0x15b
[ 3206.388595] [<ffffffffa0459af6>] btrfs_sync_file+0x38f/0x428 [btrfs]
[ 3206.388595] [<ffffffff811a8292>] vfs_fsync_range+0x8c/0x9e
[ 3206.388595] [<ffffffff811a82c0>] vfs_fsync+0x1c/0x1e
[ 3206.388595] [<ffffffff811a8417>] do_fsync+0x31/0x4a
[ 3206.388595] [<ffffffff811a8637>] SyS_fsync+0x10/0x14
[ 3206.388595] [<ffffffff8149e025>] entry_SYSCALL_64_fastpath+0x18/0xa8
[ 3206.388595] [<ffffffff81100c6b>] ? time_hardirqs_off+0x9/0x14
[ 3206.388595] [<ffffffff8108e87d>] ? trace_hardirqs_off_caller+0x1f/0xaa
This happens because when we call btrfs_map_block() from
btrfs_discard_extent() to get a btrfs_bio structure, the device replace
operation has not finished yet, but before we use the device of one of the
stripes from the returned btrfs_bio structure, the device object is freed.
This is illustrated by the following diagram.
CPU 1 CPU 2
btrfs_dev_replace_start()
(...)
btrfs_dev_replace_finishing()
btrfs_start_transaction()
btrfs_commit_transaction()
(...)
btrfs_sync_file()
btrfs_start_transaction()
(...)
btrfs_commit_transaction()
btrfs_finish_extent_commit()
btrfs_discard_extent()
btrfs_map_block()
--> returns a struct btrfs_bio
with a stripe that has a
device field pointing to
source device of the replace
operation (the device that
is being replaced)
mutex_lock(&uuid_mutex)
mutex_lock(&fs_info->fs_devices->device_list_mutex)
mutex_lock(&fs_info->chunk_mutex)
btrfs_dev_replace_update_device_in_mapping_tree()
--> iterates the mapping tree and for each
extent map that has a stripe pointing to
the source device, it updates the stripe
to point to the target device instead
btrfs_rm_dev_replace_blocked()
--> waits for fs_info->bio_counter to go down to 0
btrfs_rm_dev_replace_remove_srcdev()
--> removes source device from the list of devices
mutex_unlock(&fs_info->chunk_mutex)
mutex_unlock(&fs_info->fs_devices->device_list_mutex)
mutex_unlock(&uuid_mutex)
btrfs_rm_dev_replace_free_srcdev()
--> frees the source device
--> iterates over all stripes
of the returned struct
btrfs_bio
--> for each stripe it
dereferences its device
pointer
--> it ends up finding a
pointer to the device
used as the source
device for the replace
operation and that was
already freed
So fix this by surrounding the call to btrfs_map_block(), and the code
that uses the returned struct btrfs_bio, with calls to
btrfs_bio_counter_inc_blocked() and btrfs_bio_counter_dec(), so that
the finishing phase of the device replace operation blocks until the
the bio counter decreases to zero before it frees the source device.
This is the same approach we do at btrfs_map_bio() for example.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Relocation of a block group waits for all existing tasks flushing
dellaloc, starting direct IO writes and any ordered extents before
starting the relocation process. However for direct IO writes that end
up doing nocow (inode either has the flag nodatacow set or the write is
against a prealloc extent) we have a short time window that allows for a
race that makes relocation proceed without waiting for the direct IO
write to complete first, resulting in data loss after the relocation
finishes. This is illustrated by the following diagram:
CPU 1 CPU 2
btrfs_relocate_block_group(bg X)
direct IO write starts against
an extent in block group X
using nocow mode (inode has the
nodatacow flag or the write is
for a prealloc extent)
btrfs_direct_IO()
btrfs_get_blocks_direct()
--> can_nocow_extent() returns 1
btrfs_inc_block_group_ro(bg X)
--> turns block group into RO mode
btrfs_wait_ordered_roots()
--> returns and does not know about
the DIO write happening at CPU 2
(the task there has not created
yet an ordered extent)
relocate_block_group(bg X)
--> rc->stage == MOVE_DATA_EXTENTS
find_next_extent()
--> returns extent that the DIO
write is going to write to
relocate_data_extent()
relocate_file_extent_cluster()
--> reads the extent from disk into
pages belonging to the relocation
inode and dirties them
--> creates DIO ordered extent
btrfs_submit_direct()
--> submits bio against a location
on disk obtained from an extent
map before the relocation started
btrfs_wait_ordered_range()
--> writes all the pages read before
to disk (belonging to the
relocation inode)
relocation finishes
bio completes and wrote new data
to the old location of the block
group
So fix this by tracking the number of nocow writers for a block group and
make sure relocation waits for that number to go down to 0 before starting
to move the extents.
The same race can also happen with buffered writes in nocow mode since the
patch I recently made titled "Btrfs: don't do unnecessary delalloc flushes
when relocating", because we are no longer flushing all delalloc which
served as a synchonization mechanism (due to page locking) and ensured
the ordered extents for nocow buffered writes were created before we
called btrfs_wait_ordered_roots(). The race with direct IO writes in nocow
mode existed before that patch (no pages are locked or used during direct
IO) and that fixed only races with direct IO writes that do cow.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Before we start the actual relocation process of a block group, we do
calls to flush delalloc of all inodes and then wait for ordered extents
to complete. However we do these flush calls just to make sure we don't
race with concurrent tasks that have actually already started to run
delalloc and have allocated an extent from the block group we want to
relocate, right before we set it to readonly mode, but have not yet
created the respective ordered extents. The flush calls make us wait
for such concurrent tasks because they end up calling
filemap_fdatawrite_range() (through btrfs_start_delalloc_roots() ->
__start_delalloc_inodes() -> btrfs_alloc_delalloc_work() ->
btrfs_run_delalloc_work()) which ends up serializing us with those tasks
due to attempts to lock the same pages (and the delalloc flush procedure
calls the allocator and creates the ordered extents before unlocking the
pages).
These flushing calls not only make us waste time (cpu, IO) but also reduce
the chances of writing larger extents (applications might be writing to
contiguous ranges and we flush before they finish dirtying the whole
ranges).
So make sure we don't flush delalloc and just wait for concurrent tasks
that have already started flushing delalloc and have allocated an extent
from the block group we are about to relocate.
This change also ends up fixing a race with direct IO writes that makes
relocation not wait for direct IO ordered extents. This race is
illustrated by the following diagram:
CPU 1 CPU 2
btrfs_relocate_block_group(bg X)
starts direct IO write,
target inode currently has no
ordered extents ongoing nor
dirty pages (delalloc regions),
therefore the root for our inode
is not in the list
fs_info->ordered_roots
btrfs_direct_IO()
__blockdev_direct_IO()
btrfs_get_blocks_direct()
btrfs_lock_extent_direct()
locks range in the io tree
btrfs_new_extent_direct()
btrfs_reserve_extent()
--> extent allocated
from bg X
btrfs_inc_block_group_ro(bg X)
btrfs_start_delalloc_roots()
__start_delalloc_inodes()
--> does nothing, no dealloc ranges
in the inode's io tree so the
inode's root is not in the list
fs_info->delalloc_roots
btrfs_wait_ordered_roots()
--> does not find the inode's root in the
list fs_info->ordered_roots
--> ends up not waiting for the direct IO
write started by the task at CPU 2
relocate_block_group(rc->stage ==
MOVE_DATA_EXTENTS)
prepare_to_relocate()
btrfs_commit_transaction()
iterates the extent tree, using its
commit root and moves extents into new
locations
btrfs_add_ordered_extent_dio()
--> now a ordered extent is
created and added to the
list root->ordered_extents
and the root added to the
list fs_info->ordered_roots
--> this is too late and the
task at CPU 1 already
started the relocation
btrfs_commit_transaction()
btrfs_finish_ordered_io()
btrfs_alloc_reserved_file_extent()
--> adds delayed data reference
for the extent allocated
from bg X
relocate_block_group(rc->stage ==
UPDATE_DATA_PTRS)
prepare_to_relocate()
btrfs_commit_transaction()
--> delayed refs are run, so an extent
item for the allocated extent from
bg X is added to extent tree
--> commit roots are switched, so the
next scan in the extent tree will
see the extent item
sees the extent in the extent tree
When this happens the relocation produces the following warning when it
finishes:
[ 7260.832836] ------------[ cut here ]------------
[ 7260.834653] WARNING: CPU: 5 PID: 6765 at fs/btrfs/relocation.c:4318 btrfs_relocate_block_group+0x245/0x2a1 [btrfs]()
[ 7260.838268] Modules linked in: btrfs crc32c_generic xor ppdev raid6_pq psmouse sg acpi_cpufreq evdev i2c_piix4 tpm_tis serio_raw tpm i2c_core pcspkr parport_pc
[ 7260.850935] CPU: 5 PID: 6765 Comm: btrfs Not tainted 4.5.0-rc6-btrfs-next-28+ #1
[ 7260.852998] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 7260.852998] 0000000000000000 ffff88020bf57bc0 ffffffff812648b3 0000000000000000
[ 7260.852998] 0000000000000009 ffff88020bf57bf8 ffffffff81051608 ffffffffa03c1b2d
[ 7260.852998] ffff8800b2bbb800 0000000000000000 ffff8800b17bcc58 ffff8800399dd000
[ 7260.852998] Call Trace:
[ 7260.852998] [<ffffffff812648b3>] dump_stack+0x67/0x90
[ 7260.852998] [<ffffffff81051608>] warn_slowpath_common+0x99/0xb2
[ 7260.852998] [<ffffffffa03c1b2d>] ? btrfs_relocate_block_group+0x245/0x2a1 [btrfs]
[ 7260.852998] [<ffffffff810516d4>] warn_slowpath_null+0x1a/0x1c
[ 7260.852998] [<ffffffffa03c1b2d>] btrfs_relocate_block_group+0x245/0x2a1 [btrfs]
[ 7260.852998] [<ffffffffa039d9de>] btrfs_relocate_chunk.isra.29+0x66/0xdb [btrfs]
[ 7260.852998] [<ffffffffa039f314>] btrfs_balance+0xde1/0xe4e [btrfs]
[ 7260.852998] [<ffffffff8127d671>] ? debug_smp_processor_id+0x17/0x19
[ 7260.852998] [<ffffffffa03a9583>] btrfs_ioctl_balance+0x255/0x2d3 [btrfs]
[ 7260.852998] [<ffffffffa03ac96a>] btrfs_ioctl+0x11e0/0x1dff [btrfs]
[ 7260.852998] [<ffffffff811451df>] ? handle_mm_fault+0x443/0xd63
[ 7260.852998] [<ffffffff81491817>] ? _raw_spin_unlock+0x31/0x44
[ 7260.852998] [<ffffffff8108b36a>] ? arch_local_irq_save+0x9/0xc
[ 7260.852998] [<ffffffff811876ab>] vfs_ioctl+0x18/0x34
[ 7260.852998] [<ffffffff81187cb2>] do_vfs_ioctl+0x550/0x5be
[ 7260.852998] [<ffffffff81190c30>] ? __fget_light+0x4d/0x71
[ 7260.852998] [<ffffffff81187d77>] SyS_ioctl+0x57/0x79
[ 7260.852998] [<ffffffff81492017>] entry_SYSCALL_64_fastpath+0x12/0x6b
[ 7260.893268] ---[ end trace eb7803b24ebab8ad ]---
This is because at the end of the first stage, in relocate_block_group(),
we commit the current transaction, which makes delayed refs run, the
commit roots are switched and so the second stage will find the extent
item that the ordered extent added to the delayed refs. But this extent
was not moved (ordered extent completed after first stage finished), so
at the end of the relocation our block group item still has a positive
used bytes counter, triggering a warning at the end of
btrfs_relocate_block_group(). Later on when trying to read the extent
contents from disk we hit a BUG_ON() due to the inability to map a block
with a logical address that belongs to the block group we relocated and
is no longer valid, resulting in the following trace:
[ 7344.885290] BTRFS critical (device sdi): unable to find logical 12845056 len 4096
[ 7344.887518] ------------[ cut here ]------------
[ 7344.888431] kernel BUG at fs/btrfs/inode.c:1833!
[ 7344.888431] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[ 7344.888431] Modules linked in: btrfs crc32c_generic xor ppdev raid6_pq psmouse sg acpi_cpufreq evdev i2c_piix4 tpm_tis serio_raw tpm i2c_core pcspkr parport_pc
[ 7344.888431] CPU: 0 PID: 6831 Comm: od Tainted: G W 4.5.0-rc6-btrfs-next-28+ #1
[ 7344.888431] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS by qemu-project.org 04/01/2014
[ 7344.888431] task: ffff880215818600 ti: ffff880204684000 task.ti: ffff880204684000
[ 7344.888431] RIP: 0010:[<ffffffffa037c88c>] [<ffffffffa037c88c>] btrfs_merge_bio_hook+0x54/0x6b [btrfs]
[ 7344.888431] RSP: 0018:ffff8802046878f0 EFLAGS: 00010282
[ 7344.888431] RAX: 00000000ffffffea RBX: 0000000000001000 RCX: 0000000000000001
[ 7344.888431] RDX: ffff88023ec0f950 RSI: ffffffff8183b638 RDI: 00000000ffffffff
[ 7344.888431] RBP: ffff880204687908 R08: 0000000000000001 R09: 0000000000000000
[ 7344.888431] R10: ffff880204687770 R11: ffffffff82f2d52d R12: 0000000000001000
[ 7344.888431] R13: ffff88021afbfee8 R14: 0000000000006208 R15: ffff88006cd199b0
[ 7344.888431] FS: 00007f1f9e1d6700(0000) GS:ffff88023ec00000(0000) knlGS:0000000000000000
[ 7344.888431] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 7344.888431] CR2: 00007f1f9dc8cb60 CR3: 000000023e3b6000 CR4: 00000000000006f0
[ 7344.888431] Stack:
[ 7344.888431] 0000000000001000 0000000000001000 ffff880204687b98 ffff880204687950
[ 7344.888431] ffffffffa0395c8f ffffea0004d64d48 0000000000000000 0000000000001000
[ 7344.888431] ffffea0004d64d48 0000000000001000 0000000000000000 0000000000000000
[ 7344.888431] Call Trace:
[ 7344.888431] [<ffffffffa0395c8f>] submit_extent_page+0xf5/0x16f [btrfs]
[ 7344.888431] [<ffffffffa03970ac>] __do_readpage+0x4a0/0x4f1 [btrfs]
[ 7344.888431] [<ffffffffa039680d>] ? btrfs_create_repair_bio+0xcb/0xcb [btrfs]
[ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431] [<ffffffff8108df55>] ? trace_hardirqs_on+0xd/0xf
[ 7344.888431] [<ffffffffa039728c>] __do_contiguous_readpages.constprop.26+0xc2/0xe4 [btrfs]
[ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431] [<ffffffffa039739b>] __extent_readpages.constprop.25+0xed/0x100 [btrfs]
[ 7344.888431] [<ffffffff81129d24>] ? lru_cache_add+0xe/0x10
[ 7344.888431] [<ffffffffa0397ea8>] extent_readpages+0x160/0x1aa [btrfs]
[ 7344.888431] [<ffffffffa037eeb4>] ? btrfs_writepage_start_hook+0xbc/0xbc [btrfs]
[ 7344.888431] [<ffffffff8115daad>] ? alloc_pages_current+0xa9/0xcd
[ 7344.888431] [<ffffffffa037cdc9>] btrfs_readpages+0x1f/0x21 [btrfs]
[ 7344.888431] [<ffffffff81128316>] __do_page_cache_readahead+0x168/0x1fc
[ 7344.888431] [<ffffffff811285a0>] ondemand_readahead+0x1f6/0x207
[ 7344.888431] [<ffffffff811285a0>] ? ondemand_readahead+0x1f6/0x207
[ 7344.888431] [<ffffffff8111cf34>] ? pagecache_get_page+0x2b/0x154
[ 7344.888431] [<ffffffff8112870e>] page_cache_sync_readahead+0x3d/0x3f
[ 7344.888431] [<ffffffff8111dbf7>] generic_file_read_iter+0x197/0x4e1
[ 7344.888431] [<ffffffff8117773a>] __vfs_read+0x79/0x9d
[ 7344.888431] [<ffffffff81178050>] vfs_read+0x8f/0xd2
[ 7344.888431] [<ffffffff81178a38>] SyS_read+0x50/0x7e
[ 7344.888431] [<ffffffff81492017>] entry_SYSCALL_64_fastpath+0x12/0x6b
[ 7344.888431] Code: 8d 4d e8 45 31 c9 45 31 c0 48 8b 00 48 c1 e2 09 48 8b 80 80 fc ff ff 4c 89 65 e8 48 8b b8 f0 01 00 00 e8 1d 42 02 00 85 c0 79 02 <0f> 0b 4c 0
[ 7344.888431] RIP [<ffffffffa037c88c>] btrfs_merge_bio_hook+0x54/0x6b [btrfs]
[ 7344.888431] RSP <ffff8802046878f0>
[ 7344.970544] ---[ end trace eb7803b24ebab8ae ]---
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Before the relocation process of a block group starts, it sets the block
group to readonly mode, then flushes all delalloc writes and then finally
it waits for all ordered extents to complete. This last step includes
waiting for ordered extents destinated at extents allocated in other block
groups, making us waste unecessary time.
So improve this by waiting only for ordered extents that fall into the
block group's range.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
UBSAN: Undefined behaviour in fs/btrfs/extent-tree.c:4623:21
signed integer overflow:
10808 * 262144 cannot be represented in type 'int [8]'
If 8192<=items<16384, we request a writeback of an insane number of pages
which is benign (everything will be written). But if items>=16384, the
space reservation won't be enough.
Signed-off-by: Adam Borowski <kilobyte@angband.pl>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
fs/btrfs/extent-tree.c: In function ‘btrfs_lock_cluster’:
fs/btrfs/extent-tree.c:6399: warning: ‘used_bg’ may be used uninitialized in this function
- Replace "again: ... goto again;" by standard C "while (1) { ... }",
- Move block not processed during the first iteration of the loop to the
end of the loop, which allows to kill the "locked" variable,
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Reviewed-and-Tested-by: Miao Xie <miaox@cn.fujitsu.com>
[ the compilation warning has been fixed by other patch, now we want to
clean up the function ]
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_std_error() handles errors, puts FS into readonly mode
(as of now). So its good idea to rename it to btrfs_handle_fs_error().
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.com>
[ edit changelog ]
Signed-off-by: David Sterba <dsterba@suse.com>
Pull btrfs fixes from Chris Mason:
"These are bug fixes, including a really old fsync bug, and a few trace
points to help us track down problems in the quota code"
* 'for-linus-4.6' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/linux-btrfs:
Btrfs: fix file/data loss caused by fsync after rename and new inode
btrfs: Reset IO error counters before start of device replacing
btrfs: Add qgroup tracing
Btrfs: don't use src fd for printk
btrfs: fallback to vmalloc in btrfs_compare_tree
btrfs: handle non-fatal errors in btrfs_qgroup_inherit()
btrfs: Output more info for enospc_debug mount option
Btrfs: fix invalid reference in replace_path
Btrfs: Improve FL_KEEP_SIZE handling in fallocate
PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time
ago with promise that one day it will be possible to implement page
cache with bigger chunks than PAGE_SIZE.
This promise never materialized. And unlikely will.
We have many places where PAGE_CACHE_SIZE assumed to be equal to
PAGE_SIZE. And it's constant source of confusion on whether
PAGE_CACHE_* or PAGE_* constant should be used in a particular case,
especially on the border between fs and mm.
Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much
breakage to be doable.
Let's stop pretending that pages in page cache are special. They are
not.
The changes are pretty straight-forward:
- <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>;
- PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN};
- page_cache_get() -> get_page();
- page_cache_release() -> put_page();
This patch contains automated changes generated with coccinelle using
script below. For some reason, coccinelle doesn't patch header files.
I've called spatch for them manually.
The only adjustment after coccinelle is revert of changes to
PAGE_CAHCE_ALIGN definition: we are going to drop it later.
There are few places in the code where coccinelle didn't reach. I'll
fix them manually in a separate patch. Comments and documentation also
will be addressed with the separate patch.
virtual patch
@@
expression E;
@@
- E << (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
expression E;
@@
- E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT)
+ E
@@
@@
- PAGE_CACHE_SHIFT
+ PAGE_SHIFT
@@
@@
- PAGE_CACHE_SIZE
+ PAGE_SIZE
@@
@@
- PAGE_CACHE_MASK
+ PAGE_MASK
@@
expression E;
@@
- PAGE_CACHE_ALIGN(E)
+ PAGE_ALIGN(E)
@@
expression E;
@@
- page_cache_get(E)
+ get_page(E)
@@
expression E;
@@
- page_cache_release(E)
+ put_page(E)
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
As one user in mail list report reproducible balance ENOSPC error, it's
better to add more debug info for enospc_debug mount option.
Reported-by: Marc Haber <mh+linux-btrfs@zugschlus.de>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
We were getting build warning about:
fs/btrfs/extent-tree.c:7021:34: warning: ‘used_bg’ may be used
uninitialized in this function
It is not a valid warning as used_bg is never used uninitilized since
locked is initially false so we can never be in the section where
'used_bg' is used. But gcc is not able to understand that and we can
initialize it while declaring to silence the warning.
Signed-off-by: Sudip Mukherjee <sudip@vectorindia.org>
Signed-off-by: David Sterba <dsterba@suse.com>
We will sometimes start background flushing the various enospc related things
(delayed nodes, delalloc, etc) if we are getting close to reserving all of our
available space. We don't want to do this however when we are actually using
this space as it causes unneeded thrashing. We currently try to do this by
checking bytes_used >= thresh, but bytes_used is only part of the equation, we
need to use bytes_reserved as well as this represents space that is very likely
to become bytes_used in the future.
My tracing tool will keep count of the number of times we kick off the async
flusher, the following are counts for the entire run of generic/027
No Patch Patch
avg: 5385 5009
median: 5500 4916
We skewed lower than the average with my patch and higher than the average with
the patch, overall it cuts the flushing from anywhere from 5-10%, which in the
case of actual ENOSPC is quite helpful. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I'm writing a tool to visualize the enospc system in order to help debug enospc
bugs and I found weird data and ran it down to when we update the global block
rsv. We add all of the remaining free space to the block rsv, do a trace event,
then remove the extra and do another trace event. This makes my visualization
look silly and is unintuitive code as well. Fix this stuff to only add the
amount we are missing, or free the amount we are missing. This is less clean to
read but more explicit in what it is doing, as well as only emitting events for
values that make sense. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: David Sterba <dsterba@suse.com>
I see no_space in v4.4-rc1 again in xfstests generic/102.
It happened randomly in some node only.
(one of 4 phy-node, and a kvm with non-virtio block driver)
By bisect, we can found the first-bad is:
commit bdced438ac ("block: setup bi_phys_segments after splitting")'
But above patch only triggered the bug by making bio operation
faster(or slower).
Main reason is in our space_allocating code, we need to commit
page writeback before wait it complish, this patch fixed above
bug.
BTW, there is another reason for generic/102 fail, caused by
disable default mixed-blockgroup, I'll fix it in xfstests.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
wait_for_snapshot_creation() is in same group with oher two:
btrfs_start_write_no_snapshoting()
btrfs_end_write_no_snapshoting()
Rename wait_for_snapshot_creation() and move it into same place
with other two.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
If we return 1 here, then the caller treats it as an error and returns
-EINVAL. It causes a static checker warning to treat positive returns
as an error.
Fixes: 1aba86d67f ('Btrfs: fix easily get into ENOSPC in mixed case')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Overloading extent_map->bdev to struct map_lookup * might have started out
as a means to an end, but it's a pattern that's used all over the place
now. Let's get rid of the casting and just add a union instead.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Replace the integers by enums for better readability. The value 2 does
not have any meaning since a717531942
"Btrfs: do less aggressive btree readahead" (2009-01-22).
Signed-off-by: David Sterba <dsterba@suse.com>
We use many constants to represent size and offset value. And to make
code readable we use '256 * 1024 * 1024' instead of '268435456' to
represent '256MB'. However we can make far more readable with 'SZ_256MB'
which is defined in the 'linux/sizes.h'.
So this patch replaces 'xxx * 1024 * 1024' kind of expression with
single 'SZ_xxxMB' if 'xxx' is a power of 2 then 'xxx * SZ_1M' if 'xxx' is
not a power of 2. And I haven't touched to '4096' & '8192' because it's
more intuitive than 'SZ_4KB' & 'SZ_8KB'.
Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
btrfs_delayed_extent_op can be packed in a better way, it's 40 bytes now
and has 8 unused bytes. Reducing the level type to u8 makes it possible
to squeeze it to the padding byte after key. The bitfields were switched
to bool as there's space to store the full byte without increasing the
whole structure, besides that the generated assembly is smaller.
struct btrfs_delayed_extent_op {
struct btrfs_disk_key key; /* 0 17 */
u8 level; /* 17 1 */
bool update_key; /* 18 1 */
bool update_flags; /* 19 1 */
bool is_data; /* 20 1 */
/* XXX 3 bytes hole, try to pack */
u64 flags_to_set; /* 24 8 */
/* size: 32, cachelines: 1, members: 6 */
/* sum members: 29, holes: 1, sum holes: 3 */
/* last cacheline: 32 bytes */
};
The final size is 32 bytes which gives +26 object per slab page.
text data bss dec hex filename
938811 43670 23144 1005625 f5839 fs/btrfs/btrfs.ko.before
938747 43670 23144 1005561 f57f9 fs/btrfs/btrfs.ko.after
Signed-off-by: David Sterba <dsterba@suse.com>
While running a stress test I ran into the following trace/transaction
abort:
[471626.672243] ------------[ cut here ]------------
[471626.673322] WARNING: CPU: 9 PID: 19107 at fs/btrfs/extent-tree.c:3740 btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]()
[471626.675492] BTRFS: Transaction aborted (error -2)
[471626.676748] Modules linked in: btrfs dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse parport_pc i2c_piix
[471626.688802] CPU: 14 PID: 19107 Comm: fsstress Tainted: G W 4.3.0-rc5-btrfs-next-17+ #1
[471626.690148] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[471626.691901] 0000000000000000 ffff880016037cf0 ffffffff812566f4 ffff880016037d38
[471626.695009] ffff880016037d28 ffffffff8104d0a6 ffffffffa040c84e 00000000fffffffe
[471626.697490] ffff88011fe855f8 ffff88000c484cb0 ffff88000d195000 ffff880016037d90
[471626.699201] Call Trace:
[471626.699804] [<ffffffff812566f4>] dump_stack+0x4e/0x79
[471626.701049] [<ffffffff8104d0a6>] warn_slowpath_common+0x9f/0xb8
[471626.702542] [<ffffffffa040c84e>] ? btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]
[471626.704326] [<ffffffff8104d107>] warn_slowpath_fmt+0x48/0x50
[471626.705636] [<ffffffffa0403717>] ? write_one_cache_group.isra.32+0x77/0x82 [btrfs]
[471626.707048] [<ffffffffa040c84e>] btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]
[471626.708616] [<ffffffffa048a50a>] commit_cowonly_roots+0x1d7/0x25a [btrfs]
[471626.709950] [<ffffffffa041e34a>] btrfs_commit_transaction+0x4c4/0x991 [btrfs]
[471626.711286] [<ffffffff81081c61>] ? signal_pending_state+0x31/0x31
[471626.712611] [<ffffffffa03f6df4>] btrfs_sync_fs+0x145/0x1ad [btrfs]
[471626.715610] [<ffffffff811962a2>] ? SyS_tee+0x226/0x226
[471626.716718] [<ffffffff811962c2>] sync_fs_one_sb+0x20/0x22
[471626.717672] [<ffffffff8116fc01>] iterate_supers+0x75/0xc2
[471626.718800] [<ffffffff8119669a>] sys_sync+0x52/0x80
[471626.719990] [<ffffffff8147cd97>] entry_SYSCALL_64_fastpath+0x12/0x6f
[471626.721835] ---[ end trace baf57f43d76693f4 ]---
[471626.722954] BTRFS: error (device sdc) in btrfs_write_dirty_block_groups:3740: errno=-2 No such entry
This is a very rare situation and it happened due to a race between a free
space endio worker and writing the space caches for dirty block groups at
a transaction's commit critical section. The steps leading to this are:
1) A task calls btrfs_commit_transaction() and starts the writeout of the
space caches for all currently dirty block groups (i.e. it calls
btrfs_start_dirty_block_groups());
2) The previous step starts writeback for space caches;
3) When the writeback finishes it queues jobs for free space endio work
queue (fs_info->endio_freespace_worker) that execute
btrfs_finish_ordered_io();
4) The task committing the transaction sets the transaction's state
to TRANS_STATE_COMMIT_DOING and shortly after calls
btrfs_write_dirty_block_groups();
5) A free space endio job joins the transaction, through
btrfs_join_transaction_nolock(), and updates a free space inode item
in the root tree through btrfs_update_inode_fallback();
6) Updating the free space inode item resulted in COWing one or more
nodes/leaves of the root tree, and that resulted in creating a new
metadata block group, which gets added to the transaction's list
of dirty block groups (this is a very rare case);
7) The free space endio job has not released yet its transaction handle
at this point, so the new metadata block group was not yet fully
created (didn't go through btrfs_create_pending_block_groups() yet);
8) The transaction commit task sees the new metadata block group in
the transaction's list of dirty block groups and processes it.
When it attempts to update the block group's block group item in
the extent tree, through write_one_cache_group(), it isn't able
to find it and aborts the transaction with error -ENOENT - this
is because the free space endio job hasn't yet released its
transaction handle (which calls btrfs_create_pending_block_groups())
and therefore the block group item was not yet added to the extent
tree.
Fix this waiting for free space endio jobs if we fail to find a block
group item in the extent tree and then retry once updating the block
group item.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
This is a short term solution to make sure btrfs_run_delayed_refs()
doesn't change the extent tree while we are scanning it to create the
free space tree.
Longer term we need to synchronize scanning the block groups one by one,
similar to what happens during a balance.
Signed-off-by: Chris Mason <clm@fb.com>
We call btrfs_write_dirty_block_groups() in the critical section of a
transaction's commit, when no other tasks can join the transaction and
add more block groups to the transaction's list of dirty block groups,
so we not taking the dirty block groups spinlock when checking for the
list's emptyness, grabbing its first element or deleting elements from
it.
However there's a special and rare case where we can have a concurrent
task adding elements to this list. We trigger writeback for space
caches before at btrfs_start_dirty_block_groups() and in past iterations
of the loop at btrfs_write_dirty_block_groups(), this means that when
the writeback finishes (which happens asynchronously) it creates a
task for the endio free space work queue that executes
btrfs_finish_ordered_io() - this function is able to join the transaction,
through btrfs_join_transaction_nolock(), and update the free space cache's
inode item in the root tree, which can result in COWing nodes of this tree
and therefore allocation of a new block group can happen, which gets added
to the transaction's list of dirty block groups while the transaction
commit task is operating on it concurrently.
So fix this by taking the dirty block groups spinlock before doing
operations on the dirty block groups list at
btrfs_write_dirty_block_groups().
Signed-off-by: Filipe Manana <fdmanana@suse.com>
The free space tree is updated in tandem with the extent tree. There are
only a handful of places where we need to hook in:
1. Block group creation
2. Block group deletion
3. Delayed refs (extent creation and deletion)
4. Block group caching
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
The free space cache has turned out to be a scalability bottleneck on
large, busy filesystems. When the cache for a lot of block groups needs
to be written out, we can get extremely long commit times; if this
happens in the critical section, things are especially bad because we
block new transactions from happening.
The main problem with the free space cache is that it has to be written
out in its entirety and is managed in an ad hoc fashion. Using a B-tree
to store free space fixes this: updates can be done as needed and we get
all of the benefits of using a B-tree: checksumming, RAID handling,
well-understood behavior.
With the free space tree, we get commit times that are about the same as
the no cache case with load times slower than the free space cache case
but still much faster than the no cache case. Free space is represented
with extents until it becomes more space-efficient to use bitmaps,
giving us similar space overhead to the free space cache.
The operations on the free space tree are: adding and removing free
space, handling the creation and deletion of block groups, and loading
the free space for a block group. We can also create the free space tree
by walking the extent tree and clear the free space tree.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
We're also going to load the free space tree from caching_thread(), so
we should refactor some of the common code.
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
As of my previous change titled "Btrfs: fix scrub preventing unused block
groups from being deleted", the following warning at
extent-tree.c:btrfs_delete_unused_bgs() can be hit when we mount the a
filesysten with "-o discard":
10263 void btrfs_delete_unused_bgs(struct btrfs_fs_info *fs_info)
10264 {
(...)
10405 if (trimming) {
10406 WARN_ON(!list_empty(&block_group->bg_list));
10407 spin_lock(&trans->transaction->deleted_bgs_lock);
10408 list_move(&block_group->bg_list,
10409 &trans->transaction->deleted_bgs);
10410 spin_unlock(&trans->transaction->deleted_bgs_lock);
10411 btrfs_get_block_group(block_group);
10412 }
(...)
This happens because scrub can now add back the block group to the list of
unused block groups (fs_info->unused_bgs). This is dangerous because we
are moving the block group from the unused block groups list to the list
of deleted block groups without holding the lock that protects the source
list (fs_info->unused_bgs_lock).
The following diagram illustrates how this happens:
CPU 1 CPU 2
cleaner_kthread()
btrfs_delete_unused_bgs()
sees bg X in list
fs_info->unused_bgs
deletes bg X from list
fs_info->unused_bgs
scrub_enumerate_chunks()
searches device tree using
its commit root
finds device extent for
block group X
gets block group X from the tree
fs_info->block_group_cache_tree
(via btrfs_lookup_block_group())
sets bg X to RO (again)
scrub_chunk(bg X)
sets bg X back to RW mode
adds bg X to the list
fs_info->unused_bgs again,
since it's still unused and
currently not in that list
sets bg X to RO mode
btrfs_remove_chunk(bg X)
--> discard is enabled and bg X
is in the fs_info->unused_bgs
list again so the warning is
triggered
--> we move it from that list into
the transaction's delete_bgs
list, but we can have another
task currently manipulating
the first list (fs_info->unused_bgs)
Fix this by using the same lock (fs_info->unused_bgs_lock) to protect both
the list of unused block groups and the list of deleted block groups. This
makes it safe and there's not much worry for more lock contention, as this
lock is seldom used and only the cleaner kthread adds elements to the list
of deleted block groups. The warning goes away too, as this was previously
an impossible case (and would have been better a BUG_ON/ASSERT) but it's
not impossible anymore.
Reproduced with fstest btrfs/073 (using MOUNT_OPTIONS="-o discard").
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Commit 0ed4792 ('btrfs: qgroup: Switch to new extent-oriented qgroup
mechanism.') removed our qgroup accounting during
btrfs_drop_snapshot(). Predictably, this results in qgroup numbers
going bad shortly after a snapshot is removed.
Fix this by adding a dirty extent record when we encounter extents during
our shared subtree walk. This effectively restores the functionality we had
with the original shared subtree walking code in 1152651 (btrfs: qgroup:
account shared subtrees during snapshot delete).
The idea with the original patch (and this one) is that shared subtrees can
get skipped during drop_snapshot. The shared subtree walk then allows us a
chance to visit those extents and add them to the qgroup work for later
processing. This ultimately makes the accounting for drop snapshot work.
The new qgroup code nicely handles all the other extents during the tree
walk via the ref dec/inc functions so we don't have to add actions beyond
what we had originally.
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Signed-off-by: Chris Mason <clm@fb.com>
When a block group becomes unused and the cleaner kthread is currently
running, we can end up getting the current transaction aborted with error
-ENOENT when we try to commit the transaction, leading to the following
trace:
[59779.258768] WARNING: CPU: 3 PID: 5990 at fs/btrfs/extent-tree.c:3740 btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]()
[59779.272594] BTRFS: Transaction aborted (error -2)
(...)
[59779.291137] Call Trace:
[59779.291621] [<ffffffff812566f4>] dump_stack+0x4e/0x79
[59779.292543] [<ffffffff8104d0a6>] warn_slowpath_common+0x9f/0xb8
[59779.293435] [<ffffffffa04cb81f>] ? btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]
[59779.295000] [<ffffffff8104d107>] warn_slowpath_fmt+0x48/0x50
[59779.296138] [<ffffffffa04c2721>] ? write_one_cache_group.isra.32+0x77/0x82 [btrfs]
[59779.297663] [<ffffffffa04cb81f>] btrfs_write_dirty_block_groups+0x17c/0x214 [btrfs]
[59779.299141] [<ffffffffa0549b0d>] commit_cowonly_roots+0x1de/0x261 [btrfs]
[59779.300359] [<ffffffffa04dd5b6>] btrfs_commit_transaction+0x4c4/0x99c [btrfs]
[59779.301805] [<ffffffffa04b5df4>] btrfs_sync_fs+0x145/0x1ad [btrfs]
[59779.302893] [<ffffffff81196634>] sync_filesystem+0x7f/0x93
(...)
[59779.318186] ---[ end trace 577e2daff90da33a ]---
The following diagram illustrates a sequence of steps leading to this
problem:
CPU 1 CPU 2
<at transaction N>
adds bg A to list
fs_info->unused_bgs
adds bg B to list
fs_info->unused_bgs
<transaction kthread
commits transaction N
and wakes up the
cleaner kthread>
cleaner kthread
delete_unused_bgs()
sees bg A in list
fs_info->unused_bgs
btrfs_start_transaction()
<transaction N + 1 starts>
deletes bg A
update_block_group(bg C)
--> adds bg C to list
fs_info->unused_bgs
deletes bg B
sees bg C in the list
fs_info->unused_bgs
btrfs_remove_chunk(bg C)
btrfs_remove_block_group(bg C)
--> checks if the block group
is in a dirty list, and
because it isn't now, it
does nothing
--> the block group item
is deleted from the
extent tree
--> adds bg C to list
transaction->dirty_bgs
some task calls
btrfs_commit_transaction(t N + 1)
commit_cowonly_roots()
btrfs_write_dirty_block_groups()
--> sees bg C in cur_trans->dirty_bgs
--> calls write_one_cache_group()
which returns -ENOENT because
it did not find the block group
item in the extent tree
--> transaction aborte with -ENOENT
because write_one_cache_group()
returned that error
So fix this by adding a block group to the list of dirty block groups
before adding it to the list of unused block groups.
This happened on a stress test using fsstress plus concurrent calls to
fallocate 20G and truncate (releasing part of the space allocated with
fallocate).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Currently scrub can race with the cleaner kthread when the later attempts
to delete an unused block group, and the result is preventing the cleaner
kthread from ever deleting later the block group - unless the block group
becomes used and unused again. The following diagram illustrates that
race:
CPU 1 CPU 2
cleaner kthread
btrfs_delete_unused_bgs()
gets block group X from
fs_info->unused_bgs and
removes it from that list
scrub_enumerate_chunks()
searches device tree using
its commit root
finds device extent for
block group X
gets block group X from the tree
fs_info->block_group_cache_tree
(via btrfs_lookup_block_group())
sets bg X to RO
sees the block group is
already RO and therefore
doesn't delete it nor adds
it back to unused list
So fix this by making scrub add the block group again to the list of
unused block groups if the block group is still unused when it finished
scrubbing it and it hasn't been removed already.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
We were using only 1 transaction unit when attempting to delete an unused
block group but in reality we need 3 + N units, where N corresponds to the
number of stripes. We were accounting only for the addition of the orphan
item (for the block group's free space cache inode) but we were not
accounting that we need to delete one block group item from the extent
tree, one free space item from the tree of tree roots and N device extent
items from the device tree.
While one unit is not enough, it worked most of the time because for each
single unit we are too pessimistic and assume an entire tree path, with
the highest possible heigth (8), needs to be COWed with eventual node
splits at every possible level in the tree, so there was usually enough
reserved space for removing all the items and adding the orphan item.
However after adding the orphan item, writepages() can by called by the VM
subsystem against the btree inode when we are under memory pressure, which
causes writeback to start for the nodes we COWed before, this forces the
operation to remove the free space item to COW again some (or all of) the
same nodes (in the tree of tree roots). Even without writepages() being
called, we could fail with ENOSPC because these items are located in
multiple trees and one of them might have a higher heigth and require
node/leaf splits at many levels, exhausting all the reserved space before
removing all the items and adding the orphan.
In the kernel 4.0 release, commit 3d84be7991 ("Btrfs: fix BUG_ON in
btrfs_orphan_add() when delete unused block group"), we attempted to fix
a BUG_ON due to ENOSPC when trying to add the orphan item by making the
cleaner kthread reserve one transaction unit before attempting to remove
the block group, but this was not enough. We had a couple user reports
still hitting the same BUG_ON after 4.0, like Stefan Priebe's report on
a 4.2-rc6 kernel for example:
http://www.spinics.net/lists/linux-btrfs/msg46070.html
So fix this by reserving all the necessary units of metadata.
Reported-by: Stefan Priebe <s.priebe@profihost.ag>
Fixes: 3d84be7991 ("Btrfs: fix BUG_ON in btrfs_orphan_add() when delete unused block group")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
It's possible to reach a state where the cleaner kthread isn't able to
start a transaction to delete an unused block group due to lack of enough
free metadata space and due to lack of unallocated device space to allocate
a new metadata block group as well. If this happens try to use space from
the global block group reserve just like we do for unlink operations, so
that we don't reach a permanent state where starting a transaction for
filesystem operations (file creation, renames, etc) keeps failing with
-ENOSPC. Such an unfortunate state was observed on a machine where over
a dozen unused data block groups existed and the cleaner kthread was
failing to delete them due to ENOSPC error when attempting to start a
transaction, and even running balance with a -dusage=0 filter failed with
ENOSPC as well. Also unmounting and mounting again the filesystem didn't
help. Allowing the cleaner kthread to use the global block reserve to
delete the unused data block groups fixed the problem.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
No need to use root->fs_info in btrfs_delete_unused_bgs(),
use fs_info directly instead.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Reproduce:
(In integration-4.3 branch)
TEST_DEV=(/dev/vdg /dev/vdh)
TEST_DIR=/mnt/tmp
umount "$TEST_DEV" >/dev/null
mkfs.btrfs -f -d raid1 "${TEST_DEV[@]}"
mount -o nospace_cache "$TEST_DEV" "$TEST_DIR"
umount "$TEST_DEV"
mount -o nospace_cache "$TEST_DEV" "$TEST_DIR"
btrfs filesystem usage $TEST_DIR
We can see the data chunk changed from raid1 to single:
# btrfs filesystem usage $TEST_DIR
Data,single: Size:8.00MiB, Used:0.00B
/dev/vdg 8.00MiB
#
Reason:
When a empty filesystem mount with -o nospace_cache, the last
data blockgroup will be auto-removed in umount.
Then if we mount it again, there is no data chunk in the
filesystem, so the only available data profile is 0x0, result
is all new chunks are created as single type.
Fix:
Don't auto-delete last blockgroup for a raid type.
Test:
Test by above script, and confirmed the logic by debug output.
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
When executing generic/001 in a loop on a ppc64 machine (with both sectorsize
and nodesize set to 64k), the following call trace is observed,
WARNING: at /root/repos/linux/fs/btrfs/locking.c:253
Modules linked in:
CPU: 2 PID: 8353 Comm: umount Not tainted 4.3.0-rc5-13676-ga5e681d #54
task: c0000000f2b1f560 ti: c0000000f6008000 task.ti: c0000000f6008000
NIP: c000000000520c88 LR: c0000000004a3b34 CTR: 0000000000000000
REGS: c0000000f600a820 TRAP: 0700 Not tainted (4.3.0-rc5-13676-ga5e681d)
MSR: 8000000102029032 <SF,VEC,EE,ME,IR,DR,RI> CR: 24444884 XER: 00000000
CFAR: c0000000004a3b30 SOFTE: 1
GPR00: c0000000004a3b34 c0000000f600aaa0 c00000000108ac00 c0000000f5a808c0
GPR04: 0000000000000000 c0000000f600ae60 0000000000000000 0000000000000005
GPR08: 00000000000020a1 0000000000000001 c0000000f2b1f560 0000000000000030
GPR12: 0000000084842882 c00000000fdc0900 c0000000f600ae60 c0000000f070b800
GPR16: 0000000000000000 c0000000f3c8a000 0000000000000000 0000000000000049
GPR20: 0000000000000001 0000000000000001 c0000000f5aa01f8 0000000000000000
GPR24: 0f83e0f83e0f83e1 c0000000f5a808c0 c0000000f3c8d000 c000000000000000
GPR28: c0000000f600ae74 0000000000000001 c0000000f3c8d000 c0000000f5a808c0
NIP [c000000000520c88] .btrfs_tree_lock+0x48/0x2a0
LR [c0000000004a3b34] .btrfs_lock_root_node+0x44/0x80
Call Trace:
[c0000000f600aaa0] [c0000000f600ab80] 0xc0000000f600ab80 (unreliable)
[c0000000f600ab80] [c0000000004a3b34] .btrfs_lock_root_node+0x44/0x80
[c0000000f600ac00] [c0000000004a99dc] .btrfs_search_slot+0xa8c/0xc00
[c0000000f600ad40] [c0000000004ab878] .btrfs_insert_empty_items+0x98/0x120
[c0000000f600adf0] [c00000000050da44] .btrfs_finish_chunk_alloc+0x1d4/0x620
[c0000000f600af20] [c0000000004be854] .btrfs_create_pending_block_groups+0x1d4/0x2c0
[c0000000f600b020] [c0000000004bf188] .do_chunk_alloc+0x3c8/0x420
[c0000000f600b100] [c0000000004c27cc] .find_free_extent+0xbfc/0x1030
[c0000000f600b260] [c0000000004c2ce8] .btrfs_reserve_extent+0xe8/0x250
[c0000000f600b330] [c0000000004c2f90] .btrfs_alloc_tree_block+0x140/0x590
[c0000000f600b440] [c0000000004a47b4] .__btrfs_cow_block+0x124/0x780
[c0000000f600b530] [c0000000004a4fc0] .btrfs_cow_block+0xf0/0x250
[c0000000f600b5e0] [c0000000004a917c] .btrfs_search_slot+0x22c/0xc00
[c0000000f600b720] [c00000000050aa40] .btrfs_remove_chunk+0x1b0/0x9f0
[c0000000f600b850] [c0000000004c4e04] .btrfs_delete_unused_bgs+0x434/0x570
[c0000000f600b950] [c0000000004d3cb8] .close_ctree+0x2e8/0x3b0
[c0000000f600ba20] [c00000000049d178] .btrfs_put_super+0x18/0x30
[c0000000f600ba90] [c000000000243cd4] .generic_shutdown_super+0xa4/0x1a0
[c0000000f600bb10] [c0000000002441d8] .kill_anon_super+0x18/0x30
[c0000000f600bb90] [c00000000049c898] .btrfs_kill_super+0x18/0xc0
[c0000000f600bc10] [c0000000002444f8] .deactivate_locked_super+0x98/0xe0
[c0000000f600bc90] [c000000000269f94] .cleanup_mnt+0x54/0xa0
[c0000000f600bd10] [c0000000000bd744] .task_work_run+0xc4/0x100
[c0000000f600bdb0] [c000000000016334] .do_notify_resume+0x74/0x80
[c0000000f600be30] [c0000000000098b8] .ret_from_except_lite+0x64/0x68
Instruction dump:
fba1ffe8 fbc1fff0 fbe1fff8 7c791b78 f8010010 f821ff21 e94d0290 81030040
812a04e8 7d094a78 7d290034 5529d97e <0b090000> 3b400000 3be30050 3bc3004c
The above call trace is seen even on x86_64; albeit very rarely and that too
with nodesize set to 64k and with nospace_cache mount option being used.
The reason for the above call trace is,
btrfs_remove_chunk
check_system_chunk
Allocate chunk if required
For each physical stripe on underlying device,
btrfs_free_dev_extent
...
Take lock on Device tree's root node
btrfs_cow_block("dev tree's root node");
btrfs_reserve_extent
find_free_extent
index = BTRFS_RAID_DUP;
have_caching_bg = false;
When in LOOP_CACHING_NOWAIT state, Assume we find a block group
which is being cached; Hence have_caching_bg is set to true
When repeating the search for the next RAID index, we set
have_caching_bg to false.
Hence right after completing the LOOP_CACHING_NOWAIT state, we incorrectly
skip LOOP_CACHING_WAIT state and move to LOOP_ALLOC_CHUNK state where we
allocate a chunk and try to add entries corresponding to the chunk's physical
stripe into the device tree. When doing so the task deadlocks itself waiting
for the blocking lock on the root node of the device tree.
This commit fixes the issue by introducing a new local variable to help
indicate as to whether a block group of any RAID type is being cached.
Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com>
Reviewed-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
Between btrfs_allocerved_file_extent() and
btrfs_add_delayed_qgroup_reserve(), there is a window that delayed_refs
are run and delayed ref head maybe freed before
btrfs_add_delayed_qgroup_reserve().
This will cause btrfs_dad_delayed_qgroup_reserve() to return -ENOENT,
and cause transaction to be aborted.
This patch will record qgroup reserve space info into delayed_ref_head
at btrfs_add_delayed_ref(), to eliminate the race window.
Reported-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
In the kernel 4.2 merge window we had a big changes to the implementation
of delayed references and qgroups which made the no_quota field of delayed
references not used anymore. More specifically the no_quota field is not
used anymore as of:
commit 0ed4792af0 ("btrfs: qgroup: Switch to new extent-oriented qgroup mechanism.")
Leaving the no_quota field actually prevents delayed references from
getting merged, which in turn cause the following BUG_ON(), at
fs/btrfs/extent-tree.c, to be hit when qgroups are enabled:
static int run_delayed_tree_ref(...)
{
(...)
BUG_ON(node->ref_mod != 1);
(...)
}
This happens on a scenario like the following:
1) Ref1 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.
2) Ref2 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
It's not merged with Ref1 because Ref1->no_quota != Ref2->no_quota.
3) Ref3 bytenr X, action = BTRFS_ADD_DELAYED_REF, no_quota = 1, added.
It's not merged with the reference at the tail of the list of refs
for bytenr X because the reference at the tail, Ref2 is incompatible
due to Ref2->no_quota != Ref3->no_quota.
4) Ref4 bytenr X, action = BTRFS_DROP_DELAYED_REF, no_quota = 0, added.
It's not merged with the reference at the tail of the list of refs
for bytenr X because the reference at the tail, Ref3 is incompatible
due to Ref3->no_quota != Ref4->no_quota.
5) We run delayed references, trigger merging of delayed references,
through __btrfs_run_delayed_refs() -> btrfs_merge_delayed_refs().
6) Ref1 and Ref3 are merged as Ref1->no_quota = Ref3->no_quota and
all other conditions are satisfied too. So Ref1 gets a ref_mod
value of 2.
7) Ref2 and Ref4 are merged as Ref2->no_quota = Ref4->no_quota and
all other conditions are satisfied too. So Ref2 gets a ref_mod
value of 2.
8) Ref1 and Ref2 aren't merged, because they have different values
for their no_quota field.
9) Delayed reference Ref1 is picked for running (select_delayed_ref()
always prefers references with an action == BTRFS_ADD_DELAYED_REF).
So run_delayed_tree_ref() is called for Ref1 which triggers the
BUG_ON because Ref1->red_mod != 1 (equals 2).
So fix this by removing the no_quota field, as it's not used anymore as
of commit 0ed4792af0 ("btrfs: qgroup: Switch to new extent-oriented
qgroup mechanism.").
The use of no_quota was also buggy in at least two places:
1) At delayed-refs.c:btrfs_add_delayed_tree_ref() - we were setting
no_quota to 0 instead of 1 when the following condition was true:
is_fstree(ref_root) || !fs_info->quota_enabled
2) At extent-tree.c:__btrfs_inc_extent_ref() - we were attempting to
reset a node's no_quota when the condition "!is_fstree(root_objectid)
|| !root->fs_info->quota_enabled" was true but we did it only in
an unused local stack variable, that is, we never reset the no_quota
value in the node itself.
This fixes the remainder of problems several people have been having when
running delayed references, mostly while a balance is running in parallel,
on a 4.2+ kernel.
Very special thanks to Stéphane Lesimple for helping debugging this issue
and testing this fix on his multi terabyte filesystem (which took more
than one day to balance alone, plus fsck, etc).
Also, this fixes deadlock issue when using the clone ioctl with qgroups
enabled, as reported by Elias Probst in the mailing list. The deadlock
happens because after calling btrfs_insert_empty_item we have our path
holding a write lock on a leaf of the fs/subvol tree and then before
releasing the path we called check_ref() which did backref walking, when
qgroups are enabled, and tried to read lock the same leaf. The trace for
this case is the following:
INFO: task systemd-nspawn:6095 blocked for more than 120 seconds.
(...)
Call Trace:
[<ffffffff86999201>] schedule+0x74/0x83
[<ffffffff863ef64c>] btrfs_tree_read_lock+0xc0/0xea
[<ffffffff86137ed7>] ? wait_woken+0x74/0x74
[<ffffffff8639f0a7>] btrfs_search_old_slot+0x51a/0x810
[<ffffffff863a129b>] btrfs_next_old_leaf+0xdf/0x3ce
[<ffffffff86413a00>] ? ulist_add_merge+0x1b/0x127
[<ffffffff86411688>] __resolve_indirect_refs+0x62a/0x667
[<ffffffff863ef546>] ? btrfs_clear_lock_blocking_rw+0x78/0xbe
[<ffffffff864122d3>] find_parent_nodes+0xaf3/0xfc6
[<ffffffff86412838>] __btrfs_find_all_roots+0x92/0xf0
[<ffffffff864128f2>] btrfs_find_all_roots+0x45/0x65
[<ffffffff8639a75b>] ? btrfs_get_tree_mod_seq+0x2b/0x88
[<ffffffff863e852e>] check_ref+0x64/0xc4
[<ffffffff863e9e01>] btrfs_clone+0x66e/0xb5d
[<ffffffff863ea77f>] btrfs_ioctl_clone+0x48f/0x5bb
[<ffffffff86048a68>] ? native_sched_clock+0x28/0x77
[<ffffffff863ed9b0>] btrfs_ioctl+0xabc/0x25cb
(...)
The problem goes away by eleminating check_ref(), which no longer is
needed as its purpose was to get a value for the no_quota field of
a delayed reference (this patch removes the no_quota field as mentioned
earlier).
Reported-by: Stéphane Lesimple <stephane_btrfs@lesimple.fr>
Tested-by: Stéphane Lesimple <stephane_btrfs@lesimple.fr>
Reported-by: Elias Probst <mail@eliasprobst.eu>
Reported-by: Peter Becker <floyd.net@gmail.com>
Reported-by: Malte Schröder <malte@tnxip.de>
Reported-by: Derek Dongray <derek@valedon.co.uk>
Reported-by: Erkki Seppala <flux-btrfs@inside.org>
Cc: stable@vger.kernel.org # 4.2+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
In the kernel 4.2 merge window we had a refactoring/rework of the delayed
references implementation in order to fix certain problems with qgroups.
However that rework introduced one more regression that leads to the
following trace when running delayed references for metadata:
[35908.064664] kernel BUG at fs/btrfs/extent-tree.c:1832!
[35908.065201] invalid opcode: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
[35908.065201] Modules linked in: dm_flakey dm_mod btrfs crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse parport_pc psmouse i2
[35908.065201] CPU: 14 PID: 15014 Comm: kworker/u32:9 Tainted: G W 4.3.0-rc5-btrfs-next-17+ #1
[35908.065201] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014
[35908.065201] Workqueue: btrfs-extent-refs btrfs_extent_refs_helper [btrfs]
[35908.065201] task: ffff880114b7d780 ti: ffff88010c4c8000 task.ti: ffff88010c4c8000
[35908.065201] RIP: 0010:[<ffffffffa04928b5>] [<ffffffffa04928b5>] insert_inline_extent_backref+0x52/0xb1 [btrfs]
[35908.065201] RSP: 0018:ffff88010c4cbb08 EFLAGS: 00010293
[35908.065201] RAX: 0000000000000000 RBX: ffff88008a661000 RCX: 0000000000000000
[35908.065201] RDX: ffffffffa04dd58f RSI: 0000000000000001 RDI: 0000000000000000
[35908.065201] RBP: ffff88010c4cbb40 R08: 0000000000001000 R09: ffff88010c4cb9f8
[35908.065201] R10: 0000000000000000 R11: 000000000000002c R12: 0000000000000000
[35908.065201] R13: ffff88020a74c578 R14: 0000000000000000 R15: 0000000000000000
[35908.065201] FS: 0000000000000000(0000) GS:ffff88023edc0000(0000) knlGS:0000000000000000
[35908.065201] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b
[35908.065201] CR2: 00000000015e8708 CR3: 0000000102185000 CR4: 00000000000006e0
[35908.065201] Stack:
[35908.065201] ffff88010c4cbb18 0000000000000f37 ffff88020a74c578 ffff88015a408000
[35908.065201] ffff880154a44000 0000000000000000 0000000000000005 ffff88010c4cbbd8
[35908.065201] ffffffffa0492b9a 0000000000000005 0000000000000000 0000000000000000
[35908.065201] Call Trace:
[35908.065201] [<ffffffffa0492b9a>] __btrfs_inc_extent_ref+0x8b/0x208 [btrfs]
[35908.065201] [<ffffffffa0497117>] ? __btrfs_run_delayed_refs+0x4d4/0xd33 [btrfs]
[35908.065201] [<ffffffffa049773d>] __btrfs_run_delayed_refs+0xafa/0xd33 [btrfs]
[35908.065201] [<ffffffffa04a976a>] ? join_transaction.isra.10+0x25/0x41f [btrfs]
[35908.065201] [<ffffffffa04a97ed>] ? join_transaction.isra.10+0xa8/0x41f [btrfs]
[35908.065201] [<ffffffffa049914d>] btrfs_run_delayed_refs+0x75/0x1dd [btrfs]
[35908.065201] [<ffffffffa04992f1>] delayed_ref_async_start+0x3c/0x7b [btrfs]
[35908.065201] [<ffffffffa04d4b4f>] normal_work_helper+0x14c/0x32a [btrfs]
[35908.065201] [<ffffffffa04d4e93>] btrfs_extent_refs_helper+0x12/0x14 [btrfs]
[35908.065201] [<ffffffff81063b23>] process_one_work+0x24a/0x4ac
[35908.065201] [<ffffffff81064285>] worker_thread+0x206/0x2c2
[35908.065201] [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
[35908.065201] [<ffffffff8106407f>] ? rescuer_thread+0x2cb/0x2cb
[35908.065201] [<ffffffff8106904d>] kthread+0xef/0xf7
[35908.065201] [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[35908.065201] [<ffffffff8147d10f>] ret_from_fork+0x3f/0x70
[35908.065201] [<ffffffff81068f5e>] ? kthread_parkme+0x24/0x24
[35908.065201] Code: 6a 01 41 56 41 54 ff 75 10 41 51 4d 89 c1 49 89 c8 48 8d 4d d0 e8 f6 f1 ff ff 48 83 c4 28 85 c0 75 2c 49 81 fc ff 00 00 00 77 02 <0f> 0b 4c 8b 45 30 8b 4d 28 45 31
[35908.065201] RIP [<ffffffffa04928b5>] insert_inline_extent_backref+0x52/0xb1 [btrfs]
[35908.065201] RSP <ffff88010c4cbb08>
[35908.310885] ---[ end trace fe4299baf0666457 ]---
This happens because the new delayed references code no longer merges
delayed references that have different sequence values. The following
steps are an example sequence leading to this issue:
1) Transaction N starts, fs_info->tree_mod_seq has value 0;
2) Extent buffer (btree node) A is allocated, delayed reference Ref1 for
bytenr A is created, with a value of 1 and a seq value of 0;
3) fs_info->tree_mod_seq is incremented to 1;
4) Extent buffer A is deleted through btrfs_del_items(), which calls
btrfs_del_leaf(), which in turn calls btrfs_free_tree_block(). The
later returns the metadata extent associated to extent buffer A to
the free space cache (the range is not pinned), because the extent
buffer was created in the current transaction (N) and writeback never
happened for the extent buffer (flag BTRFS_HEADER_FLAG_WRITTEN not set
in the extent buffer).
This creates the delayed reference Ref2 for bytenr A, with a value
of -1 and a seq value of 1;
5) Delayed reference Ref2 is not merged with Ref1 when we create it,
because they have different sequence numbers (decided at
add_delayed_ref_tail_merge());
6) fs_info->tree_mod_seq is incremented to 2;
7) Some task attempts to allocate a new extent buffer (done at
extent-tree.c:find_free_extent()), but due to heavy fragmentation
and running low on metadata space the clustered allocation fails
and we fall back to unclustered allocation, which finds the
extent at offset A, so a new extent buffer at offset A is allocated.
This creates delayed reference Ref3 for bytenr A, with a value of 1
and a seq value of 2;
8) Ref3 is not merged neither with Ref2 nor Ref1, again because they
all have different seq values;
9) We start running the delayed references (__btrfs_run_delayed_refs());
10) The delayed Ref1 is the first one being applied, which ends up
creating an inline extent backref in the extent tree;
10) Next the delayed reference Ref3 is selected for execution, and not
Ref2, because select_delayed_ref() always gives a preference for
positive references (that have an action of BTRFS_ADD_DELAYED_REF);
11) When running Ref3 we encounter alreay the inline extent backref
in the extent tree at insert_inline_extent_backref(), which makes
us hit the following BUG_ON:
BUG_ON(owner < BTRFS_FIRST_FREE_OBJECTID);
This is always true because owner corresponds to the level of the
extent buffer/btree node in the btree.
For the scenario described above we hit the BUG_ON because we never merge
references that have different seq values.
We used to do the merging before the 4.2 kernel, more specifically, before
the commmits:
c6fc245499 ("btrfs: delayed-ref: Use list to replace the ref_root in ref_head.")
c43d160fcd ("btrfs: delayed-ref: Cleanup the unneeded functions.")
This issue became more exposed after the following change that was added
to 4.2 as well:
cffc3374e5 ("Btrfs: fix order by which delayed references are run")
Which in turn fixed another regression by the two commits previously
mentioned.
So fix this by bringing back the delayed reference merge code, with the
proper adaptations so that it operates against the new data structure
(linked list vs old red black tree implementation).
This issue was hit running fstest btrfs/063 in a loop. Several people have
reported this issue in the mailing list when running on kernels 4.2+.
Very special thanks to Stéphane Lesimple for helping debugging this issue
and testing this fix on his multi terabyte filesystem (which took more
than one day to balance alone, plus fsck, etc).
Fixes: c6fc245499 ("btrfs: delayed-ref: Use list to replace the ref_root in ref_head.")
Reported-by: Peter Becker <floyd.net@gmail.com>
Reported-by: Stéphane Lesimple <stephane_btrfs@lesimple.fr>
Tested-by: Stéphane Lesimple <stephane_btrfs@lesimple.fr>
Reported-by: Malte Schröder <malte@tnxip.de>
Reported-by: Derek Dongray <derek@valedon.co.uk>
Reported-by: Erkki Seppala <flux-btrfs@inside.org>
Cc: stable@vger.kernel.org # 4.2+
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Reviewed-by: Liu Bo <bo.li.liu@oracle.com>
If we are extremely fragmented then we won't be able to create a free_cluster.
So if this happens set last_ptr->fragmented so that all future allcations will
give up trying to create a cluster. When we unpin extents we will unset
->fragmented if we free up a sufficient amount of space in a block group.
Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
We try really really hard to make allocations, but sometimes it is just not
going to happen, especially when free space is extremely fragmented. So add a
few short cuts through the looping states. For example if we couldn't allocate
a chunk, just go straight to the NO_EMPTY_SIZE loop. If there are no uncached
block groups and we've done a full search, go straight to the ALLOC_CHUNK stage.
And finally if we already have empty_size and empty_cluster set to 0 go ahead
and return -ENOSPC. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
If we hit ENOSPC when setting up a space cache don't bother setting up any of
the other space cache's in this transaction, it'll just induce unnecessary
latency. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we are heavily fragmented we can induce a lot of latency trying to make an
allocation happen that is simply not going to happen. Thankfully we keep track
of our max_extent_size when going through the allocator, so if we get to the
point where we are exiting find_free_extent with ENOSPC then set our
space_info->max_extent_size so we can keep future allocations from having to pay
this cost. We reset the max_extent_size whenever we release pinned bytes back
into this space info so we can redo all the work. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
The space cache needs to have contiguous allocations, and the allocator tries to
make allocations by reducing the amount of bytes requested and re-searching.
But this just makes us waste time when we are very fragmented, so if we can't
find our space just exit, don't bother trying to search again. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
I want to set some per transaction flags, so instead of adding yet another int
lets just convert the current two int indicators to flags and add a flags field
for future use. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
In tracking down these weird bitmap problems it was helpful to artificially
create an extremely fragmented file system. These mount options let us either
fragment data or metadata or both. With these options I could reproduce all
sorts of weird latencies and hangs that occur under extreme fragmentation and
get them fixed. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
In clear_bit_hook, qgroup reserved data is already handled quite well,
either released by finish_ordered_io or invalidatepage.
So calling btrfs_qgroup_free_data() here is completely meaningless, and
since btrfs_qgroup_free_data() will lock io_tree, so it can't be called
with io_tree lock hold.
This patch will add a new function
btrfs_free_reserved_data_space_noquota() for clear_bit_hook() to cease
the lockdep warning.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
For NOCOW and inline case, there will be no delayed_ref created for
them, so we should free their reserved data space at proper
time(finish_ordered_io for NOCOW and cow_file_inline for inline).
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Cleanup the old facilities which use old btrfs_qgroup_reserve() function
call, replace them with the newer version, and remove the "__" prefix in
them.
Also, make btrfs_qgroup_reserve/free() functions private, as they are
now only used inside qgroup codes.
Now, the whole btrfs qgroup is swithed to use the new reserve facilities.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Add new version of btrfs_delalloc_reserve_space() and
btrfs_delalloc_release_space() functions, which supports accurate qgroup
reserve.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Use new reserve/free for buffered write and inode cache.
For buffered write case, as nodatacow write won't increase quota account,
so unlike old behavior which does reserve before check nocow, now we
check nocow first and then only reserve data if we can't do nocow write.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Add new functions __btrfs_check_data_free_space() and
__btrfs_free_reserved_data_space() to work with new accurate qgroup
reserved space framework.
The new function will replace old btrfs_check_data_free_space() and
btrfs_free_reserved_data_space() respectively, but until all the change
is done, let's just use the new name.
Also, export internal use function btrfs_alloc_data_chunk_ondemand(), as
now qgroup reserve requires precious bytes, some operation can't get the
accurate number in advance(like fallocate).
But data space info check and data chunk allocate doesn't need to be
that accurate, and can be called at the beginning.
So export it for later operations.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
As we have the new metadata reservation functions, use them to replace
the old btrfs_qgroup_reserve() call for metadata.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Qgroup reserved space needs to be released from inode dirty map and get
freed at different timing:
1) Release when the metadata is written into tree
After corresponding metadata is written into tree, any newer write will
be COWed(don't include NOCOW case yet).
So we must release its range from inode dirty range map, or we will
forget to reserve needed range, causing accounting exceeding the limit.
2) Free reserved bytes when delayed ref is run
When delayed refs are run, qgroup accounting will follow soon and turn
the reserved bytes into rfer/excl numbers.
As run_delayed_refs and qgroup accounting are all done at
commit_transaction() time, we are safe to free reserved space in
run_delayed_ref time().
With these timing to release/free reserved space, we should be able to
resolve the long existing qgroup reserve space leak problem.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
btrfs_raid_array[] holds attributes of all raid types.
Use btrfs_raid_array[].devs_min is best way for request
in btrfs_reduce_alloc_profile(), instead of use complex
condition of each raid types.
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Rather than have three separate if() statements for the same outcome
we should just OR them together in the same if() statement.
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: Alexandru Moise <00moses.alexander00@gmail.com>
Signed-off-by: David Sterba <dsterba@suse.com>
Josef ran into a deadlock while a transaction handle was finalizing the
creation of its block groups, which produced the following trace:
[260445.593112] fio D ffff88022a9df468 0 8924 4518 0x00000084
[260445.593119] ffff88022a9df468 ffffffff81c134c0 ffff880429693c00 ffff88022a9df488
[260445.593126] ffff88022a9e0000 ffff8803490d7b00 ffff8803490d7b18 ffff88022a9df4b0
[260445.593132] ffff8803490d7af8 ffff88022a9df488 ffffffff8175a437 ffff8803490d7b00
[260445.593137] Call Trace:
[260445.593145] [<ffffffff8175a437>] schedule+0x37/0x80
[260445.593189] [<ffffffffa0850f37>] btrfs_tree_lock+0xa7/0x1f0 [btrfs]
[260445.593197] [<ffffffff810db7c0>] ? prepare_to_wait_event+0xf0/0xf0
[260445.593225] [<ffffffffa07eac44>] btrfs_lock_root_node+0x34/0x50 [btrfs]
[260445.593253] [<ffffffffa07eff6b>] btrfs_search_slot+0x88b/0xa00 [btrfs]
[260445.593295] [<ffffffffa08389df>] ? free_extent_buffer+0x4f/0x90 [btrfs]
[260445.593324] [<ffffffffa07f1a06>] btrfs_insert_empty_items+0x66/0xc0 [btrfs]
[260445.593351] [<ffffffffa07ea94a>] ? btrfs_alloc_path+0x1a/0x20 [btrfs]
[260445.593394] [<ffffffffa08403b9>] btrfs_finish_chunk_alloc+0x1c9/0x570 [btrfs]
[260445.593427] [<ffffffffa08002ab>] btrfs_create_pending_block_groups+0x11b/0x200 [btrfs]
[260445.593459] [<ffffffffa0800964>] do_chunk_alloc+0x2a4/0x2e0 [btrfs]
[260445.593491] [<ffffffffa0803815>] find_free_extent+0xa55/0xd90 [btrfs]
[260445.593524] [<ffffffffa0803c22>] btrfs_reserve_extent+0xd2/0x220 [btrfs]
[260445.593532] [<ffffffff8119fe5d>] ? account_page_dirtied+0xdd/0x170
[260445.593564] [<ffffffffa0803e78>] btrfs_alloc_tree_block+0x108/0x4a0 [btrfs]
[260445.593597] [<ffffffffa080c9de>] ? btree_set_page_dirty+0xe/0x10 [btrfs]
[260445.593626] [<ffffffffa07eb5cd>] __btrfs_cow_block+0x12d/0x5b0 [btrfs]
[260445.593654] [<ffffffffa07ebbff>] btrfs_cow_block+0x11f/0x1c0 [btrfs]
[260445.593682] [<ffffffffa07ef8c7>] btrfs_search_slot+0x1e7/0xa00 [btrfs]
[260445.593724] [<ffffffffa08389df>] ? free_extent_buffer+0x4f/0x90 [btrfs]
[260445.593752] [<ffffffffa07f1a06>] btrfs_insert_empty_items+0x66/0xc0 [btrfs]
[260445.593830] [<ffffffffa07ea94a>] ? btrfs_alloc_path+0x1a/0x20 [btrfs]
[260445.593905] [<ffffffffa08403b9>] btrfs_finish_chunk_alloc+0x1c9/0x570 [btrfs]
[260445.593946] [<ffffffffa08002ab>] btrfs_create_pending_block_groups+0x11b/0x200 [btrfs]
[260445.593990] [<ffffffffa0815798>] btrfs_commit_transaction+0xa8/0xb40 [btrfs]
[260445.594042] [<ffffffffa085abcd>] ? btrfs_log_dentry_safe+0x6d/0x80 [btrfs]
[260445.594089] [<ffffffffa082bc84>] btrfs_sync_file+0x294/0x350 [btrfs]
[260445.594115] [<ffffffff8123e29b>] vfs_fsync_range+0x3b/0xa0
[260445.594133] [<ffffffff81023891>] ? syscall_trace_enter_phase1+0x131/0x180
[260445.594149] [<ffffffff8123e35d>] do_fsync+0x3d/0x70
[260445.594169] [<ffffffff81023bb8>] ? syscall_trace_leave+0xb8/0x110
[260445.594187] [<ffffffff8123e600>] SyS_fsync+0x10/0x20
[260445.594204] [<ffffffff8175de6e>] entry_SYSCALL_64_fastpath+0x12/0x71
This happened because the same transaction handle created a large number
of block groups and while finalizing their creation (inserting new items
and updating existing items in the chunk and device trees) a new metadata
extent had to be allocated and no free space was found in the current
metadata block groups, which made find_free_extent() attempt to allocate
a new block group via do_chunk_alloc(). However at do_chunk_alloc() we
ended up allocating a new system chunk too and exceeded the threshold
of 2Mb of reserved chunk bytes, which makes do_chunk_alloc() enter the
final part of block group creation again (at
btrfs_create_pending_block_groups()) and attempt to lock again the root
of the chunk tree when it's already write locked by the same task.
Similarly we can deadlock on extent tree nodes/leafs if while we are
running delayed references we end up creating a new metadata block group
in order to allocate a new node/leaf for the extent tree (as part of
a CoW operation or growing the tree), as btrfs_create_pending_block_groups
inserts items into the extent tree as well. In this case we get the
following trace:
[14242.773581] fio D ffff880428ca3418 0 3615 3100 0x00000084
[14242.773588] ffff880428ca3418 ffff88042d66b000 ffff88042a03c800 ffff880428ca3438
[14242.773594] ffff880428ca4000 ffff8803e4b20190 ffff8803e4b201a8 ffff880428ca3460
[14242.773600] ffff8803e4b20188 ffff880428ca3438 ffffffff8175a437 ffff8803e4b20190
[14242.773606] Call Trace:
[14242.773613] [<ffffffff8175a437>] schedule+0x37/0x80
[14242.773656] [<ffffffffa057ff07>] btrfs_tree_lock+0xa7/0x1f0 [btrfs]
[14242.773664] [<ffffffff810db7c0>] ? prepare_to_wait_event+0xf0/0xf0
[14242.773692] [<ffffffffa0519c44>] btrfs_lock_root_node+0x34/0x50 [btrfs]
[14242.773720] [<ffffffffa051ef6b>] btrfs_search_slot+0x88b/0xa00 [btrfs]
[14242.773750] [<ffffffffa0520a06>] btrfs_insert_empty_items+0x66/0xc0 [btrfs]
[14242.773758] [<ffffffff811ef4a2>] ? kmem_cache_alloc+0x1d2/0x200
[14242.773786] [<ffffffffa0520ad1>] btrfs_insert_item+0x71/0xf0 [btrfs]
[14242.773818] [<ffffffffa052f292>] btrfs_create_pending_block_groups+0x102/0x200 [btrfs]
[14242.773850] [<ffffffffa052f96e>] do_chunk_alloc+0x2ae/0x2f0 [btrfs]
[14242.773934] [<ffffffffa0532825>] find_free_extent+0xa55/0xd90 [btrfs]
[14242.773998] [<ffffffffa0532c22>] btrfs_reserve_extent+0xc2/0x1d0 [btrfs]
[14242.774041] [<ffffffffa0532e38>] btrfs_alloc_tree_block+0x108/0x4a0 [btrfs]
[14242.774078] [<ffffffffa051a5cd>] __btrfs_cow_block+0x12d/0x5b0 [btrfs]
[14242.774118] [<ffffffffa051abff>] btrfs_cow_block+0x11f/0x1c0 [btrfs]
[14242.774155] [<ffffffffa051e8c7>] btrfs_search_slot+0x1e7/0xa00 [btrfs]
[14242.774194] [<ffffffffa0528021>] ? __btrfs_free_extent.isra.70+0x2e1/0xcb0 [btrfs]
[14242.774235] [<ffffffffa0520a06>] btrfs_insert_empty_items+0x66/0xc0 [btrfs]
[14242.774274] [<ffffffffa051994a>] ? btrfs_alloc_path+0x1a/0x20 [btrfs]
[14242.774318] [<ffffffffa052c433>] __btrfs_run_delayed_refs+0xbb3/0x1020 [btrfs]
[14242.774358] [<ffffffffa052f404>] btrfs_run_delayed_refs.part.78+0x74/0x280 [btrfs]
[14242.774391] [<ffffffffa052f627>] btrfs_run_delayed_refs+0x17/0x20 [btrfs]
[14242.774432] [<ffffffffa05be236>] commit_cowonly_roots+0x8d/0x2bd [btrfs]
[14242.774474] [<ffffffffa059d07f>] ? __btrfs_run_delayed_items+0x1cf/0x210 [btrfs]
[14242.774516] [<ffffffffa05adac3>] ? btrfs_qgroup_account_extents+0x83/0x130 [btrfs]
[14242.774558] [<ffffffffa0544c40>] btrfs_commit_transaction+0x590/0xb40 [btrfs]
[14242.774599] [<ffffffffa0589b9d>] ? btrfs_log_dentry_safe+0x6d/0x80 [btrfs]
[14242.774642] [<ffffffffa055ac54>] btrfs_sync_file+0x294/0x350 [btrfs]
[14242.774650] [<ffffffff8123e29b>] vfs_fsync_range+0x3b/0xa0
[14242.774657] [<ffffffff81023891>] ? syscall_trace_enter_phase1+0x131/0x180
[14242.774663] [<ffffffff8123e35d>] do_fsync+0x3d/0x70
[14242.774669] [<ffffffff81023bb8>] ? syscall_trace_leave+0xb8/0x110
[14242.774675] [<ffffffff8123e600>] SyS_fsync+0x10/0x20
[14242.774681] [<ffffffff8175de6e>] entry_SYSCALL_64_fastpath+0x12/0x71
Fix this by never recursing into the finalization phase of block group
creation and making sure we never trigger the finalization of block group
creation while running delayed references.
Reported-by: Josef Bacik <jbacik@fb.com>
Fixes: 00d80e342c ("Btrfs: fix quick exhaustion of the system array in the superblock")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
btrfs_error() and btrfs_std_error() does the same thing
and calls _btrfs_std_error(), so consolidate them together.
And the main motivation is that btrfs_error() is closely
named with btrfs_err(), one handles error action the other
is to log the error, so don't closely name them.
Signed-off-by: Anand Jain <anand.jain@oracle.com>
Suggested-by: David Sterba <dsterba@suse.com>
Reviewed-by: David Sterba <dsterba@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
When dropping a snapshot we need to account for the qgroup changes. If we drop
the snapshot in all one go then the backref code will fail to find blocks from
the snapshot we dropped since it won't be able to find the root in the fs root
cache. This can lead to us failing to find refs from other roots that pointed
at blocks in the now deleted root. To handle this we need to not remove the fs
roots from the cache until after we process the qgroup operations. Do this by
adding dropped roots to a list on the transaction, and letting the transaction
remove the roots at the same time it drops the commit roots. This will keep all
of the backref searching code in sync properly, and fixes a problem Mark was
seeing with snapshot delete and qgroups. Thanks,
Signed-off-by: Josef Bacik <jbacik@fb.com>
Tested-by: Holger Hoffstätte <holger.hoffstaette@googlemail.com>
Signed-off-by: Chris Mason <clm@fb.com>
Commit 2e6e518335 ("Btrfs: fix block group ->space_info null pointer
dereference") accidently marked a space info as full when initializing
it with a value of 0 total bytes. This introduces an ENOSPC problem when
writing file data if we mount a filesystem that has no data block groups
allocated, because the data space info is initialized with 0 total bytes,
marked as full, and it never gets its total bytes incremented by a
(positive) value to unmark it as full (because there are no data block
groups loaded when the fs is mounted).
For metadata and system spaces this issue can never happen since we always
have at least one metadata block group and one system block group (even
for an empty filesystem).
So fix this by just not initializing a space info as full, reverting the
offending part of the commit mentioned above.
The following test case for fstests reproduces the issue:
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
tmp=/tmp/$$
status=1 # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15
_cleanup()
{
rm -f $tmp.*
}
# get standard environment, filters and checks
. ./common/rc
. ./common/filter
# real QA test starts here
_need_to_be_root
_supported_fs btrfs
_supported_os Linux
_require_scratch
rm -f $seqres.full
_scratch_mkfs >>$seqres.full 2>&1
# Mount our filesystem without space caches enabled so that we do not
# get any space used from the initial data block group that mkfs creates
# (space caches used space from data block groups).
_scratch_mount "-o nospace_cache"
# Need an fs with at least 2Gb to make sure mkfs.btrfs does not create
# an fs using mixed block groups (used both for data and metadata). We
# really need to have dedicated block groups for data to reproduce the
# issue and mkfs.btrfs defaults to mixed block groups only for small
# filesystems (up to 1Gb).
_require_fs_space $SCRATCH_MNT $((2 * 1024 * 1024))
# Run balance with the purpose of deleting the unused data block group
# that mkfs created. We could also wait for the background kthread to
# automatically delete the unused block group, but we do not have a way
# to make it run and wait for it to complete, so just do a balance
# instead of some unreliable sleep
_run_btrfs_util_prog balance start -dusage=0 $SCRATCH_MNT
# Now unmount the filesystem, mount it again (either with or with space
# caches enabled, it does not matter to trigger the problem) and attempt
# to create a file with some data - this used to fail with ENOSPC
# because there were no data block groups when the filesystem was
# mounted and the data space info object was marked as full when
# initialized (because it had 0 total bytes), which prevented the file
# write path from attempting to allocate a data block group and fail
# immediately with ENOSPC.
_scratch_remount
echo "hello world" > $SCRATCH_MNT/foobar
echo "Silence is golden"
status=0
exit
Signed-off-by: Filipe Manana <fdmanana@suse.com>
These wrong comment was copyed from another function(expired) from
init, this patch fixed them.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
More than one code call set_block_group_ro() and restore rw in fail.
Old code use bool bit to save blockgroup's ro state, it can not
support parallel case(it is confirmd exist in my debug log).
This patch use ref count to store ro state, and rename
set_block_group_ro/set_block_group_rw
to
inc_block_group_ro/dec_block_group_ro.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we clear the dirty bits in btrfs_delete_unused_bgs for extents
in the empty block group, it results in btrfs_finish_extent_commit being
unable to discard the freed extents.
The block group removal patch added an alternate path to forget extents
other than btrfs_finish_extent_commit. As a result, any extents that
would be freed when the block group is removed aren't discarded. In my
test run, with a large copy of mixed sized files followed by removal, it
left nearly 2/3 of extents undiscarded.
To clean up the block groups, we add the removed block group onto a list
that will be discarded after transaction commit.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Since we now clean up block groups automatically as they become
empty, iterating over block groups is no longer sufficient to discard
unused space.
This patch iterates over the unused chunk space and discards any regions
that are unallocated, regardless of whether they were ever used. This is
a change for btrfs but is consistent with other file systems.
We do this in a transactionless manner since the discard process can take
a substantial amount of time and a transaction would need to be started
before the acquisition of the device list lock. That would mean a
transaction would be held open across /all/ of the discards collectively.
In order to prevent other threads from allocating or freeing chunks, we
hold the chunks lock across the search and discard calls. We release it
between searches to allow the file system to perform more-or-less
normally. Since the running transaction can commit and disappear while
we're using the transaction pointer, we take a reference to it and
release it after the search. This is safe since it would happen normally
at the end of the transaction commit after any locks are released anyway.
We also take the commit_root_sem to protect against a transaction starting
and committing while we're running.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Btrfs doesn't track superblocks with extent records so there is nothing
persistent on-disk to indicate that those blocks are in use. We track
the superblocks in memory to ensure they don't get used by removing them
from the free space cache when we load a block group from disk. Prior
to 47ab2a6c6a (Btrfs: remove empty block groups automatically), that
was fine since the block group would never be reclaimed so the superblock
was always safe. Once we started removing the empty block groups, we
were protected by the fact that discards weren't being properly issued
for unused space either via FITRIM or -odiscard. The block groups were
still being released, but the blocks remained on disk.
In order to properly discard unused block groups, we need to filter out
the superblocks from the discard range. Superblocks are located at fixed
locations on each device, so it makes sense to filter them out in
btrfs_issue_discard, which is used by both -odiscard and FITRIM.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
It's possible, though unexpected, to pass unaligned offsets and lengths
to btrfs_issue_discard. We then shift the offset/length values to sector
units. If an unaligned offset has been passed, it will result in the
entire sector being discarded, possibly losing data. An unaligned
length is safe but we'll end up returning an inaccurate number of
discarded bytes.
This patch aligns the offset to the 512B boundary, adjusts the length,
and warns, since we shouldn't be discarding on an offset that isn't
aligned with our sector size.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Initially this will just be the length argument passed to it,
but the following patches will adjust that to reflect re-alignment
and skipped blocks.
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Reviewed-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Omar reported that after commit 4fbcdf6694 ("Btrfs: fix -ENOSPC when
finishing block group creation"), introduced in 4.2-rc1, the following
test was failing due to exhaustion of the system array in the superblock:
#!/bin/bash
truncate -s 100T big.img
mkfs.btrfs big.img
mount -o loop big.img /mnt/loop
num=5
sz=10T
for ((i = 0; i < $num; i++)); do
echo fallocate $i $sz
fallocate -l $sz /mnt/loop/testfile$i
done
btrfs filesystem sync /mnt/loop
for ((i = 0; i < $num; i++)); do
echo rm $i
rm /mnt/loop/testfile$i
btrfs filesystem sync /mnt/loop
done
umount /mnt/loop
This made btrfs_add_system_chunk() fail with -EFBIG due to excessive
allocation of system block groups. This happened because the test creates
a large number of data block groups per transaction and when committing
the transaction we start the writeout of the block group caches for all
the new new (dirty) block groups, which results in pre-allocating space
for each block group's free space cache using the same transaction handle.
That in turn often leads to creation of more block groups, and all get
attached to the new_bgs list of the same transaction handle to the point
of getting a list with over 1500 elements, and creation of new block groups
leads to the need of reserving space in the chunk block reserve and often
creating a new system block group too.
So that made us quickly exhaust the chunk block reserve/system space info,
because as of the commit mentioned before, we do reserve space for each
new block group in the chunk block reserve, unlike before where we would
not and would at most allocate one new system block group and therefore
would only ensure that there was enough space in the system space info to
allocate 1 new block group even if we ended up allocating thousands of
new block groups using the same transaction handle. That worked most of
the time because the computed required space at check_system_chunk() is
very pessimistic (assumes a chunk tree height of BTRFS_MAX_LEVEL/8 and
that all nodes/leafs in a path will be COWed and split) and since the
updates to the chunk tree all happen at btrfs_create_pending_block_groups
it is unlikely that a path needs to be COWed more than once (unless
writepages() for the btree inode is called by mm in between) and that
compensated for the need of creating any new nodes/leads in the chunk
tree.
So fix this by ensuring we don't accumulate a too large list of new block
groups in a transaction's handles new_bgs list, inserting/updating the
chunk tree for all accumulated new block groups and releasing the unused
space from the chunk block reserve whenever the list becomes sufficiently
large. This is a generic solution even though the problem currently can
only happen when starting the writeout of the free space caches for all
dirty block groups (btrfs_start_dirty_block_groups()).
Reported-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Tested-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Chris Mason <clm@fb.com>
When we have an extent that got N references removed and N new references
added in the same transaction, we must run the insertion of the references
first because otherwise the last removed reference will remove the extent
item from the extent tree, resulting in a failure for the insertions.
This is a regression introduced in the 4.2-rc1 release and this fix just
brings back the behaviour of selecting reference additions before any
reference removals.
The following test case for fstests reproduces the issue:
seq=`basename $0`
seqres=$RESULT_DIR/$seq
echo "QA output created by $seq"
tmp=/tmp/$$
status=1 # failure is the default!
trap "_cleanup; exit \$status" 0 1 2 3 15
_cleanup()
{
_cleanup_flakey
rm -f $tmp.*
}
# get standard environment, filters and checks
. ./common/rc
. ./common/filter
. ./common/dmflakey
# real QA test starts here
_need_to_be_root
_supported_fs btrfs
_supported_os Linux
_require_scratch
_require_dm_flakey
_require_cloner
_require_metadata_journaling $SCRATCH_DEV
rm -f $seqres.full
_scratch_mkfs >>$seqres.full 2>&1
_init_flakey
_mount_flakey
# Create prealloc extent covering range [160K, 620K[
$XFS_IO_PROG -f -c "falloc 160K 460K" $SCRATCH_MNT/foo
# Now write to the last 80K of the prealloc extent plus 40K to the unallocated
# space that immediately follows it. This creates a new extent of 40K that spans
# the range [620K, 660K[.
$XFS_IO_PROG -c "pwrite -S 0xaa 540K 120K" $SCRATCH_MNT/foo | _filter_xfs_io
# At this point, there are now 2 back references to the prealloc extent in our
# extent tree. Both are for our file offset 160K and one relates to a file
# extent item with a data offset of 0 and a length of 380K, while the other
# relates to a file extent item with a data offset of 380K and a length of 80K.
# Make sure everything done so far is durably persisted (all back references are
# in the extent tree, etc).
sync
# Now clone all extents of our file that cover the offset 160K up to its eof
# (660K at this point) into itself at offset 2M. This leaves a hole in the file
# covering the range [660K, 2M[. The prealloc extent will now be referenced by
# the file twice, once for offset 160K and once for offset 2M. The 40K extent
# that follows the prealloc extent will also be referenced twice by our file,
# once for offset 620K and once for offset 2M + 460K.
$CLONER_PROG -s $((160 * 1024)) -d $((2 * 1024 * 1024)) -l 0 $SCRATCH_MNT/foo \
$SCRATCH_MNT/foo
# Now create one new extent in our file with a size of 100Kb. It will span the
# range [3M, 3M + 100K[. It also will cause creation of a hole spanning the
# range [2M + 460K, 3M[. Our new file size is 3M + 100K.
$XFS_IO_PROG -c "pwrite -S 0xbb 3M 100K" $SCRATCH_MNT/foo | _filter_xfs_io
# At this point, there are now (in memory) 4 back references to the prealloc
# extent.
#
# Two of them are for file offset 160K, related to file extent items
# matching the file offsets 160K and 540K respectively, with data offsets of
# 0 and 380K respectively, and with lengths of 380K and 80K respectively.
#
# The other two references are for file offset 2M, related to file extent items
# matching the file offsets 2M and 2M + 380K respectively, with data offsets of
# 0 and 380K respectively, and with lengths of 389K and 80K respectively.
#
# The 40K extent has 2 back references, one for file offset 620K and the other
# for file offset 2M + 460K.
#
# The 100K extent has a single back reference and it relates to file offset 3M.
# Now clone our 100K extent into offset 600K. That offset covers the last 20K
# of the prealloc extent, the whole 40K extent and 40K of the hole starting at
# offset 660K.
$CLONER_PROG -s $((3 * 1024 * 1024)) -d $((600 * 1024)) -l $((100 * 1024)) \
$SCRATCH_MNT/foo $SCRATCH_MNT/foo
# At this point there's only one reference to the 40K extent, at file offset
# 2M + 460K, we have 4 references for the prealloc extent (2 for file offset
# 160K and 2 for file offset 2M) and 2 references for the 100K extent (1 for
# file offset 3M and a new one for file offset 600K).
# Now fsync our file to make all its new data and metadata updates are durably
# persisted and present if a power failure/crash happens after a successful
# fsync and before the next transaction commit.
$XFS_IO_PROG -c "fsync" $SCRATCH_MNT/foo
echo "File digest before power failure:"
md5sum $SCRATCH_MNT/foo | _filter_scratch
# Silently drop all writes and ummount to simulate a crash/power failure.
_load_flakey_table $FLAKEY_DROP_WRITES
_unmount_flakey
# Allow writes again, mount to trigger log replay and validate file contents.
# During log replay, the btrfs delayed references implementation used to run the
# deletion of back references before the addition of new back references, which
# made the addition fail as it didn't find the key in the extent tree that it
# was looking for. The failure triggered by this test was related to the 40K
# extent, which got 1 reference dropped and 1 reference added during the fsync
# log replay - when running the delayed references at transaction commit time,
# btrfs was applying the deletion before the insertion, resulting in a failure
# of the insertion that ended up turning the fs into read-only mode.
_load_flakey_table $FLAKEY_ALLOW_WRITES
_mount_flakey
echo "File digest after log replay:"
md5sum $SCRATCH_MNT/foo | _filter_scratch
_unmount_flakey
status=0
exit
This issue turned the filesystem into read-only mode (current transaction
aborted) and produced the following traces:
[ 8247.578385] ------------[ cut here ]------------
[ 8247.579947] WARNING: CPU: 0 PID: 11341 at fs/btrfs/extent-tree.c:1547 lookup_inline_extent_backref+0x17d/0x45d [btrfs]()
(...)
[ 8247.601697] Call Trace:
[ 8247.602222] [<ffffffff8145f077>] dump_stack+0x4f/0x7b
[ 8247.604320] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb
[ 8247.605488] [<ffffffffa0506c8d>] ? lookup_inline_extent_backref+0x17d/0x45d [btrfs]
[ 8247.608226] [<ffffffffa0506c8d>] lookup_inline_extent_backref+0x17d/0x45d [btrfs]
[ 8247.617061] [<ffffffffa0507957>] insert_inline_extent_backref+0x41/0xb2 [btrfs]
[ 8247.621856] [<ffffffffa0507c4f>] __btrfs_inc_extent_ref+0x8c/0x20a [btrfs]
[ 8247.624366] [<ffffffffa050ee60>] __btrfs_run_delayed_refs+0xb0c/0xd49 [btrfs]
[ 8247.626176] [<ffffffffa0510dcd>] btrfs_run_delayed_refs+0x6d/0x1d4 [btrfs]
[ 8247.627435] [<ffffffff81155c9b>] ? __cache_free+0x4a7/0x4b6
[ 8247.628531] [<ffffffffa0520482>] btrfs_commit_transaction+0x4c/0xa20 [btrfs]
(...)
[ 8247.648430] ---[ end trace 2461e55f92c2ac2d ]---
[ 8247.727263] WARNING: CPU: 3 PID: 11341 at fs/btrfs/extent-tree.c:2771 btrfs_run_delayed_refs+0xa4/0x1d4 [btrfs]()
[ 8247.728954] BTRFS: Transaction aborted (error -5)
(...)
[ 8247.760866] Call Trace:
[ 8247.761534] [<ffffffff8145f077>] dump_stack+0x4f/0x7b
[ 8247.764271] [<ffffffff8104b3b0>] warn_slowpath_common+0xa1/0xbb
[ 8247.767582] [<ffffffffa0510e04>] ? btrfs_run_delayed_refs+0xa4/0x1d4 [btrfs]
[ 8247.769373] [<ffffffff8104b410>] warn_slowpath_fmt+0x46/0x48
[ 8247.770836] [<ffffffffa0510e04>] btrfs_run_delayed_refs+0xa4/0x1d4 [btrfs]
[ 8247.772532] [<ffffffff81155c9b>] ? __cache_free+0x4a7/0x4b6
[ 8247.773664] [<ffffffffa0520482>] btrfs_commit_transaction+0x4c/0xa20 [btrfs]
[ 8247.775047] [<ffffffff81087310>] ? trace_hardirqs_on+0xd/0xf
[ 8247.776176] [<ffffffff81155dd5>] ? kmem_cache_free+0x12b/0x189
[ 8247.777427] [<ffffffffa055a920>] btrfs_recover_log_trees+0x2da/0x33d [btrfs]
[ 8247.778575] [<ffffffffa055898e>] ? replay_one_extent+0x4fc/0x4fc [btrfs]
[ 8247.779838] [<ffffffffa051e265>] open_ctree+0x1cc0/0x201a [btrfs]
[ 8247.781020] [<ffffffff81120f48>] ? register_shrinker+0x56/0x81
[ 8247.782285] [<ffffffffa04fb12c>] btrfs_mount+0x5f0/0x734 [btrfs]
(...)
[ 8247.793394] ---[ end trace 2461e55f92c2ac2e ]---
[ 8247.794276] BTRFS: error (device dm-0) in btrfs_run_delayed_refs:2771: errno=-5 IO failure
[ 8247.797335] BTRFS: error (device dm-0) in btrfs_replay_log:2375: errno=-5 IO failure (Failed to recover log tree)
Fixes: c6fc245499 ("btrfs: delayed-ref: Use list to replace the ref_root in ref_head.")
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Acked-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
btrfs will report no_space when we run following write and delete
file loop:
# FILE_SIZE_M=[ 75% of fs space ]
# DEV=[ some dev ]
# MNT=[ some dir ]
#
# mkfs.btrfs -f "$DEV"
# mount -o nodatacow "$DEV" "$MNT"
# for ((i = 0; i < 100; i++)); do dd if=/dev/zero of="$MNT"/file0 bs=1M count="$FILE_SIZE_M"; rm -f "$MNT"/file0; done
#
Reason:
iput() and evict() is run after write pages to block device, if
write pages work is not finished before next write, the "rm"ed space
is not freed, and caused above bug.
Fix:
We can add "-o flushoncommit" mount option to avoid above bug, but
it have performance problem. Actually, we can to wait for on-the-fly
writes only when no-space happened, it is which this patch do.
Signed-off-by: Zhao Lei <zhaolei@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
Switch from old ref_node based qgroup to extent based qgroup mechanism
for normal operations.
The new mechanism should hugely reduce the overhead of btrfs quota
system, and further more, the codes and logic should be more clean and
easier to maintain.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
__btrfs_inc_extent_ref() and __btrfs_free_extent() have already had too
many parameters, but three of them can be extracted from
btrfs_delayed_ref_node struct.
So use btrfs_delayed_ref_node struct as a single parameter to replace
the bytenr/num_byte/no_quota parameters.
The real objective of this patch is to allow btrfs_qgroup_record_ref()
get the delayed_ref_node in incoming qgroup patches.
Other functions calling btrfs_qgroup_record_ref() are not affected since
the rest will only add/sub exclusive extents, where node is not used.
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
This patch replace the rbtree used in ref_head to list.
This has the following advantage:
1) Easier merge logic.
With the new list implement, we only need to care merging the tail
ref_node with the new ref_node.
And this can be done quite easy at insert time, no need to do a
indicated merge at run_delayed_refs().
Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com>
Signed-off-by: Chris Mason <clm@fb.com>
When allocating a new chunk or removing one we need to update num_devs
device items and insert or remove a chunk item in the chunk tree, so
in the worst case the space needed in the chunk space_info is:
btrfs_calc_trunc_metadata_size(chunk_root, num_devs) +
btrfs_calc_trans_metadata_size(chunk_root, 1)
That is, in the worst case we need to cow num_devs paths and cow 1 other
path that can result in splitting every node and leaf, and each path
consisting of BTRFS_MAX_LEVEL - 1 nodes and 1 leaf. We were requiring
some additional chunk_root->nodesize * BTRFS_MAX_LEVEL * num_devs bytes,
which were unnecessary since updating the existing device items does
not result in splitting the nodes and leaf since after updating them
they remain with the same size.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
The return value of read_tree_block() can confuse callers as it always
returns NULL for either -ENOMEM or -EIO, so it's likely that callers
parse it to a wrong error, for instance, in btrfs_read_tree_root().
This fixes the above issue.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
read_tree_block may take a reference on the 'eb', a following
free_extent_buffer is necessary.
Signed-off-by: Liu Bo <bo.li.liu@oracle.com>
Reviewed-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <clm@fb.com>
Unlike when attempting to allocate a new block group, where we check
that we have enough space in the system space_info to update the device
items and insert a new chunk item in the chunk tree, we were not checking
if the system space_info had enough space for updating the device items
and deleting the chunk item in the chunk tree. This often lead to -ENOSPC
error when attempting to allocate blocks for the chunk tree (during btree
node/leaf COW operations) while updating the device items or deleting the
chunk item, which resulted in the current transaction being aborted and
turning the filesystem into read-only mode.
While running fstests generic/038, which stresses allocation of block
groups and removal of unused block groups, with a large scratch device
(750Gb) this happened often, despite more than enough unallocated space,
and resulted in the following trace:
[68663.586604] WARNING: CPU: 3 PID: 1521 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x114 [btrfs]()
[68663.600407] BTRFS: Transaction aborted (error -28)
(...)
[68663.730829] Call Trace:
[68663.732585] [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
[68663.734334] [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
[68663.739980] [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
[68663.757153] [<ffffffffa036ca6d>] ? __btrfs_abort_transaction+0x52/0x114 [btrfs]
[68663.760925] [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
[68663.762854] [<ffffffffa03b159d>] ? btrfs_update_device+0x15a/0x16c [btrfs]
[68663.764073] [<ffffffffa036ca6d>] __btrfs_abort_transaction+0x52/0x114 [btrfs]
[68663.765130] [<ffffffffa03b3638>] btrfs_remove_chunk+0x597/0x5ee [btrfs]
[68663.765998] [<ffffffffa0384663>] ? btrfs_delete_unused_bgs+0x245/0x296 [btrfs]
[68663.767068] [<ffffffffa0384676>] btrfs_delete_unused_bgs+0x258/0x296 [btrfs]
[68663.768227] [<ffffffff8143527f>] ? _raw_spin_unlock_irq+0x2d/0x4c
[68663.769081] [<ffffffffa038b109>] cleaner_kthread+0x13d/0x16c [btrfs]
[68663.799485] [<ffffffffa038afcc>] ? btrfs_alloc_root+0x28/0x28 [btrfs]
[68663.809208] [<ffffffff8105f367>] kthread+0xef/0xf7
[68663.828795] [<ffffffff810e603f>] ? time_hardirqs_on+0x15/0x28
[68663.844942] [<ffffffff8105f278>] ? __kthread_parkme+0xad/0xad
[68663.846486] [<ffffffff81435a88>] ret_from_fork+0x58/0x90
[68663.847760] [<ffffffff8105f278>] ? __kthread_parkme+0xad/0xad
[68663.849503] ---[ end trace 798477c6d6dbaad6 ]---
[68663.850525] BTRFS: error (device sdc) in btrfs_remove_chunk:2652: errno=-28 No space left
So fix this by verifying that enough space exists in system space_info,
and reserving the space in the chunk block reserve, before attempting to
delete the block group and allocate a new system chunk if we don't have
enough space to perform the necessary updates and delete in the chunk
tree. Like for the block group creation case, we don't error our if we
fail to allocate a new system chunk, since we might end up not needing
it (no node/leaf splits happen during the COW operations and/or we end
up not needing to COW any btree nodes or leafs because they were already
COWed in the current transaction and their writeback didn't start yet).
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
While creating a block group, we often end up getting ENOSPC while updating
the chunk tree, which leads to a transaction abortion that produces a trace
like the following:
[30670.116368] WARNING: CPU: 4 PID: 20735 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x106 [btrfs]()
[30670.117777] BTRFS: Transaction aborted (error -28)
(...)
[30670.163567] Call Trace:
[30670.163906] [<ffffffff8142fa46>] dump_stack+0x4f/0x7b
[30670.164522] [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad
[30670.165171] [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb
[30670.166323] [<ffffffffa035daa7>] ? __btrfs_abort_transaction+0x52/0x106 [btrfs]
[30670.167213] [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48
[30670.167862] [<ffffffffa035daa7>] __btrfs_abort_transaction+0x52/0x106 [btrfs]
[30670.169116] [<ffffffffa03743d7>] btrfs_create_pending_block_groups+0x101/0x130 [btrfs]
[30670.170593] [<ffffffffa038426a>] __btrfs_end_transaction+0x84/0x366 [btrfs]
[30670.171960] [<ffffffffa038455c>] btrfs_end_transaction+0x10/0x12 [btrfs]
[30670.174649] [<ffffffffa036eb6b>] btrfs_check_data_free_space+0x11f/0x27c [btrfs]
[30670.176092] [<ffffffffa039450d>] btrfs_fallocate+0x7c8/0xb96 [btrfs]
[30670.177218] [<ffffffff812459f2>] ? __this_cpu_preempt_check+0x13/0x15
[30670.178622] [<ffffffff81152447>] vfs_fallocate+0x14c/0x1de
[30670.179642] [<ffffffff8116b915>] ? __fget_light+0x2d/0x4f
[30670.180692] [<ffffffff81152863>] SyS_fallocate+0x47/0x62
[30670.186737] [<ffffffff81435b32>] system_call_fastpath+0x12/0x17
[30670.187792] ---[ end trace 0373e6b491c4a8cc ]---
This is because we don't do proper space reservation for the chunk block
reserve when we have multiple tasks allocating chunks in parallel.
So block group creation has 2 phases, and the first phase essentially
checks if there is enough space in the system space_info, allocating a
new system chunk if there isn't, while the second phase updates the
device, extent and chunk trees. However, because the updates to the
chunk tree happen in the second phase, if we have N tasks, each with
its own transaction handle, allocating new chunks in parallel and if
there is only enough space in the system space_info to allocate M chunks,
where M < N, none of the tasks ends up allocating a new system chunk in
the first phase and N - M tasks will get -ENOSPC when attempting to
update the chunk tree in phase 2 if they need to COW any nodes/leafs
from the chunk tree.
Fix this by doing proper reservation in the chunk block reserve.
The issue could be reproduced by running fstests generic/038 in a loop,
which eventually triggered the problem.
Signed-off-by: Filipe Manana <fdmanana@suse.com>
Signed-off-by: Chris Mason <clm@fb.com>
Omar Sandoval