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* btrfs: remove inode number cache featureNikolay Borisov2020-12-091-527/+0
| | | | | | | | | | | | | | | | | | It's been deprecated since commit b547a88ea577 ("btrfs: start deprecation of mount option inode_cache") which enumerates the reasons. A filesystem that uses the feature (mount -o inode_cache) tracks the inode numbers in bitmaps, that data stay on the filesystem after this patch. The size is roughly 5MiB for 1M inodes [1], which is considered small enough to be left there. Removal of the change can be implemented in btrfs-progs if needed. [1] https://lore.kernel.org/linux-btrfs/20201127145836.GZ6430@twin.jikos.cz/ Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: move btrfs_find_highest_objectid/btrfs_find_free_objectid to disk-io.cNikolay Borisov2020-12-091-55/+0
| | | | | | | | | Those functions are going to be used even after inode cache is removed so moved them to a more appropriate place. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: make btrfs_update_inode take btrfs_inodeNikolay Borisov2020-12-081-1/+1
| | | | | | | Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: make btrfs_delalloc_reserve_space take btrfs_inodeNikolay Borisov2020-07-271-1/+2
| | | | | | | | | | All of its children take btrfs_inode so bubble up this requirement to btrfs_delalloc_reserve_space's interface and stop calling BTRFS_I internally. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: Remove __ prefix from btrfs_block_rsv_releaseNikolay Borisov2020-03-231-1/+1
| | | | | | | | | | | | | Currently the non-prefixed version is a simple wrapper used to hide the 4th argument of the prefixed version. This doesn't bring much value in practice and only makes the code harder to follow by adding another level of indirection. Rectify this by removing the __ prefix and have only one public function to release bytes from a block reservation. No semantic changes. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: keep track of which extents have been discardedDennis Zhou2020-01-201-6/+7
| | | | | | | | | | | | | | | | | | | | Async discard will use the free space cache as backing knowledge for which extents to discard. This patch plumbs knowledge about which extents need to be discarded into the free space cache from unpin_extent_range(). An untrimmed extent can merge with everything as this is a new region. Absorbing trimmed extents is a tradeoff to for greater coalescing which makes life better for find_free_extent(). Additionally, it seems the size of a trim isn't as problematic as the trim io itself. When reading in the free space cache from disk, if sync is set, mark all extents as trimmed. The current code ensures at transaction commit that all free space is trimmed when sync is set, so this reflects that. Signed-off-by: Dennis Zhou <dennis@kernel.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Always free PREALLOC META reserve in ↵Qu Wenruo2019-10-151-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | btrfs_delalloc_release_extents() [Background] Btrfs qgroup uses two types of reserved space for METADATA space, PERTRANS and PREALLOC. PERTRANS is metadata space reserved for each transaction started by btrfs_start_transaction(). While PREALLOC is for delalloc, where we reserve space before joining a transaction, and finally it will be converted to PERTRANS after the writeback is done. [Inconsistency] However there is inconsistency in how we handle PREALLOC metadata space. The most obvious one is: In btrfs_buffered_write(): btrfs_delalloc_release_extents(BTRFS_I(inode), reserve_bytes, true); We always free qgroup PREALLOC meta space. While in btrfs_truncate_block(): btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, (ret != 0)); We only free qgroup PREALLOC meta space when something went wrong. [The Correct Behavior] The correct behavior should be the one in btrfs_buffered_write(), we should always free PREALLOC metadata space. The reason is, the btrfs_delalloc_* mechanism works by: - Reserve metadata first, even it's not necessary In btrfs_delalloc_reserve_metadata() - Free the unused metadata space Normally in: btrfs_delalloc_release_extents() |- btrfs_inode_rsv_release() Here we do calculation on whether we should release or not. E.g. for 64K buffered write, the metadata rsv works like: /* The first page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=0 total: num_bytes=calc_inode_reservations() /* The first page caused one outstanding extent, thus needs metadata rsv */ /* The 2nd page */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed /* The 2nd page doesn't cause new outstanding extent, needs no new meta rsv, so we free what we have reserved */ /* The 3rd~16th pages */ reserve_meta: num_bytes=calc_inode_reservations() free_meta: num_bytes=calc_inode_reservations() total: not changed (still space for one outstanding extent) This means, if btrfs_delalloc_release_extents() determines to free some space, then those space should be freed NOW. So for qgroup, we should call btrfs_qgroup_free_meta_prealloc() other than btrfs_qgroup_convert_reserved_meta(). The good news is: - The callers are not that hot The hottest caller is in btrfs_buffered_write(), which is already fixed by commit 336a8bb8e36a ("btrfs: Fix wrong btrfs_delalloc_release_extents parameter"). Thus it's not that easy to cause false EDQUOT. - The trans commit in advance for qgroup would hide the bug Since commit f5fef4593653 ("btrfs: qgroup: Make qgroup async transaction commit more aggressive"), when btrfs qgroup metadata free space is slow, it will try to commit transaction and free the wrongly converted PERTRANS space, so it's not that easy to hit such bug. [FIX] So to fix the problem, remove the @qgroup_free parameter for btrfs_delalloc_release_extents(), and always pass true to btrfs_inode_rsv_release(). Reported-by: Filipe Manana <fdmanana@suse.com> Fixes: 43b18595d660 ("btrfs: qgroup: Use separate meta reservation type for delalloc") CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: rename the btrfs_calc_*_metadata_size helpersJosef Bacik2019-09-091-1/+1
| | | | | | | | | | | | | | | | btrfs_calc_trunc_metadata_size differs from trans_metadata_size in that it doesn't take into account any splitting at the levels, because truncate will never split nodes. However truncate _and_ changing will never split nodes, so rename btrfs_calc_trunc_metadata_size to btrfs_calc_metadata_size. Also btrfs_calc_trans_metadata_size is purely for inserting items, so rename this to btrfs_calc_insert_metadata_size. Making these clearer will help when I start using them differently in upcoming patches. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: wake up inode cache waiters sooner to reduce waiting timeFilipe Manana2019-09-091-0/+1
| | | | | | | | | | | | | | | | If we need to start an inode caching thread, because none currently exists on disk, we can wake up all waiters as soon as we mark the range starting at root's highest objectid + 1 and ending at BTRFS_LAST_FREE_OBJECTID as free, so that they don't need to wait for the caching thread to start and do some progress. We follow the same approach within the caching thread, since as soon as it finds a free range and marks it as free space in the cache, it wakes up all waiters. So improve this by adding such a wakeup call after marking that initial range as free space. Fixes: a47d6b70e28040 ("Btrfs: setup free ino caching in a more asynchronous way") Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: fix inode cache waiters hanging on path allocation failureFilipe Manana2019-09-091-1/+3
| | | | | | | | | | | | | If the caching thread fails to allocate a path, it returns without waking up any cache waiters, leaving them hang forever. Fix this by following the same approach as when we fail to start the caching thread: print an error message, disable inode caching and make the wakers fallback to non-caching mode behaviour (calling btrfs_find_free_objectid()). Fixes: 581bb050941b4f ("Btrfs: Cache free inode numbers in memory") Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: fix inode cache waiters hanging on failure to start caching threadFilipe Manana2019-09-091-5/+18
| | | | | | | | | | | | If we fail to start the inode caching thread, we print an error message and disable the inode cache, however we never wake up any waiters, so they hang forever waiting for the caching to finish. Fix this by waking them up and have them fallback to a call to btrfs_find_free_objectid(). Fixes: e60efa84252c05 ("Btrfs: avoid triggering bug_on() when we fail to start inode caching task") Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: fix inode cache block reserve leak on failure to allocate data spaceFilipe Manana2019-09-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we failed to allocate the data extent(s) for the inode space cache, we were bailing out without releasing the previously reserved metadata. This was triggering the following warnings when unmounting a filesystem: $ cat -n fs/btrfs/inode.c (...) 9268 void btrfs_destroy_inode(struct inode *inode) 9269 { (...) 9276 WARN_ON(BTRFS_I(inode)->block_rsv.reserved); 9277 WARN_ON(BTRFS_I(inode)->block_rsv.size); (...) 9281 WARN_ON(BTRFS_I(inode)->csum_bytes); 9282 WARN_ON(BTRFS_I(inode)->defrag_bytes); (...) Several fstests test cases triggered this often, such as generic/083, generic/102, generic/172, generic/269 and generic/300 at least, producing stack traces like the following in dmesg/syslog: [82039.079546] WARNING: CPU: 2 PID: 13167 at fs/btrfs/inode.c:9276 btrfs_destroy_inode+0x203/0x270 [btrfs] (...) [82039.081543] CPU: 2 PID: 13167 Comm: umount Tainted: G W 5.2.0-rc4-btrfs-next-50 #1 [82039.081912] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014 [82039.082673] RIP: 0010:btrfs_destroy_inode+0x203/0x270 [btrfs] (...) [82039.083913] RSP: 0018:ffffac0b426a7d30 EFLAGS: 00010206 [82039.084320] RAX: ffff8ddf77691158 RBX: ffff8dde29b34660 RCX: 0000000000000002 [82039.084736] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8dde29b34660 [82039.085156] RBP: ffff8ddf5fbec000 R08: 0000000000000000 R09: 0000000000000000 [82039.085578] R10: ffffac0b426a7c90 R11: ffffffffb9aad768 R12: ffffac0b426a7db0 [82039.086000] R13: ffff8ddf5fbec0a0 R14: dead000000000100 R15: 0000000000000000 [82039.086416] FS: 00007f8db96d12c0(0000) GS:ffff8de036b00000(0000) knlGS:0000000000000000 [82039.086837] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [82039.087253] CR2: 0000000001416108 CR3: 00000002315cc001 CR4: 00000000003606e0 [82039.087672] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [82039.088089] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [82039.088504] Call Trace: [82039.088918] destroy_inode+0x3b/0x70 [82039.089340] btrfs_free_fs_root+0x16/0xa0 [btrfs] [82039.089768] btrfs_free_fs_roots+0xd8/0x160 [btrfs] [82039.090183] ? wait_for_completion+0x65/0x1a0 [82039.090607] close_ctree+0x172/0x370 [btrfs] [82039.091021] generic_shutdown_super+0x6c/0x110 [82039.091427] kill_anon_super+0xe/0x30 [82039.091832] btrfs_kill_super+0x12/0xa0 [btrfs] [82039.092233] deactivate_locked_super+0x3a/0x70 [82039.092636] cleanup_mnt+0x3b/0x80 [82039.093039] task_work_run+0x93/0xc0 [82039.093457] exit_to_usermode_loop+0xfa/0x100 [82039.093856] do_syscall_64+0x162/0x1d0 [82039.094244] entry_SYSCALL_64_after_hwframe+0x49/0xbe [82039.094634] RIP: 0033:0x7f8db8fbab37 (...) [82039.095876] RSP: 002b:00007ffdce35b468 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [82039.096290] RAX: 0000000000000000 RBX: 0000560d20b00060 RCX: 00007f8db8fbab37 [82039.096700] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000560d20b00240 [82039.097110] RBP: 0000560d20b00240 R08: 0000560d20b00270 R09: 0000000000000015 [82039.097522] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f8db94bce64 [82039.097937] R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffdce35b6f0 [82039.098350] irq event stamp: 0 [82039.098750] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [82039.099150] hardirqs last disabled at (0): [<ffffffffb7884ff2>] copy_process.part.33+0x7f2/0x1f00 [82039.099545] softirqs last enabled at (0): [<ffffffffb7884ff2>] copy_process.part.33+0x7f2/0x1f00 [82039.099925] softirqs last disabled at (0): [<0000000000000000>] 0x0 [82039.100292] ---[ end trace f2521afa616ddccc ]--- [82039.100707] WARNING: CPU: 2 PID: 13167 at fs/btrfs/inode.c:9277 btrfs_destroy_inode+0x1ac/0x270 [btrfs] (...) [82039.103050] CPU: 2 PID: 13167 Comm: umount Tainted: G W 5.2.0-rc4-btrfs-next-50 #1 [82039.103428] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014 [82039.104203] RIP: 0010:btrfs_destroy_inode+0x1ac/0x270 [btrfs] (...) [82039.105461] RSP: 0018:ffffac0b426a7d30 EFLAGS: 00010206 [82039.105866] RAX: ffff8ddf77691158 RBX: ffff8dde29b34660 RCX: 0000000000000002 [82039.106270] RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8dde29b34660 [82039.106673] RBP: ffff8ddf5fbec000 R08: 0000000000000000 R09: 0000000000000000 [82039.107078] R10: ffffac0b426a7c90 R11: ffffffffb9aad768 R12: ffffac0b426a7db0 [82039.107487] R13: ffff8ddf5fbec0a0 R14: dead000000000100 R15: 0000000000000000 [82039.107894] FS: 00007f8db96d12c0(0000) GS:ffff8de036b00000(0000) knlGS:0000000000000000 [82039.108309] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [82039.108723] CR2: 0000000001416108 CR3: 00000002315cc001 CR4: 00000000003606e0 [82039.109146] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [82039.109567] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [82039.109989] Call Trace: [82039.110405] destroy_inode+0x3b/0x70 [82039.110830] btrfs_free_fs_root+0x16/0xa0 [btrfs] [82039.111257] btrfs_free_fs_roots+0xd8/0x160 [btrfs] [82039.111675] ? wait_for_completion+0x65/0x1a0 [82039.112101] close_ctree+0x172/0x370 [btrfs] [82039.112519] generic_shutdown_super+0x6c/0x110 [82039.112988] kill_anon_super+0xe/0x30 [82039.113439] btrfs_kill_super+0x12/0xa0 [btrfs] [82039.113861] deactivate_locked_super+0x3a/0x70 [82039.114278] cleanup_mnt+0x3b/0x80 [82039.114685] task_work_run+0x93/0xc0 [82039.115083] exit_to_usermode_loop+0xfa/0x100 [82039.115476] do_syscall_64+0x162/0x1d0 [82039.115863] entry_SYSCALL_64_after_hwframe+0x49/0xbe [82039.116254] RIP: 0033:0x7f8db8fbab37 (...) [82039.117463] RSP: 002b:00007ffdce35b468 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [82039.117882] RAX: 0000000000000000 RBX: 0000560d20b00060 RCX: 00007f8db8fbab37 [82039.118330] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000560d20b00240 [82039.118743] RBP: 0000560d20b00240 R08: 0000560d20b00270 R09: 0000000000000015 [82039.119159] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f8db94bce64 [82039.119574] R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffdce35b6f0 [82039.119987] irq event stamp: 0 [82039.120387] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [82039.120787] hardirqs last disabled at (0): [<ffffffffb7884ff2>] copy_process.part.33+0x7f2/0x1f00 [82039.121182] softirqs last enabled at (0): [<ffffffffb7884ff2>] copy_process.part.33+0x7f2/0x1f00 [82039.121563] softirqs last disabled at (0): [<0000000000000000>] 0x0 [82039.121933] ---[ end trace f2521afa616ddccd ]--- [82039.122353] WARNING: CPU: 2 PID: 13167 at fs/btrfs/inode.c:9278 btrfs_destroy_inode+0x1bc/0x270 [btrfs] (...) [82039.124606] CPU: 2 PID: 13167 Comm: umount Tainted: G W 5.2.0-rc4-btrfs-next-50 #1 [82039.125008] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014 [82039.125801] RIP: 0010:btrfs_destroy_inode+0x1bc/0x270 [btrfs] (...) [82039.126998] RSP: 0018:ffffac0b426a7d30 EFLAGS: 00010202 [82039.127399] RAX: ffff8ddf77691158 RBX: ffff8dde29b34660 RCX: 0000000000000002 [82039.127803] RDX: 0000000000000001 RSI: 0000000000000001 RDI: ffff8dde29b34660 [82039.128206] RBP: ffff8ddf5fbec000 R08: 0000000000000000 R09: 0000000000000000 [82039.128611] R10: ffffac0b426a7c90 R11: ffffffffb9aad768 R12: ffffac0b426a7db0 [82039.129020] R13: ffff8ddf5fbec0a0 R14: dead000000000100 R15: 0000000000000000 [82039.129428] FS: 00007f8db96d12c0(0000) GS:ffff8de036b00000(0000) knlGS:0000000000000000 [82039.129846] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [82039.130261] CR2: 0000000001416108 CR3: 00000002315cc001 CR4: 00000000003606e0 [82039.130684] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [82039.131142] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [82039.131561] Call Trace: [82039.131990] destroy_inode+0x3b/0x70 [82039.132417] btrfs_free_fs_root+0x16/0xa0 [btrfs] [82039.132844] btrfs_free_fs_roots+0xd8/0x160 [btrfs] [82039.133262] ? wait_for_completion+0x65/0x1a0 [82039.133688] close_ctree+0x172/0x370 [btrfs] [82039.134157] generic_shutdown_super+0x6c/0x110 [82039.134575] kill_anon_super+0xe/0x30 [82039.134997] btrfs_kill_super+0x12/0xa0 [btrfs] [82039.135415] deactivate_locked_super+0x3a/0x70 [82039.135832] cleanup_mnt+0x3b/0x80 [82039.136239] task_work_run+0x93/0xc0 [82039.136637] exit_to_usermode_loop+0xfa/0x100 [82039.137029] do_syscall_64+0x162/0x1d0 [82039.137418] entry_SYSCALL_64_after_hwframe+0x49/0xbe [82039.137812] RIP: 0033:0x7f8db8fbab37 (...) [82039.139059] RSP: 002b:00007ffdce35b468 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [82039.139475] RAX: 0000000000000000 RBX: 0000560d20b00060 RCX: 00007f8db8fbab37 [82039.139890] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000560d20b00240 [82039.140302] RBP: 0000560d20b00240 R08: 0000560d20b00270 R09: 0000000000000015 [82039.140719] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f8db94bce64 [82039.141138] R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffdce35b6f0 [82039.141597] irq event stamp: 0 [82039.142043] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [82039.142443] hardirqs last disabled at (0): [<ffffffffb7884ff2>] copy_process.part.33+0x7f2/0x1f00 [82039.142839] softirqs last enabled at (0): [<ffffffffb7884ff2>] copy_process.part.33+0x7f2/0x1f00 [82039.143220] softirqs last disabled at (0): [<0000000000000000>] 0x0 [82039.143588] ---[ end trace f2521afa616ddcce ]--- [82039.167472] WARNING: CPU: 3 PID: 13167 at fs/btrfs/extent-tree.c:10120 btrfs_free_block_groups+0x30d/0x460 [btrfs] (...) [82039.173800] CPU: 3 PID: 13167 Comm: umount Tainted: G W 5.2.0-rc4-btrfs-next-50 #1 [82039.174847] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014 [82039.177031] RIP: 0010:btrfs_free_block_groups+0x30d/0x460 [btrfs] (...) [82039.180397] RSP: 0018:ffffac0b426a7dd8 EFLAGS: 00010206 [82039.181574] RAX: ffff8de010a1db40 RBX: ffff8de010a1db40 RCX: 0000000000170014 [82039.182711] RDX: ffff8ddff4380040 RSI: ffff8de010a1da58 RDI: 0000000000000246 [82039.183817] RBP: ffff8ddf5fbec000 R08: 0000000000000000 R09: 0000000000000000 [82039.184925] R10: ffff8de036404380 R11: ffffffffb8a5ea00 R12: ffff8de010a1b2b8 [82039.186090] R13: ffff8de010a1b2b8 R14: 0000000000000000 R15: dead000000000100 [82039.187208] FS: 00007f8db96d12c0(0000) GS:ffff8de036b80000(0000) knlGS:0000000000000000 [82039.188345] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [82039.189481] CR2: 00007fb044005170 CR3: 00000002315cc006 CR4: 00000000003606e0 [82039.190674] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [82039.191829] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [82039.192978] Call Trace: [82039.194160] close_ctree+0x19a/0x370 [btrfs] [82039.195315] generic_shutdown_super+0x6c/0x110 [82039.196486] kill_anon_super+0xe/0x30 [82039.197645] btrfs_kill_super+0x12/0xa0 [btrfs] [82039.198696] deactivate_locked_super+0x3a/0x70 [82039.199619] cleanup_mnt+0x3b/0x80 [82039.200559] task_work_run+0x93/0xc0 [82039.201505] exit_to_usermode_loop+0xfa/0x100 [82039.202436] do_syscall_64+0x162/0x1d0 [82039.203339] entry_SYSCALL_64_after_hwframe+0x49/0xbe [82039.204091] RIP: 0033:0x7f8db8fbab37 (...) [82039.206360] RSP: 002b:00007ffdce35b468 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [82039.207132] RAX: 0000000000000000 RBX: 0000560d20b00060 RCX: 00007f8db8fbab37 [82039.207906] RDX: 0000000000000001 RSI: 0000000000000000 RDI: 0000560d20b00240 [82039.208621] RBP: 0000560d20b00240 R08: 0000560d20b00270 R09: 0000000000000015 [82039.209285] R10: 00000000000006b4 R11: 0000000000000246 R12: 00007f8db94bce64 [82039.209984] R13: 0000000000000000 R14: 0000000000000000 R15: 00007ffdce35b6f0 [82039.210642] irq event stamp: 0 [82039.211306] hardirqs last enabled at (0): [<0000000000000000>] 0x0 [82039.211971] hardirqs last disabled at (0): [<ffffffffb7884ff2>] copy_process.part.33+0x7f2/0x1f00 [82039.212643] softirqs last enabled at (0): [<ffffffffb7884ff2>] copy_process.part.33+0x7f2/0x1f00 [82039.213304] softirqs last disabled at (0): [<0000000000000000>] 0x0 [82039.213875] ---[ end trace f2521afa616ddccf ]--- Fix this by releasing the reserved metadata on failure to allocate data extent(s) for the inode cache. Fixes: 69fe2d75dd91d0 ("btrfs: make the delalloc block rsv per inode") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: fix hang when loading existing inode cache off diskFilipe Manana2019-09-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we are able to load an existing inode cache off disk, we set the state of the cache to BTRFS_CACHE_FINISHED, but we don't wake up any one waiting for the cache to be available. This means that anyone waiting for the cache to be available, waiting on the condition that either its state is BTRFS_CACHE_FINISHED or its available free space is greather than zero, can hang forever. This could be observed running fstests with MOUNT_OPTIONS="-o inode_cache", in particular test case generic/161 triggered it very frequently for me, producing a trace like the following: [63795.739712] BTRFS info (device sdc): enabling inode map caching [63795.739714] BTRFS info (device sdc): disk space caching is enabled [63795.739716] BTRFS info (device sdc): has skinny extents [64036.653886] INFO: task btrfs-transacti:3917 blocked for more than 120 seconds. [64036.654079] Not tainted 5.2.0-rc4-btrfs-next-50 #1 [64036.654143] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [64036.654232] btrfs-transacti D 0 3917 2 0x80004000 [64036.654239] Call Trace: [64036.654258] ? __schedule+0x3ae/0x7b0 [64036.654271] schedule+0x3a/0xb0 [64036.654325] btrfs_commit_transaction+0x978/0xae0 [btrfs] [64036.654339] ? remove_wait_queue+0x60/0x60 [64036.654395] transaction_kthread+0x146/0x180 [btrfs] [64036.654450] ? btrfs_cleanup_transaction+0x620/0x620 [btrfs] [64036.654456] kthread+0x103/0x140 [64036.654464] ? kthread_create_worker_on_cpu+0x70/0x70 [64036.654476] ret_from_fork+0x3a/0x50 [64036.654504] INFO: task xfs_io:3919 blocked for more than 120 seconds. [64036.654568] Not tainted 5.2.0-rc4-btrfs-next-50 #1 [64036.654617] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [64036.654685] xfs_io D 0 3919 3633 0x00000000 [64036.654691] Call Trace: [64036.654703] ? __schedule+0x3ae/0x7b0 [64036.654716] schedule+0x3a/0xb0 [64036.654756] btrfs_find_free_ino+0xa9/0x120 [btrfs] [64036.654764] ? remove_wait_queue+0x60/0x60 [64036.654809] btrfs_create+0x72/0x1f0 [btrfs] [64036.654822] lookup_open+0x6bc/0x790 [64036.654849] path_openat+0x3bc/0xc00 [64036.654854] ? __lock_acquire+0x331/0x1cb0 [64036.654869] do_filp_open+0x99/0x110 [64036.654884] ? __alloc_fd+0xee/0x200 [64036.654895] ? do_raw_spin_unlock+0x49/0xc0 [64036.654909] ? do_sys_open+0x132/0x220 [64036.654913] do_sys_open+0x132/0x220 [64036.654926] do_syscall_64+0x60/0x1d0 [64036.654933] entry_SYSCALL_64_after_hwframe+0x49/0xbe Fix this by adding a wake_up() call right after setting the cache state to BTRFS_CACHE_FINISHED, at start_caching(), when we are able to load the cache from disk. Fixes: 82d5902d9c681b ("Btrfs: Support reading/writing on disk free ino cache") Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: migrate the delalloc space stuff to it's own homeJosef Bacik2019-07-041-0/+1
| | | | | | | | | | | We have code for data and metadata reservations for delalloc. There's quite a bit of code here, and it's used in a lot of places so I've separated it out to it's own file. inode.c and file.c are already pretty large, and this code is complicated enough to live in its own space. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: prune unused includesDavid Sterba2018-08-061-1/+0
| | | | | | | Remove includes if none of the interfaces and exports is used in the given source file. Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: Refactor count handling in btrfs_unpin_free_inoGeert Uytterhoeven2018-08-061-7/+4
| | | | | | | | | | | | | | With gcc 4.1.2: fs/btrfs/inode-map.c: In function ‘btrfs_unpin_free_ino’: fs/btrfs/inode-map.c:241: warning: ‘count’ may be used uninitialized in this function While this warning is a false-positive, it can easily be killed by refactoring the code. Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: replace GPL boilerplate by SPDX -- sourcesDavid Sterba2018-04-121-14/+1
| | | | | | | | Remove GPL boilerplate text (long, short, one-line) and keep the rest, ie. personal, company or original source copyright statements. Add the SPDX header. Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Use separate meta reservation type for delallocQu Wenruo2018-03-311-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Before this patch, btrfs qgroup is mixing per-transcation meta rsv with preallocated meta rsv, making it quite easy to underflow qgroup meta reservation. Since we have the new qgroup meta rsv types, apply it to delalloc reservation. Now for delalloc, most of its reserved space will use META_PREALLOC qgroup rsv type. And for callers reducing outstanding extent like btrfs_finish_ordered_io(), they will convert corresponding META_PREALLOC reservation to META_PERTRANS. This is mainly due to the fact that current qgroup numbers will only be updated in btrfs_commit_transaction(), that's to say if we don't keep such placeholder reservation, we can exceed qgroup limitation. And for callers freeing outstanding extent in error handler, we will just free META_PREALLOC bytes. This behavior makes callers of btrfs_qgroup_release_meta() or btrfs_qgroup_convert_meta() to be aware of which type they are. So in this patch, btrfs_delalloc_release_metadata() and its callers get an extra parameter to info qgroup to do correct meta convert/release. The good news is, even we use the wrong type (convert or free), it won't cause obvious bug, as prealloc type is always in good shape, and the type only affects how per-trans meta is increased or not. So the worst case will be at most metadata limitation can be sometimes exceeded (no convert at all) or metadata limitation is reached too soon (no free at all). Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: rework outstanding_extentsJosef Bacik2017-11-011-1/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Right now we do a lot of weird hoops around outstanding_extents in order to keep the extent count consistent. This is because we logically transfer the outstanding_extent count from the initial reservation through the set_delalloc_bits. This makes it pretty difficult to get a handle on how and when we need to mess with outstanding_extents. Fix this by revamping the rules of how we deal with outstanding_extents. Now instead everybody that is holding on to a delalloc extent is required to increase the outstanding extents count for itself. This means we'll have something like this btrfs_delalloc_reserve_metadata - outstanding_extents = 1 btrfs_set_extent_delalloc - outstanding_extents = 2 btrfs_release_delalloc_extents - outstanding_extents = 1 for an initial file write. Now take the append write where we extend an existing delalloc range but still under the maximum extent size btrfs_delalloc_reserve_metadata - outstanding_extents = 2 btrfs_set_extent_delalloc btrfs_set_bit_hook - outstanding_extents = 3 btrfs_merge_extent_hook - outstanding_extents = 2 btrfs_delalloc_release_extents - outstanding_extnets = 1 In order to make the ordered extent transition we of course must now make ordered extents carry their own outstanding_extent reservation, so for cow_file_range we end up with btrfs_add_ordered_extent - outstanding_extents = 2 clear_extent_bit - outstanding_extents = 1 btrfs_remove_ordered_extent - outstanding_extents = 0 This makes all manipulations of outstanding_extents much more explicit. Every successful call to btrfs_delalloc_reserve_metadata _must_ now be combined with btrfs_release_delalloc_extents, even in the error case, as that is the only function that actually modifies the outstanding_extents counter. The drawback to this is now we are much more likely to have transient cases where outstanding_extents is much larger than it actually should be. This could happen before as we manipulated the delalloc bits, but now it happens basically at every write. This may put more pressure on the ENOSPC flushing code, but I think making this code simpler is worth the cost. I have another change coming to mitigate this side-effect somewhat. I also added trace points for the counter manipulation. These were used by a bpf script I wrote to help track down leak issues. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Introduce extent changeset for qgroup reserve functionsQu Wenruo2017-06-291-1/+3
| | | | | | | | | | | | | | | | | | | Introduce a new parameter, struct extent_changeset for btrfs_qgroup_reserved_data() and its callers. Such extent_changeset was used in btrfs_qgroup_reserve_data() to record which range it reserved in current reserve, so it can free it in error paths. The reason we need to export it to callers is, at buffered write error path, without knowing what exactly which range we reserved in current allocation, we can free space which is not reserved by us. This will lead to qgroup reserved space underflow. Reviewed-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: all btrfs_delalloc_release_metadata take btrfs_inodeNikolay Borisov2017-02-281-1/+1
| | | | | Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: free-space-cache, clean up unnecessary root argumentsJeff Mahoney2017-02-171-1/+1
| | | | | | | | | | The free space cache APIs accept a root but always use the tree root. Also, btrfs_truncate_free_space_cache accepts a root AND an inode but the inode always points to the root anyway, so let's just pass the inode. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: take an fs_info directly when the root is not used otherwiseJeff Mahoney2016-12-061-1/+2
| | | | | | | | | There are loads of functions in btrfs that accept a root parameter but only use it to obtain an fs_info pointer. Let's convert those to just accept an fs_info pointer directly. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: root->fs_info cleanup, add fs_info convenience variablesJeff Mahoney2016-12-061-10/+10
| | | | | | | | | In routines where someptr->fs_info is referenced multiple times, we introduce a convenience variable. This makes the code considerably more readable. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: root->fs_info cleanup, btrfs_calc_{trans,trunc}_metadata_sizeJeff Mahoney2016-12-061-1/+2
| | | | | Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: convert pr_* to btrfs_* where possibleJeff Mahoney2016-09-261-14/+17
| | | | | | | | | | | | | | For many printks, we want to know which file system issued the message. This patch converts most pr_* calls to use the btrfs_* versions instead. In some cases, this means adding plumbing to allow call sites access to an fs_info pointer. fs/btrfs/check-integrity.c is left alone for another day. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: update btrfs_space_info's bytes_may_use timelyWang Xiaoguang2016-08-251-2/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This patch can fix some false ENOSPC errors, below test script can reproduce one false ENOSPC error: #!/bin/bash dd if=/dev/zero of=fs.img bs=$((1024*1024)) count=128 dev=$(losetup --show -f fs.img) mkfs.btrfs -f -M $dev mkdir /tmp/mntpoint mount $dev /tmp/mntpoint cd /tmp/mntpoint xfs_io -f -c "falloc 0 $((64*1024*1024))" testfile Above script will fail for ENOSPC reason, but indeed fs still has free space to satisfy this request. Please see call graph: btrfs_fallocate() |-> btrfs_alloc_data_chunk_ondemand() | bytes_may_use += 64M |-> btrfs_prealloc_file_range() |-> btrfs_reserve_extent() |-> btrfs_add_reserved_bytes() | alloc_type is RESERVE_ALLOC_NO_ACCOUNT, so it does not | change bytes_may_use, and bytes_reserved += 64M. Now | bytes_may_use + bytes_reserved == 128M, which is greater | than btrfs_space_info's total_bytes, false enospc occurs. | Note, the bytes_may_use decrease operation will be done in | end of btrfs_fallocate(), which is too late. Here is another simple case for buffered write: CPU 1 | CPU 2 | |-> cow_file_range() |-> __btrfs_buffered_write() |-> btrfs_reserve_extent() | | | | | | | | | ..... | |-> btrfs_check_data_free_space() | | | | |-> extent_clear_unlock_delalloc() | In CPU 1, btrfs_reserve_extent()->find_free_extent()-> btrfs_add_reserved_bytes() do not decrease bytes_may_use, the decrease operation will be delayed to be done in extent_clear_unlock_delalloc(). Assume in this case, btrfs_reserve_extent() reserved 128MB data, CPU2's btrfs_check_data_free_space() tries to reserve 100MB data space. If 100MB > data_sinfo->total_bytes - data_sinfo->bytes_used - data_sinfo->bytes_reserved - data_sinfo->bytes_pinned - data_sinfo->bytes_readonly - data_sinfo->bytes_may_use btrfs_check_data_free_space() will try to allcate new data chunk or call btrfs_start_delalloc_roots(), or commit current transaction in order to reserve some free space, obviously a lot of work. But indeed it's not necessary as long as decreasing bytes_may_use timely, we still have free space, decreasing 128M from bytes_may_use. To fix this issue, this patch chooses to update bytes_may_use for both data and metadata in btrfs_add_reserved_bytes(). For compress path, real extent length may not be equal to file content length, so introduce a ram_bytes argument for btrfs_reserve_extent(), find_free_extent() and btrfs_add_reserved_bytes(), it's becasue bytes_may_use is increased by file content length. Then compress path can update bytes_may_use correctly. Also now we can discard RESERVE_ALLOC_NO_ACCOUNT, RESERVE_ALLOC and RESERVE_FREE. As we know, usually EXTENT_DO_ACCOUNTING is used for error path. In run_delalloc_nocow(), for inode marked as NODATACOW or extent marked as PREALLOC, we also need to update bytes_may_use, but can not pass EXTENT_DO_ACCOUNTING, because it also clears metadata reservation, so here we introduce EXTENT_CLEAR_DATA_RESV flag to indicate btrfs_clear_bit_hook() to update btrfs_space_info's bytes_may_use. Meanwhile __btrfs_prealloc_file_range() will call btrfs_free_reserved_data_space() internally for both sucessful and failed path, btrfs_prealloc_file_range()'s callers does not need to call btrfs_free_reserved_data_space() any more. Signed-off-by: Wang Xiaoguang <wangxg.fnst@cn.fujitsu.com> Reviewed-by: Josef Bacik <jbacik@fb.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
* btrfs: btrfs_abort_transaction, drop root parameterJeff Mahoney2016-07-261-2/+2
| | | | | | | | | __btrfs_abort_transaction doesn't use its root parameter except to obtain an fs_info pointer. We can obtain that from trans->root->fs_info for now and from trans->fs_info in a later patch. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: btrfs_test_opt and friends should take a btrfs_fs_infoJeff Mahoney2016-07-261-6/+6
| | | | | | | | | btrfs_test_opt and friends only use the root pointer to access the fs_info. Let's pass the fs_info directly in preparation to eliminate similar patterns all over btrfs. Signed-off-by: Jeff Mahoney <jeffm@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* mm, fs: get rid of PAGE_CACHE_* and page_cache_{get,release} macrosKirill A. Shutemov2016-04-041-5/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} macros were introduced *long* time ago with promise that one day it will be possible to implement page cache with bigger chunks than PAGE_SIZE. This promise never materialized. And unlikely will. We have many places where PAGE_CACHE_SIZE assumed to be equal to PAGE_SIZE. And it's constant source of confusion on whether PAGE_CACHE_* or PAGE_* constant should be used in a particular case, especially on the border between fs and mm. Global switching to PAGE_CACHE_SIZE != PAGE_SIZE would cause to much breakage to be doable. Let's stop pretending that pages in page cache are special. They are not. The changes are pretty straight-forward: - <foo> << (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - <foo> >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) -> <foo>; - PAGE_CACHE_{SIZE,SHIFT,MASK,ALIGN} -> PAGE_{SIZE,SHIFT,MASK,ALIGN}; - page_cache_get() -> get_page(); - page_cache_release() -> put_page(); This patch contains automated changes generated with coccinelle using script below. For some reason, coccinelle doesn't patch header files. I've called spatch for them manually. The only adjustment after coccinelle is revert of changes to PAGE_CAHCE_ALIGN definition: we are going to drop it later. There are few places in the code where coccinelle didn't reach. I'll fix them manually in a separate patch. Comments and documentation also will be addressed with the separate patch. virtual patch @@ expression E; @@ - E << (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ expression E; @@ - E >> (PAGE_CACHE_SHIFT - PAGE_SHIFT) + E @@ @@ - PAGE_CACHE_SHIFT + PAGE_SHIFT @@ @@ - PAGE_CACHE_SIZE + PAGE_SIZE @@ @@ - PAGE_CACHE_MASK + PAGE_MASK @@ expression E; @@ - PAGE_CACHE_ALIGN(E) + PAGE_ALIGN(E) @@ expression E; @@ - page_cache_get(E) + get_page(E) @@ expression E; @@ - page_cache_release(E) + put_page(E) Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Acked-by: Michal Hocko <mhocko@suse.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
* Btrfs: Show a warning message if one of objectid reaches its highest valueSatoru Takeuchi2016-03-111-0/+3
| | | | | | | | | | | | It's better to show a warning message for the exceptional case that one of objectid (in most case, inode number) reaches its highest value. For example, if inode cache is off and this event happens, we can't create any file even if there are not so many files. This message ease detecting such problem. Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Merge branch 'misc-for-4.5' of ↵Chris Mason2016-01-201-8/+1
|\ | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.5
| * Btrfs: Initialize btrfs_root->highest_objectid when loading tree root and ↵Chandan Rajendra2016-01-151-8/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | subvolume roots The following call trace is seen when btrfs/031 test is executed in a loop, [ 158.661848] ------------[ cut here ]------------ [ 158.662634] WARNING: CPU: 2 PID: 890 at /home/chandan/repos/linux/fs/btrfs/ioctl.c:558 create_subvol+0x3d1/0x6ea() [ 158.664102] BTRFS: Transaction aborted (error -2) [ 158.664774] Modules linked in: [ 158.665266] CPU: 2 PID: 890 Comm: btrfs Not tainted 4.4.0-rc6-g511711a #2 [ 158.666251] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS Bochs 01/01/2011 [ 158.667392] ffffffff81c0a6b0 ffff8806c7c4f8e8 ffffffff81431fc8 ffff8806c7c4f930 [ 158.668515] ffff8806c7c4f920 ffffffff81051aa1 ffff880c85aff000 ffff8800bb44d000 [ 158.669647] ffff8808863b5c98 0000000000000000 00000000fffffffe ffff8806c7c4f980 [ 158.670769] Call Trace: [ 158.671153] [<ffffffff81431fc8>] dump_stack+0x44/0x5c [ 158.671884] [<ffffffff81051aa1>] warn_slowpath_common+0x81/0xc0 [ 158.672769] [<ffffffff81051b27>] warn_slowpath_fmt+0x47/0x50 [ 158.673620] [<ffffffff813bc98d>] create_subvol+0x3d1/0x6ea [ 158.674440] [<ffffffff813777c9>] btrfs_mksubvol.isra.30+0x369/0x520 [ 158.675376] [<ffffffff8108a4aa>] ? percpu_down_read+0x1a/0x50 [ 158.676235] [<ffffffff81377a81>] btrfs_ioctl_snap_create_transid+0x101/0x180 [ 158.677268] [<ffffffff81377b52>] btrfs_ioctl_snap_create+0x52/0x70 [ 158.678183] [<ffffffff8137afb4>] btrfs_ioctl+0x474/0x2f90 [ 158.678975] [<ffffffff81144b8e>] ? vma_merge+0xee/0x300 [ 158.679751] [<ffffffff8115be31>] ? alloc_pages_vma+0x91/0x170 [ 158.680599] [<ffffffff81123f62>] ? lru_cache_add_active_or_unevictable+0x22/0x70 [ 158.681686] [<ffffffff813d99cf>] ? selinux_file_ioctl+0xff/0x1d0 [ 158.682581] [<ffffffff8117b791>] do_vfs_ioctl+0x2c1/0x490 [ 158.683399] [<ffffffff813d3cde>] ? security_file_ioctl+0x3e/0x60 [ 158.684297] [<ffffffff8117b9d4>] SyS_ioctl+0x74/0x80 [ 158.685051] [<ffffffff819b2bd7>] entry_SYSCALL_64_fastpath+0x12/0x6a [ 158.685958] ---[ end trace 4b63312de5a2cb76 ]--- [ 158.686647] BTRFS: error (device loop0) in create_subvol:558: errno=-2 No such entry [ 158.709508] BTRFS info (device loop0): forced readonly [ 158.737113] BTRFS info (device loop0): disk space caching is enabled [ 158.738096] BTRFS error (device loop0): Remounting read-write after error is not allowed [ 158.851303] BTRFS error (device loop0): cleaner transaction attach returned -30 This occurs because, Mount filesystem Create subvol with ID 257 Unmount filesystem Mount filesystem Delete subvol with ID 257 btrfs_drop_snapshot() Add root corresponding to subvol 257 into btrfs_transaction->dropped_roots list Create new subvol (i.e. create_subvol()) 257 is returned as the next free objectid btrfs_read_fs_root_no_name() Finds the btrfs_root instance corresponding to the old subvol with ID 257 in btrfs_fs_info->fs_roots_radix. Returns error since btrfs_root_item->refs has the value of 0. To fix the issue the commit initializes tree root's and subvolume root's highest_objectid when loading the roots from disk. Signed-off-by: Chandan Rajendra <chandan@linux.vnet.ibm.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | Merge branch 'misc-cleanups-4.5' of ↵Chris Mason2016-01-111-1/+1
|\ \ | |/ |/| | | | | | | git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux into for-linus-4.5 Signed-off-by: Chris Mason <clm@fb.com>
| * Btrfs: use linux/sizes.h to represent constantsByongho Lee2016-01-071-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We use many constants to represent size and offset value. And to make code readable we use '256 * 1024 * 1024' instead of '268435456' to represent '256MB'. However we can make far more readable with 'SZ_256MB' which is defined in the 'linux/sizes.h'. So this patch replaces 'xxx * 1024 * 1024' kind of expression with single 'SZ_xxxMB' if 'xxx' is a power of 2 then 'xxx * SZ_1M' if 'xxx' is not a power of 2. And I haven't touched to '4096' & '8192' because it's more intuitive than 'SZ_4KB' & 'SZ_8KB'. Signed-off-by: Byongho Lee <bhlee.kernel@gmail.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: cleanup, use enum values for btrfs_path readaDavid Sterba2016-01-071-1/+1
| | | | | | | | | | | | | | | | Replace the integers by enums for better readability. The value 2 does not have any meaning since a717531942f488209dded30f6bc648167bcefa72 "Btrfs: do less aggressive btree readahead" (2009-01-22). Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: constify remaining structs with function pointersDavid Sterba2016-01-071-2/+2
|/ | | | | | | * struct extent_io_ops * struct btrfs_free_space_op Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: qgroup: Cleanup old inaccurate facilitiesQu Wenruo2015-10-221-3/+3
| | | | | | | | | | | | | | Cleanup the old facilities which use old btrfs_qgroup_reserve() function call, replace them with the newer version, and remove the "__" prefix in them. Also, make btrfs_qgroup_reserve/free() functions private, as they are now only used inside qgroup codes. Now, the whole btrfs qgroup is swithed to use the new reserve facilities. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
* btrfs: extent-tree: Switch to new delalloc space reserve and releaseQu Wenruo2015-10-221-3/+3
| | | | | | | | | Use new __btrfs_delalloc_reserve_space() and __btrfs_delalloc_release_space() to reserve and release space for delalloc. Signed-off-by: Qu Wenruo <quwenruo@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
* Btrfs: fix race between caching kthread and returning inode to inode cacheFilipe Manana2015-06-301-4/+11
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | While the inode cache caching kthread is calling btrfs_unpin_free_ino(), we could have a concurrent call to btrfs_return_ino() that adds a new entry to the root's free space cache of pinned inodes. This concurrent call does not acquire the fs_info->commit_root_sem before adding a new entry if the caching state is BTRFS_CACHE_FINISHED, which is a problem because the caching kthread calls btrfs_unpin_free_ino() after setting the caching state to BTRFS_CACHE_FINISHED and therefore races with the task calling btrfs_return_ino(), which is adding a new entry, while the former (caching kthread) is navigating the cache's rbtree, removing and freeing nodes from the cache's rbtree without acquiring the spinlock that protects the rbtree. This race resulted in memory corruption due to double free of struct btrfs_free_space objects because both tasks can end up doing freeing the same objects. Note that adding a new entry can result in merging it with other entries in the cache, in which case those entries are freed. This is particularly important as btrfs_free_space structures are also used for the block group free space caches. This memory corruption can be detected by a debugging kernel, which reports it with the following trace: [132408.501148] slab error in verify_redzone_free(): cache `btrfs_free_space': double free detected [132408.505075] CPU: 15 PID: 12248 Comm: btrfs-ino-cache Tainted: G W 4.1.0-rc5-btrfs-next-10+ #1 [132408.505075] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.8.1-0-g4adadbd-20150316_085822-nilsson.home.kraxel.org 04/01/2014 [132408.505075] ffff880023e7d320 ffff880163d73cd8 ffffffff8145eec7 ffffffff81095dce [132408.505075] ffff880009735d40 ffff880163d73ce8 ffffffff81154e1e ffff880163d73d68 [132408.505075] ffffffff81155733 ffffffffa054a95a ffff8801b6099f00 ffffffffa0505b5f [132408.505075] Call Trace: [132408.505075] [<ffffffff8145eec7>] dump_stack+0x4f/0x7b [132408.505075] [<ffffffff81095dce>] ? console_unlock+0x356/0x3a2 [132408.505075] [<ffffffff81154e1e>] __slab_error.isra.28+0x25/0x36 [132408.505075] [<ffffffff81155733>] __cache_free+0xe2/0x4b6 [132408.505075] [<ffffffffa054a95a>] ? __btrfs_add_free_space+0x2f0/0x343 [btrfs] [132408.505075] [<ffffffffa0505b5f>] ? btrfs_unpin_free_ino+0x8e/0x99 [btrfs] [132408.505075] [<ffffffff810f3b30>] ? time_hardirqs_off+0x15/0x28 [132408.505075] [<ffffffff81084d42>] ? trace_hardirqs_off+0xd/0xf [132408.505075] [<ffffffff811563a1>] ? kfree+0xb6/0x14e [132408.505075] [<ffffffff811563d0>] kfree+0xe5/0x14e [132408.505075] [<ffffffffa0505b5f>] btrfs_unpin_free_ino+0x8e/0x99 [btrfs] [132408.505075] [<ffffffffa0505e08>] caching_kthread+0x29e/0x2d9 [btrfs] [132408.505075] [<ffffffffa0505b6a>] ? btrfs_unpin_free_ino+0x99/0x99 [btrfs] [132408.505075] [<ffffffff8106698f>] kthread+0xef/0xf7 [132408.505075] [<ffffffff810f3b08>] ? time_hardirqs_on+0x15/0x28 [132408.505075] [<ffffffff810668a0>] ? __kthread_parkme+0xad/0xad [132408.505075] [<ffffffff814653d2>] ret_from_fork+0x42/0x70 [132408.505075] [<ffffffff810668a0>] ? __kthread_parkme+0xad/0xad [132408.505075] ffff880023e7d320: redzone 1:0x9f911029d74e35b, redzone 2:0x9f911029d74e35b. [132409.501654] slab: double free detected in cache 'btrfs_free_space', objp ffff880023e7d320 [132409.503355] ------------[ cut here ]------------ [132409.504241] kernel BUG at mm/slab.c:2571! Therefore fix this by having btrfs_unpin_free_ino() acquire the lock that protects the rbtree while doing the searches and removing entries. Fixes: 1c70d8fb4dfa ("Btrfs: fix inode caching vs tree log") Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
* Btrfs: use kmem_cache_free when freeing entry in inode cacheFilipe Manana2015-06-301-1/+1
| | | | | | | | | | | | | | | | | | | | | | The free space entries are allocated using kmem_cache_zalloc(), through __btrfs_add_free_space(), therefore we should use kmem_cache_free() and not kfree() to avoid any confusion and any potential problem. Looking at the kfree() definition at mm/slab.c it has the following comment: /* * (...) * * Don't free memory not originally allocated by kmalloc() * or you will run into trouble. */ So better be safe and use kmem_cache_free(). Cc: stable@vger.kernel.org Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
* Btrfs: allow block group cache writeout outside critical section in commitChris Mason2015-04-101-1/+1
| | | | | | | | | | | | | | | | | We loop through all of the dirty block groups during commit and write the free space cache. In order to make sure the cache is currect, we do this while no other writers are allowed in the commit. If a large number of block groups are dirty, this can introduce long stalls during the final stages of the commit, which can block new procs trying to change the filesystem. This commit changes the block group cache writeout to take appropriate locks and allow it to run earlier in the commit. We'll still have to redo some of the block groups, but it means we can get most of the work out of the way without blocking the entire FS. Signed-off-by: Chris Mason <clm@fb.com>
* Btrfs: fix race between writing free space cache and trimmingFilipe Manana2014-12-031-0/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Trimming is completely transactionless, and the way it operates consists of hiding free space entries from a block group, perform the trim/discard and then make the free space entries visible again. Therefore while a free space entry is being trimmed, we can have free space cache writing running in parallel (as part of a transaction commit) which will miss the free space entry. This means that an unmount (or crash/reboot) after that transaction commit and mount again before another transaction starts/commits after the discard finishes, we will have some free space that won't be used again unless the free space cache is rebuilt. After the unmount, fsck (btrfsck, btrfs check) reports the issue like the following example: *** fsck.btrfs output *** checking extents checking free space cache There is no free space entry for 521764864-521781248 There is no free space entry for 521764864-1103101952 cache appears valid but isnt 29360128 Checking filesystem on /dev/sdc UUID: b4789e27-4774-4626-98e9-ae8dfbfb0fb5 found 1235681286 bytes used err is -22 (...) Another issue caused by this race is a crash while writing bitmap entries to the cache, because while the cache writeout task accesses the bitmaps, the trim task can be concurrently modifying the bitmap or worse might be freeing the bitmap. The later case results in the following crash: [55650.804460] general protection fault: 0000 [#1] SMP DEBUG_PAGEALLOC [55650.804835] Modules linked in: btrfs dm_flakey dm_mod crc32c_generic xor raid6_pq nfsd auth_rpcgss oid_registry nfs_acl nfs lockd fscache sunrpc loop parport_pc parport i2c_piix4 psmouse evdev pcspkr microcode processor i2ccore serio_raw thermal_sys button ext4 crc16 jbd2 mbcache sg sd_mod crc_t10dif sr_mod cdrom crct10dif_generic crct10dif_common ata_generic virtio_scsi floppy ata_piix libata virtio_pci virtio_ring virtio scsi_mod e1000 [last unloaded: btrfs] [55650.806169] CPU: 1 PID: 31002 Comm: btrfs-transacti Tainted: G W 3.17.0-rc5-btrfs-next-1+ #1 [55650.806493] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.7.5-0-ge51488c-20140602_164612-nilsson.home.kraxel.org 04/01/2014 [55650.806867] task: ffff8800b12f6410 ti: ffff880071538000 task.ti: ffff880071538000 [55650.807166] RIP: 0010:[<ffffffffa037cf45>] [<ffffffffa037cf45>] write_bitmap_entries+0x65/0xbb [btrfs] [55650.807514] RSP: 0018:ffff88007153bc30 EFLAGS: 00010246 [55650.807687] RAX: 000000005d1ec000 RBX: ffff8800a665df08 RCX: 0000000000000400 [55650.807885] RDX: ffff88005d1ec000 RSI: 6b6b6b6b6b6b6b6b RDI: ffff88005d1ec000 [55650.808017] RBP: ffff88007153bc58 R08: 00000000ddd51536 R09: 00000000000001e0 [55650.808017] R10: 0000000000000000 R11: 0000000000000037 R12: 6b6b6b6b6b6b6b6b [55650.808017] R13: ffff88007153bca8 R14: 6b6b6b6b6b6b6b6b R15: ffff88007153bc98 [55650.808017] FS: 0000000000000000(0000) GS:ffff88023ec80000(0000) knlGS:0000000000000000 [55650.808017] CS: 0010 DS: 0000 ES: 0000 CR0: 000000008005003b [55650.808017] CR2: 0000000002273b88 CR3: 00000000b18f6000 CR4: 00000000000006e0 [55650.808017] Stack: [55650.808017] ffff88020e834e00 ffff880172d68db0 0000000000000000 ffff88019257c800 [55650.808017] ffff8801d42ea720 ffff88007153bd10 ffffffffa037d2fa ffff880224e99180 [55650.808017] ffff8801469a6188 ffff880224e99140 ffff880172d68c50 00000003000000b7 [55650.808017] Call Trace: [55650.808017] [<ffffffffa037d2fa>] __btrfs_write_out_cache+0x1ea/0x37f [btrfs] [55650.808017] [<ffffffffa037d959>] btrfs_write_out_cache+0xa1/0xd8 [btrfs] [55650.808017] [<ffffffffa033936b>] btrfs_write_dirty_block_groups+0x4b5/0x505 [btrfs] [55650.808017] [<ffffffffa03aa98e>] commit_cowonly_roots+0x15e/0x1f7 [btrfs] [55650.808017] [<ffffffff813eb9c7>] ? _raw_spin_lock+0xe/0x10 [55650.808017] [<ffffffffa0346e46>] btrfs_commit_transaction+0x411/0x882 [btrfs] [55650.808017] [<ffffffffa03432a4>] transaction_kthread+0xf2/0x1a4 [btrfs] [55650.808017] [<ffffffffa03431b2>] ? btrfs_cleanup_transaction+0x3d8/0x3d8 [btrfs] [55650.808017] [<ffffffff8105966b>] kthread+0xb7/0xbf [55650.808017] [<ffffffff810595b4>] ? __kthread_parkme+0x67/0x67 [55650.808017] [<ffffffff813ebeac>] ret_from_fork+0x7c/0xb0 [55650.808017] [<ffffffff810595b4>] ? __kthread_parkme+0x67/0x67 [55650.808017] Code: 4c 89 ef 8d 70 ff e8 d4 fc ff ff 41 8b 45 34 41 39 45 30 7d 5c 31 f6 4c 89 ef e8 80 f6 ff ff 49 8b 7d 00 4c 89 f6 b9 00 04 00 00 <f3> a5 4c 89 ef 41 8b 45 30 8d 70 ff e8 a3 fc ff ff 41 8b 45 34 [55650.808017] RIP [<ffffffffa037cf45>] write_bitmap_entries+0x65/0xbb [btrfs] [55650.808017] RSP <ffff88007153bc30> [55650.815725] ---[ end trace 1c032e96b149ff86 ]--- Fix this by serializing both tasks in such a way that cache writeout doesn't wait for the trim/discard of free space entries to finish and doesn't miss any free space entry. Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Chris Mason <clm@fb.com>
* btrfs: switch inode_cache option handling to pending changesDavid Sterba2014-11-121-1/+1
| | | | | | | | | | | | The pending mount option(s) now share namespace and bits with the normal options, and the existing one for (inode_cache) is unset unconditionally at each transaction commit. Introduce a separate namespace for pending changes and enhance the descriptions of the intended change to use separate bits for each action. Signed-off-by: David Sterba <dsterba@suse.cz>
* btrfs: cleanup ino cache members of btrfs_rootDavid Sterba2014-09-171-34/+34
| | | | | | | | The naming is confusing, generic yet used for a specific cache. Add a prefix 'ino_' or rename appropriately. Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
* btrfs: remove newline from inode cache kthread nameDavid Sterba2014-06-101-1/+1
| | | | | Signed-off-by: David Sterba <dsterba@suse.cz> Signed-off-by: Chris Mason <clm@fb.com>
* Btrfs: fix inode caching vs tree logMiao Xie2014-04-251-16/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Currently, with inode cache enabled, we will reuse its inode id immediately after unlinking file, we may hit something like following: |->iput inode |->return inode id into inode cache |->create dir,fsync |->power off An easy way to reproduce this problem is: mkfs.btrfs -f /dev/sdb mount /dev/sdb /mnt -o inode_cache,commit=100 dd if=/dev/zero of=/mnt/data bs=1M count=10 oflag=sync inode_id=`ls -i /mnt/data | awk '{print $1}'` rm -f /mnt/data i=1 while [ 1 ] do mkdir /mnt/dir_$i test1=`stat /mnt/dir_$i | grep Inode: | awk '{print $4}'` if [ $test1 -eq $inode_id ] then dd if=/dev/zero of=/mnt/dir_$i/data bs=1M count=1 oflag=sync echo b > /proc/sysrq-trigger fi sleep 1 i=$(($i+1)) done mount /dev/sdb /mnt umount /dev/sdb btrfs check /dev/sdb We fix this problem by adding unlinked inode's id into pinned tree, and we can not reuse them until committing transaction. Cc: stable@vger.kernel.org Signed-off-by: Miao Xie <miaox@cn.fujitsu.com> Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
* Btrfs: avoid triggering bug_on() when we fail to start inode caching taskWang Shilong2014-04-251-1/+5
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When running stress test(including snapshots,balance,fstress), we trigger the following BUG_ON() which is because we fail to start inode caching task. [ 181.131945] kernel BUG at fs/btrfs/inode-map.c:179! [ 181.137963] invalid opcode: 0000 [#1] SMP [ 181.217096] CPU: 11 PID: 2532 Comm: btrfs Not tainted 3.14.0 #1 [ 181.240521] task: ffff88013b621b30 ti: ffff8800b6ada000 task.ti: ffff8800b6ada000 [ 181.367506] Call Trace: [ 181.371107] [<ffffffffa036c1be>] btrfs_return_ino+0x9e/0x110 [btrfs] [ 181.379191] [<ffffffffa038082b>] btrfs_evict_inode+0x46b/0x4c0 [btrfs] [ 181.387464] [<ffffffff810b5a70>] ? autoremove_wake_function+0x40/0x40 [ 181.395642] [<ffffffff811dc5fe>] evict+0x9e/0x190 [ 181.401882] [<ffffffff811dcde3>] iput+0xf3/0x180 [ 181.408025] [<ffffffffa03812de>] btrfs_orphan_cleanup+0x1ee/0x430 [btrfs] [ 181.416614] [<ffffffffa03a6abd>] btrfs_mksubvol.isra.29+0x3bd/0x450 [btrfs] [ 181.425399] [<ffffffffa03a6cd6>] btrfs_ioctl_snap_create_transid+0x186/0x190 [btrfs] [ 181.435059] [<ffffffffa03a6e3b>] btrfs_ioctl_snap_create_v2+0xeb/0x130 [btrfs] [ 181.444148] [<ffffffffa03a9656>] btrfs_ioctl+0xf76/0x2b90 [btrfs] [ 181.451971] [<ffffffff8117e565>] ? handle_mm_fault+0x475/0xe80 [ 181.459509] [<ffffffff8167ba0c>] ? __do_page_fault+0x1ec/0x520 [ 181.467046] [<ffffffff81185b35>] ? do_mmap_pgoff+0x2f5/0x3c0 [ 181.474393] [<ffffffff811d4da8>] do_vfs_ioctl+0x2d8/0x4b0 [ 181.481450] [<ffffffff811d5001>] SyS_ioctl+0x81/0xa0 [ 181.488021] [<ffffffff81680b69>] system_call_fastpath+0x16/0x1b We should avoid triggering BUG_ON() here, instead, we output warning messages and clear inode_cache option. Signed-off-by: Wang Shilong <wangsl.fnst@cn.fujitsu.com> Signed-off-by: Chris Mason <clm@fb.com>
* Btrfs: remove transaction from sendJosef Bacik2014-04-071-7/+7
| | | | | | | | | | | | | | | | | | | | Lets try this again. We can deadlock the box if we send on a box and try to write onto the same fs with the app that is trying to listen to the send pipe. This is because the writer could get stuck waiting for a transaction commit which is being blocked by the send. So fix this by making sure looking at the commit roots is always going to be consistent. We do this by keeping track of which roots need to have their commit roots swapped during commit, and then taking the commit_root_sem and swapping them all at once. Then make sure we take a read lock on the commit_root_sem in cases where we search the commit root to make sure we're always looking at a consistent view of the commit roots. Previously we had problems with this because we would swap a fs tree commit root and then swap the extent tree commit root independently which would cause the backref walking code to screw up sometimes. With this patch we no longer deadlock and pass all the weird send/receive corner cases. Thanks, Reportedy-by: Hugo Mills <hugo@carfax.org.uk> Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Chris Mason <clm@fb.com>
* btrfs: Use WARN_ON()'s return value in place of WARN_ON(1)Dulshani Gunawardhana2013-11-121-3/+1
| | | | | | | | | | | Use WARN_ON()'s return value in place of WARN_ON(1) for cleaner source code that outputs a more descriptive warnings. Also fix the styling warning of redundant braces that came up as a result of this fix. Signed-off-by: Dulshani Gunawardhana <dulshani.gunawardhana89@gmail.com> Reviewed-by: Zach Brown <zab@redhat.com> Signed-off-by: Josef Bacik <jbacik@fusionio.com> Signed-off-by: Chris Mason <chris.mason@fusionio.com>