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xfs: don't use delalloc extents for COW on files with extsize hints 

While using delalloc for extsize hints is generally a good idea, the
current code that does so only for COW doesn't help us much and creates
a lot of special cases.  Switch it to use real allocations like we
do for direct I/O.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
hifive-unleashed-5.1
Christoph Hellwig 2019-02-18 09:38:46 -08:00 committed by Darrick J. Wong
parent 60271ab79d
commit 78f0cc9d55
3 changed files with 29 additions and 13 deletions
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29
fs/xfs/xfs_iomap.c
View File

@ -918,22 +918,29 @@ xfs_file_iomap_begin(
* been done up front, so we don't need to do them here.
*/
if (xfs_is_reflink_inode(ip)) {
struct xfs_bmbt_irec orig = imap;
/* if zeroing doesn't need COW allocation, then we are done. */
if ((flags & IOMAP_ZERO) &&
!needs_cow_for_zeroing(&imap, nimaps))
goto out_found;
if (flags & IOMAP_DIRECT) {
/* may drop and re-acquire the ilock */
error = xfs_reflink_allocate_cow(ip, &imap, &shared,
&lockmode);
if (error)
goto out_unlock;
} else {
error = xfs_reflink_reserve_cow(ip, &imap);
if (error)
goto out_unlock;
}
/* may drop and re-acquire the ilock */
error = xfs_reflink_allocate_cow(ip, &imap, &shared, &lockmode,
flags);
if (error)
goto out_unlock;
/*
* For buffered writes we need to report the address of the
* previous block (if there was any) so that the higher level
* write code can perform read-modify-write operations. For
* direct I/O code, which must be block aligned we need to
* report the newly allocated address.
*/
if (!(flags & IOMAP_DIRECT) &&
orig.br_startblock != HOLESTARTBLOCK)
imap = orig;
end_fsb = imap.br_startoff + imap.br_blockcount;
length = XFS_FSB_TO_B(mp, end_fsb) - offset;

10
fs/xfs/xfs_reflink.c
View File

@ -397,7 +397,8 @@ xfs_reflink_allocate_cow(
struct xfs_inode *ip,
struct xfs_bmbt_irec *imap,
bool *shared,
uint *lockmode)
uint *lockmode,
unsigned iomap_flags)
{
struct xfs_mount *mp = ip->i_mount;
xfs_fileoff_t offset_fsb = imap->br_startoff;
@ -471,6 +472,13 @@ xfs_reflink_allocate_cow(
if (nimaps == 0)
return -ENOSPC;
convert:
/*
* COW fork extents are supposed to remain unwritten until we're ready
* to initiate a disk write. For direct I/O we are going to write the
* data and need the conversion, but for buffered writes we're done.
*/
if (!(iomap_flags & IOMAP_DIRECT))
return 0;
return xfs_reflink_convert_cow_extent(ip, imap, offset_fsb, count_fsb);
out_unreserve:

3
fs/xfs/xfs_reflink.h
View File

@ -15,7 +15,8 @@ extern int xfs_reflink_trim_around_shared(struct xfs_inode *ip,
extern int xfs_reflink_reserve_cow(struct xfs_inode *ip,
struct xfs_bmbt_irec *imap);
extern int xfs_reflink_allocate_cow(struct xfs_inode *ip,
struct xfs_bmbt_irec *imap, bool *shared, uint *lockmode);
struct xfs_bmbt_irec *imap, bool *shared, uint *lockmode,
unsigned iomap_flags);
extern int xfs_reflink_convert_cow(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t count);