kernel/linux.git/fs/btrfs/disk-io.c, branch linux-5.3.y

btrfs: don't needlessly create extent-refs kernel thread

2019-10-29T08:22:43+00:00

commit 80ed4548d0711d15ca51be5dee0ff813051cfc90 upstream. The patch 32b593bfcb58 ("Btrfs: remove no longer used function to run delayed refs asynchronously") removed the async delayed refs but the thread has been created, without any use. Remove it to avoid resource consumption. Fixes: 32b593bfcb58 ("Btrfs: remove no longer used function to run delayed refs asynchronously") CC: stable@vger.kernel.org # 5.2+ Reviewed-by: Josef Bacik Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: Detect unbalanced tree with empty leaf before crashing btree operations

2019-10-05T13:12:12+00:00

[ Upstream commit 62fdaa52a3d00a875da771719b6dc537ca79fce1 ] [BUG] With crafted image, btrfs will panic at btree operations: kernel BUG at fs/btrfs/ctree.c:3894! invalid opcode: 0000 [#1] SMP PTI CPU: 0 PID: 1138 Comm: btrfs-transacti Not tainted 5.0.0-rc8+ #9 RIP: 0010:__push_leaf_left+0x6b6/0x6e0 RSP: 0018:ffffc0bd4128b990 EFLAGS: 00010246 RAX: 0000000000000000 RBX: ffffa0a4ab8f0e38 RCX: 0000000000000000 RDX: ffffa0a280000000 RSI: 0000000000000000 RDI: ffffa0a4b3814000 RBP: ffffc0bd4128ba38 R08: 0000000000001000 R09: ffffc0bd4128b948 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000240 R13: ffffa0a4b556fb60 R14: ffffa0a4ab8f0af0 R15: ffffa0a4ab8f0af0 FS: 0000000000000000(0000) GS:ffffa0a4b7a00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f2461c80020 CR3: 000000022b32a006 CR4: 00000000000206f0 Call Trace: ? _cond_resched+0x1a/0x50 push_leaf_left+0x179/0x190 btrfs_del_items+0x316/0x470 btrfs_del_csums+0x215/0x3a0 __btrfs_free_extent.isra.72+0x5a7/0xbe0 __btrfs_run_delayed_refs+0x539/0x1120 btrfs_run_delayed_refs+0xdb/0x1b0 btrfs_commit_transaction+0x52/0x950 ? start_transaction+0x94/0x450 transaction_kthread+0x163/0x190 kthread+0x105/0x140 ? btrfs_cleanup_transaction+0x560/0x560 ? kthread_destroy_worker+0x50/0x50 ret_from_fork+0x35/0x40 Modules linked in: ---[ end trace c2425e6e89b5558f ]--- [CAUSE] The offending csum tree looks like this: checksum tree key (CSUM_TREE ROOT_ITEM 0) node 29741056 level 1 items 14 free 107 generation 19 owner CSUM_TREE ... key (EXTENT_CSUM EXTENT_CSUM 85975040) block 29630464 gen 17 key (EXTENT_CSUM EXTENT_CSUM 89911296) block 29642752 gen 17 <<< key (EXTENT_CSUM EXTENT_CSUM 92274688) block 29646848 gen 17 ... leaf 29630464 items 6 free space 1 generation 17 owner CSUM_TREE item 0 key (EXTENT_CSUM EXTENT_CSUM 85975040) itemoff 3987 itemsize 8 range start 85975040 end 85983232 length 8192 ... leaf 29642752 items 0 free space 3995 generation 17 owner 0 ^ empty leaf invalid owner ^ leaf 29646848 items 1 free space 602 generation 17 owner CSUM_TREE item 0 key (EXTENT_CSUM EXTENT_CSUM 92274688) itemoff 627 itemsize 3368 range start 92274688 end 95723520 length 3448832 So we have a corrupted csum tree where one tree leaf is completely empty, causing unbalanced btree, thus leading to unexpected btree balance error. [FIX] For this particular case, we handle it in two directions to catch it: - Check if the tree block is empty through btrfs_verify_level_key() So that invalid tree blocks won't be read out through btrfs_search_slot() and its variants. - Check 0 tree owner in tree checker NO tree is using 0 as its tree owner, detect it and reject at tree block read time. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202821 Reviewed-by: Nikolay Borisov Signed-off-by: Qu Wenruo Signed-off-by: David Sterba Signed-off-by: Sasha Levin

Btrfs: fix sysfs warning and missing raid sysfs directories

2019-08-07T14:25:44+00:00

In the 5.3 merge window, commit 7c7e301406d0a9 ("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 75cb379d263521 ("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 7c7e301406d0a9 ("btrfs: sysfs: Replace default_attrs in ktypes with groups")). Fixes: 75cb379d263521 ("btrfs: defer adding raid type kobject until after chunk relocation") Fixes: 7c7e301406d0a9 ("btrfs: sysfs: Replace default_attrs in ktypes with groups") Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: free checksum hash on in close_ctree

2019-07-17T15:03:33+00:00

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: 6d97c6e31b55 ("btrfs: add boilerplate code for directly including the crypto framework") Reviewed-by: Qu Wenruo Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba

Btrfs: prevent send failures and crashes due to concurrent relocation

2019-07-02T10:30:49+00:00

Send always operates on read-only trees and always expected that while it is in progress, nothing changes in those trees. Due to that expectation and the fact that send is a read-only operation, it operates on commit roots and does not hold transaction handles. However relocation can COW nodes and leafs from read-only trees, which can cause unexpected failures and crashes (hitting BUG_ONs). while send using a node/leaf, it gets COWed, the transaction used to COW it is committed, a new transaction starts, the extent previously used for that node/leaf gets allocated, possibly for another tree, and the respective extent buffer' content changes while send is still using it. When this happens send normally fails with EIO being returned to user space and messages like the following are found in dmesg/syslog: [ 3408.699121] BTRFS error (device sdc): parent transid verify failed on 58703872 wanted 250 found 253 [ 3441.523123] BTRFS error (device sdc): did not find backref in send_root. inode=63211, offset=0, disk_byte=5222825984 found extent=5222825984 Other times, less often, we hit a BUG_ON() because an extent buffer that send is using used to be a node, and while send is still using it, it got COWed and got reused as a leaf while send is still using, producing the following trace: [ 3478.466280] ------------[ cut here ]------------ [ 3478.466282] kernel BUG at fs/btrfs/ctree.c:1806! [ 3478.466965] invalid opcode: 0000 [#1] SMP DEBUG_PAGEALLOC PTI [ 3478.467635] CPU: 0 PID: 2165 Comm: btrfs Not tainted 5.0.0-btrfs-next-46 #1 [ 3478.468311] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.11.2-0-gf9626ccb91-prebuilt.qemu-project.org 04/01/2014 [ 3478.469681] RIP: 0010:read_node_slot+0x122/0x130 [btrfs] (...) [ 3478.471758] RSP: 0018:ffffa437826bfaa0 EFLAGS: 00010246 [ 3478.472457] RAX: ffff961416ed7000 RBX: 000000000000003d RCX: 0000000000000002 [ 3478.473151] RDX: 000000000000003d RSI: ffff96141e387408 RDI: ffff961599b30000 [ 3478.473837] RBP: ffffa437826bfb8e R08: 0000000000000001 R09: ffffa437826bfb8e [ 3478.474515] R10: ffffa437826bfa70 R11: 0000000000000000 R12: ffff9614385c8708 [ 3478.475186] R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 [ 3478.475840] FS: 00007f8e0e9cc8c0(0000) GS:ffff9615b6a00000(0000) knlGS:0000000000000000 [ 3478.476489] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 3478.477127] CR2: 00007f98b67a056e CR3: 0000000005df6005 CR4: 00000000003606f0 [ 3478.477762] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 3478.478385] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 3478.479003] Call Trace: [ 3478.479600] ? do_raw_spin_unlock+0x49/0xc0 [ 3478.480202] tree_advance+0x173/0x1d0 [btrfs] [ 3478.480810] btrfs_compare_trees+0x30c/0x690 [btrfs] [ 3478.481388] ? process_extent+0x1280/0x1280 [btrfs] [ 3478.481954] btrfs_ioctl_send+0x1037/0x1270 [btrfs] [ 3478.482510] _btrfs_ioctl_send+0x80/0x110 [btrfs] [ 3478.483062] btrfs_ioctl+0x13fe/0x3120 [btrfs] [ 3478.483581] ? rq_clock_task+0x2e/0x60 [ 3478.484086] ? wake_up_new_task+0x1f3/0x370 [ 3478.484582] ? do_vfs_ioctl+0xa2/0x6f0 [ 3478.485075] ? btrfs_ioctl_get_supported_features+0x30/0x30 [btrfs] [ 3478.485552] do_vfs_ioctl+0xa2/0x6f0 [ 3478.486016] ? __fget+0x113/0x200 [ 3478.486467] ksys_ioctl+0x70/0x80 [ 3478.486911] __x64_sys_ioctl+0x16/0x20 [ 3478.487337] do_syscall_64+0x60/0x1b0 [ 3478.487751] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 3478.488159] RIP: 0033:0x7f8e0d7d4dd7 (...) [ 3478.489349] RSP: 002b:00007ffcf6fb4908 EFLAGS: 00000202 ORIG_RAX: 0000000000000010 [ 3478.489742] RAX: ffffffffffffffda RBX: 0000000000000105 RCX: 00007f8e0d7d4dd7 [ 3478.490142] RDX: 00007ffcf6fb4990 RSI: 0000000040489426 RDI: 0000000000000005 [ 3478.490548] RBP: 0000000000000005 R08: 00007f8e0d6f3700 R09: 00007f8e0d6f3700 [ 3478.490953] R10: 00007f8e0d6f39d0 R11: 0000000000000202 R12: 0000000000000005 [ 3478.491343] R13: 00005624e0780020 R14: 0000000000000000 R15: 0000000000000001 (...) [ 3478.493352] ---[ end trace d5f537302be4f8c8 ]--- Another possibility, much less likely to happen, is that send will not fail but the contents of the stream it produces may not be correct. To avoid this, do not allow send and relocation (balance) to run in parallel. In the long term the goal is to allow for both to be able to run concurrently without any problems, but that will take a significant effort in development and testing. Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: directly call into crypto framework for checksumming

2019-07-01T11:35:02+00:00

Currently btrfs_csum_data() relied on the crc32c() wrapper around the crypto framework for calculating the CRCs. As we have our own crypto_shash structure in the fs_info now, we can directly call into the crypto framework without going trough the wrapper. This way we can even remove the btrfs_csum_data() and btrfs_csum_final() wrappers. The module dependency on crc32c is preserved via MODULE_SOFTDEP("pre: crc32c"), which was previously provided by LIBCRC32C config option doing the same. Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add boilerplate code for directly including the crypto framework

2019-07-01T11:35:01+00:00

Add boilerplate code for directly including the crypto framework. This helps us flipping the switch for new algorithms. Reviewed-by: Nikolay Borisov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: Simplify btrfs_check_super_csum() and get rid of size assumptions

2019-07-01T11:35:01+00:00

Now that we have already checked for a valid checksum type before calling btrfs_check_super_csum(), it can be simplified even further. While at it get rid of the implicit size assumption of the resulting checksum as well. This is a preparation for changing all checksum functionality to use the crypto layer later. Reviewed-by: Nikolay Borisov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: check for supported superblock checksum type before checksum validation

2019-07-01T11:35:01+00:00

Now that we have factorerd out the superblock checksum type validation, we can check for supported superblock checksum types before doing the actual validation of the superblock read from disk. This leads the path to further simplifications of btrfs_check_super_csum() later on. Reviewed-by: Nikolay Borisov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba [ add comment ] Signed-off-by: David Sterba

btrfs: add common checksum type validation

2019-07-01T11:35:01+00:00

Currently btrfs is only supporting CRC32C as checksumming algorithm. As this is about to change provide a function to validate the checksum type in the superblock against all possible algorithms. This makes adding new algorithms easier as there are fewer places to adjust when adding new algorithms. Reviewed-by: Nikolay Borisov Signed-off-by: Johannes Thumshirn Reviewed-by: David Sterba Signed-off-by: David Sterba