Simplify the way we check for a valid imap - we know we have a valid
mapping after xfs_map_blocks returned successfully, and we know we can
call xfs_imap_valid on any imap, as it will always fail on a
zero-initialized map.
We can also remove the xfs_imap_valid function and fold it into
xfs_map_blocks now.
Signed-off-by: Christoph Hellwig <hch@xxxxxx>
Reviewed-by: Brian Foster <bfoster@xxxxxxxxxx>
Reviewed-by: Darrick J. Wong <darrick.wong@xxxxxxxxxx>
---
fs/xfs/xfs_aops.c | 89 ++++++++++++++++++++---------------------------
1 file changed, 38 insertions(+), 51 deletions(-)
diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c
index 0bfcc2d06658..09092f10cff3 100644
--- a/fs/xfs/xfs_aops.c
+++ b/fs/xfs/xfs_aops.c
@@ -30,7 +30,6 @@
*/
struct xfs_writepage_ctx {
struct xfs_bmbt_irec imap;
- bool imap_valid;
unsigned int io_type;
struct xfs_ioend *ioend;
sector_t last_block;
@@ -370,15 +369,47 @@ 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 = XFS_B_TO_FSBT(mp, offset), end_fsb;
struct xfs_bmbt_irec imap;
int whichfork = XFS_DATA_FORK;
struct xfs_iext_cursor icur;
+ bool imap_valid;
int error = 0;
+ /*
+ * We have to make sure the cached mapping is within EOF to protect
+ * against eofblocks trimming on file release leaving us with a stale
+ * mapping. Otherwise, a page for a subsequent file extending buffered
+ * write could get picked up by this writeback cycle and written to the
+ * wrong blocks.
+ *
+ * Note that what we really want here is a generic mapping invalidation
+ * mechanism to protect us from arbitrary extent modifying contexts, not
+ * just eofblocks.
+ */
+ xfs_trim_extent_eof(&wpc->imap, ip);
+
+ /*
+ * COW fork blocks can overlap data fork blocks even if the blocks
+ * aren't shared. COW I/O always takes precedent, so we must always
+ * check for overlap on reflink inodes unless the mapping is already a
+ * COW one.
+ */
+ imap_valid = offset_fsb >= wpc->imap.br_startoff &&
+ offset_fsb < wpc->imap.br_startoff + wpc->imap.br_blockcount;
+ if (imap_valid &&
+ (!xfs_is_reflink_inode(ip) || wpc->io_type == XFS_IO_COW))
+ return 0;
+
if (XFS_FORCED_SHUTDOWN(mp))
return -EIO;
+ /*
+ * If we don't have a valid map, now it's time to get a new one for this
+ * offset. This will convert delayed allocations (including COW ones)
+ * into real extents. If we return without a valid map, it means we
+ * landed in a hole and we skip the block.
+ */
xfs_ilock(ip, XFS_ILOCK_SHARED);
ASSERT(ip->i_d.di_format != XFS_DINODE_FMT_BTREE ||
(ip->i_df.if_flags & XFS_IFEXTENTS));
@@ -387,7 +418,6 @@ xfs_map_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);
/*
* Check if this is offset is covered by a COW extents, and if yes use
@@ -420,7 +450,7 @@ xfs_map_blocks(
/*
* Map valid and no COW extent in the way? We're done.
*/
- if (wpc->imap_valid) {
+ if (imap_valid) {
xfs_iunlock(ip, XFS_ILOCK_SHARED);
return 0;
}
@@ -465,31 +495,6 @@ xfs_map_blocks(
return 0;
}
-STATIC bool
-xfs_imap_valid(
- struct inode *inode,
- struct xfs_bmbt_irec *imap,
- xfs_off_t offset)
-{
- offset >>= inode->i_blkbits;
-
- /*
- * We have to make sure the cached mapping is within EOF to protect
- * against eofblocks trimming on file release leaving us with a stale
- * mapping. Otherwise, a page for a subsequent file extending buffered
- * write could get picked up by this writeback cycle and written to the
- * wrong blocks.
- *
- * Note that what we really want here is a generic mapping invalidation
- * mechanism to protect us from arbitrary extent modifying contexts, not
- * just eofblocks.
- */
- xfs_trim_extent_eof(imap, XFS_I(inode));
-
- return offset >= imap->br_startoff &&
- offset < imap->br_startoff + imap->br_blockcount;
-}
-
STATIC void
xfs_start_buffer_writeback(
struct buffer_head *bh)
@@ -856,27 +861,10 @@ xfs_writepage_map(
continue;
}
- if (wpc->imap_valid)
- wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
- file_offset);
-
- /*
- * COW fork blocks can overlap data fork blocks even if the
- * blocks aren't shared. COW I/O always takes precedent, so we
- * must always check for overlap on reflink inodes unless the
- * mapping is already a COW one.
- */
- if (!wpc->imap_valid ||
- (xfs_is_reflink_inode(XFS_I(inode)) &&
- wpc->io_type != XFS_IO_COW)) {
- error = xfs_map_blocks(wpc, inode, file_offset);
- if (error)
- goto out;
- wpc->imap_valid = xfs_imap_valid(inode, &wpc->imap,
- file_offset);
- }
-
- if (!wpc->imap_valid || wpc->io_type == XFS_IO_HOLE)
+ error = xfs_map_blocks(wpc, inode, file_offset);
+ if (error)
+ break;
+ if (wpc->io_type == XFS_IO_HOLE)
continue;
lock_buffer(bh);
@@ -887,7 +875,6 @@ xfs_writepage_map(
ASSERT(wpc->ioend || list_empty(&submit_list));
-out:
/*
* On error, we have to fail the ioend here because we have locked
* buffers in the ioend. If we don't do this, we'll deadlock
--
2.18.0
