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* Merge tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-blockLinus Torvalds2020-08-031-1/+1
|\ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Pull io_uring updates from Jens Axboe: "Lots of cleanups in here, hardening the code and/or making it easier to read and fixing bugs, but a core feature/change too adding support for real async buffered reads. With the latter in place, we just need buffered write async support and we're done relying on kthreads for the fast path. In detail: - Cleanup how memory accounting is done on ring setup/free (Bijan) - sq array offset calculation fixup (Dmitry) - Consistently handle blocking off O_DIRECT submission path (me) - Support proper async buffered reads, instead of relying on kthread offload for that. This uses the page waitqueue to drive retries from task_work, like we handle poll based retry. (me) - IO completion optimizations (me) - Fix race with accounting and ring fd install (me) - Support EPOLLEXCLUSIVE (Jiufei) - Get rid of the io_kiocb unionizing, made possible by shrinking other bits (Pavel) - Completion side cleanups (Pavel) - Cleanup REQ_F_ flags handling, and kill off many of them (Pavel) - Request environment grabbing cleanups (Pavel) - File and socket read/write cleanups (Pavel) - Improve kiocb_set_rw_flags() (Pavel) - Tons of fixes and cleanups (Pavel) - IORING_SQ_NEED_WAKEUP clear fix (Xiaoguang)" * tag 'for-5.9/io_uring-20200802' of git://git.kernel.dk/linux-block: (127 commits) io_uring: flip if handling after io_setup_async_rw fs: optimise kiocb_set_rw_flags() io_uring: don't touch 'ctx' after installing file descriptor io_uring: get rid of atomic FAA for cq_timeouts io_uring: consolidate *_check_overflow accounting io_uring: fix stalled deferred requests io_uring: fix racy overflow count reporting io_uring: deduplicate __io_complete_rw() io_uring: de-unionise io_kiocb io-wq: update hash bits io_uring: fix missing io_queue_linked_timeout() io_uring: mark ->work uninitialised after cleanup io_uring: deduplicate io_grab_files() calls io_uring: don't do opcode prep twice io_uring: clear IORING_SQ_NEED_WAKEUP after executing task works io_uring: batch put_task_struct() tasks: add put_task_struct_many() io_uring: return locked and pinned page accounting io_uring: don't miscount pinned memory io_uring: don't open-code recv kbuf managment ...
| * btrfs: flag files as supporting buffered async readsJens Axboe2020-06-211-1/+1
| | | | | | | | | | | | | | btrfs uses generic_file_read_iter(), which already supports this. Acked-by: Chris Mason <clm@fb.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
* | btrfs: make btrfs_check_data_free_space take btrfs_inodeNikolay Borisov2020-07-271-1/+2
| | | | | | | | | | | | | | | | | | Instead of calling BTRFS_I on the passed vfs_inode take btrfs_inode directly. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: make btrfs_delalloc_release_space take btrfs_inodeNikolay Borisov2020-07-271-2/+3
| | | | | | | | | | | | | | | | It needs btrfs_inode so take it as a parameter directly. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: make btrfs_free_reserved_data_space take btrfs_inodeNikolay Borisov2020-07-271-6/+7
| | | | | | | | | | | | | | | | It only uses btrfs_inode internally so take it as a parameter. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: make btrfs_qgroup_reserve_data take btrfs_inodeNikolay Borisov2020-07-271-3/+4
| | | | | | | | | | | | | | | | | | There's only a single use of vfs_inode in a tracepoint so let's take btrfs_inode directly. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: make btrfs_dirty_pages take btrfs_inodeNikolay Borisov2020-07-271-12/+12
| | | | | | | | | | | | | | | | | | There is a single use of the generic vfs_inode so let's take btrfs_inode as a parameter and remove couple of redundant BTRFS_I() calls. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: make btrfs_set_extent_delalloc take btrfs_inodeNikolay Borisov2020-07-271-1/+1
| | | | | | | | | | | | | | | | Preparation to make btrfs_dirty_pages take btrfs_inode as parameter. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: refactor btrfs_check_can_nocow() into two variantsQu Wenruo2020-07-271-35/+48
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The function btrfs_check_can_nocow() now has two completely different call patterns. For nowait variant, callers don't need to do any cleanup. While for wait variant, callers need to release the lock if they can do nocow write. This is somehow confusing, and is already a problem for the exported btrfs_check_can_nocow(). So this patch will separate the different patterns into different functions. For nowait variant, the function will be called check_nocow_nolock(). For wait variant, the function pair will be btrfs_check_nocow_lock() btrfs_check_nocow_unlock(). Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: add comments for btrfs_check_can_nocow() and can_nocow_extent()Qu Wenruo2020-07-271-0/+21
| | | | | | | | | | | | | | | | | | | | | | These two functions have extra conditions that their callers need to meet, and some not-that-common parameters used for return value. So adding some comments may save reviewers some time. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: allow btrfs_truncate_block() to fallback to nocow for data space ↵Qu Wenruo2020-07-271-6/+6
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | reservation [BUG] When the data space is exhausted, even if the inode has NOCOW attribute, we will still refuse to truncate unaligned range due to ENOSPC. The following script can reproduce it pretty easily: #!/bin/bash dev=/dev/test/test mnt=/mnt/btrfs umount $dev &> /dev/null umount $mnt &> /dev/null mkfs.btrfs -f $dev -b 1G mount -o nospace_cache $dev $mnt touch $mnt/foobar chattr +C $mnt/foobar xfs_io -f -c "pwrite -b 4k 0 4k" $mnt/foobar > /dev/null xfs_io -f -c "pwrite -b 4k 0 1G" $mnt/padding &> /dev/null sync xfs_io -c "fpunch 0 2k" $mnt/foobar umount $mnt Currently this will fail at the fpunch part. [CAUSE] Because btrfs_truncate_block() always reserves space without checking the NOCOW attribute. Since the writeback path follows NOCOW bit, we only need to bother the space reservation code in btrfs_truncate_block(). [FIX] Make btrfs_truncate_block() follow btrfs_buffered_write() to try to reserve data space first, and fall back to NOCOW check only when we don't have enough space. Such always-try-reserve is an optimization introduced in btrfs_buffered_write(), to avoid expensive btrfs_check_can_nocow() call. This patch will export check_can_nocow() as btrfs_check_can_nocow(), and use it in btrfs_truncate_block() to fix the problem. Reported-by: Martin Doucha <martin.doucha@suse.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: make __btrfs_drop_extents take btrfs_inodeNikolay Borisov2020-07-271-11/+12
| | | | | | | | | | | | | | | | | | | | It has only 4 uses of a vfs_inode for inode_sub_bytes but unifies the interface with the non __ prefixed version. Will also makes converting its callers to btrfs_inode easier. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: file: reserve qgroup space after the hole punch range is lockedQu Wenruo2020-07-271-4/+4
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | The incoming qgroup reserved space timing will move the data reservation to ordered extent completely. However in btrfs_punch_hole_lock_range() will call btrfs_invalidate_page(), which will clear QGROUP_RESERVED bit for the range. In current stage it's OK, but if we're making ordered extents handle the reserved space, then btrfs_punch_hole_lock_range() can clear the QGROUP_RESERVED bit before we submit ordered extent, leading to qgroup reserved space leakage. So here change the timing to make reserve data space after btrfs_punch_hole_lock_range(). The new timing is fine for either current code or the new code. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: don't balance btree inode pages from buffered write pathNikolay Borisov2020-07-271-2/+0
| | | | | | | | | | | | | | | | | | | | | | | | The call to btrfs_btree_balance_dirty has been there since the early days of BTRFS, when the btree was directly modified from the write path, hence dirtied btree inode pages. With the implementation of b888db2bd7b6 ("Btrfs: Add delayed allocation to the extent based page tree code") 13 years ago the btree is no longer modified from the write path, hence there is no point in calling this function. Just remove it. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: wire up iter_file_splice_writeChristoph Hellwig2020-07-091-0/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | btrfs implements the iter_write op and thus can use the more efficient iov_iter based splice implementation. For now falling back to the less efficient default is pretty harmless, but I have a pending series that removes the default, and thus would cause btrfs to not support splice at all. Reported-by: Andy Lavr <andy.lavr@gmail.com> Tested-by: Andy Lavr <andy.lavr@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: fix RWF_NOWAIT writes blocking on extent locks and waiting for IOFilipe Manana2020-06-161-11/+26
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | A RWF_NOWAIT write is not supposed to wait on filesystem locks that can be held for a long time or for ongoing IO to complete. However when calling check_can_nocow(), if the inode has prealloc extents or has the NOCOW flag set, we can block on extent (file range) locks through the call to btrfs_lock_and_flush_ordered_range(). Such lock can take a significant amount of time to be available. For example, a fiemap task may be running, and iterating through the entire file range checking all extents and doing backref walking to determine if they are shared, or a readpage operation may be in progress. Also at btrfs_lock_and_flush_ordered_range(), called by check_can_nocow(), after locking the file range we wait for any existing ordered extent that is in progress to complete. Another operation that can take a significant amount of time and defeat the purpose of RWF_NOWAIT. So fix this by trying to lock the file range and if it's currently locked return -EAGAIN to user space. If we are able to lock the file range without waiting and there is an ordered extent in the range, return -EAGAIN as well, instead of waiting for it to complete. Finally, don't bother trying to lock the snapshot lock of the root when attempting a RWF_NOWAIT write, as that is only important for buffered writes. Fixes: edf064e7c6fec3 ("btrfs: nowait aio support") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: fix RWF_NOWAIT write not failling when we need to cowFilipe Manana2020-06-161-1/+12
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we attempt to do a RWF_NOWAIT write against a file range for which we can only do NOCOW for a part of it, due to the existence of holes or shared extents for example, we proceed with the write as if it were possible to NOCOW the whole range. Example: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ touch /mnt/sdj/bar $ chattr +C /mnt/sdj/bar $ xfs_io -d -c "pwrite -S 0xab -b 256K 0 256K" /mnt/bar wrote 262144/262144 bytes at offset 0 256 KiB, 1 ops; 0.0003 sec (694.444 MiB/sec and 2777.7778 ops/sec) $ xfs_io -c "fpunch 64K 64K" /mnt/bar $ sync $ xfs_io -d -c "pwrite -N -V 1 -b 128K -S 0xfe 0 128K" /mnt/bar wrote 131072/131072 bytes at offset 0 128 KiB, 1 ops; 0.0007 sec (160.051 MiB/sec and 1280.4097 ops/sec) This last write should fail with -EAGAIN since the file range from 64K to 128K is a hole. On xfs it fails, as expected, but on ext4 it currently succeeds because apparently it is expensive to check if there are extents allocated for the whole range, but I'll check with the ext4 people. Fix the issue by checking if check_can_nocow() returns a number of NOCOW'able bytes smaller then the requested number of bytes, and if it does return -EAGAIN. Fixes: edf064e7c6fec3 ("btrfs: nowait aio support") CC: stable@vger.kernel.org # 4.14+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* | btrfs: fix hang on snapshot creation after RWF_NOWAIT writeFilipe Manana2020-06-161-0/+2
|/ | | | | | | | | | | | | | | | | | | | | | | | | | | | | | If we do a successful RWF_NOWAIT write we end up locking the snapshot lock of the inode, through a call to check_can_nocow(), but we never unlock it. This means the next attempt to create a snapshot on the subvolume will hang forever. Trivial reproducer: $ mkfs.btrfs -f /dev/sdb $ mount /dev/sdb /mnt $ touch /mnt/foobar $ chattr +C /mnt/foobar $ xfs_io -d -c "pwrite -S 0xab 0 64K" /mnt/foobar $ xfs_io -d -c "pwrite -N -V 1 -S 0xfe 0 64K" /mnt/foobar $ btrfs subvolume snapshot -r /mnt /mnt/snap --> hangs Fix this by unlocking the snapshot lock if check_can_nocow() returned success. Fixes: edf064e7c6fec3 ("btrfs: nowait aio support") CC: stable@vger.kernel.org # 4.14+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Revert "btrfs: switch to iomap_dio_rw() for dio"David Sterba2020-06-141-19/+2
| | | | | | | | | | | | | | | | | | | | | | | | | This reverts commit a43a67a2d715540c1368b9501a22b0373b5874c0. This patch reverts the main part of switching direct io implementation to iomap infrastructure. There's a problem in invalidate page that couldn't be solved as regression in this development cycle. The problem occurs when buffered and direct io are mixed, and the ranges overlap. Although this is not recommended, filesystems implement measures or fallbacks to make it somehow work. In this case, fallback to buffered IO would be an option for btrfs (this already happens when direct io is done on compressed data), but the change would be needed in the iomap code, bringing new semantics to other filesystems. Another problem arises when again the buffered and direct ios are mixed, invalidation fails, then -EIO is set on the mapping and fsync will fail, though there's no real error. There have been discussions how to fix that, but revert seems to be the least intrusive option. Link: https://lore.kernel.org/linux-btrfs/20200528192103.xm45qoxqmkw7i5yl@fiona/ Signed-off-by: David Sterba <dsterba@suse.com>
* Revert "btrfs: split btrfs_direct_IO to read and write part"David Sterba2020-06-091-78/+10
| | | | | | | | | This reverts commit d8f3e73587ce574f7a9bc165e0db69b0b148f6f8. The patch is a cleanup of direct IO port to iomap infrastructure, which gets reverted. Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: split btrfs_direct_IO to read and write partChristoph Hellwig2020-05-281-10/+78
| | | | | | | | | | The read and write versions don't have anything in common except for the call to iomap_dio_rw. So split this function, and merge each half into its only caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: switch to iomap_dio_rw() for dioGoldwyn Rodrigues2020-05-281-2/+19
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Switch from __blockdev_direct_IO() to iomap_dio_rw(). Rename btrfs_get_blocks_direct() to btrfs_dio_iomap_begin() and use it as iomap_begin() for iomap direct I/O functions. This function allocates and locks all the blocks required for the I/O. btrfs_submit_direct() is used as the submit_io() hook for direct I/O ops. Since we need direct I/O reads to go through iomap_dio_rw(), we change file_operations.read_iter() to a btrfs_file_read_iter() which calls btrfs_direct_IO() for direct reads and falls back to generic_file_buffered_read() for incomplete reads and buffered reads. We don't need address_space.direct_IO() anymore so set it to noop. Similarly, we don't need flags used in __blockdev_direct_IO(). iomap is capable of direct I/O reads from a hole, so we don't need to return -ENOENT. BTRFS direct I/O is now done under i_rwsem, shared in case of reads and exclusive in case of writes. This guards against simultaneous truncates. Use iomap->iomap_end() to check for failed or incomplete direct I/O: - for writes, call __endio_write_update_ordered() - for reads, unlock extents btrfs_dio_data is now hooked in iomap->private and not current->journal_info. It carries the reservation variable and the amount of data submitted, so we can calculate the amount of data to call __endio_write_update_ordered in case of an error. This patch removes last use of struct buffer_head from btrfs. Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: simplify iget helpersDavid Sterba2020-05-251-5/+1
| | | | | | | | | | | | | The inode lookup starting at btrfs_iget takes the full location key, while only the objectid is used to match the inode, because the lookup happens inside the given root thus the inode number is unique. The entire location key is properly set up in btrfs_init_locked_inode. Simplify the helpers and pass only inode number, renaming it to 'ino' instead of 'objectid'. This allows to remove temporary variables key, saving some stack space. Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: simplify root lookup by idDavid Sterba2020-05-251-5/+1
| | | | | | | | | | | | | The main function to lookup a root by its id btrfs_get_fs_root takes the whole key, while only using the objectid. The value of offset is preset to (u64)-1 but not actually used until btrfs_find_root that does the actual search. Switch btrfs_get_fs_root to use only objectid and remove all local variables that existed just for the lookup. The actual key for search is set up in btrfs_get_fs_root, reusing another key variable. Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLEQu Wenruo2020-05-251-1/+1
| | | | | | | | | | | | | | | | | | | | | | | The name BTRFS_ROOT_REF_COWS is not very clear about the meaning. In fact, that bit can only be set to those trees: - Subvolume roots - Data reloc root - Reloc roots for above roots All other trees won't get this bit set. So just by the result, it is obvious that, roots with this bit set can have tree blocks shared with other trees. Either shared by snapshots, or by reloc roots (an special snapshot created by relocation). This patch will rename BTRFS_ROOT_REF_COWS to BTRFS_ROOT_SHAREABLE to make it easier to understand, and update all comment mentioning "reference counted" to follow the rename. Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: make full fsyncs always operate on the entire file againFilipe Manana2020-04-081-0/+15
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | This is a revert of commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient"), with updated comment in btrfs_sync_file. Commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") made full fsyncs operate on the given range only as it assumed it was safe when using the NO_HOLES feature, since the hole detection was simplified some time ago and no longer was a source for races with ordered extent completion of adjacent file ranges. However it's still not safe to have a full fsync only operate on the given range, because extent maps for new extents might not be present in memory due to inode eviction or extent cloning. Consider the following example: 1) We are currently at transaction N; 2) We write to the file range [0, 1MiB); 3) Writeback finishes for the whole range and ordered extents complete, while we are still at transaction N; 4) The inode is evicted; 5) We open the file for writing, causing the inode to be loaded to memory again, which sets the 'full sync' bit on its flags. At this point the inode's list of modified extent maps is empty (figuring out which extents were created in the current transaction and were not yet logged by an fsync is expensive, that's why we set the 'full sync' bit when loading an inode); 6) We write to the file range [512KiB, 768KiB); 7) We do a ranged fsync (such as msync()) for file range [512KiB, 768KiB). This correctly flushes this range and logs its extent into the log tree. When the writeback started an extent map for range [512KiB, 768KiB) was added to the inode's list of modified extents, and when the fsync() finishes logging it removes that extent map from the list of modified extent maps. This fsync also clears the 'full sync' bit; 8) We do a regular fsync() (full ranged). This fsync() ends up doing nothing because the inode's list of modified extents is empty and no other changes happened since the previous ranged fsync(), so it just returns success (0) and we end up never logging extents for the file ranges [0, 512KiB) and [768KiB, 1MiB). Another scenario where this can happen is if we replace steps 2 to 4 with cloning from another file into our test file, as that sets the 'full sync' bit in our inode's flags and does not populate its list of modified extent maps. This was causing test case generic/457 to fail sporadically when using the NO_HOLES feature, as it exercised this later case where the inode has the 'full sync' bit set and has no extent maps in memory to represent the new extents due to extent cloning. Fix this by reverting commit 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") since there is no easy way to work around it. Fixes: 0a8068a3dd4294 ("btrfs: make ranged full fsyncs more efficient") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: fix missing semaphore unlock in btrfs_sync_fileRobbie Ko2020-03-251-0/+1
| | | | | | | | | | | | | Ordered ops are started twice in sync file, once outside of inode mutex and once inside, taking the dio semaphore. There was one error path missing the semaphore unlock. Fixes: aab15e8ec2576 ("Btrfs: fix rare chances for data loss when doing a fast fsync") CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Robbie Ko <robbieko@synology.com> Reviewed-by: Filipe Manana <fdmanana@suse.com> [ add changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: kill the subvol_srcuJosef Bacik2020-03-231-5/+0
| | | | | | | | | | | | | | | | | | | | | Now that we have proper root ref counting everywhere we can kill the subvol_srcu. * removal of fs_info::subvol_srcu reduces size of fs_info by 1176 bytes * the refcount_t used for the references checks for accidental 0->1 in cases where the root lifetime would not be properly protected * there's a leak detector for roots to catch unfreed roots at umount time * SRCU served us well over the years but is was not a proper synchronization mechanism for some cases Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: make ranged full fsyncs more efficientFilipe Manana2020-03-231-13/+0
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Commit 0c713cbab6200b ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges") fixed a bug where we could end up with file extent items in a log tree that represent file ranges that overlap due to a race between the hole detection of a ranged full fsync and writeback for a different file range. The problem was solved by forcing any ranged full fsync to become a non-ranged full fsync - setting the range start to 0 and the end offset to LLONG_MAX. This was a simple solution because the code that detected and marked holes was very complex, it used to be done at copy_items() and implied several searches on the fs/subvolume tree. The drawback of that solution was that we started to flush delalloc for the entire file and wait for all the ordered extents to complete for ranged full fsyncs (including ordered extents covering ranges completely outside the given range). Fortunatelly ranged full fsyncs are not the most common case (hopefully for most workloads). However a later fix for detecting and marking holes was made by commit 0e56315ca147b3 ("Btrfs: fix missing hole after hole punching and fsync when using NO_HOLES") and it simplified a lot the detection of holes, and now copy_items() no longer does it and we do it in a much more simple way at btrfs_log_holes(). This makes it now possible to simply make the code that detects holes to operate only on the initial range and no longer need to operate on the whole file, while also avoiding the need to flush delalloc for the entire file and wait for ordered extents that cover ranges that don't overlap the given range. Another special care is that we must skip file extent items that fall entirely outside the fsync range when copying inode items from the fs/subvolume tree into the log tree - this is to avoid races with ordered extent completion for extents falling outside the fsync range, which could cause us to end up with file extent items in the log tree that have overlapping ranges - for example if the fsync range is [1Mb, 2Mb], when we copy inode items we could copy an extent item for the range [0, 512K], then release the search path and before moving to the next leaf, an ordered extent for a range of [256Kb, 512Kb] completes - this would cause us to copy the new extent item for range [256Kb, 512Kb] into the log tree after we have copied one for the range [0, 512Kb] - the extents overlap, resulting in a corruption. So this change just does these steps: 1) When the NO_HOLES feature is enabled it leaves the initial range intact - no longer sets it to [0, LLONG_MAX] when the full sync bit is set in the inode. If NO_HOLES is not enabled, always set the range to a full, just like before this change, to avoid missing file extent items representing holes after replaying the log (for both full and fast fsyncs); 2) Make the hole detection code to operate only on the fsync range; 3) Make the code that copies items from the fs/subvolume tree to skip copying file extent items that cover a range completely outside the range of the fsync. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: fix missing file extent item for hole after ranged fsyncFilipe Manana2020-03-231-0/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When doing a fast fsync for a range that starts at an offset greater than zero, we can end up with a log that when replayed causes the respective inode miss a file extent item representing a hole if we are not using the NO_HOLES feature. This is because for fast fsyncs we don't log any extents that cover a range different from the one requested in the fsync. Example scenario to trigger it: $ mkfs.btrfs -O ^no-holes -f /dev/sdd $ mount /dev/sdd /mnt # Create a file with a single 256K and fsync it to clear to full sync # bit in the inode - we want the msync below to trigger a fast fsync. $ xfs_io -f -c "pwrite -S 0xab 0 256K" -c "fsync" /mnt/foo # Force a transaction commit and wipe out the log tree. $ sync # Dirty 768K of data, increasing the file size to 1Mb, and flush only # the range from 256K to 512K without updating the log tree # (sync_file_range() does not trigger fsync, it only starts writeback # and waits for it to finish). $ xfs_io -c "pwrite -S 0xcd 256K 768K" /mnt/foo $ xfs_io -c "sync_range -abw 256K 256K" /mnt/foo # Now dirty the range from 768K to 1M again and sync that range. $ xfs_io -c "mmap -w 768K 256K" \ -c "mwrite -S 0xef 768K 256K" \ -c "msync -s 768K 256K" \ -c "munmap" \ /mnt/foo <power fail> # Mount to replay the log. $ mount /dev/sdd /mnt $ umount /mnt $ btrfs check /dev/sdd Opening filesystem to check... Checking filesystem on /dev/sdd UUID: 482fb574-b288-478e-a190-a9c44a78fca6 [1/7] checking root items [2/7] checking extents [3/7] checking free space cache [4/7] checking fs roots root 5 inode 257 errors 100, file extent discount Found file extent holes: start: 262144, len: 524288 ERROR: errors found in fs roots found 720896 bytes used, error(s) found total csum bytes: 512 total tree bytes: 131072 total fs tree bytes: 32768 total extent tree bytes: 16384 btree space waste bytes: 123514 file data blocks allocated: 589824 referenced 589824 Fix this issue by setting the range to full (0 to LLONG_MAX) when the NO_HOLES feature is not enabled. This results in extra work being done but it gives the guarantee we don't end up with missing holes after replaying the log. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: move all reflink implementation code into its own fileFilipe Manana2020-03-231-0/+1
| | | | | | | | | | | | | | | | The reflink code is quite large and has been living in ioctl.c since ever. It has grown over the years after many bug fixes and improvements, and since I'm planning on making some further improvements on it, it's time to get it better organized by moving into its own file, reflink.c (similar to what xfs does for example). This change only moves the code out of ioctl.c into the new file, it doesn't do any other change. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: convert snapshot/nocow exlcusion to drew lockNikolay Borisov2020-03-231-6/+5
| | | | | | | | | | | | | | | | | | | | | | | | | This patch removes all haphazard code implementing nocow writers exclusion from pending snapshot creation and switches to using the drew lock to ensure this invariant still holds. 'Readers' are snapshot creators from create_snapshot and 'writers' are nocow writers from buffered write path or btrfs_setsize. This locking scheme allows for multiple snapshots to happen while any nocow writers are blocked, since writes to page cache in the nocow path will make snapshots inconsistent. So for performance reasons we'd like to have the ability to run multiple concurrent snapshots and also favors readers in this case. And in case there aren't pending snapshots (which will be the majority of the cases) we rely on the percpu's writers counter to avoid cacheline contention. The main gain from using the drew lock is it's now a lot easier to reason about the guarantees of the locking scheme and whether there is some silent breakage lurking. Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: drop argument tree from btrfs_lock_and_flush_ordered_rangeDavid Sterba2020-03-231-1/+1
| | | | | | | | | The tree pointer can be safely read from the inode so we can drop the redundant argument from btrfs_lock_and_flush_ordered_range. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: rename btrfs_put_fs_root and btrfs_grab_fs_rootJosef Bacik2020-03-231-1/+1
| | | | | | | | | | We are now using these for all roots, rename them to btrfs_put_root() and btrfs_grab_root(); Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: push btrfs_grab_fs_root into btrfs_get_fs_rootJosef Bacik2020-03-231-4/+0
| | | | | | | | | | | Now that all callers of btrfs_get_fs_root are subsequently calling btrfs_grab_fs_root and handling dropping the ref when they are done appropriately, go ahead and push btrfs_grab_fs_root up into btrfs_get_fs_root. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: hold a ref on the root in __btrfs_run_defrag_inodeJosef Bacik2020-03-231-0/+5
| | | | | | | | | We are looking up an arbitrary inode, we need to hold a ref on the root while we're doing this. Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: open code btrfs_read_fs_root_no_nameJosef Bacik2020-03-231-1/+1
| | | | | | | | | | | All this does is call btrfs_get_fs_root() with check_ref == true. Just use btrfs_get_fs_root() so we don't have a bunch of different helpers that do the same thing. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: replace all uses of btrfs_ordered_update_i_sizeJosef Bacik2020-03-231-1/+1
| | | | | | | | | | Now that we have a safe way to update the i_size, replace all uses of btrfs_ordered_update_i_size with btrfs_inode_safe_disk_i_size_write. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: use the file extent tree infrastructureJosef Bacik2020-03-231-0/+32
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | We want to use this everywhere we modify the file extent items permanently. These include: 1) Inserting new file extents for writes and prealloc extents. 2) Truncating inode items. 3) btrfs_cont_expand(). 4) Insert inline extents. 5) Insert new extents from log replay. 6) Insert a new extent for clone, as it could be past i_size. 7) Hole punching For hole punching in particular it might seem it's not necessary because anybody extending would use btrfs_cont_expand, however there is a corner that still can give us trouble. Start with an empty file and fallocate KEEP_SIZE 1M-2M We now have a 0 length file, and a hole file extent from 0-1M, and a prealloc extent from 1M-2M. Now punch 1M-1.5M Because this is past i_size we have [HOLE EXTENT][ NOTHING ][PREALLOC] [0 1M][1M 1.5M][1.5M 2M] with an i_size of 0. Now if we pwrite 0-1.5M we'll increas our i_size to 1.5M, but our disk_i_size is still 0 until the ordered extent completes. However if we now immediately truncate 2M on the file we'll just call btrfs_cont_expand(inode, 1.5M, 2M), since our old i_size is 1.5M. If we commit the transaction here and crash we'll expose the gap. To fix this we need to clear the file extent mapping for the range that we punched but didn't insert a corresponding file extent for. This will mean the truncate will only get an disk_i_size set to 1M if we crash before the finish ordered io happens. I've written an xfstest to reproduce the problem and validate this fix. Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: drop create parameter to btrfs_get_extent()Omar Sandoval2020-01-201-9/+8
| | | | | | | | | | | | | | | We only pass this as 1 from __extent_writepage_io(). The parameter basically means "pretend I didn't pass in a page". This is silly since we can simply not pass in the page. Get rid of the parameter from btrfs_get_extent(), and since it's used as a get_extent_t callback, remove it from get_extent_t and btree_get_extent(), neither of which need it. While we're here, let's document btrfs_get_extent(). Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: make btrfs_ordered_extent naming consistent with btrfs_file_extent_itemOmar Sandoval2020-01-201-3/+3
| | | | | | | | | | | | | | | | ordered->start, ordered->len, and ordered->disk_len correspond to fi->disk_bytenr, fi->num_bytes, and fi->disk_num_bytes, respectively. It's confusing to translate between the two naming schemes. Since a btrfs_ordered_extent is basically a pending btrfs_file_extent_item, let's make the former use the naming from the latter. Note that I didn't touch the names in tracepoints just in case there are scripts depending on the current naming. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Omar Sandoval <osandov@fb.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: fix cloning range with a hole when using the NO_HOLES featureFilipe Manana2019-12-131-2/+2
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | When using the NO_HOLES feature if we clone a range that contains a hole and a temporary ENOSPC happens while dropping extents from the target inode's range, we can end up failing and aborting the transaction with -EEXIST or with a corrupt file extent item, that has a length greater than it should and overlaps with other extents. For example when cloning the following range from inode A to inode B: Inode A: extent A1 extent A2 [ ----------- ] [ hole, implicit, 4MB length ] [ ------------- ] 0 1MB 5MB 6MB Range to clone: [1MB, 6MB) Inode B: extent B1 extent B2 extent B3 extent B4 [ ---------- ] [ --------- ] [ ---------- ] [ ---------- ] 0 1MB 1MB 2MB 2MB 5MB 5MB 6MB Target range: [1MB, 6MB) (same as source, to make it easier to explain) The following can happen: 1) btrfs_punch_hole_range() gets -ENOSPC from __btrfs_drop_extents(); 2) At that point, 'cur_offset' is set to 1MB and __btrfs_drop_extents() set 'drop_end' to 2MB, meaning it was able to drop only extent B2; 3) We then compute 'clone_len' as 'drop_end' - 'cur_offset' = 2MB - 1MB = 1MB; 4) We then attempt to insert a file extent item at inode B with a file offset of 5MB, which is the value of clone_info->file_offset. This fails with error -EEXIST because there's already an extent at that offset (extent B4); 5) We abort the current transaction with -EEXIST and return that error to user space as well. Another example, for extent corruption: Inode A: extent A1 extent A2 [ ----------- ] [ hole, implicit, 10MB length ] [ ------------- ] 0 1MB 11MB 12MB Inode B: extent B1 extent B2 [ ----------- ] [ --------- ] [ ----------------------------- ] 0 1MB 1MB 5MB 5MB 12MB Target range: [1MB, 12MB) (same as source, to make it easier to explain) 1) btrfs_punch_hole_range() gets -ENOSPC from __btrfs_drop_extents(); 2) At that point, 'cur_offset' is set to 1MB and __btrfs_drop_extents() set 'drop_end' to 5MB, meaning it was able to drop only extent B2; 3) We then compute 'clone_len' as 'drop_end' - 'cur_offset' = 5MB - 1MB = 4MB; 4) We then insert a file extent item at inode B with a file offset of 11MB which is the value of clone_info->file_offset, and a length of 4MB (the value of 'clone_len'). So we get 2 extents items with ranges that overlap and an extent length of 4MB, larger then the extent A2 from inode A (1MB length); 5) After that we end the transaction, balance the btree dirty pages and then start another or join the previous transaction. It might happen that the transaction which inserted the incorrect extent was committed by another task so we end up with extent corruption if a power failure happens. So fix this by making sure we attempt to insert the extent to clone at the destination inode only if we are past dropping the sub-range that corresponds to a hole. Fixes: 690a5dbfc51315 ("Btrfs: fix ENOSPC errors, leading to transaction aborts, when cloning extents") Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: remove extent_map::bdevDavid Sterba2019-11-181-3/+0
| | | | | | | | We can now remove the bdev from extent_map. Previous patches made sure that bio_set_dev is correctly in all places and that we don't need to grab it from latest_bdev or pass it around inside the extent map. Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: Return offset from find_desired_extentNikolay Borisov2019-11-181-15/+19
| | | | | | | | | | | | | | Instead of using an input pointer parameter as the return value and have an int as the return type of find_desired_extent, rework the function to directly return the found offset. Doing that the 'ret' variable in btrfs_llseek_file can be removed. Additional (subjective) benefit is that btrfs' llseek function now resemebles those of the other major filesystems. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: Simplify btrfs_file_llseekNikolay Borisov2019-11-181-7/+3
| | | | | | | | | | | | Handle SEEK_END/SEEK_CUR in a single 'default' case by directly returning from generic_file_llseek. This makes the 'out' label redundant. Finally return directly the vale from vfs_setpos. No semantic changes. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: Speed up btrfs_file_llseekNikolay Borisov2019-11-181-16/+10
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Modifying the file position is done on a per-file basis. This renders holding the inode lock for writing useless and makes the performance of concurrent llseek's abysmal. Fix this by holding the inode for read. This provides protection against concurrent truncates and find_desired_extent already includes proper extent locking for the range which ensures proper locking against concurrent writes. SEEK_CUR and SEEK_END can be done lockessly. The former is synchronized by file::f_lock spinlock. SEEK_END is not synchronized but atomic, but that's OK since there is not guarantee that SEEK_END will always be at the end of the file in the face of tail modifications. This change brings ~82% performance improvement when doing a lot of parallel fseeks. The workload essentially does: for (d=0; d<num_seek_read; d++) { /* offset %= 16777216; */ fseek (f, 256 * d % 16777216, SEEK_SET); fread (buffer, 64, 1, f); } Without patch: num workprocesses = 16 num fseek/fread = 8000000 step = 256 fork 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 real 0m41.412s user 0m28.777s sys 2m16.510s With patch: num workprocesses = 16 num fseek/fread = 8000000 step = 256 fork 0 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 real 0m11.479s user 0m27.629s sys 0m21.040s Signed-off-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: fix negative subv_writers counter and data space leak after buffered ↵Filipe Manana2019-11-181-1/+1
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | write When doing a buffered write it's possible to leave the subv_writers counter of the root, used for synchronization between buffered nocow writers and snapshotting. This happens in an exceptional case like the following: 1) We fail to allocate data space for the write, since there's not enough available data space nor enough unallocated space for allocating a new data block group; 2) Because of that failure, we try to go to NOCOW mode, which succeeds and therefore we set the local variable 'only_release_metadata' to true and set the root's sub_writers counter to 1 through the call to btrfs_start_write_no_snapshotting() made by check_can_nocow(); 3) The call to btrfs_copy_from_user() returns zero, which is very unlikely to happen but not impossible; 4) No pages are copied because btrfs_copy_from_user() returned zero; 5) We call btrfs_end_write_no_snapshotting() which decrements the root's subv_writers counter to 0; 6) We don't set 'only_release_metadata' back to 'false' because we do it only if 'copied', the value returned by btrfs_copy_from_user(), is greater than zero; 7) On the next iteration of the while loop, which processes the same page range, we are now able to allocate data space for the write (we got enough data space released in the meanwhile); 8) After this if we fail at btrfs_delalloc_reserve_metadata(), because now there isn't enough free metadata space, or in some other place further below (prepare_pages(), lock_and_cleanup_extent_if_need(), btrfs_dirty_pages()), we break out of the while loop with 'only_release_metadata' having a value of 'true'; 9) Because 'only_release_metadata' is 'true' we end up decrementing the root's subv_writers counter to -1 (through a call to btrfs_end_write_no_snapshotting()), and we also end up not releasing the data space previously reserved through btrfs_check_data_free_space(). As a consequence the mechanism for synchronizing NOCOW buffered writes with snapshotting gets broken. Fix this by always setting 'only_release_metadata' to false at the start of each iteration. Fixes: 8257b2dc3c1a ("Btrfs: introduce btrfs_{start, end}_nocow_write() for each subvolume") Fixes: 7ee9e4405f26 ("Btrfs: check if we can nocow if we don't have data space") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: drop unused parameter is_new from btrfs_igetDavid Sterba2019-11-181-1/+1
| | | | | | | | | The parameter is now always set to NULL and could be dropped. The last user was get_default_root but that got reworked in 05dbe6837b60 ("Btrfs: unify subvol= and subvolid= mounting") and the parameter became unused. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
* btrfs: simplify inode locking for RWF_NOWAITGoldwyn Rodrigues2019-11-181-2/+3
| | | | | | | | | | | | | | This is similar to 942491c9e6d6 ("xfs: fix AIM7 regression"). Apparently our current rwsem code doesn't like doing the trylock, then lock for real scheme. This causes extra contention on the lock and can be measured eg. by AIM7 benchmark. So change our read/write methods to just do the trylock for the RWF_NOWAIT case. Fixes: edf064e7c6fe ("btrfs: nowait aio support") Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> [ update changelog ] Signed-off-by: David Sterba <dsterba@suse.com>
* Btrfs: check for the full sync flag while holding the inode lock during fsyncFilipe Manana2019-10-171-19/+17
| | | | | | | | | | | | | | | | | | | | | | | | We were checking for the full fsync flag in the inode before locking the inode, which is racy, since at that that time it might not be set but after we acquire the inode lock some other task set it. One case where this can happen is on a system low on memory and some concurrent task failed to allocate an extent map and therefore set the full sync flag on the inode, to force the next fsync to work in full mode. A consequence of missing the full fsync flag set is hitting the problems fixed by commit 0c713cbab620 ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges"), BUG_ON() when dropping extents from a log tree, hitting assertion failures at tree-log.c:copy_items() or all sorts of weird inconsistencies after replaying a log due to file extents items representing ranges that overlap. So just move the check such that it's done after locking the inode and before starting writeback again. Fixes: 0c713cbab620 ("Btrfs: fix race between ranged fsync and writeback of adjacent ranges") CC: stable@vger.kernel.org # 5.2+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
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