xfs: don't start out with the exclusive ilock for direct I/O

There is no reason to take the ilock exclusively at the start of
xfs_file_iomap_begin for direct I/O, given that it will be demoted
just before calling xfs_iomap_write_direct anyway.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Christoph Hellwig 2018-03-01 14:12:12 -08:00 committed by Darrick J. Wong
parent 172ed391f6
commit af5b5afe9a
1 changed files with 2 additions and 4 deletions

View File

@ -965,13 +965,11 @@ static inline bool needs_cow_for_zeroing(struct xfs_bmbt_irec *imap, int nimaps)
static inline bool need_excl_ilock(struct xfs_inode *ip, unsigned flags)
{
/*
* COW writes will allocate delalloc space, so we need to make sure
* to take the lock exclusively here.
* COW writes may allocate delalloc space or convert unwritten COW
* extents, so we need to make sure to take the lock exclusively here.
*/
if (xfs_is_reflink_inode(ip) && (flags & (IOMAP_WRITE | IOMAP_ZERO)))
return true;
if ((flags & IOMAP_DIRECT) && (flags & IOMAP_WRITE))
return true;
return false;
}