- 27 8月, 2020 1 次提交
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由 Josef Bacik 提交于
With the conversion of the tree locks to rwsem I got the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Not tainted ------------------------------------------------------ compsize/11122 is trying to acquire lock: ffff889fabca8768 (&mm->mmap_lock#2){++++}-{3:3}, at: __might_fault+0x3e/0x90 but task is already holding lock: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (btrfs-fs-00){++++}-{3:3}: down_write_nested+0x3b/0x70 __btrfs_tree_lock+0x24/0x120 btrfs_search_slot+0x756/0x990 btrfs_lookup_inode+0x3a/0xb4 __btrfs_update_delayed_inode+0x93/0x270 btrfs_async_run_delayed_root+0x168/0x230 btrfs_work_helper+0xd4/0x570 process_one_work+0x2ad/0x5f0 worker_thread+0x3a/0x3d0 kthread+0x133/0x150 ret_from_fork+0x1f/0x30 -> #1 (&delayed_node->mutex){+.+.}-{3:3}: __mutex_lock+0x9f/0x930 btrfs_delayed_update_inode+0x50/0x440 btrfs_update_inode+0x8a/0xf0 btrfs_dirty_inode+0x5b/0xd0 touch_atime+0xa1/0xd0 btrfs_file_mmap+0x3f/0x60 mmap_region+0x3a4/0x640 do_mmap+0x376/0x580 vm_mmap_pgoff+0xd5/0x120 ksys_mmap_pgoff+0x193/0x230 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&mm->mmap_lock#2){++++}-{3:3}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 __might_fault+0x68/0x90 _copy_to_user+0x1e/0x80 copy_to_sk.isra.32+0x121/0x300 search_ioctl+0x106/0x200 btrfs_ioctl_tree_search_v2+0x7b/0xf0 btrfs_ioctl+0x106f/0x30a0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 other info that might help us debug this: Chain exists of: &mm->mmap_lock#2 --> &delayed_node->mutex --> btrfs-fs-00 Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-fs-00); lock(&delayed_node->mutex); lock(btrfs-fs-00); lock(&mm->mmap_lock#2); *** DEADLOCK *** 1 lock held by compsize/11122: #0: ffff889fe720fe40 (btrfs-fs-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 stack backtrace: CPU: 17 PID: 11122 Comm: compsize Kdump: loaded Not tainted 5.8.0-rc7-00165-g04ec4da5f45f-dirty #922 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? __might_fault+0x3e/0x90 ? find_held_lock+0x72/0x90 __might_fault+0x68/0x90 ? __might_fault+0x3e/0x90 _copy_to_user+0x1e/0x80 copy_to_sk.isra.32+0x121/0x300 ? btrfs_search_forward+0x2a6/0x360 search_ioctl+0x106/0x200 btrfs_ioctl_tree_search_v2+0x7b/0xf0 btrfs_ioctl+0x106f/0x30a0 ? __do_sys_newfstat+0x5a/0x70 ? ksys_ioctl+0x83/0xc0 ksys_ioctl+0x83/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x50/0x90 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The problem is we're doing a copy_to_user() while holding tree locks, which can deadlock if we have to do a page fault for the copy_to_user(). This exists even without my locking changes, so it needs to be fixed. Rework the search ioctl to do the pre-fault and then copy_to_user_nofault for the copying. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NJosef Bacik <josef@toxicpanda.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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- 27 7月, 2020 12 次提交
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由 Filipe Manana 提交于
When removing an extent map at try_release_extent_mapping(), called through the page release callback (btrfs_releasepage()), we always set the full sync flag on the inode, which forces the next fsync to use a slower code path. This hurts performance for workloads that dirty an amount of data that exceeds or is very close to the system's RAM memory and do frequent fsync operations (like database servers can for example). In particular if there are concurrent fsyncs against different files, by falling back to a full fsync we do a lot more checksum lookups in the checksums btree, as we do it for all the extents created in the current transaction, instead of only the new ones since the last fsync. These checksums lookups not only take some time but, more importantly, they also cause contention on the checksums btree locks due to the concurrency with checksum insertions in the btree by ordered extents from other inodes. We actually don't need to set the full sync flag on the inode, because we only remove extent maps that are in the list of modified extents if they were created in a past transaction, in which case an fsync skips them as it's pointless to log them. So stop setting the full fsync flag on the inode whenever we remove an extent map. This patch is part of a patchset that consists of 3 patches, which have the following subjects: 1/3 btrfs: fix race between page release and a fast fsync 2/3 btrfs: release old extent maps during page release 3/3 btrfs: do not set the full sync flag on the inode during page release Performance tests were ran against a branch (misc-next) containing the whole patchset. The test exercises a workload where there are multiple processes writing to files and fsyncing them (each writing and fsyncing its own file), and in total the amount of data dirtied ranges from 2x to 4x the system's RAM memory (16GiB), so that the page release callback is invoked frequently. The following script, using fio, was used to perform the tests: $ cat test-fsync.sh #!/bin/bash DEV=/dev/sdk MNT=/mnt/sdk MOUNT_OPTIONS="-o ssd" MKFS_OPTIONS="-d single -m single" if [ $# -ne 3 ]; then echo "Use $0 NUM_JOBS FILE_SIZE FSYNC_FREQ" exit 1 fi NUM_JOBS=$1 FILE_SIZE=$2 FSYNC_FREQ=$3 cat <<EOF > /tmp/fio-job.ini [writers] rw=write fsync=$FSYNC_FREQ fallocate=none group_reporting=1 direct=0 bs=64k ioengine=sync size=$FILE_SIZE directory=$MNT numjobs=$NUM_JOBS thread EOF echo "Using config:" echo cat /tmp/fio-job.ini echo mkfs.btrfs -f $MKFS_OPTIONS $DEV &> /dev/null mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The tests were performed for different numbers of jobs, file sizes and fsync frequency. A qemu VM using kvm was used, with 8 cores (the host has 12 cores, with cpu governance set to performance mode on all cores), 16GiB of ram (the host has 64GiB) and using a NVMe device directly (without an intermediary filesystem in the host). While running the tests, the host was not used for anything else, to avoid disturbing the tests. The obtained results were the following, and the last line printed by fio is pasted (includes aggregated throughput and test run time). ***************************************************** **** 1 job, 32GiB file, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=29.1MiB/s (30.5MB/s), 29.1MiB/s-29.1MiB/s (30.5MB/s-30.5MB/s), io=32.0GiB (34.4GB), run=1127557-1127557msec After patchset: WRITE: bw=29.3MiB/s (30.7MB/s), 29.3MiB/s-29.3MiB/s (30.7MB/s-30.7MB/s), io=32.0GiB (34.4GB), run=1119042-1119042msec (+0.7% throughput, -0.8% run time) ***************************************************** **** 2 jobs, 16GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=33.5MiB/s (35.1MB/s), 33.5MiB/s-33.5MiB/s (35.1MB/s-35.1MB/s), io=32.0GiB (34.4GB), run=979000-979000msec After patchset: WRITE: bw=39.9MiB/s (41.8MB/s), 39.9MiB/s-39.9MiB/s (41.8MB/s-41.8MB/s), io=32.0GiB (34.4GB), run=821283-821283msec (+19.1% throughput, -16.1% runtime) ***************************************************** **** 4 jobs, 8GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=52.1MiB/s (54.6MB/s), 52.1MiB/s-52.1MiB/s (54.6MB/s-54.6MB/s), io=32.0GiB (34.4GB), run=629130-629130msec After patchset: WRITE: bw=71.8MiB/s (75.3MB/s), 71.8MiB/s-71.8MiB/s (75.3MB/s-75.3MB/s), io=32.0GiB (34.4GB), run=456357-456357msec (+37.8% throughput, -27.5% runtime) ***************************************************** **** 8 jobs, 4GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=76.1MiB/s (79.8MB/s), 76.1MiB/s-76.1MiB/s (79.8MB/s-79.8MB/s), io=32.0GiB (34.4GB), run=430708-430708msec After patchset: WRITE: bw=133MiB/s (140MB/s), 133MiB/s-133MiB/s (140MB/s-140MB/s), io=32.0GiB (34.4GB), run=245458-245458msec (+74.7% throughput, -43.0% run time) ***************************************************** **** 16 jobs, 2GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=74.7MiB/s (78.3MB/s), 74.7MiB/s-74.7MiB/s (78.3MB/s-78.3MB/s), io=32.0GiB (34.4GB), run=438625-438625msec After patchset: WRITE: bw=184MiB/s (193MB/s), 184MiB/s-184MiB/s (193MB/s-193MB/s), io=32.0GiB (34.4GB), run=177864-177864msec (+146.3% throughput, -59.5% run time) ***************************************************** **** 32 jobs, 2GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=72.6MiB/s (76.1MB/s), 72.6MiB/s-72.6MiB/s (76.1MB/s-76.1MB/s), io=64.0GiB (68.7GB), run=902615-902615msec After patchset: WRITE: bw=227MiB/s (238MB/s), 227MiB/s-227MiB/s (238MB/s-238MB/s), io=64.0GiB (68.7GB), run=288936-288936msec (+212.7% throughput, -68.0% run time) ***************************************************** **** 64 jobs, 1GiB files, fsync frequency 1 **** ***************************************************** Before patchset: WRITE: bw=98.8MiB/s (104MB/s), 98.8MiB/s-98.8MiB/s (104MB/s-104MB/s), io=64.0GiB (68.7GB), run=663126-663126msec After patchset: WRITE: bw=294MiB/s (308MB/s), 294MiB/s-294MiB/s (308MB/s-308MB/s), io=64.0GiB (68.7GB), run=222940-222940msec (+197.6% throughput, -66.4% run time) Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Filipe Manana 提交于
When removing an extent map at try_release_extent_mapping(), called through the page release callback (btrfs_releasepage()), we never release an extent map that is in the list of modified extents. This is to prevent races with a concurrent fsync using the fast path, which could lead to not logging an extent created in the current transaction. However we can safely remove an extent map created in a past transaction that is still in the list of modified extents (because no one fsynced yet the inode after that transaction got commited), because such extents are skipped during an fsync as it is pointless to log them. This change does that. Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Filipe Manana 提交于
When releasing an extent map, done through the page release callback, we can race with an ongoing fast fsync and cause the fsync to miss a new extent and not log it. The steps for this to happen are the following: 1) A page is dirtied for some inode I; 2) Writeback for that page is triggered by a path other than fsync, for example by the system due to memory pressure; 3) When the ordered extent for the extent (a single 4K page) finishes, we unpin the corresponding extent map and set its generation to N, the current transaction's generation; 4) The btrfs_releasepage() callback is invoked by the system due to memory pressure for that no longer dirty page of inode I; 5) At the same time, some task calls fsync on inode I, joins transaction N, and at btrfs_log_inode() it sees that the inode does not have the full sync flag set, so we proceed with a fast fsync. But before we get into btrfs_log_changed_extents() and lock the inode's extent map tree: 6) Through btrfs_releasepage() we end up at try_release_extent_mapping() and we remove the extent map for the new 4Kb extent, because it is neither pinned anymore nor locked. By calling remove_extent_mapping(), we remove the extent map from the list of modified extents, since the extent map does not have the logging flag set. We unlock the inode's extent map tree; 7) The task doing the fast fsync now enters btrfs_log_changed_extents(), locks the inode's extent map tree and iterates its list of modified extents, which no longer has the 4Kb extent in it, so it does not log the extent; 8) The fsync finishes; 9) Before transaction N is committed, a power failure happens. After replaying the log, the 4K extent of inode I will be missing, since it was not logged due to the race with try_release_extent_mapping(). So fix this by teaching try_release_extent_mapping() to not remove an extent map if it's still in the list of modified extents. Fixes: ff44c6e3 ("Btrfs: do not hold the write_lock on the extent tree while logging") CC: stable@vger.kernel.org # 5.4+ Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Josef Bacik 提交于
Eric reported seeing this message while running generic/475 BTRFS: error (device dm-3) in btrfs_sync_log:3084: errno=-117 Filesystem corrupted Full stack trace: BTRFS: error (device dm-0) in btrfs_commit_transaction:2323: errno=-5 IO failure (Error while writing out transaction) BTRFS info (device dm-0): forced readonly BTRFS warning (device dm-0): Skipping commit of aborted transaction. ------------[ cut here ]------------ BTRFS: error (device dm-0) in cleanup_transaction:1894: errno=-5 IO failure BTRFS: Transaction aborted (error -117) BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6480 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6488 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6490 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c6498 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64a0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64a8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64b0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64b8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3555 rw 0,0 sector 0x1c64c0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3572 rw 0,0 sector 0x1b85e8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3572 rw 0,0 sector 0x1b85f0 len 4096 err no 10 WARNING: CPU: 3 PID: 23985 at fs/btrfs/tree-log.c:3084 btrfs_sync_log+0xbc8/0xd60 [btrfs] BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4288 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4290 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d4298 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42a0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42a8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42b0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42b8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42c0 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42c8 len 4096 err no 10 BTRFS warning (device dm-0): direct IO failed ino 3548 rw 0,0 sector 0x1d42d0 len 4096 err no 10 CPU: 3 PID: 23985 Comm: fsstress Tainted: G W L 5.8.0-rc4-default+ #1181 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.0-59-gc9ba527-rebuilt.opensuse.org 04/01/2014 RIP: 0010:btrfs_sync_log+0xbc8/0xd60 [btrfs] RSP: 0018:ffff909a44d17bd0 EFLAGS: 00010286 RAX: 0000000000000000 RBX: 0000000000000001 RCX: 0000000000000001 RDX: ffff8f3be41cb940 RSI: ffffffffb0108d2b RDI: ffffffffb0108ff7 RBP: ffff909a44d17e70 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000037988 R12: ffff8f3bd20e4000 R13: ffff8f3bd20e4428 R14: 00000000ffffff8b R15: ffff909a44d17c70 FS: 00007f6a6ed3fb80(0000) GS:ffff8f3c3dc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f6a6ed3e000 CR3: 00000000525c0003 CR4: 0000000000160ee0 Call Trace: ? finish_wait+0x90/0x90 ? __mutex_unlock_slowpath+0x45/0x2a0 ? lock_acquire+0xa3/0x440 ? lockref_put_or_lock+0x9/0x30 ? dput+0x20/0x4a0 ? dput+0x20/0x4a0 ? do_raw_spin_unlock+0x4b/0xc0 ? _raw_spin_unlock+0x1f/0x30 btrfs_sync_file+0x335/0x490 [btrfs] do_fsync+0x38/0x70 __x64_sys_fsync+0x10/0x20 do_syscall_64+0x50/0xe0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x7f6a6ef1b6e3 Code: Bad RIP value. RSP: 002b:00007ffd01e20038 EFLAGS: 00000246 ORIG_RAX: 000000000000004a RAX: ffffffffffffffda RBX: 000000000007a120 RCX: 00007f6a6ef1b6e3 RDX: 00007ffd01e1ffa0 RSI: 00007ffd01e1ffa0 RDI: 0000000000000003 RBP: 0000000000000003 R08: 0000000000000001 R09: 00007ffd01e2004c R10: 0000000000000000 R11: 0000000000000246 R12: 000000000000009f R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 irq event stamp: 0 hardirqs last enabled at (0): [<0000000000000000>] 0x0 hardirqs last disabled at (0): [<ffffffffb007fe0b>] copy_process+0x67b/0x1b00 softirqs last enabled at (0): [<ffffffffb007fe0b>] copy_process+0x67b/0x1b00 softirqs last disabled at (0): [<0000000000000000>] 0x0 ---[ end trace af146e0e38433456 ]--- BTRFS: error (device dm-0) in btrfs_sync_log:3084: errno=-117 Filesystem corrupted This ret came from btrfs_write_marked_extents(). If we get an aborted transaction via EIO before, we'll see it in btree_write_cache_pages() and return EUCLEAN, which gets printed as "Filesystem corrupted". Except we shouldn't be returning EUCLEAN here, we need to be returning EROFS because EUCLEAN is reserved for actual corruption, not IO errors. We are inconsistent about our handling of BTRFS_FS_STATE_ERROR elsewhere, but we want to use EROFS for this particular case. The original transaction abort has the real error code for why we ended up with an aborted transaction, all subsequent actions just need to return EROFS because they may not have a trans handle and have no idea about the original cause of the abort. After patch "btrfs: don't WARN if we abort a transaction with EROFS" the stacktrace will not be dumped either. Reported-by: NEric Sandeen <esandeen@redhat.com> CC: stable@vger.kernel.org # 5.4+ Signed-off-by: NJosef Bacik <josef@toxicpanda.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> [ add full test stacktrace ] Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
Since there is not common cleanup run after the label it makes it somewhat redundant. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
Make the function directly return a pointer to a failure record and adjust callers to handle it. Also refactor the logic inside so that the case which allocates the failure record for the first time is not handled in an 'if' arm, saving us a level of indentation. Finally make the function static as it's not used outside of extent_io.c . Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
Only failure that get_state_failrec can get is if there is no failure for the given address. There is no reason why the function should return a status code and use a separate parameter for returning the actual failure rec (if one is found). Simplify it by making the return type a pointer and return ERR_PTR value in case of errors. Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
Only find_lock_delalloc_range uses vfs_inode so let's take the btrfs_inode as a parameter. Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
It has only a single use for a generic vfs inode vs 3 for btrfs_inode. Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
All children now take btrfs_inode so convert it to taking it as a parameter as well. Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
The fiemap callback is not part of UAPI interface and the prototypes don't have the __u64 types either. Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Nikolay Borisov 提交于
It has one VFS and 1 btrfs inode usages but converting it to btrfs_inode interface will allow seamless conversion of its callers. Signed-off-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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- 22 7月, 2020 1 次提交
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由 Robbie Ko 提交于
When locking pages for delalloc, we check if it's dirty and mapping still matches. If it does not match, we need to return -EAGAIN and release all pages. Only the current page was put though, iterate over all the remaining pages too. CC: stable@vger.kernel.org # 4.14+ Reviewed-by: NFilipe Manana <fdmanana@suse.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NRobbie Ko <robbieko@synology.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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- 02 7月, 2020 1 次提交
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由 Boris Burkov 提交于
Under somewhat convoluted conditions, it is possible to attempt to release an extent_buffer that is under io, which triggers a BUG_ON in btrfs_release_extent_buffer_pages. This relies on a few different factors. First, extent_buffer reads done as readahead for searching use WAIT_NONE, so they free the local extent buffer reference while the io is outstanding. However, they should still be protected by TREE_REF. However, if the system is doing signficant reclaim, and simultaneously heavily accessing the extent_buffers, it is possible for releasepage to race with two concurrent readahead attempts in a way that leaves TREE_REF unset when the readahead extent buffer is released. Essentially, if two tasks race to allocate a new extent_buffer, but the winner who attempts the first io is rebuffed by a page being locked (likely by the reclaim itself) then the loser will still go ahead with issuing the readahead. The loser's call to find_extent_buffer must also race with the reclaim task reading the extent_buffer's refcount as 1 in a way that allows the reclaim to re-clear the TREE_REF checked by find_extent_buffer. The following represents an example execution demonstrating the race: CPU0 CPU1 CPU2 reada_for_search reada_for_search readahead_tree_block readahead_tree_block find_create_tree_block find_create_tree_block alloc_extent_buffer alloc_extent_buffer find_extent_buffer // not found allocates eb lock pages associate pages to eb insert eb into radix tree set TREE_REF, refs == 2 unlock pages read_extent_buffer_pages // WAIT_NONE not uptodate (brand new eb) lock_page if !trylock_page goto unlock_exit // not an error free_extent_buffer release_extent_buffer atomic_dec_and_test refs to 1 find_extent_buffer // found try_release_extent_buffer take refs_lock reads refs == 1; no io atomic_inc_not_zero refs to 2 mark_buffer_accessed check_buffer_tree_ref // not STALE, won't take refs_lock refs == 2; TREE_REF set // no action read_extent_buffer_pages // WAIT_NONE clear TREE_REF release_extent_buffer atomic_dec_and_test refs to 1 unlock_page still not uptodate (CPU1 read failed on trylock_page) locks pages set io_pages > 0 submit io return free_extent_buffer release_extent_buffer dec refs to 0 delete from radix tree btrfs_release_extent_buffer_pages BUG_ON(io_pages > 0)!!! We observe this at a very low rate in production and were also able to reproduce it in a test environment by introducing some spurious delays and by introducing probabilistic trylock_page failures. To fix it, we apply check_tree_ref at a point where it could not possibly be unset by a competing task: after io_pages has been incremented. All the codepaths that clear TREE_REF check for io, so they would not be able to clear it after this point until the io is done. Stack trace, for reference: [1417839.424739] ------------[ cut here ]------------ [1417839.435328] kernel BUG at fs/btrfs/extent_io.c:4841! [1417839.447024] invalid opcode: 0000 [#1] SMP [1417839.502972] RIP: 0010:btrfs_release_extent_buffer_pages+0x20/0x1f0 [1417839.517008] Code: ed e9 ... [1417839.558895] RSP: 0018:ffffc90020bcf798 EFLAGS: 00010202 [1417839.570816] RAX: 0000000000000002 RBX: ffff888102d6def0 RCX: 0000000000000028 [1417839.586962] RDX: 0000000000000002 RSI: ffff8887f0296482 RDI: ffff888102d6def0 [1417839.603108] RBP: ffff88885664a000 R08: 0000000000000046 R09: 0000000000000238 [1417839.619255] R10: 0000000000000028 R11: ffff88885664af68 R12: 0000000000000000 [1417839.635402] R13: 0000000000000000 R14: ffff88875f573ad0 R15: ffff888797aafd90 [1417839.651549] FS: 00007f5a844fa700(0000) GS:ffff88885f680000(0000) knlGS:0000000000000000 [1417839.669810] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [1417839.682887] CR2: 00007f7884541fe0 CR3: 000000049f609002 CR4: 00000000003606e0 [1417839.699037] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [1417839.715187] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [1417839.731320] Call Trace: [1417839.737103] release_extent_buffer+0x39/0x90 [1417839.746913] read_block_for_search.isra.38+0x2a3/0x370 [1417839.758645] btrfs_search_slot+0x260/0x9b0 [1417839.768054] btrfs_lookup_file_extent+0x4a/0x70 [1417839.778427] btrfs_get_extent+0x15f/0x830 [1417839.787665] ? submit_extent_page+0xc4/0x1c0 [1417839.797474] ? __do_readpage+0x299/0x7a0 [1417839.806515] __do_readpage+0x33b/0x7a0 [1417839.815171] ? btrfs_releasepage+0x70/0x70 [1417839.824597] extent_readpages+0x28f/0x400 [1417839.833836] read_pages+0x6a/0x1c0 [1417839.841729] ? startup_64+0x2/0x30 [1417839.849624] __do_page_cache_readahead+0x13c/0x1a0 [1417839.860590] filemap_fault+0x6c7/0x990 [1417839.869252] ? xas_load+0x8/0x80 [1417839.876756] ? xas_find+0x150/0x190 [1417839.884839] ? filemap_map_pages+0x295/0x3b0 [1417839.894652] __do_fault+0x32/0x110 [1417839.902540] __handle_mm_fault+0xacd/0x1000 [1417839.912156] handle_mm_fault+0xaa/0x1c0 [1417839.921004] __do_page_fault+0x242/0x4b0 [1417839.930044] ? page_fault+0x8/0x30 [1417839.937933] page_fault+0x1e/0x30 [1417839.945631] RIP: 0033:0x33c4bae [1417839.952927] Code: Bad RIP value. [1417839.960411] RSP: 002b:00007f5a844f7350 EFLAGS: 00010206 [1417839.972331] RAX: 000000000000006e RBX: 1614b3ff6a50398a RCX: 0000000000000000 [1417839.988477] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000002 [1417840.004626] RBP: 00007f5a844f7420 R08: 000000000000006e R09: 00007f5a94aeccb8 [1417840.020784] R10: 00007f5a844f7350 R11: 0000000000000000 R12: 00007f5a94aecc79 [1417840.036932] R13: 00007f5a94aecc78 R14: 00007f5a94aecc90 R15: 00007f5a94aecc40 CC: stable@vger.kernel.org # 4.4+ Reviewed-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NBoris Burkov <boris@bur.io> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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- 30 6月, 2020 1 次提交
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由 Paul E. McKenney 提交于
Very large I/Os can cause the following RCU CPU stall warning: RIP: 0010:rb_prev+0x8/0x50 Code: 49 89 c0 49 89 d1 48 89 c2 48 89 f8 e9 e5 fd ff ff 4c 89 48 10 c3 4c = 89 06 c3 4c 89 40 10 c3 0f 1f 00 48 8b 0f 48 39 cf 74 38 <48> 8b 47 10 48 85 c0 74 22 48 8b 50 08 48 85 d2 74 0c 48 89 d0 48 RSP: 0018:ffffc9002212bab0 EFLAGS: 00000287 ORIG_RAX: ffffffffffffff13 RAX: ffff888821f93630 RBX: ffff888821f93630 RCX: ffff888821f937e0 RDX: 0000000000000000 RSI: 0000000000102000 RDI: ffff888821f93630 RBP: 0000000000103000 R08: 000000000006c000 R09: 0000000000000238 R10: 0000000000102fff R11: ffffc9002212bac8 R12: 0000000000000001 R13: ffffffffffffffff R14: 0000000000102000 R15: ffff888821f937e0 __lookup_extent_mapping+0xa0/0x110 try_release_extent_mapping+0xdc/0x220 btrfs_releasepage+0x45/0x70 shrink_page_list+0xa39/0xb30 shrink_inactive_list+0x18f/0x3b0 shrink_lruvec+0x38e/0x6b0 shrink_node+0x14d/0x690 do_try_to_free_pages+0xc6/0x3e0 try_to_free_mem_cgroup_pages+0xe6/0x1e0 reclaim_high.constprop.73+0x87/0xc0 mem_cgroup_handle_over_high+0x66/0x150 exit_to_usermode_loop+0x82/0xd0 do_syscall_64+0xd4/0x100 entry_SYSCALL_64_after_hwframe+0x44/0xa9 On a PREEMPT=n kernel, the try_release_extent_mapping() function's "while" loop might run for a very long time on a large I/O. This commit therefore adds a cond_resched() to this loop, providing RCU any needed quiescent states. Signed-off-by: NPaul E. McKenney <paulmck@kernel.org>
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- 03 6月, 2020 2 次提交
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由 Guoqing Jiang 提交于
Since the new pair function is introduced, we can call them to clean the code in btrfs. Signed-off-by: NGuoqing Jiang <guoqing.jiang@cloud.ionos.com> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NAndrew Morton <akpm@linux-foundation.org> Acked-by: NDavid Sterba <dsterba@suse.com> Cc: Chris Mason <clm@fb.com> Cc: Josef Bacik <josef@toxicpanda.com> Link: http://lkml.kernel.org/r/20200517214718.468-4-guoqing.jiang@cloud.ionos.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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由 Matthew Wilcox (Oracle) 提交于
Implement the new readahead method in btrfs using the new readahead_page_batch() function. Signed-off-by: NMatthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: NAndrew Morton <akpm@linux-foundation.org> Reviewed-by: NWilliam Kucharski <william.kucharski@oracle.com> Cc: Chao Yu <yuchao0@huawei.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Cong Wang <xiyou.wangcong@gmail.com> Cc: Darrick J. Wong <darrick.wong@oracle.com> Cc: Dave Chinner <dchinner@redhat.com> Cc: Eric Biggers <ebiggers@google.com> Cc: Gao Xiang <gaoxiang25@huawei.com> Cc: Jaegeuk Kim <jaegeuk@kernel.org> Cc: John Hubbard <jhubbard@nvidia.com> Cc: Joseph Qi <joseph.qi@linux.alibaba.com> Cc: Junxiao Bi <junxiao.bi@oracle.com> Cc: Michal Hocko <mhocko@suse.com> Cc: Zi Yan <ziy@nvidia.com> Cc: Johannes Thumshirn <johannes.thumshirn@wdc.com> Cc: Miklos Szeredi <mszeredi@redhat.com> Link: http://lkml.kernel.org/r/20200414150233.24495-18-willy@infradead.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
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- 25 5月, 2020 8 次提交
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由 David Sterba 提交于
Helpers that iterate over extent buffer pages set up several variables, one of them is finding out offset of the extent buffer start within a page. Right now we have extent buffers aligned to page sizes so this is effectively storing zero. This makes the code harder the follow and can be simplified. The same change is done in all the helpers: * remove: size_t start_offset = offset_in_page(eb->start); * simplify code using start_offset Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
There are many helpers around extent buffers, found in extent_io.h and ctree.h. Most of them can be converted to take constified eb as there are no changes to the extent buffer structure itself but rather the pages. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
All uses of map_private_extent_buffer have been replaced by more effective way. The set/get helpers have their own bounds checker. The function name was confusing since the non-private helper was removed in a6591715 ("Btrfs: stop using highmem for extent_buffers") many years ago. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Omar Sandoval 提交于
Currently, direct I/O has its own versions of bio_readpage_error() and btrfs_check_repairable() (dio_read_error() and btrfs_check_dio_repairable(), respectively). The main difference is that the direct I/O version doesn't do read validation. The rework of direct I/O repair makes it possible to do validation, so we can get rid of btrfs_check_dio_repairable() and combine bio_readpage_error() and dio_read_error() into a new helper, btrfs_submit_read_repair(). Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Omar Sandoval 提交于
Direct I/O read repair was originally implemented in commit 8b110e39 ("Btrfs: implement repair function when direct read fails"). This implementation is unnecessarily complicated. There is major code duplication between __btrfs_subio_endio_read() (checks checksums and handles I/O errors for files with checksums), __btrfs_correct_data_nocsum() (handles I/O errors for files without checksums), btrfs_retry_endio() (checks checksums and handles I/O errors for retries of files with checksums), and btrfs_retry_endio_nocsum() (handles I/O errors for retries of files without checksum). If it sounds like these should be one function, that's because they should. Additionally, these functions are very hard to follow due to their excessive use of goto. This commit replaces the original implementation. After the previous commit getting rid of orig_bio, we can reuse the same endio callback for repair I/O and the original I/O, we just need to track the file offset and original iterator in the repair bio. We can also unify the handling of files with and without checksums and simplify the control flow. We also no longer have to wait for each repair I/O to complete one by one. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Omar Sandoval 提交于
Since its introduction in commit 2fe6303e ("Btrfs: split bio_readpage_error into several functions"), btrfs_check_repairable() has only been used from extent_io.c where it is defined. Reviewed-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Omar Sandoval 提交于
The purpose of the validation step is to distinguish between good and bad sectors in a failed multi-sector read. If a multi-sector read succeeded but some of those sectors had checksum errors, we don't need to validate anything; we know the sectors with bad checksums need to be repaired. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Omar Sandoval 提交于
Read repair does two things: it finds a good copy of data to return to the reader, and it corrects the bad copy on disk. If a read of multiple sectors has an I/O error, repair does an extra "validation" step that issues a separate read for each sector. This allows us to find the exact failing sectors and only rewrite those. This heuristic is implemented in bio_readpage_error()/btrfs_check_repairable() as: failed_bio_pages = failed_bio->bi_iter.bi_size >> PAGE_SHIFT; if (failed_bio_pages > 1) do validation However, at this point, bi_iter may have already been advanced. This means that we'll skip the validation step and rewrite the entire failed read. Fix it by getting the actual size from the biovec (which we can do because this is only called for non-cloned bios, although that will change in a later commit). Fixes: 8a2ee44a ("btrfs: look at bi_size for repair decisions") Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: NOmar Sandoval <osandov@fb.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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- 24 3月, 2020 14 次提交
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由 Josef Bacik 提交于
There are a few different ways to free roots, either you allocated them yourself and you just do free_extent_buffer(root->node); free_extent_buffer(root->commit_node); btrfs_put_root(root); Which is the pattern for log roots. Or for snapshots/subvolumes that are being dropped you simply call btrfs_free_fs_root() which does all the cleanup for you. Unify this all into btrfs_put_root(), so that we don't free up things associated with the root until the last reference is dropped. This makes the root freeing code much more significant. The only caveat is at close_ctree() time we have to free the extent buffers for all of our main roots (extent_root, chunk_root, etc) because we have to drop the btree_inode and we'll run into issues if we hold onto those nodes until ->kill_sb() time. This will be addressed in the future when we kill the btree_inode. Signed-off-by: NJosef Bacik <josef@toxicpanda.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Josef Bacik 提交于
I'm going to make the entire destruction of btrfs_root's controlled by their refcount, so it will be helpful to notice if we're leaking their eb's on umount. Signed-off-by: NJosef Bacik <josef@toxicpanda.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Qu Wenruo 提交于
[BUG] There is a fuzzed image which could cause KASAN report at unmount time. BUG: KASAN: use-after-free in btrfs_queue_work+0x2c1/0x390 Read of size 8 at addr ffff888067cf6848 by task umount/1922 CPU: 0 PID: 1922 Comm: umount Tainted: G W 5.0.21 #1 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014 Call Trace: dump_stack+0x5b/0x8b print_address_description+0x70/0x280 kasan_report+0x13a/0x19b btrfs_queue_work+0x2c1/0x390 btrfs_wq_submit_bio+0x1cd/0x240 btree_submit_bio_hook+0x18c/0x2a0 submit_one_bio+0x1be/0x320 flush_write_bio.isra.41+0x2c/0x70 btree_write_cache_pages+0x3bb/0x7f0 do_writepages+0x5c/0x130 __writeback_single_inode+0xa3/0x9a0 writeback_single_inode+0x23d/0x390 write_inode_now+0x1b5/0x280 iput+0x2ef/0x600 close_ctree+0x341/0x750 generic_shutdown_super+0x126/0x370 kill_anon_super+0x31/0x50 btrfs_kill_super+0x36/0x2b0 deactivate_locked_super+0x80/0xc0 deactivate_super+0x13c/0x150 cleanup_mnt+0x9a/0x130 task_work_run+0x11a/0x1b0 exit_to_usermode_loop+0x107/0x130 do_syscall_64+0x1e5/0x280 entry_SYSCALL_64_after_hwframe+0x44/0xa9 [CAUSE] The fuzzed image has a completely screwd up extent tree: leaf 29421568 gen 8 total ptrs 6 free space 3587 owner EXTENT_TREE refs 2 lock (w:0 r:0 bw:0 br:0 sw:0 sr:0) lock_owner 0 current 5938 item 0 key (12587008 168 4096) itemoff 3942 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 259 offset 0 count 1 item 1 key (12591104 168 8192) itemoff 3889 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 271 offset 0 count 1 item 2 key (12599296 168 4096) itemoff 3836 itemsize 53 extent refs 1 gen 9 flags 1 ref#0: extent data backref root 5 objectid 259 offset 4096 count 1 item 3 key (29360128 169 0) itemoff 3803 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 item 4 key (29368320 169 1) itemoff 3770 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 item 5 key (29372416 169 0) itemoff 3737 itemsize 33 extent refs 1 gen 9 flags 2 ref#0: tree block backref root 5 Note that leaf 29421568 doesn't have its backref in the extent tree. Thus extent allocator can re-allocate leaf 29421568 for other trees. In short, the bug is caused by: - Existing tree block gets allocated to log tree This got its generation bumped. - Log tree balance cleaned dirty bit of offending tree block It will not be written back to disk, thus no WRITTEN flag. - Original owner of the tree block gets COWed Since the tree block has higher transid, no WRITTEN flag, it's reused, and not traced by transaction::dirty_pages. - Transaction aborted Tree blocks get cleaned according to transaction::dirty_pages. But the offending tree block is not recorded at all. - Filesystem unmount All pages are assumed to be are clean, destroying all workqueue, then call iput(btree_inode). But offending tree block is still dirty, which triggers writeback, and causes use-after-free bug. The detailed sequence looks like this: - Initial status eb: 29421568, header=WRITTEN bflags_dirty=0, page_dirty=0, gen=8, not traced by any dirty extent_iot_tree. - New tree block is allocated Since there is no backref for 29421568, it's re-allocated as new tree block. Keep in mind that tree block 29421568 is still referred by extent tree. - Tree block 29421568 is filled for log tree eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 << (gen bumped) traced by btrfs_root::dirty_log_pages - Some log tree operations Since the fs is using node size 4096, the log tree can easily go a level higher. - Log tree needs balance Tree block 29421568 gets all its content pushed to right, thus now it is empty, and we don't need it. btrfs_clean_tree_block() from __push_leaf_right() get called. eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9 traced by btrfs_root::dirty_log_pages - Log tree write back btree_write_cache_pages() goes through dirty pages ranges, but since page of tree block 29421568 gets cleaned already, it's not written back to disk. Thus it doesn't have WRITTEN bit set. But ranges in dirty_log_pages are cleared. eb: 29421568, header=0 bflags_dirty=0, page_dirty=0, gen=9 not traced by any dirty extent_iot_tree. - Extent tree update when committing transaction Since tree block 29421568 has transid equal to running trans, and has no WRITTEN bit, should_cow_block() will use it directly without adding it to btrfs_transaction::dirty_pages. eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 not traced by any dirty extent_iot_tree. At this stage, we're doomed. We have a dirty eb not tracked by any extent io tree. - Transaction gets aborted due to corrupted extent tree Btrfs cleans up dirty pages according to transaction::dirty_pages and btrfs_root::dirty_log_pages. But since tree block 29421568 is not tracked by neither of them, it's still dirty. eb: 29421568, header=0 bflags_dirty=1, page_dirty=1, gen=9 not traced by any dirty extent_iot_tree. - Filesystem unmount Since all cleanup is assumed to be done, all workqueus are destroyed. Then iput(btree_inode) is called, expecting no dirty pages. But tree 29421568 is still dirty, thus triggering writeback. Since all workqueues are already freed, we cause use-after-free. This shows us that, log tree blocks + bad extent tree can cause wild dirty pages. [FIX] To fix the problem, don't submit any btree write bio if the filesytem has any error. This is the last safe net, just in case other cleanup haven't caught catch it. Link: https://github.com/bobfuzzer/CVE/tree/master/CVE-2019-19377 CC: stable@vger.kernel.org # 5.4+ Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NQu Wenruo <wqu@suse.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 Jules Irenge 提交于
Sparse reports a warning at release_extent_buffer() warning: context imbalance in release_extent_buffer() - unexpected unlock The root cause is the missing annotation at release_extent_buffer() Add the missing __releases(&eb->refs_lock) annotation Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NJules Irenge <jbi.octave@gmail.com> Reviewed-by: NDavid Sterba <dsterba@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Filipe Manana 提交于
When attempting to set bits on a range of an exent io tree that already has those bits set we can end up splitting an extent state record, use the preallocated extent state record, insert it into the red black tree, do another search on the red black tree, merge the preallocated extent state record with the previous extent state record, remove that previous record from the red black tree and then free it. This is all unnecessary work that consumes time. This happens specifically at the following case at __set_extent_bit(): $ cat -n fs/btrfs/extent_io.c 957 static int __must_check 958 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, (...) 1044 /* 1045 * | ---- desired range ---- | 1046 * | state | 1047 * or 1048 * | ------------- state -------------- | 1049 * (...) 1060 if (state->start < start) { 1061 if (state->state & exclusive_bits) { 1062 *failed_start = start; 1063 err = -EEXIST; 1064 goto out; 1065 } 1066 1067 prealloc = alloc_extent_state_atomic(prealloc); 1068 BUG_ON(!prealloc); 1069 err = split_state(tree, state, prealloc, start); 1070 if (err) 1071 extent_io_tree_panic(tree, err); 1072 1073 prealloc = NULL; So if our extent state represents a range from 0 to 1MiB for example, and we want to set bits in the range 128KiB to 256KiB for example, and that extent state record already has all those bits set, we end up splitting that record, so we end up with extent state records in the tree which represent the ranges from 0 to 128KiB and from 128KiB to 1MiB. This is temporary because a subsequent iteration in that function will end up merging the records. The splitting requires using the preallocated extent state record, so a future iteration that needs to do another split will need to allocate another extent state record in an atomic context, something not ideal that we try to avoid as much as possible. The splitting also requires an insertion in the red black tree, and a subsequent merge will require a deletion from the red black tree and freeing an extent state record. This change just skips the splitting of an extent state record when it already has all the bits the we need to set. Setting a bit that is already set for a range is very common in the inode's 'file_extent_tree' extent io tree for example, where we keep setting the EXTENT_DIRTY bit every time we replace an extent. This change also fixes a bug that happens after the recent patchset from Josef that avoids having implicit holes after a power failure when not using the NO_HOLES feature, more specifically the patch with the subject: "btrfs: introduce the inode->file_extent_tree" This patch introduced an extent io tree per inode to keep track of completed ordered extents and figure out at any time what is the safe value for the inode's disk_i_size. This assumes that for contiguous ranges in a file we always end up with a single extent state record in the io tree, but that is not the case, as there is a short time window where we can have two extent state records representing contiguous ranges. When this happens we end setting up an incorrect value for the inode's disk_i_size, resulting in data loss after a clean unmount of the filesystem. The following example explains how this can happen. Suppose we have an inode with an i_size and a disk_i_size of 1MiB, so in the inode's file_extent_tree we have a single extent state record that represents the range [0, 1MiB) with the EXTENT_DIRTY bit set. Then the following steps happen: 1) A buffered write against file range [512KiB, 768KiB) is made. At this point delalloc was not flushed yet; 2) Deduplication from some other inode into this inode's range [128KiB, 256KiB) is made. This causes btrfs_inode_set_file_extent_range() to be called, from btrfs_insert_clone_extent(), to mark the range [128KiB, 256KiB) with EXTENT_DIRTY in the inode's file_extent_tree; 3) When btrfs_inode_set_file_extent_range() calls set_extent_bits(), we end up at __set_extent_bit(). In the first iteration of that function's loop we end up in the following branch: $ cat -n fs/btrfs/extent_io.c 957 static int __must_check 958 __set_extent_bit(struct extent_io_tree *tree, u64 start, u64 end, (...) 1044 /* 1045 * | ---- desired range ---- | 1046 * | state | 1047 * or 1048 * | ------------- state -------------- | 1049 * (...) 1060 if (state->start < start) { 1061 if (state->state & exclusive_bits) { 1062 *failed_start = start; 1063 err = -EEXIST; 1064 goto out; 1065 } 1066 1067 prealloc = alloc_extent_state_atomic(prealloc); 1068 BUG_ON(!prealloc); 1069 err = split_state(tree, state, prealloc, start); 1070 if (err) 1071 extent_io_tree_panic(tree, err); 1072 1073 prealloc = NULL; (...) 1089 goto search_again; This splits the state record into two, one for range [0, 128KiB) and another for the range [128KiB, 1MiB). Both already have the EXTENT_DIRTY bit set. Then we jump to the 'search_again' label, where we unlock the the spinlock protecting the extent io tree before jumping to the 'again' label to perform the next iteration; 4) In the meanwhile, delalloc is flushed, the ordered extent for the range [512KiB, 768KiB) is created and when it completes, at btrfs_finish_ordered_io(), it calls btrfs_inode_safe_disk_i_size_write() with a value of 0 for its 'new_size' argument; 5) Before the deduplication task currently at __set_extent_bit() moves to the next iteration, the task finishing the ordered extent calls find_first_extent_bit() through btrfs_inode_safe_disk_i_size_write() and gets 'start' set to 0 and 'end' set to 128KiB - because at this moment the io tree has two extent state records, one representing the range [0, 128KiB) and another representing the range [128KiB, 1MiB), both with EXTENT_DIRTY set. Then we set 'isize' to: isize = min(isize, end + 1) = min(1MiB, 128KiB - 1 + 1) = 128KiB Then we set the inode's disk_i_size to 128KiB (isize). After a clean unmount of the filesystem and mounting it again, we have the file with a size of 128KiB, and effectively lost all the data it had before in the range from 128KiB to 1MiB. This change fixes that issue too, as we never end up splitting extent state records when they already have all the bits we want set. Reviewed-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com> -
由 David Sterba 提交于
The tree pointer can be safely read from the inode, use it and drop the redundant argument. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
The tree pointer can be safely read from the inode, use it and drop the redundant argument. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
The tree pointer can be safely read from the inode, use it and drop the redundant argument. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
The tree pointer can be safely read from the page's inode, use it and drop the redundant argument. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
The tree pointer can be safely read from the inode so we can drop the redundant argument from btrfs_lock_and_flush_ordered_range. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
Add assertions to all helpers that get tree as argument and verify that it's the same that can be obtained from the inode or from its pages. In followup patches the redundant arguments and assertions will be removed one by one. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
Now that we're sure the tree from argument is same as the one we can get from the page's inode io_tree, drop the redundant argument. Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Reviewed-by: NAnand Jain <anand.jain@oracle.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 David Sterba 提交于
All functions that set up extent_page_data::tree set it to the inode io_tree. That's passed down the callstack that accesses either the same inode or its pages. In the end submit_extent_page can pull the tree out of the page and we don't have to store it in the structure. Reviewed-by: NAnand Jain <anand.jain@oracle.com> Reviewed-by: NJohannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: NNikolay Borisov <nborisov@suse.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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由 Josef Bacik 提交于
In order to keep track of where we have file extents on disk, and thus where it is safe to adjust the i_size to, we need to have a tree in place to keep track of the contiguous areas we have file extents for. Add helpers to use this tree, as it's not required for NO_HOLES file systems. We will use this by setting DIRTY for areas we know we have file extent item's set, and clearing it when we remove file extent items for truncation. Reviewed-by: NFilipe Manana <fdmanana@suse.com> Signed-off-by: NJosef Bacik <josef@toxicpanda.com> Signed-off-by: NDavid Sterba <dsterba@suse.com>
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