- 16 May, 2018 22 commits
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Darrick J. Wong authored
In normal operation, the XFS convention is to take an inode's iolock and then allocate a transaction. However, when scrubbing parent inodes this is inverted -- we allocated the transaction to do the scrub, and now we're trying to grab the parent's iolock. This can lead to ABBA deadlocks: some thread grabbed the parent's iolock and is waiting for space for a transaction while our parent scrubber is sitting on a transaction trying to get the parent's iolock. Therefore, convert all iolock attempts to use trylock; if that fails, they can use the existing mechanisms to back off and try again. The ABBA deadlock didn't happen with a non-repair scrub because the transactions don't reserve any space, but repair scrubs require reservation in order to update metadata. However, any other concurrent metadata update (e.g. directory create in the parent) could also induce this deadlock with the parent scrubber. Signed-off-by:
Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by:
Brian Foster <bfoster@redhat.com>
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Darrick J. Wong authored
The realtime bitmap and summary inodes live on the metadata device, so we can scrub their data forks with the regular scrubbers. Signed-off-by:
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Darrick J. Wong authored
Replace the quota scrubber's open-coded data fork scrubber with a redirected call to the bmapbtd scrubber. This strengthens the quota scrub to include all the cross-referencing that it does. Signed-off-by:
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Darrick J. Wong authored
If we've already decided that something is corrupt, we might as well abort all the loops and exit as quickly as possible. Signed-off-by:
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Darrick J. Wong authored
Replace all the if (!error) weirdness with helper functions that follow our regular coding practices, and factor out the ternary expression soup. Signed-off-by:
Dave Chinner <dchinner@redhat.com>
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Darrick J. Wong authored
Secondary superblocks are rarely used, so create a helper to read a given non-primary AG's superblock and ensure that it won't stick around hogging memory. Signed-off-by:
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Darrick J. Wong authored
Don't bother looking for cross-referencing problems if the metadata is already corrupt or we've already found a cross-referencing problem. Since we added a helper function for flags testing, convert existing users to use it. Signed-off-by:
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Dave Chinner authored
We recently had an oops reported on a 4.14 kernel in xfs_reclaim_inodes_count() where sb->s_fs_info pointed to garbage and so the m_perag_tree lookup walked into lala land. Essentially, the machine was under memory pressure when the mount was being run, xfs_fs_fill_super() failed after allocating the xfs_mount and attaching it to sb->s_fs_info. It then cleaned up and freed the xfs_mount, but the sb->s_fs_info field still pointed to the freed memory. Hence when the superblock shrinker then ran it fell off the bad pointer. With the superblock shrinker problem fixed at teh VFS level, this stale s_fs_info pointer is still a problem - we use it unconditionally in ->put_super when the superblock is being torn down, and hence we can still trip over it after a ->fill_super call failure. Hence we need to clear s_fs_info if xfs-fs_fill_super() fails, and we need to check if it's valid in the places it can potentially be dereferenced after a ->fill_super failure. Signed-Off-By:
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Dave Chinner authored
Similar to log_recovery_delay, this delay occurs between the VFS superblock being initialised and the xfs_mount being fully initialised. It also poisons the per-ag radix tree node so that it can be used for triggering shrinker races during mount such as the following: <run memory pressure workload in background> $ cat dirty-mount.sh #! /bin/bash umount -f /dev/pmem0 mkfs.xfs -f /dev/pmem0 mount /dev/pmem0 /mnt/test rm -f /mnt/test/foo xfs_io -fxc "pwrite 0 4k" -c fsync -c "shutdown" /mnt/test/foo umount /dev/pmem0 # let's crash it now! echo 30 > /sys/fs/xfs/debug/mount_delay mount /dev/pmem0 /mnt/test echo 0 > /sys/fs/xfs/debug/mount_delay umount /dev/pmem0 $ sudo ./dirty-mount.sh ..... [ 60.378118] CPU: 3 PID: 3577 Comm: fs_mark Tainted: G D W 4.16.0-rc5-dgc #440 [ 60.378120] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1 04/01/2014 [ 60.378124] RIP: 0010:radix_tree_next_chunk+0x76/0x320 [ 60.378127] RSP: 0018:ffffc9000276f4f8 EFLAGS: 00010282 [ 60.383670] RAX: a5a5a5a5a5a5a5a4 RBX: 0000000000000010 RCX: 000000000000001a [ 60.385277] RDX: 0000000000000000 RSI: ffffc9000276f540 RDI: 0000000000000000 [ 60.386554] RBP: 0000000000000000 R08: 0000000000000000 R09: a5a5a5a5a5a5a5a5 [ 60.388194] R10: 0000000000000006 R11: 0000000000000001 R12: ffffc9000276f598 [ 60.389288] R13: 0000000000000040 R14: 0000000000000228 R15: ffff880816cd6458 [ 60.390827] FS: 00007f5c124b9740(0000) GS:ffff88083fc00000(0000) knlGS:0000000000000000 [ 60.392253] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 60.393423] CR2: 00007f5c11bba0b8 CR3: 000000035580e001 CR4: 00000000000606e0 [ 60.394519] Call Trace: [ 60.395252] radix_tree_gang_lookup_tag+0xc4/0x130 [ 60.395948] xfs_perag_get_tag+0x37/0xf0 [ 60.396522] xfs_reclaim_inodes_count+0x32/0x40 [ 60.397178] xfs_fs_nr_cached_objects+0x11/0x20 [ 60.397837] super_cache_count+0x35/0xc0 [ 60.399159] shrink_slab.part.66+0xb1/0x370 [ 60.400194] shrink_node+0x7e/0x1a0 [ 60.401058] try_to_free_pages+0x199/0x470 [ 60.402081] __alloc_pages_slowpath+0x3a1/0xd20 [ 60.403729] __alloc_pages_nodemask+0x1c3/0x200 [ 60.404941] cache_grow_begin+0x20b/0x2e0 [ 60.406164] fallback_alloc+0x160/0x200 [ 60.407088] kmem_cache_alloc+0x111/0x4e0 [ 60.408038] ? xfs_buf_rele+0x61/0x430 [ 60.408925] kmem_zone_alloc+0x61/0xe0 [ 60.409965] xfs_inode_alloc+0x24/0x1d0 ..... Signed-Off-By:
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Brian Foster authored
The changes to skip discards of speculative preallocation and unwritten extents introduced several new wrapper functions through the bunmapi -> extent free codepath to reduce churn in all of the associated callers. In several cases, these wrappers simply toggle a single flag to skip or not skip discards for the resulting blocks. The explicit _nodiscard() wrappers for such an isolated set of callers is a bit overkill. Kill off these wrappers and replace with the calls to the underlying functions in the contexts that need to control discard behavior. Retain the wrappers that preserve the original calling conventions to serve the original purpose of reducing code churn. This is a refactoring patch and does not change behavior. Signed-off-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
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Darrick J. Wong authored
Add a new iomap_swapfile_activate function so that filesystems can activate swap files without having to use the obsolete and slow bmap function. This enables XFS to support fallocate'd swap files and swap files on realtime devices. Signed-off-by:
Jan Kara <jack@suse.cz>
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Darrick J. Wong authored
Rebuilding the reverse-mapping tree requires us to quiesce all inodes in the filesystem, so we must stop background reclamation of post-EOF and CoW prealloc blocks. Signed-off-by:
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Darrick J. Wong authored
Add a new flag, XFS_BMAPI_NORMAP, which will perform file block remapping without updating the rmapbt. This will be used by the repair code to reconstruct bmbts from the rmapbt, in which case we don't want the rmapbt update. Signed-off-by:
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Darrick J. Wong authored
Add a couple of functions to the refcount btree and generic btree code that will be used to repair the refcountbt. Signed-off-by:
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Darrick J. Wong authored
Add a couple of functions to the reverse mapping btree that will be used to repair the rmapbt. Signed-off-by:
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Darrick J. Wong authored
Expose various helpers that the repair code will want to use. Signed-off-by:
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Darrick J. Wong authored
Add a bunch of helper functions that calculate the sizes of various btrees. These will be used to repair btrees and btree headers. Signed-off-by:
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Darrick J. Wong authored
Since the transaction allocation helper is about to become more complex, move it to common.c and remove the redundant parameters. Signed-off-by:
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Darrick J. Wong authored
Strengthen the btree block header checks to detect the number of records being less than the btree type's minimum record count. Certain blocks are allowed to violate this constraint -- specifically any btree block at the top of the tree can have fewer than minrecs records. Signed-off-by:
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Darrick J. Wong authored
All scrub code runs in transaction context, which means that memory allocations are automatically run in PF_MEMALLOC_NOFS context. It's therefore unnecessary to pass in KM_NOFS to allocation routines, so clean them all out. Signed-off-by:
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Darrick J. Wong authored
Refactor the quota scrubber to take the quotaofflock and grab the quota inode in the setup function so that we can treat quota in the same "scrub in the context of this inode" (i.e. sc->ip) manner as we treat any other inode. We do have to drop the quota inode's ILOCK_EXCL to use dqiterate, but since dquots have their own individual locks the ILOCK wasn't helping us anyway. Signed-off-by:
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Darrick J. Wong authored
Create a helper function to iterate all the dquots of a given type in the system, and refactor the dquot scrub to use it. This will get more use in the quota repair code. Signed-off-by:
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- 10 May, 2018 18 commits
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Darrick J. Wong authored
The function 'xfs_qm_dqiterate' doesn't iterate dquots at all, it iterates all dquot blocks of a quota inode and clears the counters. Therefore, change the name to something more descriptive so that we can introduce a real dquot iterator later. Signed-off-by:
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Darrick J. Wong authored
DQALLOC is only ever used with xfs_qm_dqget*, and the only flag that the _dqget family of functions cares about is DQALLOC. Therefore, change it to a boolean 'can alloc?' flag for the dqget interfaces where that makes sense. Signed-off-by:
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Darrick J. Wong authored
The quota initialization code needs an "uncached" variant of _dqget to read in default quota limits and timers before the dquot cache is fully set up. We've already split up _dqget into its component pieces so create a fourth variant to address this need, and make dqread internal to xfs_dquot.c again. Signed-off-by:
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Darrick J. Wong authored
Separate the disk dquot read and allocation functionality into two helper functions, then refactor dqread to call them directly. Signed-off-by:
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Darrick J. Wong authored
Create two incore dquot initialization functions that will help us to disentangle dqget and dqread. Signed-off-by:
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Darrick J. Wong authored
Quotacheck only runs during mount, which means that there are no other processes in the system that could be doing chown or chproj. Therefore there's no potential for racing to attach dquots to the inode so we can drop all the ILOCK and race detection bits from quotacheck. Signed-off-by:
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Darrick J. Wong authored
There are two uses of dqget here -- one is to return the dquot for a given type and id, and the other is to return the dquot for a given type and inode. Those are two separate things, so split them into two smaller functions. Signed-off-by:
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Darrick J. Wong authored
The flags argument is always zero, get rid of it. Signed-off-by:
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Darrick J. Wong authored
Move the dqget input checks to a separate function in preparation for splitting up the dqget functionality. Signed-off-by:
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Darrick J. Wong authored
Delegate the dquot cache handling (radix tree lookup and insertion) to separate helper functions so that we can continue to simplify the body of dqget. Signed-off-by:
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Darrick J. Wong authored
There's only one caller of DQNEXT and its semantics can be moved into a separate function, so create the function and get rid of the flag. Signed-off-by:
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Darrick J. Wong authored
When dquot flush or purge fail there's no need to spam the logs, we've already logged the IO error or fs shutdown that caused the flush failures. Signed-off-by:
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Darrick J. Wong authored
In commit efa092f3 "[XFS] Fixes a bug in the quota code when allocating a new dquot record", we allocate a new dquot block, grab a buffer to initialize it, and return the locked initialized dquot buffer to the caller for further in-core dquot initialization. Unfortunately, if the _bmap_finish errored out, _qm_dqalloc would also error out without bothering to free the (locked) buffer. Leaking a locked buffer caused hangs in generic/388 when quotas are enabled. Furthermore, the _bmap_finish -> _defer_finish conversion in 310a75a3 ("xfs: change xfs_bmap_{finish,cancel,init,free} -> xfs_defer_*") failed to observe that the buffer was held going into _defer_finish and therefore failed to notice that the buffer lock is /not/ maintained afterwards. Now that we can bjoin a buffer to a defer_ops, use this mechanism to ensure that the buffer stays locked across the _defer_finish. Release the holds and locks on the buffer as appropriate if we have to error out. There is a subtlety here for the caller in that the buffer emerges locked and held to the transaction, so if the _trans_commit fails we have to release the buffer explicitly. This fixes the unmount hang in generic/388 when quotas are enabled. Signed-off-by:
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Brian Foster authored
Unwritten extents by definition have not been written to until they are converted to normal written extents. If unwritten extents are freed from a file, it is therefore guaranteed that the blocks have not been written to since allocation (note that zero range punches and reallocates blocks). To cut down on online discards generated from workloads that make use of preallocation, skip discards of extents if they are in the unwritten state when the extent is freed. Note that this optimization does not apply to log recovery, during which all freed extents are discarded if online discard is enabled. Also note that it may be possible for a filesystem crash to occur after write completion of an unwritten extent but before unwritten conversion such that the extent remains unwritten after log recovery. Since this pseudo-inconsistency may already be possible after a crash (consider writing to recently allocated blocks where the allocation transaction is lost after a crash), this change shouldn't introduce any fundamental limitations that don't already exist. In short, on storage stacks where discards are important, it's good practice to run an occasional fstrim even with online discard enabled in the filesystem, particularly after a crash. Signed-off-by:
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Brian Foster authored
We've had reports of online discard operations being sent from XFS on write-only workloads. These discards occur as a result of eofblocks trims that can occur after a large file copy completes. These discards are slightly confusing for users who might be paying close attention to online discards (i.e., vdo) due to performance sensitivity. They also happen to be spurious because freed post-eof blocks by definition have not been written to during the current allocation cycle. Update xfs_free_eofblocks() to skip discards that are purely attributed to eofblocks trims. This cuts down the number of spurious discards that may occur on write-only workloads due to normal preallocation activity. Note that discards of post-eof extents can still occur from other codepaths that do not isolate handling of post-eof blocks from those within eof. For example, file unlinks and truncates may still cause discards for any file blocks affected by the operation. Signed-off-by:
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Brian Foster authored
Freed extents are unconditionally discarded when online discard is enabled. Define XFS_BMAPI_NODISCARD to allow callers to bypass discards when unnecessary. For example, this will be useful for eofblocks trimming. This patch does not change behavior. Signed-off-by:
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Dave Chinner authored
It's just a connector between a transaction and a log item. There's a 1:1 relationship between a log item descriptor and a log item, and a 1:1 relationship between a log item descriptor and a transaction. Both relationships are created and terminated at the same time, so why do we even have the descriptor? Replace it with a specific list_head in the log item and a new log item dirtied flag to replace the XFS_LID_DIRTY flag. Signed-Off-By:
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Dave Chinner authored
Just to make sure the item isn't associated with another transaction when we try to reuse it. Signed-Off-By:
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