- 17 Oct, 2019 1 commit
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Qu Wenruo authored
[BUG] For btrfs:qgroup_meta_reserve event, the trace event can output garbage: qgroup_meta_reserve: 9c7f6acc-b342-4037-bc47-7f6e4d2232d7: refroot=5(FS_TREE) type=DATA diff=2 The diff should always be alinged to sector size (4k), so there is definitely something wrong. [CAUSE] For the wrong @diff, it's caused by wrong parameter order. The correct parameters are: struct btrfs_root, s64 diff, int type. However the parameters used are: struct btrfs_root, int type, s64 diff. Fixes: 4ee0d883 ("btrfs: qgroup: Update trace events for metadata reservation") CC: stable@vger.kernel.org # 4.19+ Reviewed-by:
Nikolay Borisov <nborisov@suse.com> Signed-off-by:
Qu Wenruo <wqu@suse.com> Reviewed-by:
David Sterba <dsterba@suse.com> Signed-off-by:
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- 15 Oct, 2019 2 commits
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Qu Wenruo authored
[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 336a8bb8 ("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 f5fef459 ("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: 43b18595 ("btrfs: qgroup: Use separate meta reservation type for delalloc") CC: stable@vger.kernel.org # 4.19+ Reviewed-by:
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David Sterba authored
The patch 32b593bf ("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: 32b593bf ("Btrfs: remove no longer used function to run delayed refs asynchronously") CC: stable@vger.kernel.org # 5.2+ Reviewed-by:
Josef Bacik <josef@toxicpanda.com> Signed-off-by:
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- 11 Oct, 2019 2 commits
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Qu Wenruo authored
In btrfs_read_block_groups(), if we have an invalid block group which has mixed type (DATA|METADATA) while the fs doesn't have MIXED_GROUPS feature, we error out without freeing the block group cache. This patch will add the missing btrfs_put_block_group() to prevent memory leak. Note for stable backports: the file to patch in versions <= 5.3 is fs/btrfs/extent-tree.c Fixes: 49303381 ("Btrfs: bail out if block group has different mixed flag") CC: stable@vger.kernel.org # 4.9+ Reviewed-by:
Anand Jain <anand.jain@oracle.com> Reviewed-by:
Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by:
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Filipe Manana authored
If we error out when finding a page at relocate_file_extent_cluster(), we need to release the outstanding extents counter on the relocation inode, set by the previous call to btrfs_delalloc_reserve_metadata(), otherwise the inode's block reserve size can never decrease to zero and metadata space is leaked. Therefore add a call to btrfs_delalloc_release_extents() in case we can't find the target page. Fixes: 8b62f87b ("Btrfs: rework outstanding_extents") CC: stable@vger.kernel.org # 4.19+ Signed-off-by:
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- 08 Oct, 2019 1 commit
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Austin Kim authored
GCC throws warning message as below: ‘clone_src_i_size’ may be used uninitialized in this function [-Wmaybe-uninitialized] #define IS_ALIGNED(x, a) (((x) & ((typeof(x))(a) - 1)) == 0) ^ fs/btrfs/send.c:5088:6: note: ‘clone_src_i_size’ was declared here u64 clone_src_i_size; ^ The clone_src_i_size is only used as call-by-reference in a call to get_inode_info(). Silence the warning by initializing clone_src_i_size to 0. Note that the warning is a false positive and reported by older versions of GCC (eg. 7.x) but not eg 9.x. As there have been numerous people, the patch is applied. Setting clone_src_i_size to 0 does not otherwise make sense and would not do any action in case the code changes in the future. Signed-off-by:Austin Kim <austindh.kim@gmail.com> Reviewed-by:
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- 03 Oct, 2019 1 commit
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Josef Bacik authored
Coverity caught a case where we could return with a uninitialized value in ret in process_leaf. This is actually pretty likely because we could very easily run into a block group item key and have a garbage value in ret and think there was an errror. Fix this by initializing ret to 0. Reported-by:
Colin Ian King <colin.king@canonical.com> Fixes: fd708b81 ("Btrfs: add a extent ref verify tool") CC: stable@vger.kernel.org # 4.19+ Signed-off-by:
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- 01 Oct, 2019 4 commits
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Josef Bacik authored
A user reported a lockdep splat ====================================================== WARNING: possible circular locking dependency detected 5.2.11-gentoo #2 Not tainted ------------------------------------------------------ kswapd0/711 is trying to acquire lock: 000000007777a663 (sb_internal){.+.+}, at: start_transaction+0x3a8/0x500 but task is already holding lock: 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (fs_reclaim){+.+.}: kmem_cache_alloc+0x1f/0x1c0 btrfs_alloc_inode+0x1f/0x260 alloc_inode+0x16/0xa0 new_inode+0xe/0xb0 btrfs_new_inode+0x70/0x610 btrfs_symlink+0xd0/0x420 vfs_symlink+0x9c/0x100 do_symlinkat+0x66/0xe0 do_syscall_64+0x55/0x1c0 entry_SYSCALL_64_after_hwframe+0x49/0xbe -> #0 (sb_internal){.+.+}: __sb_start_write+0xf6/0x150 start_transaction+0x3a8/0x500 btrfs_commit_inode_delayed_inode+0x59/0x110 btrfs_evict_inode+0x19e/0x4c0 evict+0xbc/0x1f0 inode_lru_isolate+0x113/0x190 __list_lru_walk_one.isra.4+0x5c/0x100 list_lru_walk_one+0x32/0x50 prune_icache_sb+0x36/0x80 super_cache_scan+0x14a/0x1d0 do_shrink_slab+0x131/0x320 shrink_node+0xf7/0x380 balance_pgdat+0x2d5/0x640 kswapd+0x2ba/0x5e0 kthread+0x147/0x160 ret_from_fork+0x24/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(sb_internal); lock(fs_reclaim); lock(sb_internal); *** DEADLOCK *** 3 locks held by kswapd0/711: #0: 000000000ba86300 (fs_reclaim){+.+.}, at: __fs_reclaim_acquire+0x0/0x30 #1: 000000004a5100f8 (shrinker_rwsem){++++}, at: shrink_node+0x9a/0x380 #2: 00000000f956fa46 (&type->s_umount_key#30){++++}, at: super_cache_scan+0x35/0x1d0 stack backtrace: CPU: 7 PID: 711 Comm: kswapd0 Not tainted 5.2.11-gentoo #2 Hardware name: Dell Inc. Precision Tower 3620/0MWYPT, BIOS 2.4.2 09/29/2017 Call Trace: dump_stack+0x85/0xc7 print_circular_bug.cold.40+0x1d9/0x235 __lock_acquire+0x18b1/0x1f00 lock_acquire+0xa6/0x170 ? start_transaction+0x3a8/0x500 __sb_start_write+0xf6/0x150 ? start_transaction+0x3a8/0x500 start_transaction+0x3a8/0x500 btrfs_commit_inode_delayed_inode+0x59/0x110 btrfs_evict_inode+0x19e/0x4c0 ? var_wake_function+0x20/0x20 evict+0xbc/0x1f0 inode_lru_isolate+0x113/0x190 ? discard_new_inode+0xc0/0xc0 __list_lru_walk_one.isra.4+0x5c/0x100 ? discard_new_inode+0xc0/0xc0 list_lru_walk_one+0x32/0x50 prune_icache_sb+0x36/0x80 super_cache_scan+0x14a/0x1d0 do_shrink_slab+0x131/0x320 shrink_node+0xf7/0x380 balance_pgdat+0x2d5/0x640 kswapd+0x2ba/0x5e0 ? __wake_up_common_lock+0x90/0x90 kthread+0x147/0x160 ? balance_pgdat+0x640/0x640 ? __kthread_create_on_node+0x160/0x160 ret_from_fork+0x24/0x30 This is because btrfs_new_inode() calls new_inode() under the transaction. We could probably move the new_inode() outside of this but for now just wrap it in memalloc_nofs_save(). Reported-by:Zdenek Sojka <zsojka@seznam.cz> Fixes: 712e36c5 ("btrfs: use GFP_KERNEL in btrfs_alloc_inode") CC: stable@vger.kernel.org # 4.16+ Reviewed-by:
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Zygo Blaxell authored
Currently, the command: btrfs balance start -dconvert=single,soft . on a Raspberry Pi produces the following kernel message: BTRFS error (device mmcblk0p2): balance: invalid convert data profile single This fails because we use is_power_of_2(unsigned long) to validate the new data profile, the constant for 'single' profile uses bit 48, and there are only 32 bits in a long on ARM. Fix by open-coding the check using u64 variables. Tested by completing the original balance command on several Raspberry Pis. Fixes: 818255fe ("btrfs: use common helper instead of open coding a bit test") CC: stable@vger.kernel.org # 4.20+ Signed-off-by:
Zygo Blaxell <ce3g8jdj@umail.furryterror.org> Reviewed-by:
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Josef Bacik authored
We've historically had reports of being unable to mount file systems because the tree log root couldn't be read. Usually this is the "parent transid failure", but could be any of the related errors, including "fsid mismatch" or "bad tree block", depending on which block got allocated. The modification of the individual log root items are serialized on the per-log root root_mutex. This means that any modification to the per-subvol log root_item is completely protected. However we update the root item in the log root tree outside of the log root tree log_mutex. We do this in order to allow multiple subvolumes to be updated in each log transaction. This is problematic however because when we are writing the log root tree out we update the super block with the _current_ log root node information. Since these two operations happen independently of each other, you can end up updating the log root tree in between writing out the dirty blocks and setting the super block to point at the current root. This means we'll point at the new root node that hasn't been written out, instead of the one we should be pointing at. Thus whatever garbage or old block we end up pointing at complains when we mount the file system later and try to replay the log. Fix this by copying the log's root item into a local root item copy. Then once we're safely under the log_root_tree->log_mutex we update the root item in the log_root_tree. This way we do not modify the log_root_tree while we're committing it, fixing the problem. CC: stable@vger.kernel.org # 4.4+ Reviewed-by:
Chris Mason <clm@fb.com> Reviewed-by:
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Filipe Manana authored
When we have a buffered write that starts at an offset greater than or equals to the file's size happening concurrently with a full ranged fiemap, we can end up leaking an extent state structure. Suppose we have a file with a size of 1Mb, and before the buffered write and fiemap are performed, it has a single extent state in its io tree representing the range from 0 to 1Mb, with the EXTENT_DELALLOC bit set. The following sequence diagram shows how the memory leak happens if a fiemap a buffered write, starting at offset 1Mb and with a length of 4Kb, are performed concurrently. CPU 1 CPU 2 extent_fiemap() --> it's a full ranged fiemap range from 0 to LLONG_MAX - 1 (9223372036854775807) --> locks range in the inode's io tree --> after this we have 2 extent states in the io tree: --> 1 for range [0, 1Mb[ with the bits EXTENT_LOCKED and EXTENT_DELALLOC_BITS set --> 1 for the range [1Mb, LLONG_MAX[ with the EXTENT_LOCKED bit set --> start buffered write at offset 1Mb with a length of 4Kb btrfs_file_write_iter() btrfs_buffered_write() --> cached_state is NULL lock_and_cleanup_extent_if_need() --> returns 0 and does not lock range because it starts at current i_size / eof --> cached_state remains NULL btrfs_dirty_pages() btrfs_set_extent_delalloc() (...) __set_extent_bit() --> splits extent state for range [1Mb, LLONG_MAX[ and now we have 2 extent states: --> one for the range [1Mb, 1Mb + 4Kb[ with EXTENT_LOCKED set --> another one for the range [1Mb + 4Kb, LLONG_MAX[ with EXTENT_LOCKED set as well --> sets EXTENT_DELALLOC on the extent state for the range [1Mb, 1Mb + 4Kb[ --> caches extent state [1Mb, 1Mb + 4Kb[ into @cached_state because it has the bit EXTENT_LOCKED set --> btrfs_buffered_write() ends up with a non-NULL cached_state and never calls anything to release its reference on it, resulting in a memory leak Fix this by calling free_extent_state() on cached_state if the range was not locked by lock_and_cleanup_extent_if_need(). The same issue can happen if anything else other than fiemap locks a range that covers eof and beyond. This could be triggered, sporadically, by test case generic/561 from the fstests suite, which makes duperemove run concurrently with fsstress, and duperemove does plenty of calls to fiemap. When CONFIG_BTRFS_DEBUG is set the leak is reported in dmesg/syslog when removing the btrfs module with a message like the following: [77100.039461] BTRFS: state leak: start 6574080 end 6582271 state 16402 in tree 0 refs 1 Otherwise (CONFIG_BTRFS_DEBUG not set) detectable with kmemleak. CC: stable@vger.kernel.org # 4.16+ Reviewed-by:
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- 27 Sep, 2019 2 commits
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Qu Wenruo authored
[BUG] The following script can cause btrfs qgroup data space leak: mkfs.btrfs -f $dev mount $dev -o nospace_cache $mnt btrfs subv create $mnt/subv btrfs quota en $mnt btrfs quota rescan -w $mnt btrfs qgroup limit 128m $mnt/subv for (( i = 0; i < 3; i++)); do # Create 3 64M holes for latter fallocate to fail truncate -s 192m $mnt/subv/file xfs_io -c "pwrite 64m 4k" $mnt/subv/file > /dev/null xfs_io -c "pwrite 128m 4k" $mnt/subv/file > /dev/null sync # it's supposed to fail, and each failure will leak at least 64M # data space xfs_io -f -c "falloc 0 192m" $mnt/subv/file &> /dev/null rm $mnt/subv/file sync done # Shouldn't fail after we removed the file xfs_io -f -c "falloc 0 64m" $mnt/subv/file [CAUSE] Btrfs qgroup data reserve code allow multiple reservations to happen on a single extent_changeset: E.g: btrfs_qgroup_reserve_data(inode, &data_reserved, 0, SZ_1M); btrfs_qgroup_reserve_data(inode, &data_reserved, SZ_1M, SZ_2M); btrfs_qgroup_reserve_data(inode, &data_reserved, 0, SZ_4M); Btrfs qgroup code has its internal tracking to make sure we don't double-reserve in above example. The only pattern utilizing this feature is in the main while loop of btrfs_fallocate() function. However btrfs_qgroup_reserve_data()'s error handling has a bug in that on error it clears all ranges in the io_tree with EXTENT_QGROUP_RESERVED flag but doesn't free previously reserved bytes. This bug has a two fold effect: - Clearing EXTENT_QGROUP_RESERVED ranges This is the correct behavior, but it prevents btrfs_qgroup_check_reserved_leak() to catch the leakage as the detector is purely EXTENT_QGROUP_RESERVED flag based. - Leak the previously reserved data bytes. The bug manifests when N calls to btrfs_qgroup_reserve_data are made and the last one fails, leaking space reserved in the previous ones. [FIX] Also free previously reserved data bytes when btrfs_qgroup_reserve_data fails. Fixes: 52472553 ("btrfs: qgroup: Introduce btrfs_qgroup_reserve_data function") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: -
Qu Wenruo authored
[BUG] Under the following case with qgroup enabled, if some error happened after we have reserved delalloc space, then in error handling path, we could cause qgroup data space leakage: From btrfs_truncate_block() in inode.c: ret = btrfs_delalloc_reserve_space(inode, &data_reserved, block_start, blocksize); if (ret) goto out; again: page = find_or_create_page(mapping, index, mask); if (!page) { btrfs_delalloc_release_space(inode, data_reserved, block_start, blocksize, true); btrfs_delalloc_release_extents(BTRFS_I(inode), blocksize, true); ret = -ENOMEM; goto out; } [CAUSE] In the above case, btrfs_delalloc_reserve_space() will call btrfs_qgroup_reserve_data() and mark the io_tree range with EXTENT_QGROUP_RESERVED flag. In the error handling path, we have the following call stack: btrfs_delalloc_release_space() |- btrfs_free_reserved_data_space() |- btrsf_qgroup_free_data() |- __btrfs_qgroup_release_data(reserved=@reserved, free=1) |- qgroup_free_reserved_data(reserved=@reserved) |- clear_record_extent_bits(); |- freed += changeset.bytes_changed; However due to a completion bug, qgroup_free_reserved_data() will clear EXTENT_QGROUP_RESERVED flag in BTRFS_I(inode)->io_failure_tree, other than the correct BTRFS_I(inode)->io_tree. Since io_failure_tree is never marked with that flag, btrfs_qgroup_free_data() will not free any data reserved space at all, causing a leakage. This type of error handling can only be triggered by errors outside of qgroup code. So EDQUOT error from qgroup can't trigger it. [FIX] Fix the wrong target io_tree. Reported-by:
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- 25 Sep, 2019 2 commits
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Qu Wenruo authored
[BUG] With v5.3 kernel, we can't convert to SINGLE profile: # btrfs balance start -f -dconvert=single $mnt ERROR: error during balancing '/mnt/btrfs': Invalid argument # dmesg -t | tail validate_convert_profile: data profile=0x1000000000000 allowed=0x20 is_valid=1 final=0x1000000000000 ret=1 BTRFS error (device dm-3): balance: invalid convert data profile single [CAUSE] With the extra debug output added, it shows that the @allowed bit is lacking the special in-memory only SINGLE profile bit. Thus we fail at that (profile & ~allowed) check. This regression is caused by commit 081db89b ("btrfs: use raid_attr to get allowed profiles for balance conversion") and the fact that we don't use any bit to indicate SINGLE profile on-disk, but uses special in-memory only bit to help distinguish different profiles. [FIX] Add that BTRFS_AVAIL_ALLOC_BIT_SINGLE to @allowed, so the code should be the same as it was and fix the regression. Reported-by:
Chris Murphy <lists@colorremedies.com> Fixes: 081db89b ("btrfs: use raid_attr to get allowed profiles for balance conversion") CC: stable@vger.kernel.org # 5.3+ Reviewed-by:
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Qu Wenruo authored
[BUG] One user reported a reproducible KASAN report about use-after-free: BTRFS info (device sdi1): balance: start -dvrange=1256811659264..1256811659265 BTRFS info (device sdi1): relocating block group 1256811659264 flags data|raid0 ================================================================== BUG: KASAN: use-after-free in btrfs_init_reloc_root+0x2cd/0x340 [btrfs] Write of size 8 at addr ffff88856f671710 by task kworker/u24:10/261579 CPU: 2 PID: 261579 Comm: kworker/u24:10 Tainted: P OE 5.2.11-arch1-1-kasan #4 Hardware name: To Be Filled By O.E.M. To Be Filled By O.E.M./X99 Extreme4, BIOS P3.80 04/06/2018 Workqueue: btrfs-endio-write btrfs_endio_write_helper [btrfs] Call Trace: dump_stack+0x7b/0xba print_address_description+0x6c/0x22e ? btrfs_init_reloc_root+0x2cd/0x340 [btrfs] __kasan_report.cold+0x1b/0x3b ? btrfs_init_reloc_root+0x2cd/0x340 [btrfs] kasan_report+0x12/0x17 __asan_report_store8_noabort+0x17/0x20 btrfs_init_reloc_root+0x2cd/0x340 [btrfs] record_root_in_trans+0x2a0/0x370 [btrfs] btrfs_record_root_in_trans+0xf4/0x140 [btrfs] start_transaction+0x1ab/0xe90 [btrfs] btrfs_join_transaction+0x1d/0x20 [btrfs] btrfs_finish_ordered_io+0x7bf/0x18a0 [btrfs] ? lock_repin_lock+0x400/0x400 ? __kmem_cache_shutdown.cold+0x140/0x1ad ? btrfs_unlink_subvol+0x9b0/0x9b0 [btrfs] finish_ordered_fn+0x15/0x20 [btrfs] normal_work_helper+0x1bd/0xca0 [btrfs] ? process_one_work+0x819/0x1720 ? kasan_check_read+0x11/0x20 btrfs_endio_write_helper+0x12/0x20 [btrfs] process_one_work+0x8c9/0x1720 ? pwq_dec_nr_in_flight+0x2f0/0x2f0 ? worker_thread+0x1d9/0x1030 worker_thread+0x98/0x1030 kthread+0x2bb/0x3b0 ? process_one_work+0x1720/0x1720 ? kthread_park+0x120/0x120 ret_from_fork+0x35/0x40 Allocated by task 369692: __kasan_kmalloc.part.0+0x44/0xc0 __kasan_kmalloc.constprop.0+0xba/0xc0 kasan_kmalloc+0x9/0x10 kmem_cache_alloc_trace+0x138/0x260 btrfs_read_tree_root+0x92/0x360 [btrfs] btrfs_read_fs_root+0x10/0xb0 [btrfs] create_reloc_root+0x47d/0xa10 [btrfs] btrfs_init_reloc_root+0x1e2/0x340 [btrfs] record_root_in_trans+0x2a0/0x370 [btrfs] btrfs_record_root_in_trans+0xf4/0x140 [btrfs] start_transaction+0x1ab/0xe90 [btrfs] btrfs_start_transaction+0x1e/0x20 [btrfs] __btrfs_prealloc_file_range+0x1c2/0xa00 [btrfs] btrfs_prealloc_file_range+0x13/0x20 [btrfs] prealloc_file_extent_cluster+0x29f/0x570 [btrfs] relocate_file_extent_cluster+0x193/0xc30 [btrfs] relocate_data_extent+0x1f8/0x490 [btrfs] relocate_block_group+0x600/0x1060 [btrfs] btrfs_relocate_block_group+0x3a0/0xa00 [btrfs] btrfs_relocate_chunk+0x9e/0x180 [btrfs] btrfs_balance+0x14e4/0x2fc0 [btrfs] btrfs_ioctl_balance+0x47f/0x640 [btrfs] btrfs_ioctl+0x119d/0x8380 [btrfs] do_vfs_ioctl+0x9f5/0x1060 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x73/0xb0 do_syscall_64+0xa5/0x370 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 369692: __kasan_slab_free+0x14f/0x210 kasan_slab_free+0xe/0x10 kfree+0xd8/0x270 btrfs_drop_snapshot+0x154c/0x1eb0 [btrfs] clean_dirty_subvols+0x227/0x340 [btrfs] relocate_block_group+0x972/0x1060 [btrfs] btrfs_relocate_block_group+0x3a0/0xa00 [btrfs] btrfs_relocate_chunk+0x9e/0x180 [btrfs] btrfs_balance+0x14e4/0x2fc0 [btrfs] btrfs_ioctl_balance+0x47f/0x640 [btrfs] btrfs_ioctl+0x119d/0x8380 [btrfs] do_vfs_ioctl+0x9f5/0x1060 ksys_ioctl+0x67/0x90 __x64_sys_ioctl+0x73/0xb0 do_syscall_64+0xa5/0x370 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff88856f671100 which belongs to the cache kmalloc-4k of size 4096 The buggy address is located 1552 bytes inside of 4096-byte region [ffff88856f671100, ffff88856f672100) The buggy address belongs to the page: page:ffffea0015bd9c00 refcount:1 mapcount:0 mapping:ffff88864400e600 index:0x0 compound_mapcount: 0 flags: 0x2ffff0000010200(slab|head) raw: 02ffff0000010200 dead000000000100 dead000000000200 ffff88864400e600 raw: 0000000000000000 0000000000070007 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88856f671600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88856f671680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff88856f671700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff88856f671780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff88856f671800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== BTRFS info (device sdi1): 1 enospc errors during balance BTRFS info (device sdi1): balance: ended with status: -28 [CAUSE] The problem happens when finish_ordered_io() get called with balance still running, while the reloc root of that subvolume is already dead. (Tree is swap already done, but tree not yet deleted for possible qgroup usage.) That means root->reloc_root still exists, but that reloc_root can be under btrfs_drop_snapshot(), thus we shouldn't access it. The following race could cause the use-after-free problem: CPU1 | CPU2 -------------------------------------------------------------------------- | relocate_block_group() | |- unset_reloc_control(rc) | |- btrfs_commit_transaction() btrfs_finish_ordered_io() | |- clean_dirty_subvols() |- btrfs_join_transaction() | | |- record_root_in_trans() | | |- btrfs_init_reloc_root() | | |- if (root->reloc_root) | | | | |- root->reloc_root = NULL | | |- btrfs_drop_snapshot(reloc_root); |- reloc_root->last_trans| = trans->transid | ^^^^^^^^^^^^^^^^^^^^^^ Use after free [FIX] Fix it by the following modifications: - Test if the root has dead reloc tree before accessing root->reloc_root If the root has BTRFS_ROOT_DEAD_RELOC_TREE, then we don't need to create or update root->reloc_tree - Clear the BTRFS_ROOT_DEAD_RELOC_TREE flag until we have fully dropped reloc tree To co-operate with above modification, so as long as BTRFS_ROOT_DEAD_RELOC_TREE is still set, we won't try to re-create reloc tree at record_root_in_trans(). Reported-by:Cebtenzzre <cebtenzzre@gmail.com> Fixes: d2311e69 ("btrfs: relocation: Delay reloc tree deletion after merge_reloc_roots") CC: stable@vger.kernel.org # 5.1+ Reviewed-by:
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- 24 Sep, 2019 4 commits
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Filipe Manana authored
There is a race between setting up a qgroup rescan worker and completing a qgroup rescan worker that can lead to callers of the qgroup rescan wait ioctl to either not wait for the rescan worker to complete or to hang forever due to missing wake ups. The following diagram shows a sequence of steps that illustrates the race. CPU 1 CPU 2 CPU 3 btrfs_ioctl_quota_rescan() btrfs_qgroup_rescan() qgroup_rescan_init() mutex_lock(&fs_info->qgroup_rescan_lock) spin_lock(&fs_info->qgroup_lock) fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN init_completion( &fs_info->qgroup_rescan_completion) fs_info->qgroup_rescan_running = true mutex_unlock(&fs_info->qgroup_rescan_lock) spin_unlock(&fs_info->qgroup_lock) btrfs_init_work() --> starts the worker btrfs_qgroup_rescan_worker() mutex_lock(&fs_info->qgroup_rescan_lock) fs_info->qgroup_flags &= ~BTRFS_QGROUP_STATUS_FLAG_RESCAN mutex_unlock(&fs_info->qgroup_rescan_lock) starts transaction, updates qgroup status item, etc btrfs_ioctl_quota_rescan() btrfs_qgroup_rescan() qgroup_rescan_init() mutex_lock(&fs_info->qgroup_rescan_lock) spin_lock(&fs_info->qgroup_lock) fs_info->qgroup_flags |= BTRFS_QGROUP_STATUS_FLAG_RESCAN init_completion( &fs_info->qgroup_rescan_completion) fs_info->qgroup_rescan_running = true mutex_unlock(&fs_info->qgroup_rescan_lock) spin_unlock(&fs_info->qgroup_lock) btrfs_init_work() --> starts another worker mutex_lock(&fs_info->qgroup_rescan_lock) fs_info->qgroup_rescan_running = false mutex_unlock(&fs_info->qgroup_rescan_lock) complete_all(&fs_info->qgroup_rescan_completion) Before the rescan worker started by the task at CPU 3 completes, if another task calls btrfs_ioctl_quota_rescan(), it will get -EINPROGRESS because the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN is set at fs_info->qgroup_flags, which is expected and correct behaviour. However if other task calls btrfs_ioctl_quota_rescan_wait() before the rescan worker started by the task at CPU 3 completes, it will return immediately without waiting for the new rescan worker to complete, because fs_info->qgroup_rescan_running is set to false by CPU 2. This race is making test case btrfs/171 (from fstests) to fail often: btrfs/171 9s ... - output mismatch (see /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad) --- tests/btrfs/171.out 2018-09-16 21:30:48.505104287 +0100 +++ /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad 2019-09-19 02:01:36.938486039 +0100 @@ -1,2 +1,3 @@ QA output created by 171 +ERROR: quota rescan failed: Operation now in progress Silence is golden ... (Run 'diff -u /home/fdmanana/git/hub/xfstests/tests/btrfs/171.out /home/fdmanana/git/hub/xfstests/results//btrfs/171.out.bad' to see the entire diff) That is because the test calls the btrfs-progs commands "qgroup quota rescan -w", "qgroup assign" and "qgroup remove" in a sequence that makes calls to the rescan start ioctl fail with -EINPROGRESS (note the "btrfs" commands 'qgroup assign' and 'qgroup remove' often call the rescan start ioctl after calling the qgroup assign ioctl, btrfs_ioctl_qgroup_assign()), since previous waits didn't actually wait for a rescan worker to complete. Another problem the race can cause is missing wake ups for waiters, since the call to complete_all() happens outside a critical section and after clearing the flag BTRFS_QGROUP_STATUS_FLAG_RESCAN. In the sequence diagram above, if we have a waiter for the first rescan task (executed by CPU 2), then fs_info->qgroup_rescan_completion.wait is not empty, and if after the rescan worker clears BTRFS_QGROUP_STATUS_FLAG_RESCAN and before it calls complete_all() against fs_info->qgroup_rescan_completion, the task at CPU 3 calls init_completion() against fs_info->qgroup_rescan_completion which re-initilizes its wait queue to an empty queue, therefore causing the rescan worker at CPU 2 to call complete_all() against an empty queue, never waking up the task waiting for that rescan worker. Fix this by clearing BTRFS_QGROUP_STATUS_FLAG_RESCAN and setting fs_info->qgroup_rescan_running to false in the same critical section, delimited by the mutex fs_info->qgroup_rescan_lock, as well as doing the call to complete_all() in that same critical section. This gives the protection needed to avoid rescan wait ioctl callers not waiting for a running rescan worker and the lost wake ups problem, since setting that rescan flag and boolean as well as initializing the wait queue is done already in a critical section delimited by that mutex (at qgroup_rescan_init()). Fixes: 57254b6e ("Btrfs: add ioctl to wait for qgroup rescan completion") Fixes: d2c609b8 ("btrfs: properly track when rescan worker is running") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: -
Filipe Manana authored
If lock_extent_buffer_for_io() fails, it returns a negative value, but its caller btree_write_cache_pages() ignores such error. This means that a call to flush_write_bio(), from lock_extent_buffer_for_io(), might have failed. We should make btree_write_cache_pages() notice such error values and stop immediatelly, making sure filemap_fdatawrite_range() returns an error to the transaction commit path. A failure from flush_write_bio() should also result in the endio callback end_bio_extent_buffer_writepage() being invoked, which sets the BTRFS_FS_*_ERR bits appropriately, so that there's no risk a transaction or log commit doesn't catch a writeback failure. Reviewed-by:
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Dennis Zhou authored
Before, if a eb failed to write out, we would end up triggering a BUG_ON(). As of f4340622 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up"), we no longer BUG_ON(), so we should make life consistent and add back the unwritten bytes to dirty_metadata_bytes. Fixes: f4340622 ("btrfs: extent_io: Move the BUG_ON() in flush_write_bio() one level up") CC: stable@vger.kernel.org # 5.2+ Reviewed-by:
Filipe Manana <fdmanana@kernel.org> Signed-off-by:
Dennis Zhou <dennis@kernel.org> Signed-off-by:
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Filipe Manana authored
Some of the self tests create a test inode, setup some extents and then do calls to btrfs_get_extent() to test that the corresponding extent maps exist and are correct. However btrfs_get_extent(), since the 5.2 merge window, now errors out when it finds a regular or prealloc extent for an inode that does not correspond to a regular file (its ->i_mode is not S_IFREG). This causes the self tests to fail sometimes, specially when KASAN, slub_debug and page poisoning are enabled: $ modprobe btrfs modprobe: ERROR: could not insert 'btrfs': Invalid argument $ dmesg [ 9414.691648] Btrfs loaded, crc32c=crc32c-intel, debug=on, assert=on, integrity-checker=on, ref-verify=on [ 9414.692655] BTRFS: selftest: sectorsize: 4096 nodesize: 4096 [ 9414.692658] BTRFS: selftest: running btrfs free space cache tests [ 9414.692918] BTRFS: selftest: running extent only tests [ 9414.693061] BTRFS: selftest: running bitmap only tests [ 9414.693366] BTRFS: selftest: running bitmap and extent tests [ 9414.696455] BTRFS: selftest: running space stealing from bitmap to extent tests [ 9414.697131] BTRFS: selftest: running extent buffer operation tests [ 9414.697133] BTRFS: selftest: running btrfs_split_item tests [ 9414.697564] BTRFS: selftest: running extent I/O tests [ 9414.697583] BTRFS: selftest: running find delalloc tests [ 9415.081125] BTRFS: selftest: running find_first_clear_extent_bit test [ 9415.081278] BTRFS: selftest: running extent buffer bitmap tests [ 9415.124192] BTRFS: selftest: running inode tests [ 9415.124195] BTRFS: selftest: running btrfs_get_extent tests [ 9415.127909] BTRFS: selftest: running hole first btrfs_get_extent test [ 9415.128343] BTRFS critical (device (efault)): regular/prealloc extent found for non-regular inode 256 [ 9415.131428] BTRFS: selftest: fs/btrfs/tests/inode-tests.c:904 expected a real extent, got 0 This happens because the test inodes are created without ever initializing the i_mode field of the inode, and neither VFS's new_inode() nor the btrfs callback btrfs_alloc_inode() initialize the i_mode. Initialization of the i_mode is done through the various callbacks used by the VFS to create new inodes (regular files, directories, symlinks, tmpfiles, etc), which all call btrfs_new_inode() which in turn calls inode_init_owner(), which sets the inode's i_mode. Since the tests only uses new_inode() to create the test inodes, the i_mode was never initialized. This always happens on a VM I used with kasan, slub_debug and many other debug facilities enabled. It also happened to someone who reported this on bugzilla (on a 5.3-rc). Fix this by setting i_mode to S_IFREG at btrfs_new_test_inode(). Fixes: 6bf9e4bd ("btrfs: inode: Verify inode mode to avoid NULL pointer dereference") Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=204397Signed-off-by:
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- 09 Sep, 2019 21 commits
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Nikolay Borisov authored
When doing any form of incremental send the parent and the child trees need to be compared via btrfs_compare_trees. This can result in long loop chains without ever relinquishing the CPU. This causes softlockup detector to trigger when comparing trees with a lot of items. Example report: watchdog: BUG: soft lockup - CPU#0 stuck for 24s! [snapperd:16153] CPU: 0 PID: 16153 Comm: snapperd Not tainted 5.2.9-1-default #1 openSUSE Tumbleweed (unreleased) Hardware name: QEMU KVM Virtual Machine, BIOS 0.0.0 02/06/2015 pstate: 40000005 (nZcv daif -PAN -UAO) pc : __ll_sc_arch_atomic_sub_return+0x14/0x20 lr : btrfs_release_extent_buffer_pages+0xe0/0x1e8 [btrfs] sp : ffff00001273b7e0 Call trace: __ll_sc_arch_atomic_sub_return+0x14/0x20 release_extent_buffer+0xdc/0x120 [btrfs] free_extent_buffer.part.0+0xb0/0x118 [btrfs] free_extent_buffer+0x24/0x30 [btrfs] btrfs_release_path+0x4c/0xa0 [btrfs] btrfs_free_path.part.0+0x20/0x40 [btrfs] btrfs_free_path+0x24/0x30 [btrfs] get_inode_info+0xa8/0xf8 [btrfs] finish_inode_if_needed+0xe0/0x6d8 [btrfs] changed_cb+0x9c/0x410 [btrfs] btrfs_compare_trees+0x284/0x648 [btrfs] send_subvol+0x33c/0x520 [btrfs] btrfs_ioctl_send+0x8a0/0xaf0 [btrfs] btrfs_ioctl+0x199c/0x2288 [btrfs] do_vfs_ioctl+0x4b0/0x820 ksys_ioctl+0x84/0xb8 __arm64_sys_ioctl+0x28/0x38 el0_svc_common.constprop.0+0x7c/0x188 el0_svc_handler+0x34/0x90 el0_svc+0x8/0xc Fix this by adding a call to cond_resched at the beginning of the main loop in btrfs_compare_trees. Fixes: 7069830a ("Btrfs: add btrfs_compare_trees function") CC: stable@vger.kernel.org # 4.4+ Reviewed-by:
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Nikolay Borisov authored
Those function are simple boolean predicates there is no need to assign their return values to interim variables. Use them directly as predicates. No functional changes. Signed-off-by:
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Johannes Thumshirn authored
Create a structure to encode the type and length for the known on-disk checksums. This makes it easier to add new checksums later. The structure and helpers are moved from ctree.h so they don't occupy space in all headers including ctree.h. This save some space in the final object. Reviewed-by:
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Johannes Thumshirn authored
Turn the checksum type definition into a enum. This eases later addition of new checksums. Reviewed-by:
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Josef Bacik authored
When debugging weird enospc problems it's handy to be able to dump the space info when we wake up all tickets, and see what the ticket values are. This helped me figure out cases where we were enospc'ing when we shouldn't have been. Reviewed-by:
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Josef Bacik authored
We ran into a problem in production where a box with plenty of space was getting wedged doing ENOSPC flushing. These boxes only had 20% of the disk allocated, but their metadata space + global reserve was right at the size of their metadata chunk. In this case can_overcommit should be allowing allocations without problem, but there's logic in can_overcommit that doesn't allow us to overcommit if there's not enough real space to satisfy the global reserve. This is for historical reasons. Before there were only certain places we could allocate chunks. We could go to commit the transaction and not have enough space for our pending delayed refs and such and be unable to allocate a new chunk. This would result in a abort because of ENOSPC. This code was added to solve this problem. However since then we've gained the ability to always be able to allocate a chunk. So we can easily overcommit in these cases without risking a transaction abort because of ENOSPC. Also prior to now the global reserve really would be used because that's the space we relied on for delayed refs. With delayed refs being tracked separately we no longer have to worry about running out of delayed refs space while committing. We are much less likely to exhaust our global reserve space during transaction commit. Fix the can_overcommit code to simply see if our current usage + what we want is less than our current free space plus whatever slack space we have in the disk is. This solves the problem we were seeing in production and keeps us from flushing as aggressively as we approach our actual metadata size usage. Reviewed-by:
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Josef Bacik authored
We have some annoying xfstests tests that will create a very small fs, fill it up, delete it, and repeat to make sure everything works right. This trips btrfs up sometimes because we may commit a transaction to free space, but most of the free metadata space was being reserved by the global reserve. So we commit and update the global reserve, but the space is simply added to bytes_may_use directly, instead of trying to add it to existing tickets. This results in ENOSPC when we really did have space. Fix this by calling btrfs_try_granting_tickets once we add back our excess space to wake any pending tickets. Reviewed-by:
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Josef Bacik authored
While messing with the overcommit logic I noticed that sometimes we'd ENOSPC out when really we should have run out of space much earlier. It turns out it's because we'll only reserve up to the free amount left in the space info for the global reserve, but that doesn't make sense with overcommit because we could be well above our actual size. This results in the global reserve not carving out it's entire reservation, and thus not putting enough pressure on the rest of the infrastructure to do the right thing and ENOSPC out at a convenient time. Fix this by always taking our full reservation amount for the global reserve. Reviewed-by:
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Josef Bacik authored
It made sense to have the global reserve set at 16M in the past, but since it is used less nowadays set the minimum size to the number of items we'll need to update the main trees we update during a transaction commit, plus some slop area so we can do unlinks if we need to. In practice this doesn't affect normal file systems, but for xfstests where we do things like fill up a fs and then rm * it can fall over in weird ways. This enables us for more sane behavior at extremely small file system sizes. Signed-off-by:
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Josef Bacik authored
This name doesn't really fit with how the space reservation stuff works now, rename it to btrfs_space_info_free_bytes_may_use so it's clear what the function is doing. Reviewed-by:
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Josef Bacik authored
Now that we do not do partial filling of tickets simply remove orig_bytes, it is no longer needed. Reviewed-by:
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Josef Bacik authored
Now that we aren't partially filling tickets we may have some slack space left in the space_info. We need to account for this in may_commit_transaction, otherwise we may choose to not commit the transaction despite it actually having enough space to satisfy our ticket. Calculate the free space we have in the space_info, if any, and subtract this from the ticket we have and use that amount to determine if we will need to commit to reclaim enough space. Reviewed-by:
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Josef Bacik authored
Now that we no longer partially fill tickets we need to rework wake_all_tickets to call btrfs_try_to_wakeup_tickets() in order to see if any subsequent tickets are able to be satisfied. If our tickets_id changes we know something happened and we can keep flushing. Also if we find a ticket that is smaller than the first ticket in our queue then we want to retry the flushing loop again in case may_commit_transaction() decides we could satisfy the ticket by committing the transaction. Rename this to maybe_fail_all_tickets() while we're at it, to better reflect what the function is actually doing. Signed-off-by:
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Josef Bacik authored
Now that btrfs_space_info_add_old_bytes simply checks if we can make the reservation and updates bytes_may_use, there's no reason to have both helpers in place. Factor out the ticket wakeup logic into it's own helper, make btrfs_space_info_add_old_bytes() update bytes_may_use and then call the wakeup helper, and replace all calls to btrfs_space_info_add_new_bytes() with the wakeup helper. Reviewed-by:
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Josef Bacik authored
btrfs_space_info_add_old_bytes is used when adding the extra space from an existing reservation back into the space_info to be used by any waiting tickets. In order to keep us from overcommitting we check to make sure that we can still use this space for our reserve ticket, and if we cannot we'll simply subtract it from space_info->bytes_may_use. However this is problematic, because it assumes that only changes to bytes_may_use would affect our ability to make reservations. Any changes to bytes_reserved would be missed. If we were unable to make a reservation prior because of reserved space, but that reserved space was free'd due to unlink or truncate and we were allowed to immediately reclaim that metadata space we would still ENOSPC. Consider the example where we create a file with a bunch of extents, using up 2MiB of actual space for the new tree blocks. Then we try to make a reservation of 2MiB but we do not have enough space to make this reservation. The iput() occurs in another thread and we remove this space, and since we did not write the blocks we simply do space_info->bytes_reserved -= 2MiB. We would never see this because we do not check our space info used, we just try to re-use the freed reservations. To fix this problem, and to greatly simplify the wakeup code, do away with this partial refilling nonsense. Use btrfs_space_info_add_old_bytes to subtract the reservation from space_info->bytes_may_use, and then check the ticket against the total used of the space_info the same way we do with the initial reservation attempt. This keeps the reservation logic consistent and solves the problem of early ENOSPC in the case that we free up space in places other than bytes_may_use and bytes_pinned. Thanks, Signed-off-by:
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Josef Bacik authored
I noticed when folding the trace_btrfs_space_reservation() tracepoint into the btrfs_space_info_update_* helpers that we didn't emit a tracepoint when doing btrfs_add_reserved_bytes(). I know this is because we were swapping bytes_may_use for bytes_reserved, so in my mind there was no reason to have the tracepoint there. But now there is because we always emit the unreserve for the bytes_may_use side, and this would have broken if compression was on anyway. Add a tracepoint to cover the bytes_reserved counter so the math still comes out right. Signed-off-by:
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Josef Bacik authored
We duplicate this tracepoint everywhere we call these helpers, so update the helper to have the tracepoint as well. Signed-off-by:
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Josef Bacik authored
If we already have tickets on the list we don't want to steal their reservations. This is a preparation patch for upcoming changes, technically this shouldn't happen today because of the way we add bytes to tickets before adding them to the space_info in most cases. This does not change the FIFO nature of reserve tickets, it simply allows us to enforce it in a different way. Previously it was enforced because any new space would be added to the first ticket on the list, which would result in new reservations getting a reserve ticket. This replaces that mechanism by simply checking to see if we have outstanding reserve tickets and skipping straight to adding a ticket for our reservation. Reviewed-by:
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Omar Sandoval authored
Since commit fee187d9 ("Btrfs: do not set EXTENT_DIRTY along with EXTENT_DELALLOC"), we never set EXTENT_DIRTY in inode->io_tree, so we can simplify and stop trying to clear it. Reviewed-by:
Omar Sandoval <osandov@fb.com> Reviewed-by:
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Omar Sandoval authored
The VFS indicates a synchronous write to ->write_iter() via iocb->ki_flags. The IOCB_{,D}SYNC flags may be set based on the file (see iocb_flags()) or the RWF_* flags passed to a syscall like pwritev2() (see kiocb_set_rw_flags()). However, in btrfs_file_write_iter(), we're checking if a write is synchronous based only on the file; we use this to decide when to bump the sync_writers counter and thus do CRCs synchronously. Make sure we do this for all synchronous writes as determined by the VFS. Reviewed-by: -
Omar Sandoval authored
generic_write_checks() may modify iov_iter_count(), so we must get the count after the call, not before. Using the wrong one has a couple of consequences: 1. We check a longer range in check_can_nocow() for nowait than we're actually writing. 2. We create extra hole extent maps in btrfs_cont_expand(). As far as I can tell, this is harmless, but I might be missing something. These issues are pretty minor, but let's fix it before something more important trips on it. Fixes: edf064e7 ("btrfs: nowait aio support") Reviewed-by:
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