[PATCH 08/18] xfs: remove xfs_reflink_find_cow_mapping

Christoph Hellwig
2018-05-30T10:00:55Z

We only have one caller left, and open coding the simple extent list
lookup in it allows us to make the code both more understandable and
reuse calculations and variables already present.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/xfs_aops.c | 17 ++++++++++++-----
fs/xfs/xfs_reflink.c | 30 ------------------------------
fs/xfs/xfs_reflink.h | 2 --
fs/xfs/xfs_trace.h | 1 -
4 files changed, 12 insertions(+), 38 deletions(-)

diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 8cc41a786b5e..e2671b223409 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -385,6 +385,7 @@ xfs_map_blocks(
ssize_t count = i_blocksize(inode);
xfs_fileoff_t offset_fsb, end_fsb;
int whichfork = XFS_DATA_FORK;
+ struct xfs_iext_cursor icur;
int error = 0;
int nimaps = 1;

@@ -396,8 +397,18 @@ xfs_map_blocks(
(ip->i_df.if_flags & XFS_IFEXTENTS));
ASSERT(offset <= mp->m_super->s_maxbytes);

+ if (offset > mp->m_super->s_maxbytes - count)
+ count = mp->m_super->s_maxbytes - offset;
+ end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
+ offset_fsb = XFS_B_TO_FSBT(mp, offset);
+
+ /*
+ * Check if this is offset is covered by a COW extents, and if yes use
+ * it directly instead of looking up anything in the data fork.
+ */
if (xfs_is_reflink_inode(ip) &&
- xfs_reflink_find_cow_mapping(ip, offset, imap)) {
+ xfs_iext_lookup_extent(ip, ip->i_cowfp, offset_fsb, &icur, imap) &&
+ imap->br_startoff <= offset_fsb) {
xfs_iunlock(ip, XFS_ILOCK_SHARED);
/*
* Truncate can race with writeback since writeback doesn't
@@ -417,10 +428,6 @@ xfs_map_blocks(
goto allocate_blocks;
}

- if (offset > mp->m_super->s_maxbytes - count)
- count = mp->m_super->s_maxbytes - offset;
- end_fsb = XFS_B_TO_FSB(mp, (xfs_ufsize_t)offset + count);
- offset_fsb = XFS_B_TO_FSBT(mp, offset);
error = xfs_bmapi_read(ip, offset_fsb, end_fsb - offset_fsb,
imap, &nimaps, XFS_BMAPI_ENTIRE);
if (!nimaps) {
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 713e857d9ffa..8e5eb8e70c89 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -484,36 +484,6 @@ xfs_reflink_allocate_cow(
return error;
}

-/*
- * Find the CoW reservation for a given byte offset of a file.
- */
-bool
-xfs_reflink_find_cow_mapping(
- struct xfs_inode *ip,
- xfs_off_t offset,
- struct xfs_bmbt_irec *imap)
-{
- struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, XFS_COW_FORK);
- xfs_fileoff_t offset_fsb;
- struct xfs_bmbt_irec got;
- struct xfs_iext_cursor icur;
-
- ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL | XFS_ILOCK_SHARED));
-
- if (!xfs_is_reflink_inode(ip))
- return false;
- offset_fsb = XFS_B_TO_FSBT(ip->i_mount, offset);
- if (!xfs_iext_lookup_extent(ip, ifp, offset_fsb, &icur, &got))
- return false;
- if (got.br_startoff > offset_fsb)
- return false;
-
- trace_xfs_reflink_find_cow_mapping(ip, offset, 1, XFS_IO_OVERWRITE,
- &got);
- *imap = got;
- return true;
-}
-
/*
* Trim an extent to end at the next CoW reservation past offset_fsb.
*/
diff --git a/fs/xfs/xfs_reflink.h b/fs/xfs/xfs_reflink.h
index 701487bab468..15a456492667 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 bool xfs_reflink_find_cow_mapping(struct xfs_inode *ip, xfs_off_t offset,
- struct xfs_bmbt_irec *imap);
extern void xfs_reflink_trim_irec_to_next_cow(struct xfs_inode *ip,
xfs_fileoff_t offset_fsb, struct xfs_bmbt_irec *imap);

diff --git a/fs/xfs/xfs_trace.h b/fs/xfs/xfs_trace.h
index 9d4c4ca24fe6..ed8f774944ba 100644
--- a/fs/xfs/xfs_trace.h
+++ b/fs/xfs/xfs_trace.h
@@ -3227,7 +3227,6 @@ DEFINE_INODE_IREC_EVENT(xfs_reflink_convert_cow);
DEFINE_RW_EVENT(xfs_reflink_reserve_cow);

DEFINE_SIMPLE_IO_EVENT(xfs_reflink_bounce_dio_write);
-DEFINE_IOMAP_EVENT(xfs_reflink_find_cow_mapping);
DEFINE_INODE_IREC_EVENT(xfs_reflink_trim_irec);

DEFINE_SIMPLE_IO_EVENT(xfs_reflink_cancel_cow_range);
--
2.17.0