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authorFilipe Manana <fdmanana@suse.com>2015-04-25 17:29:16 (GMT)
committerChris Mason <clm@fb.com>2015-04-26 13:26:37 (GMT)
commitb58d1a9ef92031a6fc2f418c01abafb4458ba009 (patch)
treeedf1cf7d38effb41856f836cec5250192b68c5e7 /net/atm/lec.h
parenta3bdccc4e683f0ac69230707ed3fa20e7cf73a79 (diff)
downloadlinux-b58d1a9ef92031a6fc2f418c01abafb4458ba009.tar.xz
Btrfs: fix race between start dirty bg cache writeout and bg deletion
While running xfstests I ran into the following: [20892.242791] ------------[ cut here ]------------ [20892.243776] WARNING: CPU: 0 PID: 13299 at fs/btrfs/super.c:260 __btrfs_abort_transaction+0x52/0x114 [btrfs]() [20892.245874] BTRFS: Transaction aborted (error -2) [20892.247329] Modules linked in: btrfs dm_snapshot dm_bufio dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd grace fscache sunrpc loop fuse$ [20892.258488] CPU: 0 PID: 13299 Comm: fsstress Tainted: G W 4.0.0-rc5-btrfs-next-9+ #2 [20892.262011] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [20892.264738] 0000000000000009 ffff880427f8bc18 ffffffff8142fa46 ffffffff8108b6a2 [20892.266244] ffff880427f8bc68 ffff880427f8bc58 ffffffff81045ea5 ffff880427f8bc48 [20892.267761] ffffffffa0509a6d 00000000fffffffe ffff8803545d6f40 ffffffffa05a15a0 [20892.269378] Call Trace: [20892.269915] [<ffffffff8142fa46>] dump_stack+0x4f/0x7b [20892.271097] [<ffffffff8108b6a2>] ? console_unlock+0x361/0x3ad [20892.272173] [<ffffffff81045ea5>] warn_slowpath_common+0xa1/0xbb [20892.273386] [<ffffffffa0509a6d>] ? __btrfs_abort_transaction+0x52/0x114 [btrfs] [20892.274857] [<ffffffff81045f05>] warn_slowpath_fmt+0x46/0x48 [20892.275851] [<ffffffffa0509a6d>] __btrfs_abort_transaction+0x52/0x114 [btrfs] [20892.277341] [<ffffffffa0515e10>] write_one_cache_group+0x68/0xaf [btrfs] [20892.278628] [<ffffffffa052088a>] btrfs_start_dirty_block_groups+0x18d/0x29b [btrfs] [20892.280191] [<ffffffffa052f077>] btrfs_commit_transaction+0x130/0x9c9 [btrfs] [20892.281781] [<ffffffff8107d33d>] ? trace_hardirqs_on+0xd/0xf [20892.282873] [<ffffffffa054163b>] btrfs_sync_file+0x313/0x387 [btrfs] [20892.284111] [<ffffffff8117acad>] vfs_fsync_range+0x95/0xa4 [20892.285203] [<ffffffff810e603f>] ? time_hardirqs_on+0x15/0x28 [20892.286290] [<ffffffff8123960b>] ? trace_hardirqs_on_thunk+0x3a/0x3f [20892.287469] [<ffffffff8117acd8>] vfs_fsync+0x1c/0x1e [20892.288412] [<ffffffff8117ae54>] do_fsync+0x34/0x4e [20892.289348] [<ffffffff8117b07c>] SyS_fsync+0x10/0x14 [20892.290255] [<ffffffff81435b32>] system_call_fastpath+0x12/0x17 [20892.291316] ---[ end trace 597f77e664245373 ]--- [20892.293955] BTRFS: error (device sdg) in write_one_cache_group:3184: errno=-2 No such entry [20892.297390] BTRFS info (device sdg): forced readonly This happens because in btrfs_start_dirty_block_groups() we splice the transaction's list of dirty block groups into a local list and then we keep extracting the first element of the list without holding the cache_write_mutex mutex. This means that before we acquire that mutex the first block group on the list might be removed by a conurrent task running btrfs_remove_block_group(). So make sure we extract the first element (and test the list emptyness) while holding that mutex. Fixes: 1bbc621ef284 ("Btrfs: allow block group cache writeout outside critical section in commit") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
Diffstat (limited to 'net/atm/lec.h')
0 files changed, 0 insertions, 0 deletions