Running xfstests 269 with some tracing my scripts kept spitting out errors about
releasing bytes that we didn't actually have reserved. This took me down a huge
rabbit hole and it turns out the way we deal with reserved_extents is wrong,
we need to only be setting it if the reservation succeeds, otherwise the free()
method will come in and unreserve space that isn't actually reserved yet, which
can lead to other warnings and such. The math was all working out right in the
end, but it caused all sorts of other issues in addition to making my scripts
yell and scream and generally make it impossible for me to track down the
original issue I was looking for. The other problem is with our error handling
in the reservation code. There are two cases that we need to deal with
1) We raced with free. In this case free won't free anything because csum_bytes
is modified before we dro the lock in our reservation path, so free rightly
doesn't release any space because the reservation code may be depending on that
reservation. However if we fail, we need the reservation side to do the free at
that point since that space is no longer in use. So as it stands the code was
doing this fine and it worked out, except in case #2
2) We don't race with free. Nobody comes in and changes anything, and our
reservation fails. In this case we didn't reserve anything anyway and we just
need to clean up csum_bytes but not free anything. So we keep track of
csum_bytes before we drop the lock and if it hasn't changed we know we can just
decrement csum_bytes and carry on.
Because of the case where we can race with free()'s since we have to drop our
spin_lock to do the reservation, I'm going to serialize all reservations with
the i_mutex. We already get this for free in the heavy use paths, truncate and
file write all hold the i_mutex, just needed to add it to page_mkwrite and
various ioctl/balance things. With this patch my space leak scripts no longer
scream bloody murder. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
It seems overly harsh to fail a resize of a btrfs file system to the
same size when a shrink or grow would succeed. User app GParted trips
over this error. Allow it by bypassing the shrink or grow operation.
Signed-off-by: Mike Fleetwood <mike.fleetwood@googlemail.com>
For the user it is confusing to find something like:
[10197.627710] new size for /dev/mapper/vg0-usr_share is 3221225472
in kernel log, because it doesn't point directly to btrfs.
This patch prefixes those messages with "btrfs:" like other btrfs
related printks.
Signed-off-by: Arnd Hannemann <arnd@arndnet.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This patch casts to unsigned long before casting to a pointer and fixes
the following warnings:
fs/btrfs/extent_io.c:2289:20: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
fs/btrfs/ioctl.c:2933:37: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
fs/btrfs/ioctl.c:2937:21: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/ioctl.c:3020:21: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/scrub.c:275:4: warning: cast to pointer from integer of different size [-Wint-to-pointer-cast]
fs/btrfs/backref.c:686:27: warning: cast from pointer to integer of different size [-Wpointer-to-int-cast]
Signed-off-by: Jeff Mahoney <jeffm@suse.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The new ioctls to follow backrefs are not clean for 32/64 bit
compat. This reworks them for u64s everywhere. They are brand new, so
there are no problems with changing the interface now.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
fs_info has now ~9kb, more than fits into one page. This will cause
mount failure when memory is too fragmented. Top space consumers are
super block structures super_copy and super_for_commit, ~2.8kb each.
Allocate them dynamically. fs_info will be ~3.5kb. (measured on x86_64)
Add a wrapper for freeing fs_info and all of it's dynamically allocated
members.
Signed-off-by: David Sterba <dsterba@suse.cz>
We should retirn EINVAL if the start is beyond the end of the file
system in the btrfs_ioctl_fitrim(). Fix that by adding the appropriate
check for it.
Also in the btrfs_trim_fs() it is possible that len+start might overflow
if big values are passed. Fix it by decrementing the len so that start+len
is equal to the file system size in the worst case.
Signed-off-by: Lukas Czerner <lczerner@redhat.com>
We won't defrag an extent, if it's bigger than the threshold we
specified and there's no small extent before it, but actually
the code doesn't work this way.
There are three bugs:
- When should_defrag_range() decides we should keep on defragmenting
an extent, last_len is not incremented. (old bug)
- The length that passes to should_defrag_range() is not the length
we're going to defrag. (new bug)
- We always defrag 256K bytes data, and a big extent can be part of
this range. (new bug)
For a file with 4 extents:
| 4K | 4K | 256K | 256K |
The result of defrag with (the default) 256K extent thresh should be:
| 264K | 256K |
but with those bugs, we'll get:
| 520K |
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
It's off-by-one, and thus we may skip the last page while defragmenting.
An example case:
# create /mnt/file with 2 4K file extents
# btrfs fi defrag /mnt/file
# sync
# filefrag /mnt/file
/mnt/file: 2 extents found
So it's not defragmented.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Don't use inode->i_size directly, since we're not holding i_mutex.
This also fixes another bug, that i_size can change after it's checked
against 0 and then (i_size - 1) can be negative.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Xfstests 79 was failing because we were inheriting the S_APPEND flag when we
weren't supposed to. There isn't any specific documentation on this so I'm
taking the test as the standard of how things work, and having S_APPEND set on a
directory doesn't mean that S_APPEND gets inherited by its children according to
this test. So only inherit btrfs specific things. This will let us set
compress/nocompress on specific directories and everything in the directories
will inherit this flag, same with nodatacow. With this patch test 79 passes.
Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Johannes pointed out we were allocating only kernel pages for doing writes,
which is kind of a big deal if you are on 32bit and have more than a gig of ram.
So fix our allocations to use the mapping's gfp but still clear __GFP_FS so we
don't re-enter. Thanks,
Reported-by: Johannes Weiner <jweiner@redhat.com>
Signed-off-by: Josef Bacik <josef@redhat.com>
The btrfs file defrag code will loop through the extents and
force COW on them. But there is a concurrent truncate in the middle of
the defrag, it might end up defragging the same range over and over
again.
The problem is that writepage won't go through and do anything on pages
past i_size, so the cow won't happen, so the file will appear to still
be fragmented. defrag will end up hitting the same extents again and
again.
In the worst case, the truncate can actually live lock with the defrag
because the defrag keeps creating new ordered extents which the truncate
code keeps waiting on.
The fix here is to make defrag check for i_size inside the main loop,
instead of just once before the looping starts.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Follow those steps:
# mount -o autodefrag /dev/sda7 /mnt
# dd if=/dev/urandom of=/mnt/tmp bs=200K count=1
# sync
# dd if=/dev/urandom of=/mnt/tmp bs=8K count=1 conv=notrunc
and then it'll go into a loop: writeback -> defrag -> writeback ...
It's because writeback writes [8K, 200K] and then writes [0, 8K].
I tried to make writeback know if the pages are dirtied by defrag,
but the patch was a bit intrusive. Here I simply set writeback_index
when we defrag a file.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
these ioctls make use of the new functions initially added for scrub. they
return all inodes belonging to a logical address (BTRFS_IOC_LOGICAL_INO) and
all paths belonging to an inode (BTRFS_IOC_INO_PATHS).
Signed-off-by: Jan Schmidt <list.btrfs@jan-o-sch.net>
Fix a crash/BUG_ON in the clone ioctl due to insufficient reservation. We
need to reserve space for:
- adjusting the old extent (possibly splitting it)
- adding the new extent
- updating the inode
Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
The dst file will have the same inode flags with dst file after
file clone, and I think it's unexpected.
For example, the dst file will suddenly become immutable after
getting some share of data with src file, if the src is immutable.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
To reproduce the bug:
# mount /dev/sda7 /mnt
# dd if=/dev/zero of=/mnt/src bs=4K count=1
# umount /mnt
# mount -o nodatasum /dev/sda7 /mnt
# dd if=/dev/zero of=/mnt/dst bs=4K count=1
# clone_range -s 4K -l 4K /mnt/src /mnt/dst
# echo 3 > /proc/sys/vm/drop_caches
# cat /mnt/dst
# dmesg
...
btrfs no csum found for inode 258 start 0
btrfs csum failed ino 258 off 0 csum 2566472073 private 0
It's because part of the file is checksummed and the other part is not,
and then btrfs will complain checksum is not found when we read the file.
Disallow file clone if src and dst file have different checksum flag,
so we ensure a file is completely checksummed or unchecksummed.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
It's a bug in commit f81c9cdc56
(Btrfs: truncate pages from clone ioctl target range)
We should pass the dest range to the truncate function, but not the
src range.
Also move the function before locking extent state.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://github.com/chrismason/linux:
Btrfs: add dummy extent if dst offset excceeds file end in
Btrfs: calc file extent num_bytes correctly in file clone
btrfs: xattr: fix attribute removal
Btrfs: fix wrong nbytes information of the inode
Btrfs: fix the file extent gap when doing direct IO
Btrfs: fix unclosed transaction handle in btrfs_cont_expand
Btrfs: fix misuse of trans block rsv
Btrfs: reset to appropriate block rsv after orphan operations
Btrfs: skip locking if searching the commit root in csum lookup
btrfs: fix warning in iput for bad-inode
Btrfs: fix an oops when deleting snapshots
You can see there's no file extent with range [0, 4096]. Check this by
btrfsck:
# btrfsck /dev/sda7
root 5 inode 258 errors 100
...
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
We need to truncate page cache pages for the clone ioctl target range or
else we'll confuse ourselves to no end. If the old data was cached, we
used to still see it (until remount). If the page was partially updated
we used to get a mix of old and new data.
Signed-off-by: Sage Weil <sage@newdream.net>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable: (31 commits)
Btrfs: don't call writepages from within write_full_page
Btrfs: Remove unused variable 'last_index' in file.c
Btrfs: clean up for find_first_extent_bit()
Btrfs: clean up for wait_extent_bit()
Btrfs: clean up for insert_state()
Btrfs: remove unused members from struct extent_state
Btrfs: clean up code for merging extent maps
Btrfs: clean up code for extent_map lookup
Btrfs: clean up search_extent_mapping()
Btrfs: remove redundant code for dir item lookup
Btrfs: make acl functions really no-op if acl is not enabled
Btrfs: remove remaining ref-cache code
Btrfs: remove a BUG_ON() in btrfs_commit_transaction()
Btrfs: use wait_event()
Btrfs: check the nodatasum flag when writing compressed files
Btrfs: copy string correctly in INO_LOOKUP ioctl
Btrfs: don't print the leaf if we had an error
btrfs: make btrfs_set_root_node void
Btrfs: fix oops while writing data to SSD partitions
Btrfs: Protect the readonly flag of block group
...
Fix up trivial conflicts (due to acl and writeback cleanups) in
- fs/btrfs/acl.c
- fs/btrfs/ctree.h
- fs/btrfs/extent_io.c
Memory areas [ptr, ptr+total_len] and [name, name+total_len]
may overlap, so it's wrong to use memcpy().
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
Btrfs: make sure reserve_metadata_bytes doesn't leak out strange errors
Btrfs: use the commit_root for reading free_space_inode crcs
Btrfs: reduce extent_state lock contention for metadata
Btrfs: remove lockdep magic from btrfs_next_leaf
Btrfs: make a lockdep class for each root
Btrfs: switch the btrfs tree locks to reader/writer
Btrfs: fix deadlock when throttling transactions
Btrfs: stop using highmem for extent_buffers
Btrfs: fix BUG_ON() caused by ENOSPC when relocating space
Btrfs: tag pages for writeback in sync
Btrfs: fix enospc problems with delalloc
Btrfs: don't flush delalloc arbitrarily
Btrfs: use find_or_create_page instead of grab_cache_page
Btrfs: use a worker thread to do caching
Btrfs: fix how we merge extent states and deal with cached states
Btrfs: use the normal checksumming infrastructure for free space cache
Btrfs: serialize flushers in reserve_metadata_bytes
Btrfs: do transaction space reservation before joining the transaction
Btrfs: try to only do one btrfs_search_slot in do_setxattr
So I had this brilliant idea to use atomic counters for outstanding and reserved
extents, but this turned out to be a bad idea. Consider this where we have 1
outstanding extent and 1 reserved extent
Reserver Releaser
atomic_dec(outstanding) now 0
atomic_read(outstanding)+1 get 1
atomic_read(reserved) get 1
don't actually reserve anything because
they are the same
atomic_cmpxchg(reserved, 1, 0)
atomic_inc(outstanding)
atomic_add(0, reserved)
free reserved space for 1 extent
Then the reserver now has no actual space reserved for it, and when it goes to
finish the ordered IO it won't have enough space to do it's allocation and you
get those lovely warnings.
Signed-off-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
grab_cache_page will use mapping_gfp_mask(), which for all inodes is set to
GFP_HIGHUSER_MOVABLE. So instead use find_or_create_page in all cases where we
need GFP_NOFS so we don't deadlock. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
both callers there have dentry->d_parent stabilized by the fact that
their caller had obtained dentry from lookup_one_len() and had not
dropped ->i_mutex on parent since then.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Currently there is nothing protecting the pending_snapshots list on the
transaction. We only hold the directory mutex that we are snapshotting and a
read lock on the subvol_sem, so we could race with somebody else creating a
snapshot in a different directory and end up with list corruption. So protect
this list with the trans_lock. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
The size of struct btrfs_ioctl_fs_info_args is as big as 1KB, so
don't declare the variable on stack.
Signed-off-by: Li Zefan <lizf@cn.fujitsu.com>
Reviewed-by: Josef Bacik <josef@redhat.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
commit 4cb5300bc ("Btrfs: add mount -o auto_defrag") accesses inode
number directly while it should use the helper with the new inode
number allocator.
Signed-off-by: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This will detect small random writes into files and
queue the up for an auto defrag process. It isn't well suited to
database workloads yet, but works for smaller files such as rpm, sqlite
or bdb databases.
Signed-off-by: Chris Mason <chris.mason@oracle.com>
fs_devices->devices is only updated on remove and add device paths, so we can
use rcu to protect it in the reader side
Signed-off-by: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Btrfs's tree search ioctl has a field to indicate that no more than a
given number of records should be returned. The ioctl doesn't honour
this, as the tested value is not incremented until the end of the
copy_to_sk function. This patch removes an unnecessary local variable,
and updates the num_found counter as each key is found in the tree.
Signed-off-by: Hugo Mills <hugo@carfax.org.uk>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
Originally this was going to be used as a way to give hints to the allocator,
but frankly we can get much better hints elsewhere and it's not even used at all
for anything usefull. In addition to be completely useless, when we initialize
an inode we try and find a freeish block group to set as the inodes block group,
and with a completely full 40gb fs this takes _forever_, so I imagine with say
1tb fs this is just unbearable. So just axe the thing altoghether, we don't
need it and it saves us 8 bytes in the inode and saves us 500 microseconds per
inode lookup in my testcase. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
We use trans_mutex for lots of things, here's a basic list
1) To serialize trans_handles joining the currently running transaction
2) To make sure that no new trans handles are started while we are committing
3) To protect the dead_roots list and the transaction lists
Really the serializing trans_handles joining is not too hard, and can really get
bogged down in acquiring a reference to the transaction. So replace the
trans_mutex with a trans_lock spinlock and use it to do the following
1) Protect fs_info->running_transaction. All trans handles have to do is check
this, and then take a reference of the transaction and keep on going.
2) Protect the fs_info->trans_list. This doesn't get used too much, basically
it just holds the current transactions, which will usually just be the currently
committing transaction and the currently running transaction at most.
3) Protect the dead roots list. This is only ever processed by splicing the
list so this is relatively simple.
4) Protect the fs_info->reloc_ctl stuff. This is very lightweight and was using
the trans_mutex before, so this is a pretty straightforward change.
5) Protect fs_info->no_trans_join. Because we don't hold the trans_lock over
the entirety of the commit we need to have a way to block new people from
creating a new transaction while we're doing our work. So we set no_trans_join
and in join_transaction we test to see if that is set, and if it is we do a
wait_on_commit.
6) Make the transaction use count atomic so we don't need to take locks to
modify it when we're dropping references.
7) Add a commit_lock to the transaction to make sure multiple people trying to
commit the same transaction don't race and commit at the same time.
8) Make open_ioctl_trans an atomic so we don't have to take any locks for ioctl
trans.
I have tested this with xfstests, but obviously it is a pretty hairy change so
lots of testing is greatly appreciated. Thanks,
Signed-off-by: Josef Bacik <josef@redhat.com>
Chris Mason