Commit Graph

49302 Commits

Author SHA1 Message Date
Darrick J. Wong c684010115 xfs: expose errortag knobs via sysfs
Creates a /sys/fs/xfs/$dev/errortag/ directory to control the errortag
values directly.  This enables us to control the randomness values,
rather than having to accept the defaults.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
2017-06-27 18:23:20 -07:00
Darrick J. Wong 31965ef348 xfs: make errortag a per-mountpoint structure
Remove the xfs_etest structure in favor of a per-mountpoint structure.
This will give us the flexibility to set as many error injection points
as we want, and later enable us to set up sysfs knobs to set the trigger
frequency as we wish.  This comes at a cost of higher memory use, but
unti we hit 1024 injection points (we're at 29) or a lot of mounts this
shouldn't be a huge issue.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
2017-06-27 18:23:19 -07:00
Brian Foster 39775431f8 xfs: free uncommitted transactions during log recovery
Log recovery allocates in-core transaction and member item data
structures on-demand as it processes the on-disk log. Transactions
are allocated on first encounter on-disk and stored in a hash table
structure where they are easily accessible for subsequent lookups.
Transaction items are also allocated on demand and are attached to
the associated transactions.

When a commit record is encountered in the log, the transaction is
committed to the fs and the in-core structures are freed. If a
filesystem crashes or shuts down before all in-core log buffers are
flushed to the log, however, not all transactions may have commit
records in the log. As expected, the modifications in such an
incomplete transaction are not replayed to the fs. The in-core data
structures for the partial transaction are never freed, however,
resulting in a memory leak.

Update xlog_do_recovery_pass() to first correctly initialize the
hash table array so empty lists can be distinguished from populated
lists on function exit. Update xlog_recover_free_trans() to always
remove the transaction from the list prior to freeing the associated
memory. Finally, walk the hash table of transaction lists as the
last step before it goes out of scope and free any transactions that
may remain on the lists. This prevents a memory leak of partial
transactions in the log.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-24 10:11:41 -07:00
Darrick J. Wong 61d819e7bc xfs: don't allow bmap on rt files
bmap returns a dumb LBA address but not the block device that goes with
that LBA.  Swapfiles don't care about this and will blindly assume that
the data volume is the correct blockdev, which is totally bogus for
files on the rt subvolume.  This results in the swap code doing IOs to
arbitrary locations on the data device(!) if the passed in mapping is a
realtime file, so just turn off bmap for rt files.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2017-06-20 10:45:22 -07:00
Darrick J. Wong 5da8f2f890 xfs: allow reading of already-locked remote symbolic link
Expose the readlink variant that doesn't take the inode lock so that
the scrubber can inspect symlink contents.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-20 10:45:22 -07:00
Darrick J. Wong ad017f6537 xfs: pass along transaction context when reading xattr block buffers
Teach the extended attribute reading functions to pass along a
transaction context if one was supplied.  The extended attribute scrub
code will use transactions to lock buffers and avoid deadlocking with
itself in the case of loops; since it will already have the inode
locked, also create xattr get/list helpers that don't take locks.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-20 10:45:22 -07:00
Darrick J. Wong acb9553cab xfs: pass along transaction context when reading directory block buffers
Teach the directory reading functions to pass along a transaction context
if one was supplied.  The directory scrub code will use transactions to
lock buffers and avoid deadlocking with itself in the case of loops.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-20 10:45:22 -07:00
Darrick J. Wong 8e8877e6ed xfs: return the hash value of a leaf1 directory block
Modify the existing dir leafn lasthash function to enable us to
calculate the highest hash value of a leaf1 block.  This will be used by
the directory scrubbing code to check the sanity of hashes in leaf1
directory blocks.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-20 10:45:21 -07:00
Darrick J. Wong e7f5d5ca36 xfs: refactor the ifork block counting function
Refactor the inode fork block counting function to count extents for us
at the same time.  This will be used by the bmbt scrubber function.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-20 10:45:21 -07:00
Darrick J. Wong d29cb3e45e xfs: make _bmap_count_blocks consistent wrt delalloc extent behavior
There is an inconsistency in the way that _bmap_count_blocks deals with
delalloc reservations -- if the specified fork is in extents format,
*count is set to the total number of blocks referenced by the in-core
fork, including delalloc extents.  However, if the fork is in btree
format, *count is set to the number of blocks referenced by the on-disk
fork, which does /not/ include delalloc extents.

For the lone existing caller of _bmap_count_blocks this hasn't been an
issue because the function is only used to count xattr fork blocks
(where there aren't any delalloc reservations).  However, when scrub
comes along it will use this same function to check di_nblocks against
both on-disk extent maps, so we need this behavior to be consistent.

Therefore, fix _bmap_count_leaves not to include delalloc extents and
remove unnecessary parameters.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-20 10:45:21 -07:00
Darrick J. Wong ea7cdd7b7b xfs: separate function to check if inode shares extents
Separate the "clear reflink flag" function into one function that checks
if the flag is needed, and a second function that checks and clears the
flag.  The inode scrub code will want to check the necessity of the flag
without clearing it.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-19 14:11:35 -07:00
Darrick J. Wong 92ff7285f1 xfs: reflink find shared should take a transaction
Adapt _reflink_find_shared to take an optional transaction pointer.  The
inode scrubber code will need to decide (within transaction context) if
a file has shared blocks.  To avoid buffer deadlocks, we must pass the
tp through to this function's utility calls.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-19 14:11:35 -07:00
Darrick J. Wong 378f681c4b xfs: check if an inode is cached and allocated
Check the inode cache for a particular inode number.  If it's in the
cache, check that it's not currently being reclaimed.  If it's not being
reclaimed, return zero if the inode is allocated.  This function will be
used by various scrubbers to decide if the cache is more up to date
than the disk in terms of checking if an inode is allocated.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-19 14:11:34 -07:00
Darrick J. Wong e936945ee4 xfs: export _inobt_btrec_to_irec and _ialloc_cluster_alignment for scrub
Create a function to extract an in-core inobt record from a generic
btree_rec union so that scrub will be able to check inobt records
and check inode block alignment.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-19 14:11:34 -07:00
Darrick J. Wong 118bb47e28 xfs: plumb in needed functions for range querying of various btrees
Plumb in the pieces (init_high_key, diff_two_keys) necessary to call
query_range on the inode space and block mapping btrees and to extract
raw btree records.  This will eventually be used by the inobt and bmbt
scrubbers.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-19 14:11:34 -07:00
Darrick J. Wong 2678809799 xfs: export various function for the online scrubber
Export various internal functions so that the online scrubber can use
them to check the state of metadata.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-19 14:11:34 -07:00
Darrick J. Wong 38dee376d6 xfs: always compile the btree inorder check functions
The btree record and key inorder check functions will be used by the
btree scrubber code, so make sure they're always built.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-19 14:11:33 -07:00
Darrick J. Wong c8ce540db5 xfs: remove double-underscore integer types
This is a purely mechanical patch that removes the private
__{u,}int{8,16,32,64}_t typedefs in favor of using the system
{u,}int{8,16,32,64}_t typedefs.  This is the sed script used to perform
the transformation and fix the resulting whitespace and indentation
errors:

s/typedef\t__uint8_t/typedef __uint8_t\t/g
s/typedef\t__uint/typedef __uint/g
s/typedef\t__int\([0-9]*\)_t/typedef int\1_t\t/g
s/__uint8_t\t/__uint8_t\t\t/g
s/__uint/uint/g
s/__int\([0-9]*\)_t\t/__int\1_t\t\t/g
s/__int/int/g
/^typedef.*int[0-9]*_t;$/d

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2017-06-19 14:11:33 -07:00
Darrick J. Wong 5a4c73342a xfs: optimize _btree_query_all
Don't bother wandering our way through the leaf nodes when the caller
issues a query_all; just zoom down the left side of the tree and walk
rightwards along level zero.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
2017-06-19 14:11:33 -07:00
Brian Foster 3d4b4a3e30 xfs: remove bli from AIL before release on transaction abort
When a buffer is modified, logged and committed, it ultimately ends
up sitting on the AIL with a dirty bli waiting for metadata
writeback. If another transaction locks and invalidates the buffer
(freeing an inode chunk, for example) in the meantime, the bli is
flagged as stale, the dirty state is cleared and the bli remains in
the AIL.

If a shutdown occurs before the transaction that has invalidated the
buffer is committed, the transaction is ultimately aborted. The log
items are flagged as such and ->iop_unlock() handles the aborted
items. Because the bli is clean (due to the invalidation),
->iop_unlock() unconditionally releases it. The log item may still
reside in the AIL, however, which means the I/O completion handler
may still run and attempt to access it. This results in assert
failure due to the release of the bli while still present in the AIL
and a subsequent NULL dereference and panic in the buffer I/O
completion handling. This can be reproduced by running generic/388
in repetition.

To avoid this problem, update xfs_buf_item_unlock() to first check
whether the bli is aborted and if so, remove it from the AIL before
it is released. This ensures that the bli is no longer accessed
during the shutdown sequence after it has been freed.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Brian Foster 79e641ce29 xfs: release bli from transaction properly on fs shutdown
If a filesystem shutdown occurs with a buffer log item in the CIL
and a log force occurs, the ->iop_unpin() handler is generally
expected to tear down the bli properly. This entails freeing the bli
memory and releasing the associated hold on the buffer so it can be
released and the filesystem unmounted.

If this sequence occurs while ->bli_refcount is elevated (i.e.,
another transaction is open and attempting to modify the buffer),
however, ->iop_unpin() may not be responsible for releasing the bli.
Instead, the transaction may release the final ->bli_refcount
reference and thus xfs_trans_brelse() is responsible for tearing
down the bli.

While xfs_trans_brelse() does drop the reference count, it only
attempts to release the bli if it is clean (i.e., not in the
CIL/AIL). If the filesystem is shutdown and the bli is sitting dirty
in the CIL as noted above, this ends up skipping the last
opportunity to release the bli. In turn, this leaves the hold on the
buffer and causes an unmount hang. This can be reproduced by running
generic/388 in repetition.

Update xfs_trans_brelse() to handle this shutdown corner case
correctly. If the final bli reference is dropped and the filesystem
is shutdown, remove the bli from the AIL (if necessary) and release
the bli to drop the buffer hold and ensure an unmount does not hang.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Arnd Bergmann 0cbe48cc58 xfs: avoid harmless gcc-7 warnings
gcc-7 flags the use of integer math inside of a condition
as a potential bug:

fs/xfs/xfs_bmap_util.c: In function 'xfs_swap_extents_check_format':
fs/xfs/xfs_bmap_util.c:1619:8: error: '<<' in boolean context, did you mean '<' ? [-Werror=int-in-bool-context]
fs/xfs/xfs_bmap_util.c:1629:8: error: '<<' in boolean context, did you mean '<' ? [-Werror=int-in-bool-context]

There is already a helper function for testing the di_forkoff
field for zero, so let's use that instead to shut up the warning.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Shan Hai f990fc5ad1 xfs: remove lsn relevant fields from xfs_trans structure and its users
The t_lsn is not used anymore and the t_commit_lsn is used as a tmp
storage for the checkpoint sequence number only in the current code.

And the start/commit lsn are tracked as a transaction group tag in
the xfs_cil_ctx instead of a single transaction, so remove them from
the xfs_trans structure and their users to match with the design.

Signed-off-by: Shan Hai <shan.hai@oracle.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Christoph Hellwig 3398a4005f xfs: remove XFS_HSIZE
XFS_HSIZE is an extremly confusing way to calculate the size of handle_t.
Given that handle_t always only had two sizes, and one of them isn't
even covered by XFS_HSIZE to start with just remove the macro and use
a constant sizeof expression.

Note that XFS_HSIZE isn't used in xfsprogs, xfsdump or xfstests either.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Eric Sandeen <sandeen@sandeen.net>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Brian Foster d4ca1d550d xfs: dump transaction usage details on log reservation overrun
If a transaction log reservation overrun occurs, the ticket data
associated with the reservation is dumped in xfs_log_commit_cil().
This occurs long after the transaction items and details have been
removed from the transaction and effectively lost. This limited set
of ticket data provides very little information to support debugging
transaction overruns based on the typical report.

To improve transaction log reservation overrun reporting, create a
helper to dump transaction details such as log items, log vector
data, etc., as well as the underlying ticket data for the
transaction. Move the overrun detection from xfs_log_commit_cil() to
xlog_cil_insert_items() so it occurs prior to migration of the
logged items to the CIL. Call the new helper such that it is able to
dump this transaction data before it is lost.

Also, warn on overrun to provide callstack context for the offending
transaction and include a few additional messages from
xlog_cil_insert_items() to display the reservation consumed locally
for overhead such as log vector headers, split region headers and
the context ticket. This provides a complete general breakdown of
the reservation consumption of a transaction when/if it happens to
overrun the reservation.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Brian Foster e2f2342639 xfs: refactor xlog_cil_insert_items() to facilitate transaction dump
Transaction reservation overrun detection currently occurs too late
to print useful information about the offending transaction.
Ideally, the transaction data is printed before the associated log
items are moved from the transaction to the CIL, which occurs in
xlog_cil_insert_items(), such that details of the items logged by
the transaction are available for analysis.

Refactor xlog_cil_insert_items() to facilitate moving tx overrun
detection to this function. Update the function to track each bit of
extra log reservation stolen from the transaction (i.e., such as for
the CIL context ticket) and perform the log item migration as the
last operation before the CIL lock is released. This creates a
context where the transaction reservation consumption has been fully
calculated when the log items are moved to the CIL. This patch makes
no functional changes.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Brian Foster 7d2d565346 xfs: separate shutdown from ticket reservation print helper
xlog_print_tic_res() pre-dates delayed logging and the committed
items list (CIL) and thus retains some factoring warts, such as hard
coded function names in the output and the fact that it induces a
shutdown.

In preparation for more detailed logging of regular transaction
overrun situations, refactor xlog_print_tic_res() to be slightly
more generic. Reword some of the warning messages and pull the
shutdown into the callers.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Brian Foster 1040960efa xfs: define fatal assert build time tunable
While configurable at runtime, the DEBUG mode assert failure
behavior is usually either desired or not for a particular
situation. For example, developers using kernel modules may prefer
for fatal asserts to remain disabled across module reloads while QE
engineers doing broad regression testing may prefer to have fatal
asserts enabled on boot to facilitate data collection for bug
reports.

To provide a compromise/convenience for developers, create a Kconfig
option that sets the default value of the DEBUG mode 'bug_on_assert'
sysfs tunable. The default behavior remains to trigger kernel BUGs
on assert failures to preserve existing behavior across kernel
configuration updates with DEBUG mode enabled.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Brian Foster ccdab3d6e8 xfs: define bug_on_assert debug mode sysfs tunable
In DEBUG mode, assert failures unconditionally trigger a kernel BUG.
This is useful in diagnostic situations to panic a system and
collect detailed state information at the time of a failure.

This can also cause problems in cases where DEBUG mode code is
desired but it is preferable not trigger kernel BUGs on assert
failure. For example, during development of new code or during
certain xfstests tests that intentionally cause corruption and test
the kernel for survival (but otherwise may expect to trigger assert
failures).

To provide additional flexibility, create the
<sysfs>/fs/xfs/debug/bug_on_assert tunable to configure assert
failure behavior at runtime. This tunable is only available in DEBUG
mode and is enabled by default to preserve existing default
behavior. When disabled, assert failures in DEBUG mode result in
kernel warnings.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Darrick J. Wong e1a4e37cc7 xfs: try to avoid blowing out the transaction reservation when bunmaping a shared extent
In a pathological scenario where we are trying to bunmapi a single
extent in which every other block is shared, it's possible that trying
to unmap the entire large extent in a single transaction can generate so
many EFIs that we overflow the transaction reservation.

Therefore, use a heuristic to guess at the number of blocks we can
safely unmap from a reflink file's data fork in an single transaction.
This should prevent problems such as the log head slamming into the tail
and ASSERTs that trigger because we've exceeded the transaction
reservation.

Note that since bunmapi can fail to unmap the entire range, we must also
teach the deferred unmap code to roll into a new transaction whenever we
get low on reservation.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
[hch: random edits, all bugs are my fault]
Signed-off-by: Christoph Hellwig <hch@lst.de>
2017-06-19 08:59:10 -07:00
Darrick J. Wong d205a7d0ec xfs: refactor dir2 leaf readahead shadow buffer cleverness
Currently, the dir2 leaf block getdents function uses a complex state
tracking mechanism to create a shadow copy of the block mappings and
then uses the shadow copy to schedule readahead.  Since the read and
readahead functions are perfectly capable of reading the mappings
themselves, we can tear all that out in favor of a simpler function that
simply keeps pushing the readahead window further out.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
2017-06-19 08:59:10 -07:00
Brian Foster 7912e7fef2 xfs: push buffer of flush locked dquot to avoid quotacheck deadlock
Reclaim during quotacheck can lead to deadlocks on the dquot flush
lock:

 - Quotacheck populates a local delwri queue with the physical dquot
   buffers.
 - Quotacheck performs the xfs_qm_dqusage_adjust() bulkstat and
   dirties all of the dquots.
 - Reclaim kicks in and attempts to flush a dquot whose buffer is
   already queud on the quotacheck queue. The flush succeeds but
   queueing to the reclaim delwri queue fails as the backing buffer is
   already queued. The flush unlock is now deferred to I/O completion
   of the buffer from the quotacheck queue.
 - The dqadjust bulkstat continues and dirties the recently flushed
   dquot once again.
 - Quotacheck proceeds to the xfs_qm_flush_one() walk which requires
   the flush lock to update the backing buffers with the in-core
   recalculated values. It deadlocks on the redirtied dquot as the
   flush lock was already acquired by reclaim, but the buffer resides
   on the local delwri queue which isn't submitted until the end of
   quotacheck.

This is reproduced by running quotacheck on a filesystem with a
couple million inodes in low memory (512MB-1GB) situations. This is
a regression as of commit 43ff2122e6 ("xfs: on-stack delayed write
buffer lists"), which removed a trylock and buffer I/O submission
from the quotacheck dquot flush sequence.

Quotacheck first resets and collects the physical dquot buffers in a
delwri queue. Then, it traverses the filesystem inodes via bulkstat,
updates the in-core dquots, flushes the corrected dquots to the
backing buffers and finally submits the delwri queue for I/O. Since
the backing buffers are queued across the entire quotacheck
operation, dquot reclaim cannot possibly complete a dquot flush
before quotacheck completes.

Therefore, quotacheck must submit the buffer for I/O in order to
cycle the flush lock and flush the dirty in-core dquot to the
buffer. Add a delwri queue buffer push mechanism to submit an
individual buffer for I/O without losing the delwri queue status and
use it from quotacheck to avoid the deadlock. This restores
quotacheck behavior to as before the regression was introduced.

Reported-by: Martin Svec <martin.svec@zoner.cz>
Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-06-19 08:59:10 -07:00
Hugh Dickins 1be7107fbe mm: larger stack guard gap, between vmas
Stack guard page is a useful feature to reduce a risk of stack smashing
into a different mapping. We have been using a single page gap which
is sufficient to prevent having stack adjacent to a different mapping.
But this seems to be insufficient in the light of the stack usage in
userspace. E.g. glibc uses as large as 64kB alloca() in many commonly
used functions. Others use constructs liks gid_t buffer[NGROUPS_MAX]
which is 256kB or stack strings with MAX_ARG_STRLEN.

This will become especially dangerous for suid binaries and the default
no limit for the stack size limit because those applications can be
tricked to consume a large portion of the stack and a single glibc call
could jump over the guard page. These attacks are not theoretical,
unfortunatelly.

Make those attacks less probable by increasing the stack guard gap
to 1MB (on systems with 4k pages; but make it depend on the page size
because systems with larger base pages might cap stack allocations in
the PAGE_SIZE units) which should cover larger alloca() and VLA stack
allocations. It is obviously not a full fix because the problem is
somehow inherent, but it should reduce attack space a lot.

One could argue that the gap size should be configurable from userspace,
but that can be done later when somebody finds that the new 1MB is wrong
for some special case applications.  For now, add a kernel command line
option (stack_guard_gap) to specify the stack gap size (in page units).

Implementation wise, first delete all the old code for stack guard page:
because although we could get away with accounting one extra page in a
stack vma, accounting a larger gap can break userspace - case in point,
a program run with "ulimit -S -v 20000" failed when the 1MB gap was
counted for RLIMIT_AS; similar problems could come with RLIMIT_MLOCK
and strict non-overcommit mode.

Instead of keeping gap inside the stack vma, maintain the stack guard
gap as a gap between vmas: using vm_start_gap() in place of vm_start
(or vm_end_gap() in place of vm_end if VM_GROWSUP) in just those few
places which need to respect the gap - mainly arch_get_unmapped_area(),
and and the vma tree's subtree_gap support for that.

Original-patch-by: Oleg Nesterov <oleg@redhat.com>
Original-patch-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Hugh Dickins <hughd@google.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Tested-by: Helge Deller <deller@gmx.de> # parisc
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-19 21:50:20 +08:00
Linus Torvalds 6e20350659 A fix for an old ceph ->fh_to_* bug from Luis and two timestamp
fixups from Zheng, prompted by the ongoing y2038 work.
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Merge tag 'ceph-for-4.12-rc6' of git://github.com/ceph/ceph-client

Pull ceph fixes from Ilya Dryomov:
 "A fix for an old ceph ->fh_to_* bug from Luis and two timestamp fixups
  from Zheng, prompted by the ongoing y2038 work"

* tag 'ceph-for-4.12-rc6' of git://github.com/ceph/ceph-client:
  ceph: unify inode i_ctime update
  ceph: use current_kernel_time() to get request time stamp
  ceph: check i_nlink while converting a file handle to dentry
2017-06-18 08:23:02 +09:00
Linus Torvalds adc311034c Changes since last update:
- Fix some bogus ASSERT failures on CONFIG_SMP=n and CONFIG_XFS_DEBUG=y.
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Merge tag 'xfs-4.12-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux

Pull xfs fix from Darrick Wong:
 "One more bugfix for you for 4.12-rc6 to fix something that came up in
  an earlier rc:

   - Fix some bogus ASSERT failures on CONFIG_SMP=n and CONFIG_XFS_DEBUG=y"

* tag 'xfs-4.12-fixes-4' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
  xfs: fix spurious spin_is_locked() assert failures on non-smp kernels
2017-06-17 17:34:41 +09:00
Linus Torvalds c8636b90a0 Merge branch 'ufs-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull ufs fixes from Al Viro:
 "Fix assorted ufs bugs: a couple of deadlocks, fs corruption in
  truncate(), oopsen on tail unpacking and truncate when racing with
  vmscan, mild fs corruption (free blocks stats summary buggered, *BSD
  fsck would complain and fix), several instances of broken logics
  around reserved blocks (starting with "check almost never triggers
  when it should" and then there are issues with sufficiently large
  UFS2)"

[ Note: ufs hasn't gotten any loving in a long time, because nobody
  really seems to use it. These ufs fixes are triggered by people
  actually caring now, not some sudden influx of new bugs.  - Linus ]

* 'ufs-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  ufs_truncate_blocks(): fix the case when size is in the last direct block
  ufs: more deadlock prevention on tail unpacking
  ufs: avoid grabbing ->truncate_mutex if possible
  ufs_get_locked_page(): make sure we have buffer_heads
  ufs: fix s_size/s_dsize users
  ufs: fix reserved blocks check
  ufs: make ufs_freespace() return signed
  ufs: fix logics in "ufs: make fsck -f happy"
2017-06-17 17:30:07 +09:00
Linus Torvalds ccd3d905f7 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs fixes from Al Viro:
 "A couple of fixes; a leak in mntns_install() caught by Andrei (this
  cycle regression) + d_invalidate() softlockup fix - that had been
  reported by a bunch of people lately, but the problem is pretty old"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  fs: don't forget to put old mntns in mntns_install
  Hang/soft lockup in d_invalidate with simultaneous calls
2017-06-17 17:26:53 +09:00
Andrea Arcangeli 64c2b20301 userfaultfd: shmem: handle coredumping in handle_userfault()
Anon and hugetlbfs handle FOLL_DUMP set by get_dump_page() internally to
__get_user_pages().

shmem as opposed has no special FOLL_DUMP handling there so
handle_mm_fault() is invoked without mmap_sem and ends up calling
handle_userfault() that isn't expecting to be invoked without mmap_sem
held.

This makes handle_userfault() fail immediately if invoked through
shmem_vm_ops->fault during coredumping and solves the problem.

The side effect is a BUG_ON with no lock held triggered by the
coredumping process which exits.  Only 4.11 is affected, pre-4.11 anon
memory holes are skipped in __get_user_pages by checking FOLL_DUMP
explicitly against empty pagetables (mm/gup.c:no_page_table()).

It's zero cost as we already had a check for current->flags to prevent
futex to trigger userfaults during exit (PF_EXITING).

Link: http://lkml.kernel.org/r/20170615214838.27429-1-aarcange@redhat.com
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Reported-by: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: <stable@vger.kernel.org>	[4.11+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-17 06:37:05 +09:00
Linus Torvalds ab2789b72d A fix from Nic for a race seen in production (including a stable tag).
And while I'm sending you this I'm also sneaking in a trivial new helper
 from Bart so that we don't need inter-tree dependencies for the next merge
 window.
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Merge tag 'configfs-for-4.12' of git://git.infradead.org/users/hch/configfs

Pull configfs updates from Christoph Hellwig:
 "A fix from Nic for a race seen in production (including a stable tag).

  And while I'm sending you this I'm also sneaking in a trivial new
  helper from Bart so that we don't need inter-tree dependencies for the
  next merge window"

* tag 'configfs-for-4.12' of git://git.infradead.org/users/hch/configfs:
  configfs: Introduce config_item_get_unless_zero()
  configfs: Fix race between create_link and configfs_rmdir
2017-06-16 18:45:47 +09:00
Christoph Hellwig 20223f0f39 fs: pass on flags in compat_writev
Fixes: 793b80ef14 ("vfs: pass a flags argument to vfs_readv/vfs_writev")
Signed-off-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-06-16 18:40:51 +09:00
Andrei Vagin 4068367c9c fs: don't forget to put old mntns in mntns_install
Fixes: 4f757f3cbf ("make sure that mntns_install() doesn't end up with referral for root")
Cc: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Andrei Vagin <avagin@openvz.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-15 06:53:05 -04:00
Al Viro 81be24d263 Hang/soft lockup in d_invalidate with simultaneous calls
It's not hard to trigger a bunch of d_invalidate() on the same
dentry in parallel.  They end up fighting each other - any
dentry picked for removal by one will be skipped by the rest
and we'll go for the next iteration through the entire
subtree, even if everything is being skipped.  Morevoer, we
immediately go back to scanning the subtree.  The only thing
we really need is to dissolve all mounts in the subtree and
as soon as we've nothing left to do, we can just unhash the
dentry and bugger off.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-15 06:52:09 -04:00
Linus Torvalds 54ed0f71f0 Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
Pull crypto fix from Herbert Xu:
 "This fixes a bug on sparc where we may dereference freed stack memory"

* 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6:
  crypto: Work around deallocated stack frame reference gcc bug on sparc.
2017-06-15 17:54:51 +09:00
Al Viro a8fad98483 ufs_truncate_blocks(): fix the case when size is in the last direct block
The logics when deciding whether we need to do anything with direct blocks
is broken when new size is within the last direct block.  It's better to
find the path to the last byte _not_ to be removed and use that instead
of the path to the beginning of the first block to be freed...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-15 03:57:46 -04:00
Al Viro 289dec5b89 ufs: more deadlock prevention on tail unpacking
->s_lock is not needed for ufs_change_blocknr()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-15 00:42:56 -04:00
Al Viro 09bf4f5b6e ufs: avoid grabbing ->truncate_mutex if possible
tail unpacking is done in a wrong place; the deadlocks galore
is best dealt with by doing that in ->write_iter() (and switching
to iomap, while we are at it), but that's rather painful to
backport.  The trouble comes from grabbing pages that cover
the beginning of tail from inside of ufs_new_fragments(); ongoing
pageout of any of those is going to deadlock on ->truncate_mutex
with process that got around to extending the tail holding that
and waiting for page to get unlocked, while ->writepage() on
that page is waiting on ->truncate_mutex.

The thing is, we don't need ->truncate_mutex when the fragment
we are trying to map is within the tail - the damn thing is
allocated (tail can't contain holes).

Let's do a plain lookup and if the fragment is present, we can
just pretend that we'd won the race in almost all cases.  The
only exception is a fragment between the end of tail and the
end of block containing tail.

Protect ->i_lastfrag with ->meta_lock - read_seqlock_excl() is
sufficient.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-15 00:41:18 -04:00
Al Viro 267309f394 ufs_get_locked_page(): make sure we have buffer_heads
callers rely upon that, but find_lock_page() racing with attempt of
page eviction by memory pressure might have left us with
	* try_to_free_buffers() successfully done
	* __remove_mapping() failed, leaving the page in our mapping
	* find_lock_page() returning an uptodate page with no
buffer_heads attached.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-14 23:32:19 -04:00
Al Viro c596961d1b ufs: fix s_size/s_dsize users
For UFS2 we need 64bit variants; we even store them in uspi, but
use 32bit ones instead.  One wrinkle is in handling of reserved
space - recalculating it every time had been stupid all along, but
now it would become really ugly.  Just calculate it once...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-14 16:43:03 -04:00
Al Viro b451cec4bb ufs: fix reserved blocks check
a) honour ->s_minfree; don't just go with default (5)
b) don't bother with capability checks until we know we'll need them

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-14 15:46:05 -04:00
Al Viro fffd70f588 ufs: make ufs_freespace() return signed
as it is, checking that its return value is <= 0 is useless and
that's how it's being used.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2017-06-14 15:36:31 -04:00