[PATCH 09/18] xfs: remove xfs_reflink_trim_irec_to_next_cow

Christoph Hellwig
2018-05-30T10:00:58Z

In the only caller we just did a lookup in the COW extent tree for
the same offset. Reuse that result and save a lookup, as well as
shortening the ilock hold time.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_aops.c | 25 ++++++++++++++++---------
fs/xfs/xfs_reflink.c | 33 ---------------------------------
fs/xfs/xfs_reflink.h | 2 --
3 files changed, 16 insertions(+), 44 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index e2671b223409..587493e9c8a1 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -383,7 +383,7 @@ xfs_map_blocks(
struct xfs_inode *ip = XFS_I(inode);
struct xfs_mount *mp = ip->i_mount;
ssize_t count = i_blocksize(inode);
- xfs_fileoff_t offset_fsb, end_fsb;
+ xfs_fileoff_t offset_fsb, end_fsb, cow_fsb = NULLFILEOFF;
int whichfork = XFS_DATA_FORK;
struct xfs_iext_cursor icur;
int error = 0;
@@ -407,8 +407,9 @@ xfs_map_blocks(
* it directly instead of looking up anything in the data fork.
*/
if (xfs_is_reflink_inode(ip) &&
- xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, imap) &&
- imap->br_startoff <= offset_fsb) {
+ xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, imap))
+ cow_fsb = imap->br_startoff;
+ if (cow_fsb != NULLFILEOFF && cow_fsb <= offset_fsb) {
xfs_iunlock(ip, XFS_ILOCK_SHARED);
/*
* Truncate can race with writeback since writeback doesn't
@@ -430,6 +431,10 @@ xfs_map_blocks(

error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
imap, &nimaps, XFS_BMAPI_ENTIRE);
+ xfs_iunlock(ip, XFS_ILOCK_SHARED);
+ if (error)
+ return error;
+
if (!nimaps) {
/*
* Lookup returns no match? Beyond eof? regardless,
@@ -454,21 +459,23 @@ xfs_map_blocks(
* is a pending CoW reservation before the end of this extent,
* so that we pick up the COW extents in the next iteration.
*/
- xfs_reflink_trim_irec_to_next_cow(ip, offset_fsb, imap);
+ if (cow_fsb != NULLFILEOFF &&
+ cow_fsb < imap->br_startoff + imap->br_blockcount) {
+ imap->br_blockcount = cow_fsb - imap->br_startoff;
+ trace_xfs_reflink_trim_irec(ip, imap);
+ }
+
if (imap->br_state == XFS_EXT_UNWRITTEN)
*type = XFS_IO_UNWRITTEN;
else
*type = XFS_IO_OVERWRITE;
}
- xfs_iunlock(ip, XFS_ILOCK_SHARED);

trace_xfs_map_blocks_found(ip, offset, count, *type, imap);
- return error;
+ return 0;

allocate_blocks:
- xfs_iunlock(ip, XFS_ILOCK_SHARED);
- if (!error)
- error = xfs_iomap_write_allocate(ip, whichfork, offset, imap);
+ error = xfs_iomap_write_allocate(ip, whichfork, offset, imap);
if (!error)
trace_xfs_map_blocks_alloc(ip, offset, count, *type, imap);
return error;
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 8e5eb8e70c89..ff76bc56ff3d 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -484,39 +484,6 @@ xfs_reflink_allocate_cow(
return error;
}

-/*
- * Trim an extent to end at the next CoW reservation past offset_fsb.
- */
-void
-xfs_reflink_trim_irec_to_next_cow(
- struct xfs_inode *ip,
- xfs_fileoff_t offset_fsb,
- struct xfs_bmbt_irec *imap)
-{
- struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
- struct xfs_bmbt_irec got;
- struct xfs_iext_cursor icur;
-
- if (!xfs_is_reflink_inode(ip))
- return;
-
- /* Find the extent in the CoW fork. */
- if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got))
- return;
-
- /* This is the extent before; try sliding up one. */
- if (got.br_startoff < offset_fsb) {
- if (!xfs_iext_next_extent(ifp, &icur, &got))
- return;
- }
-
- if (got.br_startoff >= imap->br_startoff + imap->br_blockcount)
- return;
-
- imap->br_blockcount = got.br_startoff - imap->br_startoff;
- trace_xfs_reflink_trim_irec(ip, imap);
-}
-
/*
* Cancel CoW reservations for some block range of an inode.
*
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 15a456492667..e8d4d50c629f 100644
--- a/fs/xfs/xfs_reflink.h
+++ b/fs/xfs/xfs_reflink.h
@@ -32,8 +32,6 @@ extern int xfs_reflink_allocate_cow(struct xfs_inode *ip,
struct xfs_bmbt_irec *imap, bool *shared, uint *lockmode);
extern int xfs_reflink_convert_cow(struct xfs_inode *ip, xfs_off_t offset,
xfs_off_t count);
-extern void xfs_reflink_trim_irec_to_next_cow(struct xfs_inode *ip,
- xfs_fileoff_t offset_fsb, struct xfs_bmbt_irec *imap);

extern int xfs_reflink_cancel_cow_blocks(struct xfs_inode *ip,
struct xfs_trans **tpp, xfs_fileoff_t offset_fsb,
--
2.17.0