- 12 Sep, 2019 2 commits
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Filipe Manana authored
The lock_extent_buffer_io() returns 1 to the caller to tell it everything went fine and the callers needs to start writeback for the extent buffer (submit a bio, etc), 0 to tell the caller everything went fine but it does not need to start writeback for the extent buffer, and a negative value if some error happened. When it's about to return 1 it tries to lock all pages, and if a try lock on a page fails, and we didn't flush any existing bio in our "epd", it calls flush_write_bio(epd) and overwrites the return value of 1 to 0 or an error. The page might have been locked elsewhere, not with the goal of starting writeback of the extent buffer, and even by some code other than btrfs, like page migration for example, so it does not mean the writeback of the extent buffer was already started by some other task, so returning a 0 tells the caller (btree_write_cache_pages()) to not start writeback for the extent buffer. Note that epd might currently have either no bio, so flush_write_bio() returns 0 (success) or it might have a bio for another extent buffer with a lower index (logical address). Since we return 0 with the EXTENT_BUFFER_WRITEBACK bit set on the extent buffer and writeback is never started for the extent buffer, future attempts to writeback the extent buffer will hang forever waiting on that bit to be cleared, since it can only be cleared after writeback completes. Such hang is reported with a trace like the following: [49887.347053] INFO: task btrfs-transacti:1752 blocked for more than 122 seconds. [49887.347059] Not tainted 5.2.13-gentoo #2 [49887.347060] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [49887.347062] btrfs-transacti D 0 1752 2 0x80004000 [49887.347064] Call Trace: [49887.347069] ? __schedule+0x265/0x830 [49887.347071] ? bit_wait+0x50/0x50 [49887.347072] ? bit_wait+0x50/0x50 [49887.347074] schedule+0x24/0x90 [49887.347075] io_schedule+0x3c/0x60 [49887.347077] bit_wait_io+0x8/0x50 [49887.347079] __wait_on_bit+0x6c/0x80 [49887.347081] ? __lock_release.isra.29+0x155/0x2d0 [49887.347083] out_of_line_wait_on_bit+0x7b/0x80 [49887.347084] ? var_wake_function+0x20/0x20 [49887.347087] lock_extent_buffer_for_io+0x28c/0x390 [49887.347089] btree_write_cache_pages+0x18e/0x340 [49887.347091] do_writepages+0x29/0xb0 [49887.347093] ? kmem_cache_free+0x132/0x160 [49887.347095] ? convert_extent_bit+0x544/0x680 [49887.347097] filemap_fdatawrite_range+0x70/0x90 [49887.347099] btrfs_write_marked_extents+0x53/0x120 [49887.347100] btrfs_write_and_wait_transaction.isra.4+0x38/0xa0 [49887.347102] btrfs_commit_transaction+0x6bb/0x990 [49887.347103] ? start_transaction+0x33e/0x500 [49887.347105] transaction_kthread+0x139/0x15c So fix this by not overwriting the return value (ret) with the result from flush_write_bio(). We also need to clear the EXTENT_BUFFER_WRITEBACK bit in case flush_write_bio() returns an error, otherwise it will hang any future attempts to writeback the extent buffer, and undo all work done before (set back EXTENT_BUFFER_DIRTY, etc). This is a regression introduced in the 5.2 kernel. Fixes: 2e3c2513 ("btrfs: extent_io: add proper error handling to lock_extent_buffer_for_io()") Fixes: f4340622 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up") Reported-by:
Zdenek Sojka <zsojka@seznam.cz> Link: https://lore.kernel.org/linux-btrfs/GpO.2yos.3WGDOLpx6t%7D.1TUDYM@seznam.cz/T/#uReported-by:
Stefan Priebe - Profihost AG <s.priebe@profihost.ag> Link: https://lore.kernel.org/linux-btrfs/5c4688ac-10a7-fb07-70e8-c5d31a3fbb38@profihost.ag/T/#tReported-by:
Drazen Kacar <drazen.kacar@oradian.com> Link: https://lore.kernel.org/linux-btrfs/DB8PR03MB562876ECE2319B3E579590F799C80@DB8PR03MB5628.eurprd03.prod.outlook.com/ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204377Signed-off-by:
Filipe Manana <fdmanana@suse.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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Filipe Manana authored
Sometimes when fsync'ing a file we need to log that other inodes exist and when we need to do that we acquire a reference on the inodes and then drop that reference using iput() after logging them. That generally is not a problem except if we end up doing the final iput() (dropping the last reference) on the inode and that inode has a link count of 0, which can happen in a very short time window if the logging path gets a reference on the inode while it's being unlinked. In that case we end up getting the eviction callback, btrfs_evict_inode(), invoked through the iput() call chain which needs to drop all of the inode's items from its subvolume btree, and in order to do that, it needs to join a transaction at the helper function evict_refill_and_join(). However because the task previously started a transaction at the fsync handler, btrfs_sync_file(), it has current->journal_info already pointing to a transaction handle and therefore evict_refill_and_join() will get that transaction handle from btrfs_join_transaction(). From this point on, two different problems can happen: 1) evict_refill_and_join() will often change the transaction handle's block reserve (->block_rsv) and set its ->bytes_reserved field to a value greater than 0. If evict_refill_and_join() never commits the transaction, the eviction handler ends up decreasing the reference count (->use_count) of the transaction handle through the call to btrfs_end_transaction(), and after that point we have a transaction handle with a NULL ->block_rsv (which is the value prior to the transaction join from evict_refill_and_join()) and a ->bytes_reserved value greater than 0. If after the eviction/iput completes the inode logging path hits an error or it decides that it must fallback to a transaction commit, the btrfs fsync handle, btrfs_sync_file(), gets a non-zero value from btrfs_log_dentry_safe(), and because of that non-zero value it tries to commit the transaction using a handle with a NULL ->block_rsv and a non-zero ->bytes_reserved value. This makes the transaction commit hit an assertion failure at btrfs_trans_release_metadata() because ->bytes_reserved is not zero but the ->block_rsv is NULL. The produced stack trace for that is like the following: [192922.917158] assertion failed: !trans->bytes_reserved, file: fs/btrfs/transaction.c, line: 816 [192922.917553] ------------[ cut here ]------------ [192922.917922] kernel BUG at fs/btrfs/ctree.h:3532! [192922.918310] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI [192922.918666] CPU: 2 PID: 883 Comm: fsstress Tainted: G W 5.1.4-btrfs-next-47 #1 [192922.919035] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014 [192922.919801] RIP: 0010:assfail.constprop.25+0x18/0x1a [btrfs] (...) [192922.920925] RSP: 0018:ffffaebdc8a27da8 EFLAGS: 00010286 [192922.921315] RAX: 0000000000000051 RBX: ffff95c9c16a41c0 RCX: 0000000000000000 [192922.921692] RDX: 0000000000000000 RSI: ffff95cab6b16838 RDI: ffff95cab6b16838 [192922.922066] RBP: ffff95c9c16a41c0 R08: 0000000000000000 R09: 0000000000000000 [192922.922442] R10: ffffaebdc8a27e70 R11: 0000000000000000 R12: ffff95ca731a0980 [192922.922820] R13: 0000000000000000 R14: ffff95ca84c73338 R15: ffff95ca731a0ea8 [192922.923200] FS: 00007f337eda4e80(0000) GS:ffff95cab6b00000(0000) knlGS:0000000000000000 [192922.923579] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [192922.923948] CR2: 00007f337edad000 CR3: 00000001e00f6002 CR4: 00000000003606e0 [192922.924329] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [192922.924711] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [192922.925105] Call Trace: [192922.925505] btrfs_trans_release_metadata+0x10c/0x170 [btrfs] [192922.925911] btrfs_commit_transaction+0x3e/0xaf0 [btrfs] [192922.926324] btrfs_sync_file+0x44c/0x490 [btrfs] [192922.926731] do_fsync+0x38/0x60 [192922.927138] __x64_sys_fdatasync+0x13/0x20 [192922.927543] do_syscall_64+0x60/0x1c0 [192922.927939] entry_SYSCALL_64_after_hwframe+0x49/0xbe (...) [192922.934077] ---[ end trace f00808b12068168f ]--- 2) If evict_refill_and_join() decides to commit the transaction, it will be able to do it, since the nested transaction join only increments the transaction handle's ->use_count reference counter and it does not prevent the transaction from getting committed. This means that after eviction completes, the fsync logging path will be using a transaction handle that refers to an already committed transaction. What happens when using such a stale transaction can be unpredictable, we are at least having a use-after-free on the transaction handle itself, since the transaction commit will call kmem_cache_free() against the handle regardless of its ->use_count value, or we can end up silently losing all the updates to the log tree after that iput() in the logging path, or using a transaction handle that in the meanwhile was allocated to another task for a new transaction, etc, pretty much unpredictable what can happen. In order to fix both of them, instead of using iput() during logging, use btrfs_add_delayed_iput(), so that the logging path of fsync never drops the last reference on an inode, that step is offloaded to a safe context (usually the cleaner kthread). The assertion failure issue was sporadically triggered by the test case generic/475 from fstests, which loads the dm error target while fsstress is running, which lead to fsync failing while logging inodes with -EIO errors and then trying later to commit the transaction, triggering the assertion failure. CC: stable@vger.kernel.org # 4.4+ Reviewed-by:
Josef Bacik <josef@toxicpanda.com> Signed-off-by:
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- 07 Aug, 2019 2 commits
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Qu Wenruo authored
Normally the range->len is set to default value (U64_MAX), but when it's not default value, we should check if the range overflows. And if it overflows, return -EINVAL before doing anything. Reviewed-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
Anand Jain <anand.jain@oracle.com> Signed-off-by:
Qu Wenruo <wqu@suse.com> Signed-off-by:
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Filipe Manana authored
In the 5.3 merge window, commit 7c7e3014 ("btrfs: sysfs: Replace default_attrs in ktypes with groups"), we started using the member "defaults_groups" for the kobject type "btrfs_raid_ktype". That leads to a series of warnings when running some test cases of fstests, such as btrfs/027, btrfs/124 and btrfs/176. The traces produced by those warnings are like the following: [116648.059212] kernfs: can not remove 'total_bytes', no directory [116648.060112] WARNING: CPU: 3 PID: 28500 at fs/kernfs/dir.c:1504 kernfs_remove_by_name_ns+0x75/0x80 (...) [116648.066482] CPU: 3 PID: 28500 Comm: umount Tainted: G W 5.3.0-rc3-btrfs-next-54 #1 (...) [116648.069376] RIP: 0010:kernfs_remove_by_name_ns+0x75/0x80 (...) [116648.072385] RSP: 0018:ffffabfd0090bd08 EFLAGS: 00010282 [116648.073437] RAX: 0000000000000000 RBX: ffffffffc0c11998 RCX: 0000000000000000 [116648.074201] RDX: ffff9fff603a7a00 RSI: ffff9fff603978a8 RDI: ffff9fff603978a8 [116648.074956] RBP: ffffffffc0b9ca2f R08: 0000000000000000 R09: 0000000000000001 [116648.075708] R10: ffff9ffe1f72e1c0 R11: 0000000000000000 R12: ffffffffc0b94120 [116648.076434] R13: ffffffffb3d9b4e0 R14: 0000000000000000 R15: dead000000000100 [116648.077143] FS: 00007f9cdc78a2c0(0000) GS:ffff9fff60380000(0000) knlGS:0000000000000000 [116648.077852] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [116648.078546] CR2: 00007f9fc4747ab4 CR3: 00000005c7832003 CR4: 00000000003606e0 [116648.079235] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [116648.079907] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [116648.080585] Call Trace: [116648.081262] remove_files+0x31/0x70 [116648.081929] sysfs_remove_group+0x38/0x80 [116648.082596] sysfs_remove_groups+0x34/0x70 [116648.083258] kobject_del+0x20/0x60 [116648.083933] btrfs_free_block_groups+0x405/0x430 [btrfs] [116648.084608] close_ctree+0x19a/0x380 [btrfs] [116648.085278] generic_shutdown_super+0x6c/0x110 [116648.085951] kill_anon_super+0xe/0x30 [116648.086621] btrfs_kill_super+0x12/0xa0 [btrfs] [116648.087289] deactivate_locked_super+0x3a/0x70 [116648.087956] cleanup_mnt+0xb4/0x160 [116648.088620] task_work_run+0x7e/0xc0 [116648.089285] exit_to_usermode_loop+0xfa/0x100 [116648.089933] do_syscall_64+0x1cb/0x220 [116648.090567] entry_SYSCALL_64_after_hwframe+0x49/0xbe [116648.091197] RIP: 0033:0x7f9cdc073b37 (...) [116648.100046] ---[ end trace 22e24db328ccadf8 ]--- [116648.100618] ------------[ cut here ]------------ [116648.101175] kernfs: can not remove 'used_bytes', no directory [116648.101731] WARNING: CPU: 3 PID: 28500 at fs/kernfs/dir.c:1504 kernfs_remove_by_name_ns+0x75/0x80 (...) [116648.105649] CPU: 3 PID: 28500 Comm: umount Tainted: G W 5.3.0-rc3-btrfs-next-54 #1 (...) [116648.107461] RIP: 0010:kernfs_remove_by_name_ns+0x75/0x80 (...) [116648.109336] RSP: 0018:ffffabfd0090bd08 EFLAGS: 00010282 [116648.109979] RAX: 0000000000000000 RBX: ffffffffc0c119a0 RCX: 0000000000000000 [116648.110625] RDX: ffff9fff603a7a00 RSI: ffff9fff603978a8 RDI: ffff9fff603978a8 [116648.111283] RBP: ffffffffc0b9ca41 R08: 0000000000000000 R09: 0000000000000001 [116648.111940] R10: ffff9ffe1f72e1c0 R11: 0000000000000000 R12: ffffffffc0b94120 [116648.112603] R13: ffffffffb3d9b4e0 R14: 0000000000000000 R15: dead000000000100 [116648.113268] FS: 00007f9cdc78a2c0(0000) GS:ffff9fff60380000(0000) knlGS:0000000000000000 [116648.113939] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [116648.114607] CR2: 00007f9fc4747ab4 CR3: 00000005c7832003 CR4: 00000000003606e0 [116648.115286] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [116648.115966] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [116648.116649] Call Trace: [116648.117326] remove_files+0x31/0x70 [116648.117997] sysfs_remove_group+0x38/0x80 [116648.118671] sysfs_remove_groups+0x34/0x70 [116648.119342] kobject_del+0x20/0x60 [116648.120022] btrfs_free_block_groups+0x405/0x430 [btrfs] [116648.120707] close_ctree+0x19a/0x380 [btrfs] [116648.121396] generic_shutdown_super+0x6c/0x110 [116648.122057] kill_anon_super+0xe/0x30 [116648.122702] btrfs_kill_super+0x12/0xa0 [btrfs] [116648.123335] deactivate_locked_super+0x3a/0x70 [116648.123961] cleanup_mnt+0xb4/0x160 [116648.124586] task_work_run+0x7e/0xc0 [116648.125210] exit_to_usermode_loop+0xfa/0x100 [116648.125830] do_syscall_64+0x1cb/0x220 [116648.126463] entry_SYSCALL_64_after_hwframe+0x49/0xbe [116648.127080] RIP: 0033:0x7f9cdc073b37 (...) [116648.135923] ---[ end trace 22e24db328ccadf9 ]--- These happen because, during the unmount path, we call kobject_del() for raid kobjects that are not fully initialized, meaning that we set their ktype (as btrfs_raid_ktype) through link_block_group() but we didn't set their parent kobject, which is done through btrfs_add_raid_kobjects(). We have this split raid kobject setup since commit 75cb379d ("btrfs: defer adding raid type kobject until after chunk relocation") in order to avoid triggering reclaim during contextes where we can not (either we are holding a transaction handle or some lock required by the transaction commit path), so that we do the calls to kobject_add(), which triggers GFP_KERNEL allocations, through btrfs_add_raid_kobjects() in contextes where it is safe to trigger reclaim. That change expected that a new raid kobject can only be created either when mounting the filesystem or after raid profile conversion through the relocation path. However, we can have new raid kobject created in other two cases at least: 1) During device replace (or scrub) after adding a device a to the filesystem. The replace procedure (and scrub) do calls to btrfs_inc_block_group_ro() which can allocate a new block group with a new raid profile (because we now have more devices). This can be triggered by test cases btrfs/027 and btrfs/176. 2) During a degraded mount trough any write path. This can be triggered by test case btrfs/124. Fixing this by adding extra calls to btrfs_add_raid_kobjects(), not only makes things more complex and fragile, can also introduce deadlocks with reclaim the following way: 1) Calling btrfs_add_raid_kobjects() at btrfs_inc_block_group_ro() or anywhere in the replace/scrub path will cause a deadlock with reclaim because if reclaim happens and a transaction commit is triggered, the transaction commit path will block at btrfs_scrub_pause(). 2) During degraded mounts it is essentially impossible to figure out where to add extra calls to btrfs_add_raid_kobjects(), because allocation of a block group with a new raid profile can happen anywhere, which means we can't safely figure out which contextes are safe for reclaim, as we can either hold a transaction handle or some lock needed by the transaction commit path. So it is too complex and error prone to have this split setup of raid kobjects. So fix the issue by consolidating the setup of the kobjects in a single place, at link_block_group(), and setup a nofs context there in order to prevent reclaim being triggered by the memory allocations done through the call chain of kobject_add(). Besides fixing the sysfs warnings during kobject_del(), this also ensures the sysfs directories for the new raid profiles end up created and visible to users (a bug that existed before the 5.3 commit 7c7e3014 ("btrfs: sysfs: Replace default_attrs in ktypes with groups")). Fixes: 75cb379d ("btrfs: defer adding raid type kobject until after chunk relocation") Fixes: 7c7e3014 ("btrfs: sysfs: Replace default_attrs in ktypes with groups") Signed-off-by:
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- 30 Jul, 2019 3 commits
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Filipe Manana authored
The fiemap handler locks a file range that can have unflushed delalloc, and after locking the range, it tries to attach to a running transaction. If the running transaction started its commit, that is, it is in state TRANS_STATE_COMMIT_START, and either the filesystem was mounted with the flushoncommit option or the transaction is creating a snapshot for the subvolume that contains the file that fiemap is operating on, we end up deadlocking. This happens because fiemap is blocked on the transaction, waiting for it to complete, and the transaction is waiting for the flushed dealloc to complete, which requires locking the file range that the fiemap task already locked. The following stack traces serve as an example of when this deadlock happens: (...) [404571.515510] Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs] [404571.515956] Call Trace: [404571.516360] ? __schedule+0x3ae/0x7b0 [404571.516730] schedule+0x3a/0xb0 [404571.517104] lock_extent_bits+0x1ec/0x2a0 [btrfs] [404571.517465] ? remove_wait_queue+0x60/0x60 [404571.517832] btrfs_finish_ordered_io+0x292/0x800 [btrfs] [404571.518202] normal_work_helper+0xea/0x530 [btrfs] [404571.518566] process_one_work+0x21e/0x5c0 [404571.518990] worker_thread+0x4f/0x3b0 [404571.519413] ? process_one_work+0x5c0/0x5c0 [404571.519829] kthread+0x103/0x140 [404571.520191] ? kthread_create_worker_on_cpu+0x70/0x70 [404571.520565] ret_from_fork+0x3a/0x50 [404571.520915] kworker/u8:6 D 0 31651 2 0x80004000 [404571.521290] Workqueue: btrfs-flush_delalloc btrfs_flush_delalloc_helper [btrfs] (...) [404571.537000] fsstress D 0 13117 13115 0x00004000 [404571.537263] Call Trace: [404571.537524] ? __schedule+0x3ae/0x7b0 [404571.537788] schedule+0x3a/0xb0 [404571.538066] wait_current_trans+0xc8/0x100 [btrfs] [404571.538349] ? remove_wait_queue+0x60/0x60 [404571.538680] start_transaction+0x33c/0x500 [btrfs] [404571.539076] btrfs_check_shared+0xa3/0x1f0 [btrfs] [404571.539513] ? extent_fiemap+0x2ce/0x650 [btrfs] [404571.539866] extent_fiemap+0x2ce/0x650 [btrfs] [404571.540170] do_vfs_ioctl+0x526/0x6f0 [404571.540436] ksys_ioctl+0x70/0x80 [404571.540734] __x64_sys_ioctl+0x16/0x20 [404571.540997] do_syscall_64+0x60/0x1d0 [404571.541279] entry_SYSCALL_64_after_hwframe+0x49/0xbe (...) [404571.543729] btrfs D 0 14210 14208 0x00004000 [404571.544023] Call Trace: [404571.544275] ? __schedule+0x3ae/0x7b0 [404571.544526] ? wait_for_completion+0x112/0x1a0 [404571.544795] schedule+0x3a/0xb0 [404571.545064] schedule_timeout+0x1ff/0x390 [404571.545351] ? lock_acquire+0xa6/0x190 [404571.545638] ? wait_for_completion+0x49/0x1a0 [404571.545890] ? wait_for_completion+0x112/0x1a0 [404571.546228] wait_for_completion+0x131/0x1a0 [404571.546503] ? wake_up_q+0x70/0x70 [404571.546775] btrfs_wait_ordered_extents+0x27c/0x400 [btrfs] [404571.547159] btrfs_commit_transaction+0x3b0/0xae0 [btrfs] [404571.547449] ? btrfs_mksubvol+0x4a4/0x640 [btrfs] [404571.547703] ? remove_wait_queue+0x60/0x60 [404571.547969] btrfs_mksubvol+0x605/0x640 [btrfs] [404571.548226] ? __sb_start_write+0xd4/0x1c0 [404571.548512] ? mnt_want_write_file+0x24/0x50 [404571.548789] btrfs_ioctl_snap_create_transid+0x169/0x1a0 [btrfs] [404571.549048] btrfs_ioctl_snap_create_v2+0x11d/0x170 [btrfs] [404571.549307] btrfs_ioctl+0x133f/0x3150 [btrfs] [404571.549549] ? mem_cgroup_charge_statistics+0x4c/0xd0 [404571.549792] ? mem_cgroup_commit_charge+0x84/0x4b0 [404571.550064] ? __handle_mm_fault+0xe3e/0x11f0 [404571.550306] ? do_raw_spin_unlock+0x49/0xc0 [404571.550608] ? _raw_spin_unlock+0x24/0x30 [404571.550976] ? __handle_mm_fault+0xedf/0x11f0 [404571.551319] ? do_vfs_ioctl+0xa2/0x6f0 [404571.551659] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [404571.552087] do_vfs_ioctl+0xa2/0x6f0 [404571.552355] ksys_ioctl+0x70/0x80 [404571.552621] __x64_sys_ioctl+0x16/0x20 [404571.552864] do_syscall_64+0x60/0x1d0 [404571.553104] entry_SYSCALL_64_after_hwframe+0x49/0xbe (...) If we were joining the transaction instead of attaching to it, we would not risk a deadlock because a join only blocks if the transaction is in a state greater then or equals to TRANS_STATE_COMMIT_DOING, and the delalloc flush performed by a transaction is done before it reaches that state, when it is in the state TRANS_STATE_COMMIT_START. However a transaction join is intended for use cases where we do modify the filesystem, and fiemap only needs to peek at delayed references from the current transaction in order to determine if extents are shared, and, besides that, when there is no current transaction or when it blocks to wait for a current committing transaction to complete, it creates a new transaction without reserving any space. Such unnecessary transactions, besides doing unnecessary IO, can cause transaction aborts (-ENOSPC) and unnecessary rotation of the precious backup roots. So fix this by adding a new transaction join variant, named join_nostart, which behaves like the regular join, but it does not create a transaction when none currently exists or after waiting for a committing transaction to complete. Fixes: 03628cdb ("Btrfs: do not start a transaction during fiemap") Signed-off-by:
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Filipe Manana authored
When one transaction is finishing its commit, it is possible for another transaction to start and enter its initial commit phase as well. If the first ends up getting aborted, we have a small time window where the second transaction commit does not notice that the previous transaction aborted and ends up committing, writing a superblock that points to btrees that reference extent buffers (nodes and leafs) that were not persisted to disk. The consequence is that after mounting the filesystem again, we will be unable to load some btree nodes/leafs, either because the content on disk is either garbage (or just zeroes) or corresponds to the old content of a previouly COWed or deleted node/leaf, resulting in the well known error messages "parent transid verify failed on ...". The following sequence diagram illustrates how this can happen. CPU 1 CPU 2 <at transaction N> btrfs_commit_transaction() (...) --> sets transaction state to TRANS_STATE_UNBLOCKED --> sets fs_info->running_transaction to NULL (...) btrfs_start_transaction() start_transaction() wait_current_trans() --> returns immediately because fs_info->running_transaction is NULL join_transaction() --> creates transaction N + 1 --> sets fs_info->running_transaction to transaction N + 1 --> adds transaction N + 1 to the fs_info->trans_list list --> returns transaction handle pointing to the new transaction N + 1 (...) btrfs_sync_file() btrfs_start_transaction() --> returns handle to transaction N + 1 (...) btrfs_write_and_wait_transaction() --> writeback of some extent buffer fails, returns an error btrfs_handle_fs_error() --> sets BTRFS_FS_STATE_ERROR in fs_info->fs_state --> jumps to label "scrub_continue" cleanup_transaction() btrfs_abort_transaction(N) --> sets BTRFS_FS_STATE_TRANS_ABORTED flag in fs_info->fs_state --> sets aborted field in the transaction and transaction handle structures, for transaction N only --> removes transaction from the list fs_info->trans_list btrfs_commit_transaction(N + 1) --> transaction N + 1 was not aborted, so it proceeds (...) --> sets the transaction's state to TRANS_STATE_COMMIT_START --> does not find the previous transaction (N) in the fs_info->trans_list, so it doesn't know that transaction was aborted, and the commit of transaction N + 1 proceeds (...) --> sets transaction N + 1 state to TRANS_STATE_UNBLOCKED btrfs_write_and_wait_transaction() --> succeeds writing all extent buffers created in the transaction N + 1 write_all_supers() --> succeeds --> we now have a superblock on disk that points to trees that refer to at least one extent buffer that was never persisted So fix this by updating the transaction commit path to check if the flag BTRFS_FS_STATE_TRANS_ABORTED is set on fs_info->fs_state if after setting the transaction to the TRANS_STATE_COMMIT_START we do not find any previous transaction in the fs_info->trans_list. If the flag is set, just fail the transaction commit with -EROFS, as we do in other places. The exact error code for the previous transaction abort was already logged and reported. Fixes: 49b25e05 ("btrfs: enhance transaction abort infrastructure") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: -
Filipe Manana authored
When doing an incremental send operation we can fail if we previously did deduplication operations against a file that exists in both snapshots. In that case we will fail the send operation with -EIO and print a message to dmesg/syslog like the following: BTRFS error (device sdc): Send: inconsistent snapshot, found updated \ extent for inode 257 without updated inode item, send root is 258, \ parent root is 257 This requires that we deduplicate to the same file in both snapshots for the same amount of times on each snapshot. The issue happens because a deduplication only updates the iversion of an inode and does not update any other field of the inode, therefore if we deduplicate the file on each snapshot for the same amount of time, the inode will have the same iversion value (stored as the "sequence" field on the inode item) on both snapshots, therefore it will be seen as unchanged between in the send snapshot while there are new/updated/deleted extent items when comparing to the parent snapshot. This makes the send operation return -EIO and print an error message. Example reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt # Create our first file. The first half of the file has several 64Kb # extents while the second half as a single 512Kb extent. $ xfs_io -f -s -c "pwrite -S 0xb8 -b 64K 0 512K" /mnt/foo $ xfs_io -c "pwrite -S 0xb8 512K 512K" /mnt/foo # Create the base snapshot and the parent send stream from it. $ btrfs subvolume snapshot -r /mnt /mnt/mysnap1 $ btrfs send -f /tmp/1.snap /mnt/mysnap1 # Create our second file, that has exactly the same data as the first # file. $ xfs_io -f -c "pwrite -S 0xb8 0 1M" /mnt/bar # Create the second snapshot, used for the incremental send, before # doing the file deduplication. $ btrfs subvolume snapshot -r /mnt /mnt/mysnap2 # Now before creating the incremental send stream: # # 1) Deduplicate into a subrange of file foo in snapshot mysnap1. This # will drop several extent items and add a new one, also updating # the inode's iversion (sequence field in inode item) by 1, but not # any other field of the inode; # # 2) Deduplicate into a different subrange of file foo in snapshot # mysnap2. This will replace an extent item with a new one, also # updating the inode's iversion by 1 but not any other field of the # inode. # # After these two deduplication operations, the inode items, for file # foo, are identical in both snapshots, but we have different extent # items for this inode in both snapshots. We want to check this doesn't # cause send to fail with an error or produce an incorrect stream. $ xfs_io -r -c "dedupe /mnt/bar 0 0 512K" /mnt/mysnap1/foo $ xfs_io -r -c "dedupe /mnt/bar 512K 512K 512K" /mnt/mysnap2/foo # Create the incremental send stream. $ btrfs send -p /mnt/mysnap1 -f /tmp/2.snap /mnt/mysnap2 ERROR: send ioctl failed with -5: Input/output error This issue started happening back in 2015 when deduplication was updated to not update the inode's ctime and mtime and update only the iversion. Back then we would hit a BUG_ON() in send, but later in 2016 send was updated to return -EIO and print the error message instead of doing the BUG_ON(). A test case for fstests follows soon. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=203933 Fixes: 1c919a5e ("btrfs: don't update mtime/ctime on deduped inodes") CC: stable@vger.kernel.org # 4.4+ Signed-off-by:
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- 26 Jul, 2019 1 commit
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Naohiro Aota authored
btrfs_lock_and_flush_ordered_range() loads given "*cached_state" into cachedp, which, in general, is NULL. Then, lock_extent_bits() updates "cachedp", but it never goes backs to the caller. Thus the caller still see its "cached_state" to be NULL and never free the state allocated under btrfs_lock_and_flush_ordered_range(). As a result, we will see massive state leak with e.g. fstests btrfs/005. Fix this bug by properly handling the pointers. Fixes: bd80d94e ("btrfs: Always use a cached extent_state in btrfs_lock_and_flush_ordered_range") Reviewed-by:
Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by:
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- 25 Jul, 2019 1 commit
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Nikolay Borisov authored
Commit 06297d8c ("btrfs: switch extent_buffer blocking_writers from atomic to int") changed the type of blocking_writers but forgot to adjust relevant code in btrfs_tree_unlock by converting the smp_mb__after_atomic to smp_mb. This opened up the possibility of a deadlock due to re-ordering of setting blocking_writers and checking/waking up the waiter. This particular lockup is explained in a comment above waitqueue_active() function. Fix it by converting the memory barrier to a full smp_mb, accounting for the fact that blocking_writers is a simple integer. Fixes: 06297d8c ("btrfs: switch extent_buffer blocking_writers from atomic to int") Tested-by:
Johannes Thumshirn <jthumshirn@suse.com> Signed-off-by:
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- 17 Jul, 2019 4 commits
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Johannes Thumshirn authored
btrfs_get_io_geometry() calls btrfs_get_chunk_map() to acquire a reference on a extent_map, but on normal operation it does not drop this reference anymore. This leads to excessive kmemleak reports. Always call free_extent_map(), not just in the error case. Fixes: 5f141126 ("btrfs: Introduce btrfs_io_geometry infrastructure") Reviewed-by:
Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by:
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Johannes Thumshirn authored
fs_info::csum_hash gets initialized in btrfs_init_csum_hash() which is called by open_ctree(). But it only gets freed if open_ctree() fails, not on normal operation. This leads to a memory leak like the following found by kmemleak: unreferenced object 0xffff888132cb8720 (size 96): comm "mount", pid 450, jiffies 4294912436 (age 17.584s) hex dump (first 32 bytes): 04 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<000000000c9643d4>] crypto_create_tfm+0x2d/0xd0 [<00000000ae577f68>] crypto_alloc_tfm+0x4b/0xb0 [<000000002b5cdf30>] open_ctree+0xb84/0x2060 [btrfs] [<0000000043204297>] btrfs_mount_root+0x552/0x640 [btrfs] [<00000000c99b10ea>] legacy_get_tree+0x22/0x40 [<0000000071a6495f>] vfs_get_tree+0x1f/0xc0 [<00000000f180080e>] fc_mount+0x9/0x30 [<000000009e36cebd>] vfs_kern_mount.part.11+0x6a/0x80 [<0000000004594c05>] btrfs_mount+0x174/0x910 [btrfs] [<00000000c99b10ea>] legacy_get_tree+0x22/0x40 [<0000000071a6495f>] vfs_get_tree+0x1f/0xc0 [<00000000b86e92c5>] do_mount+0x6b0/0x940 [<0000000097464494>] ksys_mount+0x7b/0xd0 [<0000000057213c80>] __x64_sys_mount+0x1c/0x20 [<00000000cb689b5e>] do_syscall_64+0x43/0x130 [<000000002194e289>] entry_SYSCALL_64_after_hwframe+0x44/0xa9 Free fs_info::csum_hash in close_ctree() to avoid the memory leak. Fixes: 6d97c6e3 ("btrfs: add boilerplate code for directly including the crypto framework") Reviewed-by: -
YueHaibing authored
If CONFIG_BTRFS_FS is y and CONFIG_LIBCRC32C is m, building fails: fs/btrfs/super.o: In function `btrfs_mount_root': super.c:(.text+0xb7f9): undefined reference to `crc32c_impl' fs/btrfs/super.o: In function `init_btrfs_fs': super.c:(.init.text+0x3465): undefined reference to `crc32c_impl' fs/btrfs/extent-tree.o: In function `hash_extent_data_ref': extent-tree.c:(.text+0xe60): undefined reference to `crc32c' extent-tree.c:(.text+0xe78): undefined reference to `crc32c' extent-tree.c:(.text+0xe8b): undefined reference to `crc32c' fs/btrfs/dir-item.o: In function `btrfs_insert_xattr_item': dir-item.c:(.text+0x291): undefined reference to `crc32c' fs/btrfs/dir-item.o: In function `btrfs_insert_dir_item': dir-item.c:(.text+0x429): undefined reference to `crc32c' Select LIBCRC32C to fix it. Reported-by:
Hulk Robot <hulkci@huawei.com> Fixes: d5178578 ("btrfs: directly call into crypto framework for checksumming") Reviewed-by:
YueHaibing <yuehaibing@huawei.com> Reviewed-by:
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Qu Wenruo authored
As btrfs(5) specified: Note If nodatacow or nodatasum are enabled, compression is disabled. If NODATASUM or NODATACOW set, we should not compress the extent. Normally NODATACOW is detected properly in run_delalloc_range() so compression won't happen for NODATACOW. However for NODATASUM we don't have any check, and it can cause compressed extent without csum pretty easily, just by: mkfs.btrfs -f $dev mount $dev $mnt -o nodatasum touch $mnt/foobar mount -o remount,datasum,compress $mnt xfs_io -f -c "pwrite 0 128K" $mnt/foobar And in fact, we have a bug report about corrupted compressed extent without proper data checksum so even RAID1 can't recover the corruption. (https://bugzilla.kernel.org/show_bug.cgi?id=199707) Running compression without proper checksum could cause more damage when corruption happens, as compressed data could make the whole extent unreadable, so there is no need to allow compression for NODATACSUM. The fix will refactor the inode compression check into two parts: - inode_can_compress() As the hard requirement, checked at btrfs_run_delalloc_range(), so no compression will happen for NODATASUM inode at all. - inode_need_compress() As the soft requirement, checked at btrfs_run_delalloc_range() and compress_file_range(). Reported-by:
James Harvey <jamespharvey20@gmail.com> CC: stable@vger.kernel.org # 4.4+ Signed-off-by:
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- 05 Jul, 2019 1 commit
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Colin Ian King authored
Currently if the allocation of roots or tmp_ulist fails the error handling does not free up the allocation of path causing a memory leak. Fix this and other similar leaks by moving the call of btrfs_free_path from label out to label out_free_ulist. Kudos to David Sterba for spotting the issue in my original fix and suggesting the correct way to fix the leak and Anand Jain for spotting a double free issue. Addresses-Coverity: ("Resource leak") Fixes: 5911c8fe ("btrfs: fiemap: preallocate ulists for btrfs_check_shared") Reviewed-by:Colin Ian King <colin.king@canonical.com> Reviewed-by:
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- 04 Jul, 2019 5 commits
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Josef Bacik authored
This is just two functions, put it in root-tree.c since it involves root items. Signed-off-by:
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Josef Bacik authored
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:
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Josef Bacik authored
Move this into transaction.c with the rest of the transaction related code. Signed-off-by:
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Josef Bacik authored
These belong with the delayed refs related code, not in extent-tree.c. Signed-off-by:
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Goldwyn Rodrigues authored
Simplification. No point passing the tree variable when it can be evaluated from inode. The tests now use the io_tree from btrfs_inode as opposed to creating one. Signed-off-by:
Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by:
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- 02 Jul, 2019 21 commits
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Josef Bacik authored
These helpers belong in block-rsv.c Signed-off-by:
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Josef Bacik authored
This moves everything out of extent-tree.c to block-rsv.c. Signed-off-by:
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Josef Bacik authored
block_rsv_release_bytes() is the internal to the block_rsv code, and shouldn't be called directly by anything else. Switch all users to the exported helpers. Signed-off-by:
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Josef Bacik authored
This works for all callers already, but if we wanted to use the helper for the global_block_rsv it would end up trying to refill itself. Fix the logic to be able to be used no matter which block rsv is passed in to this helper. Signed-off-by:
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Josef Bacik authored
The delalloc reserve stuff calls this directly because it cares about the qgroup accounting stuff, so export it so we can move it around. Fix btrfs_block_rsv_release() to just be a static inline since it just calls __btrfs_block_rsv_release() with NULL for the qgroup stuff. Signed-off-by:
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Josef Bacik authored
This is used in a few places, we need to make sure it's exported so we can move it around. Signed-off-by:
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Josef Bacik authored
Prep work for separating out all of the block_rsv related code into its own file. Signed-off-by:
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Goldwyn Rodrigues authored
We don't need an if-else-if chain where we can use a simple OR since both conditions are performing the same action. The short-circuit for OR will ensure that if the first condition is true, can_overcommit() is not called. Reviewed-by:
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Josef Bacik authored
Now that we've moved all of the users to space-info.c, unexport it and name it back to can_overcommit. Reviewed-by:
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Josef Bacik authored
This moves all of the metadata reservation code into space-info.c. Reviewed-by:
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Josef Bacik authored
We'll need this exported so we can use it in all the various was we need to use it. This is prep work to move reserve_metadata_bytes. Reviewed-by:
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Josef Bacik authored
We are going to need this to move the metadata reservation stuff to space_info.c. Reviewed-by:
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Josef Bacik authored
Now that we've moved all the pre-requisite stuff, move these two functions. Reviewed-by:
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Josef Bacik authored
Also rename it to btrfs_space_info_update_* so it's clear what we're updating. Reviewed-by:
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Josef Bacik authored
This is the first piece of moving the space reservation code to space-info.c Reviewed-by:
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Josef Bacik authored
These are the basic init and lookup functions and some helper functions, fairly straightforward before the bad stuff starts. Reviewed-by:
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Josef Bacik authored
Prep work for consolidating all of the space_info code into one file. We need to export these so multiple files can use them. Reviewed-by:
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Josef Bacik authored
Really we just need the enum, but as we break more things up it'll help to have this external to extent-tree.c. Reviewed-by:
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Josef Bacik authored
Migrate the struct definition and the one helper that's in ctree.h into space-info.h Reviewed-by:
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David Sterba authored
The block device is passed around for the only purpose to set it in new bios. Move the assignment one level up. This is a preparatory patch for further bdev cleanups. Signed-off-by: -
David Sterba authored
Minimum stripe count matches the minimum devices required for a given profile. The open coded assignments match the raid_attr table. What's changed here is the meaning for RAID5/6. Previously their min_stripes would be 1, while newly it's devs_min. This however shold be the same as before because it's not possible to create filesystem on fewer devices than the raid_attr table allows. There's no adjustment regarding the parity stripes (like calc_data_stripes does), because we're interested in overall space that would fit on the devices. Missing devices make no difference for the whole calculation, we have the size stored in the structures. Signed-off-by:
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