- 21 Jun, 2022 3 commits
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Filipe Manana authored
At btrfs_replace_file_extents(), if we fail to migrate reserved metadata space from the transaction block reserve into the local block reserve, we trigger a BUG_ON(). This is because it should not be possible to have a failure here, as we reserved more space when we started the transaction than the space we want to migrate. However having a BUG_ON() is way too drastic, we can perfectly handle the failure and return the error to the caller. So just do that instead, and add a WARN_ON() to make it easier to notice the failure if it ever happens (which is particularly useful for fstests, and the warning will trigger a failure of a test case). Reviewed-by:
Boris Burkov <boris@bur.io> Signed-off-by:
Filipe Manana <fdmanana@suse.com> Signed-off-by:
David Sterba <dsterba@suse.com>
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Filipe Manana authored
When replacing file extents, called during fallocate, hole punching, clone and deduplication, we may not be able to replace/drop all the target file extent items with a single transaction handle. We may get -ENOSPC while doing it, in which case we release the transaction handle, balance the dirty pages of the btree inode, flush delayed items and get a new transaction handle to operate on what's left of the target range. By dropping and replacing file extent items we have effectively modified the inode, so we should bump its iversion and update its mtime/ctime before we update the inode item. This is because if the transaction we used for partially modifying the inode gets committed by someone after we release it and before we finish the rest of the range, a power failure happens, then after mounting the filesystem our inode has an outdated iversion and mtime/ctime, corresponding to the values it had before we changed it. So add the missing iversion and mtime/ctime updates. Reviewed-by:
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Filipe Manana authored
While doing a reflink operation, if an ordered extent for a file range that does not overlap with the source and destination ranges of the reflink operation happens, we can end up having a failure in the reflink operation and return -EINVAL to user space. The following sequence of steps explains how this can happen: 1) We have the page at file offset 315392 dirty (under delalloc); 2) A reflink operation for this file starts, using the same file as both source and destination, the source range is [372736, 409600) (length of 36864 bytes) and the destination range is [208896, 245760); 3) At btrfs_remap_file_range_prep(), we flush all delalloc in the source and destination ranges, and wait for any ordered extents in those range to complete; 4) Still at btrfs_remap_file_range_prep(), we then flush all delalloc in the inode, but we neither wait for it to complete nor any ordered extents to complete. This results in starting delalloc for the page at file offset 315392 and creating an ordered extent for that single page range; 5) We then move to btrfs_clone() and enter the loop to find file extent items to copy from the source range to destination range; 6) In the first iteration we end up at last file extent item stored in leaf A: (...) item 131 key (143616 108 315392) itemoff 5101 itemsize 53 extent data disk bytenr 1903988736 nr 73728 extent data offset 12288 nr 61440 ram 73728 This represents the file range [315392, 376832), which overlaps with the source range to clone. @datal is set to 61440, key.offset is 315392 and @next_key_min_offset is therefore set to 376832 (315392 + 61440). @off (372736) is > key.offset (315392), so @new_key.offset is set to the value of @destoff (208896). @new_key.offset == @last_dest_end (208896) so @drop_start is set to 208896 (@new_key.offset). @datal is adjusted to 4096, as @off is > @key.offset. So in this iteration we call btrfs_replace_file_extents() for the range [208896, 212991] (a single page, which is [@drop_start, @new_key.offset + @datal - 1]). @last_dest_end is set to 212992 (@new_key.offset + @datal = 208896 + 4096 = 212992). Before the next iteration of the loop, @key.offset is set to the value 376832, which is @next_key_min_offset; 7) On the second iteration btrfs_search_slot() leaves us again at leaf A, but this time pointing beyond the last slot of leaf A, as that's where a key with offset 376832 should be at if it existed. So end up calling btrfs_next_leaf(); 8) btrfs_next_leaf() releases the path, but before it searches again the tree for the next key/leaf, the ordered extent for the single page range at file offset 315392 completes. That results in trimming the file extent item we processed before, adjusting its key offset from 315392 to 319488, reducing its length from 61440 to 57344 and inserting a new file extent item for that single page range, with a key offset of 315392 and a length of 4096. Leaf A now looks like: (...) item 132 key (143616 108 315392) itemoff 4995 itemsize 53 extent data disk bytenr 1801666560 nr 4096 extent data offset 0 nr 4096 ram 4096 item 133 key (143616 108 319488) itemoff 4942 itemsize 53 extent data disk bytenr 1903988736 nr 73728 extent data offset 16384 nr 57344 ram 73728 9) When btrfs_next_leaf() returns, it gives us a path pointing to leaf A at slot 133, since it's the first key that follows what was the last key we saw (143616 108 315392). In fact it's the same item we processed before, but its key offset was changed, so it counts as a new key; 10) So now we have: @key.offset == 319488 @datal == 57344 @off (372736) is > key.offset (319488), so @new_key.offset is set to 208896 (@destoff value). @new_key.offset (208896) != @last_dest_end (212992), so @drop_start is set to 212992 (@last_dest_end value). @datal is adjusted to 4096 because @off > @key.offset. So in this iteration we call btrfs_replace_file_extents() for the invalid range of [212992, 212991] (which is [@drop_start, @new_key.offset + @datal - 1]). This range is empty, the end offset is smaller than the start offset so btrfs_replace_file_extents() returns -EINVAL, which we end up returning to user space and fail the reflink operation. This all happens because the range of this file extent item was already processed in the previous iteration. This scenario can be triggered very sporadically by fsx from fstests, for example with test case generic/522. So fix this by having btrfs_clone() skip file extent items that cover a file range that we have already processed. CC: stable@vger.kernel.org # 5.10+ Reviewed-by:
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- 07 Jun, 2022 1 commit
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David Sterba authored
Almost none of the errors stemming from a valid mount option but wrong value prints a descriptive message which would help to identify why mount failed. Like in the linked report: $ uname -r v4.19 $ mount -o compress=zstd /dev/sdb /mnt mount: /mnt: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper program, or other error. $ dmesg ... BTRFS error (device sdb): open_ctree failed Errors caused by memory allocation failures are left out as it's not a user error so reporting that would be confusing. Link: https://lore.kernel.org/linux-btrfs/9c3fec36-fc61-3a33-4977-a7e207c3fa4e@gmx.de/ CC: stable@vger.kernel.org # 4.9+ Reviewed-by:
Qu Wenruo <wqu@suse.com> Reviewed-by:
Nikolay Borisov <nborisov@suse.com> Reviewed-by:
Anand Jain <anand.jain@oracle.com> Signed-off-by:
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- 06 Jun, 2022 2 commits
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Qu Wenruo authored
Upstream commit 9f73f1ae ("btrfs: force v2 space cache usage for subpage mount") forces subpage mount to use v2 cache, to avoid deprecated v1 cache which doesn't support subpage properly. But there is a loophole that user can still remount to v1 cache. The existing check will only give users a warning, but does not really prevent to do the remount. Although remounting to v1 will not cause any problems since the v1 cache will always be marked invalid when mounted with a different page size, it's still better to prevent v1 cache at all for subpage mounts. Fixes: 9f73f1ae ("btrfs: force v2 space cache usage for subpage mount") CC: stable@vger.kernel.org # 5.15+ Signed-off-by:
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Filipe Manana authored
When we start an unmount, at close_ctree(), if we have the reclaim task running and in the middle of a data block group relocation, we can trigger a deadlock when stopping an async reclaim task, producing a trace like the following: [629724.498185] task:kworker/u16:7 state:D stack: 0 pid:681170 ppid: 2 flags:0x00004000 [629724.499760] Workqueue: events_unbound btrfs_async_reclaim_metadata_space [btrfs] [629724.501267] Call Trace: [629724.501759] <TASK> [629724.502174] __schedule+0x3cb/0xed0 [629724.502842] schedule+0x4e/0xb0 [629724.503447] btrfs_wait_on_delayed_iputs+0x7c/0xc0 [btrfs] [629724.504534] ? prepare_to_wait_exclusive+0xc0/0xc0 [629724.505442] flush_space+0x423/0x630 [btrfs] [629724.506296] ? rcu_read_unlock_trace_special+0x20/0x50 [629724.507259] ? lock_release+0x220/0x4a0 [629724.507932] ? btrfs_get_alloc_profile+0xb3/0x290 [btrfs] [629724.508940] ? do_raw_spin_unlock+0x4b/0xa0 [629724.509688] btrfs_async_reclaim_metadata_space+0x139/0x320 [btrfs] [629724.510922] process_one_work+0x252/0x5a0 [629724.511694] ? process_one_work+0x5a0/0x5a0 [629724.512508] worker_thread+0x52/0x3b0 [629724.513220] ? process_one_work+0x5a0/0x5a0 [629724.514021] kthread+0xf2/0x120 [629724.514627] ? kthread_complete_and_exit+0x20/0x20 [629724.515526] ret_from_fork+0x22/0x30 [629724.516236] </TASK> [629724.516694] task:umount state:D stack: 0 pid:719055 ppid:695412 flags:0x00004000 [629724.518269] Call Trace: [629724.518746] <TASK> [629724.519160] __schedule+0x3cb/0xed0 [629724.519835] schedule+0x4e/0xb0 [629724.520467] schedule_timeout+0xed/0x130 [629724.521221] ? lock_release+0x220/0x4a0 [629724.521946] ? lock_acquired+0x19c/0x420 [629724.522662] ? trace_hardirqs_on+0x1b/0xe0 [629724.523411] __wait_for_common+0xaf/0x1f0 [629724.524189] ? usleep_range_state+0xb0/0xb0 [629724.524997] __flush_work+0x26d/0x530 [629724.525698] ? flush_workqueue_prep_pwqs+0x140/0x140 [629724.526580] ? lock_acquire+0x1a0/0x310 [629724.527324] __cancel_work_timer+0x137/0x1c0 [629724.528190] close_ctree+0xfd/0x531 [btrfs] [629724.529000] ? evict_inodes+0x166/0x1c0 [629724.529510] generic_shutdown_super+0x74/0x120 [629724.530103] kill_anon_super+0x14/0x30 [629724.530611] btrfs_kill_super+0x12/0x20 [btrfs] [629724.531246] deactivate_locked_super+0x31/0xa0 [629724.531817] cleanup_mnt+0x147/0x1c0 [629724.532319] task_work_run+0x5c/0xa0 [629724.532984] exit_to_user_mode_prepare+0x1a6/0x1b0 [629724.533598] syscall_exit_to_user_mode+0x16/0x40 [629724.534200] do_syscall_64+0x48/0x90 [629724.534667] entry_SYSCALL_64_after_hwframe+0x44/0xae [629724.535318] RIP: 0033:0x7fa2b90437a7 [629724.535804] RSP: 002b:00007ffe0b7e4458 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 [629724.536912] RAX: 0000000000000000 RBX: 00007fa2b9182264 RCX: 00007fa2b90437a7 [629724.538156] RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000555d6cf20dd0 [629724.539053] RBP: 0000555d6cf20ba0 R08: 0000000000000000 R09: 00007ffe0b7e3200 [629724.539956] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 [629724.540883] R13: 0000555d6cf20dd0 R14: 0000555d6cf20cb0 R15: 0000000000000000 [629724.541796] </TASK> This happens because: 1) Before entering close_ctree() we have the async block group reclaim task running and relocating a data block group; 2) There's an async metadata (or data) space reclaim task running; 3) We enter close_ctree() and park the cleaner kthread; 4) The async space reclaim task is at flush_space() and runs all the existing delayed iputs; 5) Before the async space reclaim task calls btrfs_wait_on_delayed_iputs(), the block group reclaim task which is doing the data block group relocation, creates a delayed iput at replace_file_extents() (called when COWing leaves that have file extent items pointing to relocated data extents, during the merging phase of relocation roots); 6) The async reclaim space reclaim task blocks at btrfs_wait_on_delayed_iputs(), since we have a new delayed iput; 7) The task at close_ctree() then calls cancel_work_sync() to stop the async space reclaim task, but it blocks since that task is waiting for the delayed iput to be run; 8) The delayed iput is never run because the cleaner kthread is parked, and no one else runs delayed iputs, resulting in a hang. So fix this by stopping the async block group reclaim task before we park the cleaner kthread. Fixes: 18bb8bbf ("btrfs: zoned: automatically reclaim zones") CC: stable@vger.kernel.org # 5.15+ Signed-off-by:
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- 17 May, 2022 6 commits
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Johannes Thumshirn authored
Zoned devices are expected to have zone sizes in the range of 1-2GB for ZNS SSDs and SMR HDDs have zone sizes of 256MB, so there is no need to allow arbitrarily small zone sizes on btrfs. But for testing purposes with emulated devices it is sometimes desirable to create devices with as small as 4MB zone size to uncover errors. So use 4MB as the smallest possible zone size and reject mounts of devices with a smaller zone size. Reviewed-by:
Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by:
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Qu Wenruo authored
Btrfs defaults to max_inline=2K to make small writes inlined into metadata. The default value is always a win, as even DUP/RAID1/RAID10 doubles the metadata usage, it should still cause less physical space used compared to a 4K regular extents. But since the introduction of RAID1C3 and RAID1C4 it's no longer the case, users may find inlined extents causing too much space wasted, and want to convert those inlined extents back to regular extents. Unfortunately defrag will unconditionally skip all inline extents, no matter if the user is trying to converting them back to regular extents. So this patch will add a small exception for defrag_collect_targets() to allow defragging inline extents, if and only if the inlined extents are larger than max_inline, allowing users to convert them to regular ones. This also allows us to defrag extents like the following: item 6 key (257 EXTENT_DATA 0) itemoff 15794 itemsize 69 generation 7 type 0 (inline) inline extent data size 48 ram_bytes 4096 compression 1 (zlib) item 7 key (257 EXTENT_DATA 4096) itemoff 15741 itemsize 53 generation 7 type 1 (regular) extent data disk byte 13631488 nr 4096 extent data offset 0 nr 16384 ram 16384 extent compression 1 (zlib) Previously we're unable to do any defrag, since the first extent is inlined, and the second one has no extent to merge. Now we can defrag it to just one single extent, saving 48 bytes metadata space. item 6 key (257 EXTENT_DATA 0) itemoff 15810 itemsize 53 generation 8 type 1 (regular) extent data disk byte 13635584 nr 4096 extent data offset 0 nr 20480 ram 20480 extent compression 1 (zlib) Reviewed-by:
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Qu Wenruo authored
The following error message lack the "0x" obviously: cannot mount because of unsupported optional features (4000) Add the prefix to make it less confusing. This can happen on older kernels that try to mount a filesystem with newer features so it makes sense to backport to older trees. CC: stable@vger.kernel.org # 4.14+ Reviewed-by:
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Filipe Manana authored
When reserving metadata units for creating an inode, we don't need to reserve one extra unit for the inode ref item because when creating the inode, at btrfs_create_new_inode(), we always insert the inode item and the inode ref item in a single batch (a single btree insert operation, and both ending up in the same leaf). As we have accounted already one unit for the inode item, the extra unit for the inode ref item is superfluous, it only makes us reserve more metadata than necessary and often adding more reclaim pressure if we are low on available metadata space. Reviewed-by:
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Naohiro Aota authored
The block_group->alloc_offset is an offset from the start of the block group. OTOH, the ->meta_write_pointer is an address in the logical space. So, we should compare the alloc_offset shifted with the block_group->start. Fixes: afba2bc0 ("btrfs: zoned: implement active zone tracking") CC: stable@vger.kernel.org # 5.16+ Signed-off-by:
Naohiro Aota <naohiro.aota@wdc.com> Signed-off-by:
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Filipe Manana authored
A send operation reads extent data using the buffered IO path for getting extent data to send in write commands and this is both because it's simple and to make use of the generic readahead infrastructure, which results in a massive speedup. However this fills the page cache with data that, most of the time, is really only used by the send operation - once the write commands are sent, it's not useful to have the data in the page cache anymore. For large snapshots, bringing all data into the page cache eventually leads to the need to evict other data from the page cache that may be more useful for applications (and kernel subsystems). Even if extents are shared with the subvolume on which a snapshot is based on and the data is currently on the page cache due to being read through the subvolume, attempting to read the data through the snapshot will always result in bringing a new copy of the data into another location in the page cache (there's currently no shared memory for shared extents). So make send evict the data it has read before if when it first opened the inode, its mapping had no pages currently loaded: when inode->i_mapping->nr_pages has a value of 0. Do this instead of deciding based on the return value of filemap_range_has_page() before reading an extent because the generic readahead mechanism may read pages beyond the range we request (and it very often does it), which means a call to filemap_range_has_page() will return true due to the readahead that was triggered when processing a previous extent - we don't have a simple way to distinguish this case from the case where the data was brought into the page cache through someone else. So checking for the mapping number of pages being 0 when we first open the inode is simple, cheap and it generally accomplishes the goal of not trashing the page cache - the only exception is if part of data was previously loaded into the page cache through the snapshot by some other process, in that case we end up not evicting any data send brings into the page cache, just like before this change - but that however is not the common case. Example scenario, on a box with 32G of RAM: $ btrfs subvolume create /mnt/sv1 $ xfs_io -f -c "pwrite 0 4G" /mnt/sv1/file1 $ btrfs subvolume snapshot -r /mnt/sv1 /mnt/snap1 $ free -m total used free shared buff/cache available Mem: 31937 186 26866 0 4883 31297 Swap: 8188 0 8188 # After this we get less 4G of free memory. $ btrfs send /mnt/snap1 >/dev/null $ free -m total used free shared buff/cache available Mem: 31937 186 22814 0 8935 31297 Swap: 8188 0 8188 The same, obviously, applies to an incremental send. Signed-off-by:
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- 16 May, 2022 28 commits
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Filipe Manana authored
Every time we send a write command, we open the inode, read some data to a buffer and then close the inode. The amount of data we read for each write command is at most 48K, returned by max_send_read_size(), and that corresponds to: BTRFS_SEND_BUF_SIZE - 16K = 48K. In practice this does not add any significant overhead, because the time elapsed between every close (iput()) and open (btrfs_iget()) is very short, so the inode is kept in the VFS's cache after the iput() and it's still there by the time we do the next btrfs_iget(). As between processing extents of the current inode we don't do anything else, it makes sense to keep the inode open after we process its first extent that needs to be sent and keep it open until we start processing the next inode. This serves to facilitate the next change, which aims to avoid having send operations trash the page cache with data extents. Signed-off-by:
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Christoph Hellwig authored
Create a new bio_set that contains all the per-bio private data needed by btrfs for direct I/O and tell the iomap code to use that instead of separately allocation the btrfs_dio_private structure. Reviewed-by:
Christoph Hellwig <hch@lst.de> Reviewed-by:
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Christoph Hellwig authored
The btrfs_dio_private structure is only used in inode.c, so move the definition there. Reviewed-by:
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Christoph Hellwig authored
This field is never used, so remove it. Last use was probably in 23ea8e5a ("Btrfs: load checksum data once when submitting a direct read io"). Reviewed-by:
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Christoph Hellwig authored
Make use of the new iomap_iter->private field to avoid a memory allocation per iomap range. Reviewed-by:
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Christoph Hellwig authored
Allow the file system to keep state for all iterations. For now only wire it up for direct I/O as there is an immediate need for it there. Reviewed-by:
Darrick J. Wong <djwong@kernel.org> Reviewed-by:
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Christoph Hellwig authored
Allow the file system to provide a specific bio_set for allocating direct I/O bios. This will allow file systems that use the ->submit_io hook to stash away additional information for file system use. To make use of this additional space for information in the completion path, the file system needs to override the ->bi_end_io callback and then call back into iomap, so export iomap_dio_bio_end_io for that. Reviewed-by:
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Christoph Hellwig authored
Add a wrapper around iomap_dio_rw that keeps the direct I/O internals isolated in inode.c. Reviewed-by:
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Naohiro Aota authored
While the active zones within an active block group are reset, and their active resource is released, the block group itself is kept in the active block group list and marked as active. As a result, the list will contain more than max_active_zones block groups. That itself is not fatal for the device as the zones are properly reset. However, that inflated list is, of course, strange. Also, a to-appear patch series, which deactivates an active block group on demand, gets confused with the wrong list. So, fix the issue by finishing the unused block group once it gets read-only, so that we can release the active resource in an early stage. Fixes: be1a1d7a ("btrfs: zoned: finish fully written block group") CC: stable@vger.kernel.org # 5.16+ Reviewed-by:
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Naohiro Aota authored
Commit be1a1d7a ("btrfs: zoned: finish fully written block group") introduced zone finishing code both for data and metadata end_io path. However, the metadata side is not working as it should. First, it compares logical address (eb->start + eb->len) with offset within a block group (cache->zone_capacity) in submit_eb_page(). That essentially disabled zone finishing on metadata end_io path. Furthermore, fixing the issue above revealed we cannot call btrfs_zone_finish_endio() in end_extent_buffer_writeback(). We cannot call btrfs_lookup_block_group() which require spin lock inside end_io context. Introduce btrfs_schedule_zone_finish_bg() to wait for the extent buffer writeback and do the zone finish IO in a workqueue. Also, drop EXTENT_BUFFER_ZONE_FINISH as it is no longer used. Fixes: be1a1d7a ("btrfs: zoned: finish fully written block group") CC: stable@vger.kernel.org # 5.16+ Reviewed-by:
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Naohiro Aota authored
Currently, btrfs_zone_finish_endio() finishes a block group only when the written region reaches the end of the block group. We can also finish the block group when no more allocation is possible. Fixes: be1a1d7a ("btrfs: zoned: finish fully written block group") CC: stable@vger.kernel.org # 5.16+ Reviewed-by:
Pankaj Raghav <p.raghav@samsung.com> Reviewed-by:
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Naohiro Aota authored
btrfs_zone_finish() and btrfs_zone_finish_endio() have similar code. Introduce do_zone_finish() to factor out the common code. Reviewed-by:
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Naohiro Aota authored
Introduce a wrapper to check if all the space in a block group is allocated or not. Reviewed-by:
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Nikolay Borisov authored
When iterating the backrefs in an extent item if the ptr to the 'current' backref record goes beyond the extent item a warning is generated and -ENOENT is returned. However what's more appropriate to debug such cases would be to return EUCLEAN and also print identifying information about the performed search as well as the current content of the leaf containing the possibly corrupted extent item. Reviewed-by:
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David Sterba authored
The bio_ctrl is the last use of bio_flags that has been converted to compress type everywhere else. Reviewed-by:
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David Sterba authored
Several functions take parameter bio_flags that was simplified to just compress type, unify it and change the type accordingly. Reviewed-by:
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David Sterba authored
The bio_flags is now used to store unchanged compress type, so unify that. Reviewed-by:
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David Sterba authored
The helpers extent_set_compress_type and extent_compress_type have become trivial after previous cleanups and can be removed. Reviewed-by:
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David Sterba authored
The bio_flags are used only to encode the compression and there are no other EXTENT_BIO_* flags, so the compress type can be stored directly. The struct member name is left unchanged and will be cleaned in later patches. Reviewed-by:
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David Sterba authored
The helper used to do more with the wbc state but now it's just one subtraction, no need to have a special helper. It became trivial in a9132667 ("Btrfs: make mapping->writeback_index point to the last written page"). Reviewed-by:
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David Sterba authored
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David Sterba authored
The value of btrfs_delayed_extent_op::is_data is always false, we can cascade the change and simplify code that depends on it, removing the structure member eventually. Reviewed-by:
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David Sterba authored
The parameter has been added in 2009 in the infamous monster commit 5d4f98a2 ("Btrfs: Mixed back reference (FORWARD ROLLING FORMAT CHANGE)") but not used ever since. We can sink it and allow further simplifications. Reviewed-by:
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Filipe Manana authored
When reserving data space for a direct IO write we can end up deadlocking if we have multiple tasks attempting a write to the same file range, there are multiple extents covered by that file range, we are low on available space for data and the writes don't expand the inode's i_size. The deadlock can happen like this: 1) We have a file with an i_size of 1M, at offset 0 it has an extent with a size of 128K and at offset 128K it has another extent also with a size of 128K; 2) Task A does a direct IO write against file range [0, 256K), and because the write is within the i_size boundary, it takes the inode's lock (VFS level) in shared mode; 3) Task A locks the file range [0, 256K) at btrfs_dio_iomap_begin(), and then gets the extent map for the extent covering the range [0, 128K). At btrfs_get_blocks_direct_write(), it creates an ordered extent for that file range ([0, 128K)); 4) Before returning from btrfs_dio_iomap_begin(), it unlocks the file range [0, 256K); 5) Task A executes btrfs_dio_iomap_begin() again, this time for the file range [128K, 256K), and locks the file range [128K, 256K); 6) Task B starts a direct IO write against file range [0, 256K) as well. It also locks the inode in shared mode, as it's within the i_size limit, and then tries to lock file range [0, 256K). It is able to lock the subrange [0, 128K) but then blocks waiting for the range [128K, 256K), as it is currently locked by task A; 7) Task A enters btrfs_get_blocks_direct_write() and tries to reserve data space. Because we are low on available free space, it triggers the async data reclaim task, and waits for it to reserve data space; 8) The async reclaim task decides to wait for all existing ordered extents to complete (through btrfs_wait_ordered_roots()). It finds the ordered extent previously created by task A for the file range [0, 128K) and waits for it to complete; 9) The ordered extent for the file range [0, 128K) can not complete because it blocks at btrfs_finish_ordered_io() when trying to lock the file range [0, 128K). This results in a deadlock, because: - task B is holding the file range [0, 128K) locked, waiting for the range [128K, 256K) to be unlocked by task A; - task A is holding the file range [128K, 256K) locked and it's waiting for the async data reclaim task to satisfy its space reservation request; - the async data reclaim task is waiting for ordered extent [0, 128K) to complete, but the ordered extent can not complete because the file range [0, 128K) is currently locked by task B, which is waiting on task A to unlock file range [128K, 256K) and task A waiting on the async data reclaim task. This results in a deadlock between 4 task: task A, task B, the async data reclaim task and the task doing ordered extent completion (a work queue task). This type of deadlock can sporadically be triggered by the test case generic/300 from fstests, and results in a stack trace like the following: [12084.033689] INFO: task kworker/u16:7:123749 blocked for more than 241 seconds. [12084.034877] Not tainted 5.18.0-rc2-btrfs-next-115 #1 [12084.035562] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [12084.036548] task:kworker/u16:7 state:D stack: 0 pid:123749 ppid: 2 flags:0x00004000 [12084.036554] Workqueue: btrfs-flush_delalloc btrfs_work_helper [btrfs] [12084.036599] Call Trace: [12084.036601] <TASK> [12084.036606] __schedule+0x3cb/0xed0 [12084.036616] schedule+0x4e/0xb0 [12084.036620] btrfs_start_ordered_extent+0x109/0x1c0 [btrfs] [12084.036651] ? prepare_to_wait_exclusive+0xc0/0xc0 [12084.036659] btrfs_run_ordered_extent_work+0x1a/0x30 [btrfs] [12084.036688] btrfs_work_helper+0xf8/0x400 [btrfs] [12084.036719] ? lock_is_held_type+0xe8/0x140 [12084.036727] process_one_work+0x252/0x5a0 [12084.036736] ? process_one_work+0x5a0/0x5a0 [12084.036738] worker_thread+0x52/0x3b0 [12084.036743] ? process_one_work+0x5a0/0x5a0 [12084.036745] kthread+0xf2/0x120 [12084.036747] ? kthread_complete_and_exit+0x20/0x20 [12084.036751] ret_from_fork+0x22/0x30 [12084.036765] </TASK> [12084.036769] INFO: task kworker/u16:11:153787 blocked for more than 241 seconds. [12084.037702] Not tainted 5.18.0-rc2-btrfs-next-115 #1 [12084.038540] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [12084.039506] task:kworker/u16:11 state:D stack: 0 pid:153787 ppid: 2 flags:0x00004000 [12084.039511] Workqueue: events_unbound btrfs_async_reclaim_data_space [btrfs] [12084.039551] Call Trace: [12084.039553] <TASK> [12084.039557] __schedule+0x3cb/0xed0 [12084.039566] schedule+0x4e/0xb0 [12084.039569] schedule_timeout+0xed/0x130 [12084.039573] ? mark_held_locks+0x50/0x80 [12084.039578] ? _raw_spin_unlock_irq+0x24/0x50 [12084.039580] ? lockdep_hardirqs_on+0x7d/0x100 [12084.039585] __wait_for_common+0xaf/0x1f0 [12084.039587] ? usleep_range_state+0xb0/0xb0 [12084.039596] btrfs_wait_ordered_extents+0x3d6/0x470 [btrfs] [12084.039636] btrfs_wait_ordered_roots+0x175/0x240 [btrfs] [12084.039670] flush_space+0x25b/0x630 [btrfs] [12084.039712] btrfs_async_reclaim_data_space+0x108/0x1b0 [btrfs] [12084.039747] process_one_work+0x252/0x5a0 [12084.039756] ? process_one_work+0x5a0/0x5a0 [12084.039758] worker_thread+0x52/0x3b0 [12084.039762] ? process_one_work+0x5a0/0x5a0 [12084.039765] kthread+0xf2/0x120 [12084.039766] ? kthread_complete_and_exit+0x20/0x20 [12084.039770] ret_from_fork+0x22/0x30 [12084.039783] </TASK> [12084.039800] INFO: task kworker/u16:17:217907 blocked for more than 241 seconds. [12084.040709] Not tainted 5.18.0-rc2-btrfs-next-115 #1 [12084.041398] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [12084.042404] task:kworker/u16:17 state:D stack: 0 pid:217907 ppid: 2 flags:0x00004000 [12084.042411] Workqueue: btrfs-endio-write btrfs_work_helper [btrfs] [12084.042461] Call Trace: [12084.042463] <TASK> [12084.042471] __schedule+0x3cb/0xed0 [12084.042485] schedule+0x4e/0xb0 [12084.042490] wait_extent_bit.constprop.0+0x1eb/0x260 [btrfs] [12084.042539] ? prepare_to_wait_exclusive+0xc0/0xc0 [12084.042551] lock_extent_bits+0x37/0x90 [btrfs] [12084.042601] btrfs_finish_ordered_io.isra.0+0x3fd/0x960 [btrfs] [12084.042656] ? lock_is_held_type+0xe8/0x140 [12084.042667] btrfs_work_helper+0xf8/0x400 [btrfs] [12084.042716] ? lock_is_held_type+0xe8/0x140 [12084.042727] process_one_work+0x252/0x5a0 [12084.042742] worker_thread+0x52/0x3b0 [12084.042750] ? process_one_work+0x5a0/0x5a0 [12084.042754] kthread+0xf2/0x120 [12084.042757] ? kthread_complete_and_exit+0x20/0x20 [12084.042763] ret_from_fork+0x22/0x30 [12084.042783] </TASK> [12084.042798] INFO: task fio:234517 blocked for more than 241 seconds. [12084.043598] Not tainted 5.18.0-rc2-btrfs-next-115 #1 [12084.044282] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [12084.045244] task:fio state:D stack: 0 pid:234517 ppid:234515 flags:0x00004000 [12084.045248] Call Trace: [12084.045250] <TASK> [12084.045254] __schedule+0x3cb/0xed0 [12084.045263] schedule+0x4e/0xb0 [12084.045266] wait_extent_bit.constprop.0+0x1eb/0x260 [btrfs] [12084.045298] ? prepare_to_wait_exclusive+0xc0/0xc0 [12084.045306] lock_extent_bits+0x37/0x90 [btrfs] [12084.045336] btrfs_dio_iomap_begin+0x336/0xc60 [btrfs] [12084.045370] ? lock_is_held_type+0xe8/0x140 [12084.045378] iomap_iter+0x184/0x4c0 [12084.045383] __iomap_dio_rw+0x2c6/0x8a0 [12084.045406] iomap_dio_rw+0xa/0x30 [12084.045408] btrfs_do_write_iter+0x370/0x5e0 [btrfs] [12084.045440] aio_write+0xfa/0x2c0 [12084.045448] ? __might_fault+0x2a/0x70 [12084.045451] ? kvm_sched_clock_read+0x14/0x40 [12084.045455] ? lock_release+0x153/0x4a0 [12084.045463] io_submit_one+0x615/0x9f0 [12084.045467] ? __might_fault+0x2a/0x70 [12084.045469] ? kvm_sched_clock_read+0x14/0x40 [12084.045478] __x64_sys_io_submit+0x83/0x160 [12084.045483] ? syscall_enter_from_user_mode+0x1d/0x50 [12084.045489] do_syscall_64+0x3b/0x90 [12084.045517] entry_SYSCALL_64_after_hwframe+0x44/0xae [12084.045521] RIP: 0033:0x7fa76511af79 [12084.045525] RSP: 002b:00007ffd6d6b9058 EFLAGS: 00000246 ORIG_RAX: 00000000000000d1 [12084.045530] RAX: ffffffffffffffda RBX: 00007fa75ba6e760 RCX: 00007fa76511af79 [12084.045532] RDX: 0000557b304ff3f0 RSI: 0000000000000001 RDI: 00007fa75ba4c000 [12084.045535] RBP: 00007fa75ba4c000 R08: 00007fa751b76000 R09: 0000000000000330 [12084.045537] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000001 [12084.045540] R13: 0000000000000000 R14: 0000557b304ff3f0 R15: 0000557b30521eb0 [12084.045561] </TASK> Fix this issue by always reserving data space before locking a file range at btrfs_dio_iomap_begin(). If we can't reserve the space, then we don't error out immediately - instead after locking the file range, check if we can do a NOCOW write, and if we can we don't error out since we don't need to allocate a data extent, however if we can't NOCOW then error out with -ENOSPC. This also implies that we may end up reserving space when it's not needed because the write will end up being done in NOCOW mode - in that case we just release the space after we noticed we did a NOCOW write - this is the same type of logic that is done in the path for buffered IO writes. Fixes: f0bfa76a ("btrfs: fix ENOSPC failure when attempting direct IO write into NOCOW range") CC: stable@vger.kernel.org # 5.17+ Signed-off-by: -
Goldwyn Rodrigues authored
Derive the compression type from extent map as opposed to the bio flags passed. This makes it more precise and not reliant on function parameters. Reviewed-by:
Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by:
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Qu Wenruo authored
[SUSPICIOUS CODE] When refactoring scrub code, I noticed a very strange behavior around scrub_remap_extent(): if (sctx->is_dev_replace) scrub_remap_extent(fs_info, cur_logical, scrub_len, &cur_physical, &target_dev, &cur_mirror); As replace target is a 1:1 copy of the source device, thus physical offset inside the target should be the same as physical inside source, thus this remap call makes no sense to me. [REAL FUNCTIONALITY] After more investigation, the function name scrub_remap_extent() doesn't tell anything of the truth, nor does its if () condition. The real story behind this function is that, for scrub_pages() we never expect missing device, even for replacing missing device. What scrub_remap_extent() is really doing is to find a live mirror, and make later scrub_pages() to read data from the good copy, other than from the missing device and increase error counters unnecessarily. [IMPROVEMENT] We have no need to bother scrub_remap_extent() in scrub_simple_mirror() at all, we only need to call it before we call scrub_pages(). And rename the function to scrub_find_live_copy(), add extra comments on them. By this we can remove one parameter from scrub_extent(), and reduce the unnecessary calls to scrub_remap_extent() for regular replace. Signed-off-by:
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Qu Wenruo authored
Since we have find_first_extent_item() to iterate the extent items of a certain range, there is no need to use the open-coded version. Replace the final scrub call site with find_first_extent_item(). Signed-off-by:
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Qu Wenruo authored
Currently scrub_raid56_parity() has a large double loop, handling the following things at the same time: - Iterate each data stripe - Iterate each extent item in one data stripe Refactor this by: - Introduce a new helper to handle data stripe iteration The new helper is scrub_raid56_data_stripe_for_parity(), which only has one while() loop handling the extent items inside the data stripe. The code is still mostly the same as the old code. - Call cond_resched() for each extent Previously we only call cond_resched() under a complex if () check. I see no special reason to do that, and for other scrub functions, like scrub_simple_mirror() we're already doing the same cond_resched() after scrubbing one extent. - Add more comments Please note that, this patch is only to address the double loop, there are incoming patches to do extra cleanup. Signed-off-by:
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