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Commit edf064e7 authored by Goldwyn Rodrigues's avatar Goldwyn Rodrigues Committed by Jens Axboe
Browse files

btrfs: nowait aio support 



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

Acked-by: default avatarDavid Sterba <dsterba@suse.com>
Signed-off-by: default avatarGoldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 29a5d29e

fs/btrfs/file.c

+27 −6
Original line number Diff line number Diff line
@@ -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;



	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) {
@@ -3071,13 +3086,19 @@ static loff_t btrfs_file_llseek(struct file *file, loff_t offset, int whence) 
	return offset;

}



static int btrfs_file_open(struct inode *inode, struct file *filp)

{

	filp->f_mode |= FMODE_AIO_NOWAIT;

	return generic_file_open(inode, filp);

}



const struct file_operations btrfs_file_operations = {

	.llseek		= btrfs_file_llseek,

	.read_iter      = generic_file_read_iter,

	.splice_read	= generic_file_splice_read,

	.write_iter	= btrfs_file_write_iter,

	.mmap		= btrfs_file_mmap,

	.open		= generic_file_open,

	.open		= btrfs_file_open,

	.release	= btrfs_release_file,

	.fsync		= btrfs_sync_file,

	.fallocate	= btrfs_fallocate,

fs/btrfs/inode.c

+3 −0
Original line number Diff line number Diff line
@@ -8754,6 +8754,9 @@ 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)