[PATCH 10/10] btrfs: nowait aio support
From: Goldwyn Rodrigues <hidden>
Date: 2017-05-24 16:42:22
Also in:
linux-block, linux-btrfs, linux-ext4, linux-fsdevel, linux-xfs
Subsystem:
btrfs file system, filesystems (vfs and infrastructure), the rest · Maintainers:
Chris Mason, David Sterba, Alexander Viro, Christian Brauner, Linus Torvalds
From: Goldwyn Rodrigues <redacted> Return EAGAIN if any of the following checks fail + i_rwsem is not lockable + NODATACOW or PREALLOC is not set + Cannot nocow at the desired location + Writing beyond end of file which is not allocated Signed-off-by: Goldwyn Rodrigues <redacted> Acked-by: David Sterba <dsterba@suse.com> --- fs/btrfs/file.c | 25 ++++++++++++++++++++----- fs/btrfs/inode.c | 3 +++ 2 files changed, 23 insertions(+), 5 deletions(-)
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index da1096eb1a40..aae088e49915 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c@@ -1875,12 +1875,29 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, ssize_t num_written = 0; bool sync = (file->f_flags & O_DSYNC) || IS_SYNC(file->f_mapping->host); ssize_t err; - loff_t pos; - size_t count; + loff_t pos = iocb->ki_pos; + size_t count = iov_iter_count(from); loff_t oldsize; int clean_page = 0; - inode_lock(inode); + if ((iocb->ki_flags & IOCB_NOWAIT) && + (iocb->ki_flags & IOCB_DIRECT)) { + /* Don't sleep on inode rwsem */ + if (!inode_trylock(inode)) + return -EAGAIN; + /* + * We will allocate space in case nodatacow is not set, + * so bail + */ + if (!(BTRFS_I(inode)->flags & (BTRFS_INODE_NODATACOW | + BTRFS_INODE_PREALLOC)) || + check_can_nocow(BTRFS_I(inode), pos, &count) <= 0) { + inode_unlock(inode); + return -EAGAIN; + } + } else + inode_lock(inode); + err = generic_write_checks(iocb, from); if (err <= 0) { inode_unlock(inode);
@@ -1914,8 +1931,6 @@ static ssize_t btrfs_file_write_iter(struct kiocb *iocb, */ update_time_for_write(inode); - pos = iocb->ki_pos; - count = iov_iter_count(from); start_pos = round_down(pos, fs_info->sectorsize); oldsize = i_size_read(inode); if (start_pos > oldsize) {
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 17cbe9306faf..2ab71b946829 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c@@ -8755,6 +8755,9 @@ static ssize_t btrfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) dio_data.overwrite = 1; inode_unlock(inode); relock = true; + } else if (iocb->ki_flags & IOCB_NOWAIT) { + ret = -EAGAIN; + goto out; } ret = btrfs_delalloc_reserve_space(inode, offset, count); if (ret)
--
2.12.0