xfs_bmapi_write() always expects a valid firstblock pointer. It
immediately dereferences the pointer to help determine how to
initialize the bma.minleft field. The remaining accesses are
related to modifying btree format forks, which is only relevant for
!COW fork callers.
The reflink code passes a NULL transaction to xfs_bmapi_write() in a
couple places that do COW fork unwritten conversion. The purpose of
the firstblock field is to track the first block allocation in the
current transaction, so technically firstblock should not be
required for these callers either.
Tweak xfs_bmapi_write() to initialize the bma correctly without
accessing the firstblock pointer if no transaction is provided in
the first place. Update the reflink callers to pass NULL instead of
otherwise unused firstblock references.
Signed-off-by: Brian Foster <bfoster@xxxxxxxxxx>
---
fs/xfs/libxfs/xfs_bmap.c | 2 +-
fs/xfs/xfs_reflink.c | 9 +++------
2 files changed, 4 insertions(+), 7 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 2e2a9661600b..c6a5a957674d 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -4304,7 +4304,7 @@ xfs_bmapi_write(
XFS_STATS_INC(mp, xs_blk_mapw);
- if (*firstblock == NULLFSBLOCK) {
+ if (!tp || *firstblock == NULLFSBLOCK) {
if (XFS_IFORK_FORMAT(ip, whichfork) == XFS_DINODE_FMT_BTREE)
bma.minleft = be16_to_cpu(ifp->if_broot->bb_level) + 1;
else
diff --git a/fs/xfs/xfs_reflink.c b/fs/xfs/xfs_reflink.c
index 8496312dde6a..92b6e1b5d33c 100644
--- a/fs/xfs/xfs_reflink.c
+++ b/fs/xfs/xfs_reflink.c
@@ -314,7 +314,6 @@ xfs_reflink_convert_cow_extent(
xfs_fileoff_t offset_fsb,
xfs_filblks_t count_fsb)
{
- xfs_fsblock_t first_block = NULLFSBLOCK;
int nimaps = 1;
if (imap->br_state == XFS_EXT_NORM)
@@ -325,8 +324,8 @@ xfs_reflink_convert_cow_extent(
if (imap->br_blockcount == 0)
return 0;
return xfs_bmapi_write(NULL, ip, imap->br_startoff, imap->br_blockcount,
- XFS_BMAPI_COWFORK | XFS_BMAPI_CONVERT, &first_block,
- 0, imap, &nimaps);
+ XFS_BMAPI_COWFORK | XFS_BMAPI_CONVERT, NULL, 0, imap,
+ &nimaps);
}
/* Convert all of the unwritten CoW extents in a file's range to real ones. */
@@ -341,7 +340,6 @@ xfs_reflink_convert_cow(
xfs_fileoff_t end_fsb = XFS_B_TO_FSB(mp, offset + count);
xfs_filblks_t count_fsb = end_fsb - offset_fsb;
struct xfs_bmbt_irec imap;
- xfs_fsblock_t first_block = NULLFSBLOCK;
int nimaps = 1, error = 0;
ASSERT(count != 0);
@@ -349,8 +347,7 @@ xfs_reflink_convert_cow(
xfs_ilock(ip, XFS_ILOCK_EXCL);
error = xfs_bmapi_write(NULL, ip, offset_fsb, count_fsb,
XFS_BMAPI_COWFORK | XFS_BMAPI_CONVERT |
- XFS_BMAPI_CONVERT_ONLY, &first_block, 0, &imap,
- &nimaps);
+ XFS_BMAPI_CONVERT_ONLY, NULL, 0, &imap, &nimaps);
xfs_iunlock(ip, XFS_ILOCK_EXCL);
return error;
}
--
2.17.1
--
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