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@xxxxxx>
---
fs/xfs/xfs_iomap.c | 28 +++++++++++++++++-----------
fs/xfs/xfs_reflink.c | 10 +++++++++-
fs/xfs/xfs_reflink.h | 3 ++-
3 files changed, 28 insertions(+), 13 deletions(-)
diff --git a/fs/xfs/xfs_iomap.c b/fs/xfs/xfs_iomap.c
index 9f1fd224bb06..d851abac16a9 100644
--- a/fs/xfs/xfs_iomap.c
+++ b/fs/xfs/xfs_iomap.c
@@ -1039,22 +1039,28 @@ 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;
- }
+ 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;
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 2babc2cbe103..8a5353daf9ab 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -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:
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 6d73daef1f13..70d68a1a9b49 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -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);
--
2.20.1
