kernel/linux.git/fs/btrfs/compression.c, branch linux-6.0.y

Merge tag 'for-5.20-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2022-08-03T21:54:52+00:00

Pull btrfs updates from David Sterba: "This brings some long awaited changes, the send protocol bump, otherwise lots of small improvements and fixes. The main core part is reworking bio handling, cleaning up the submission and endio and improving error handling. There are some changes outside of btrfs adding helpers or updating API, listed at the end of the changelog. Features: - sysfs: - export chunk size, in debug mode add tunable for setting its size - show zoned among features (was only in debug mode) - show commit stats (number, last/max/total duration) - send protocol updated to 2 - new commands: - ability write larger data chunks than 64K - send raw compressed extents (uses the encoded data ioctls), ie. no decompression on send side, no compression needed on receive side if supported - send 'otime' (inode creation time) among other timestamps - send file attributes (a.k.a file flags and xflags) - this is first version bump, backward compatibility on send and receive side is provided - there are still some known and wanted commands that will be implemented in the near future, another version bump will be needed, however we want to minimize that to avoid causing usability issues - print checksum type and implementation at mount time - don't print some messages at mount (mentioned as people asked about it), we want to print messages namely for new features so let's make some space for that - big metadata - this has been supported for a long time and is not a feature that's worth mentioning - skinny metadata - same reason, set by default by mkfs Performance improvements: - reduced amount of reserved metadata for delayed items - when inserted items can be batched into one leaf - when deleting batched directory index items - when deleting delayed items used for deletion - overall improved count of files/sec, decreased subvolume lock contention - metadata item access bounds checker micro-optimized, with a few percent of improved runtime for metadata-heavy operations - increase direct io limit for read to 256 sectors, improved throughput by 3x on sample workload Notable fixes: - raid56 - reduce parity writes, skip sectors of stripe when there are no data updates - restore reading from on-disk data instead of using stripe cache, this reduces chances to damage correct data due to RMW cycle - refuse to replay log with unknown incompat read-only feature bit set - zoned - fix page locking when COW fails in the middle of allocation - improved tracking of active zones, ZNS drives may limit the number and there are ENOSPC errors due to that limit and not actual lack of space - adjust maximum extent size for zone append so it does not cause late ENOSPC due to underreservation - mirror reading error messages show the mirror number - don't fallback to buffered IO for NOWAIT direct IO writes, we don't have the NOWAIT semantics for buffered io yet - send, fix sending link commands for existing file paths when there are deleted and created hardlinks for same files - repair all mirrors for profiles with more than 1 copy (raid1c34) - fix repair of compressed extents, unify where error detection and repair happen Core changes: - bio completion cleanups - don't double defer compression bios - simplify endio workqueues - add more data to btrfs_bio to avoid allocation for read requests - rework bio error handling so it's same what block layer does, the submission works and errors are consumed in endio - when asynchronous bio offload fails fall back to synchronous checksum calculation to avoid errors under writeback or memory pressure - new trace points - raid56 events - ordered extent operations - super block log_root_transid deprecated (never used) - mixed_backref and big_metadata sysfs feature files removed, they've been default for sufficiently long time, there are no known users and mixed_backref could be confused with mixed_groups Non-btrfs changes, API updates: - minor highmem API update to cover const arguments - switch all kmap/kmap_atomic to kmap_local - remove redundant flush_dcache_page() - address_space_operations::writepage callback removed - add bdev_max_segments() helper" * tag 'for-5.20-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (163 commits) btrfs: don't call btrfs_page_set_checked in finish_compressed_bio_read btrfs: fix repair of compressed extents btrfs: remove the start argument to check_data_csum and export btrfs: pass a btrfs_bio to btrfs_repair_one_sector btrfs: simplify the pending I/O counting in struct compressed_bio btrfs: repair all known bad mirrors btrfs: merge btrfs_dev_stat_print_on_error with its only caller btrfs: join running log transaction when logging new name btrfs: simplify error handling in btrfs_lookup_dentry btrfs: send: always use the rbtree based inode ref management infrastructure btrfs: send: fix sending link commands for existing file paths btrfs: send: introduce recorded_ref_alloc and recorded_ref_free btrfs: zoned: wait until zone is finished when allocation didn't progress btrfs: zoned: write out partially allocated region btrfs: zoned: activate necessary block group btrfs: zoned: activate metadata block group on flush_space btrfs: zoned: disable metadata overcommit for zoned btrfs: zoned: introduce space_info->active_total_bytes btrfs: zoned: finish least available block group on data bg allocation btrfs: let can_allocate_chunk return error ...

btrfs: don't call btrfs_page_set_checked in finish_compressed_bio_read

2022-07-25T17:56:16+00:00

This flag was used to communicate that the low-level compression code already did verify the checksum to the high-level I/O completion code. But it has been unused for a long time as the upper btrfs_bio for the decompressed data had a NULL csum pointer basically since that pointer existed and the code already checks for that a little later. Note that this does not affect the other use of the checked flag, which is only used for the COW fixup worker. Reviewed-by: Nikolay Borisov Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba

btrfs: fix repair of compressed extents

2022-07-25T17:56:16+00:00

Currently the checksum of compressed extents is verified based on the compressed data and the lower btrfs_bio, but the actual repair process is driven by end_bio_extent_readpage on the upper btrfs_bio for the decompressed data. This has a bunch of issues, including not being able to properly communicate the failed mirror up in case that the I/O submission got preempted, a general loss of if an error was an I/O error or a checksum verification failure, but most importantly that this design causes btrfs_clean_io_failure to eventually write back the uncompressed good data onto the disk sectors that are supposed to contain compressed data. Fix this by moving the repair to the lower btrfs_bio. To do so, a fair amount of code has to be reshuffled: a) the lower btrfs_bio now needs a valid csum pointer. The easiest way to achieve that is to pass NULL btrfs_lookup_bio_sums and just use the btrfs_bio management of csums. For a compressed_bio that is split into multiple btrfs_bios this means additional memory allocations, but the code becomes a lot more regular. b) checksum verification now runs directly on the lower btrfs_bio instead of the compressed_bio. This actually nicely simplifies the end I/O processing. c) btrfs_repair_one_sector can't just look up the logical address for the file offset any more, as there is no corresponding relative offsets that apply to the file offset and the logic address for compressed extents. Instead require that the saved bvec_iter in the btrfs_bio is filled out for all read bios and use that, which again removes a fair amount of code. Reviewed-by: Nikolay Borisov Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba

btrfs: simplify the pending I/O counting in struct compressed_bio

2022-07-25T17:54:47+00:00

Instead of counting the sectors just count the bios, with an extra reference held during submission. This significantly simplifies the submission side error handling. This slightly changes completion and error handling of btrfs_submit_compressed_{read,write} because with the old code the compressed_bio could have been completed in submit_compressed_{read,write} only if there was an error during submission for one of the lower bio, whilst with the new code there is a chance for this to happen even for successful submission if the all the lower bios complete before the end of the function is reached. Reviewed-by: Nikolay Borisov Reviewed-by: Boris Burkov Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba

btrfs: do not return errors from btrfs_map_bio

2022-07-25T15:45:39+00:00

Always consume the bio and call the end_io handler on error instead of returning an error and letting the caller handle it. This matches what the block layer submission does and avoids any confusion on who needs to handle errors. As this requires touching all the callers, rename the function to btrfs_submit_bio, which describes the functionality much better. Reviewed-by: Nikolay Borisov Tested-by: Nikolay Borisov Reviewed-by: Johannes Thumshirn Reviewed-by: Qu Wenruo Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba

btrfs: remove btrfs_end_io_wq

2022-07-25T15:45:33+00:00

All reads bio that go through btrfs_map_bio need to be completed in user context. And read I/Os are the most common and timing critical in almost any file system workloads. Embed a work_struct into struct btrfs_bio and use it to complete all read bios submitted through btrfs_map, using the REQ_META flag to decide which workqueue they are placed on. This removes the need for a separate 128 byte allocation (typically rounded up to 192 bytes by slab) for all reads with a size increase of 24 bytes for struct btrfs_bio. Future patches will reorganize struct btrfs_bio to make use of this extra space for writes as well. (All sizes are based a on typical 64-bit non-debug build) Reviewed-by: Qu Wenruo Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba

btrfs: don't use btrfs_bio_wq_end_io for compressed writes

2022-07-25T15:45:33+00:00

Compressed write bio completion is the only user of btrfs_bio_wq_end_io for writes, and the use of btrfs_bio_wq_end_io is a little suboptimal here as we only real need user context for the final completion of a compressed_bio structure, and not every single bio completion. Add a work_struct to struct compressed_bio instead and use that to call finish_compressed_bio_write. This allows to remove all handling of write bios in the btrfs_bio_wq_end_io infrastructure. Signed-off-by: Christoph Hellwig Signed-off-by: David Sterba

btrfs: remove redundant calls to flush_dcache_page

2022-07-25T15:44:34+00:00

Both memzero_page and memcpy_to_page already call flush_dcache_page so we can remove the calls from btrfs code. Reviewed-by: Christoph Hellwig Signed-off-by: David Sterba

btrfs: introduce a data checksum checking helper

2022-07-25T15:44:33+00:00

Although we have several data csum verification code, we never have a function really just to verify checksum for one sector. Function check_data_csum() do extra work for error reporting, thus it requires a lot of extra things like file offset, bio_offset etc. Function btrfs_verify_data_csum() is even worse, it will utilize page checked flag, which means it can not be utilized for direct IO pages. Here we introduce a new helper, btrfs_check_sector_csum(), which really only accept a sector in page, and expected checksum pointer. We use this function to implement check_data_csum(), and export it for incoming patch. Reviewed-by: Nikolay Borisov Signed-off-by: Qu Wenruo [hch: keep passing the csum array as an arguments, as the callers want to print it, rename per request] Signed-off-by: Christoph Hellwig Reviewed-by: David Sterba Signed-off-by: David Sterba

fs/btrfs: Use the enum req_op and blk_opf_t types

2022-07-14T18:14:32+00:00

Improve static type checking by using the enum req_op type for variables that represent a request operation and the new blk_opf_t type for variables that represent request flags. Acked-by: David Sterba Cc: Josef Bacik Signed-off-by: Bart Van Assche Link: https://lore.kernel.org/r/20220714180729.1065367-51-bvanassche@acm.org Signed-off-by: Jens Axboe