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authorLinus Torvalds <torvalds@linux-foundation.org>2022-08-02 13:27:23 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2022-08-02 13:27:23 -0700
commit98e247464088a11ce2328a214fdb87d4c06f8db6 (patch)
tree1f876a9b06b189855adfbefd1da6b6753effd1bb /fs/read_write.c
parentb349b1181d24af1c151134a3c39725e94a5619dd (diff)
parent0dd316ba8692c2374fbb82cce57c0b23144f2977 (diff)
Merge tag 'for-5.20/io_uring-buffered-writes-2022-07-29' of git://git.kernel.dk/linux-block
Pull io_uring buffered writes support from Jens Axboe: "This contains support for buffered writes, specifically for XFS. btrfs is in progress, will be coming in the next release. io_uring does support buffered writes on any file type, but since the buffered write path just always -EAGAIN (or -EOPNOTSUPP) any attempt to do so if IOCB_NOWAIT is set, any buffered write will effectively be handled by io-wq offload. This isn't very efficient, and we even have specific code in io-wq to serialize buffered writes to the same inode to avoid further inefficiencies with thread offload. This is particularly sad since most buffered writes don't block, they simply copy data to a page and dirty it. With this pull request, we can handle buffered writes a lot more effiently. If balance_dirty_pages() needs to block, we back off on writes as indicated. This improves buffered write support by 2-3x. Jan Kara helped with the mm bits for this, and Stefan handled the fs/iomap/xfs/io_uring parts of it" * tag 'for-5.20/io_uring-buffered-writes-2022-07-29' of git://git.kernel.dk/linux-block: mm: honor FGP_NOWAIT for page cache page allocation xfs: Add async buffered write support xfs: Specify lockmode when calling xfs_ilock_for_iomap() io_uring: Add tracepoint for short writes io_uring: fix issue with io_write() not always undoing sb_start_write() io_uring: Add support for async buffered writes fs: Add async write file modification handling. fs: Split off inode_needs_update_time and __file_update_time fs: add __remove_file_privs() with flags parameter fs: add a FMODE_BUF_WASYNC flags for f_mode iomap: Return -EAGAIN from iomap_write_iter() iomap: Add async buffered write support iomap: Add flags parameter to iomap_page_create() mm: Add balance_dirty_pages_ratelimited_flags() function mm: Move updates of dirty_exceeded into one place mm: Move starting of background writeback into the main balancing loop
Diffstat (limited to 'fs/read_write.c')
-rw-r--r--fs/read_write.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/read_write.c b/fs/read_write.c
index 397da0236607..0131d0df0476 100644
--- a/fs/read_write.c
+++ b/fs/read_write.c
@@ -1663,7 +1663,9 @@ int generic_write_checks_count(struct kiocb *iocb, loff_t *count)
if (iocb->ki_flags & IOCB_APPEND)
iocb->ki_pos = i_size_read(inode);
- if ((iocb->ki_flags & IOCB_NOWAIT) && !(iocb->ki_flags & IOCB_DIRECT))
+ if ((iocb->ki_flags & IOCB_NOWAIT) &&
+ !((iocb->ki_flags & IOCB_DIRECT) ||
+ (file->f_mode & FMODE_BUF_WASYNC)))
return -EINVAL;
return generic_write_check_limits(iocb->ki_filp, iocb->ki_pos, count);