[PATCH 12/12] xfs: remove the NULL fork handling in xfs_bmapi_read

Christoph Hellwig
2020-05-08T06:34:55Z

Now that we fully verify the inode forks before they are added to the
inode cache, the crash reported in

https://bugzilla.kernel.org/show_bug.cgi?id=204031

can't happen anymore, as we'll never let an inode that has inconsistent
nextents counts vs the presence of an in-core attr fork leak into the
inactivate code path. So remove the work around to try to handle the
case, and just return an error and warn if the fork is not present.

Signed-off-by: Christoph Hellwig <hch@lst.de>
---
fs/xfs/libxfs/xfs_bmap.c | 22 +++++-----------------
1 file changed, 5 insertions(+), 17 deletions(-)

diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c
index 76be1a18e2442..34518a6dc7376 100644
--- a/fs/xfs/libxfs/xfs_bmap.c
+++ b/fs/xfs/libxfs/xfs_bmap.c
@@ -3891,7 +3891,8 @@ xfs_bmapi_read(
int flags)
{
struct xfs_mount *mp = ip->i_mount;
- struct xfs_ifork *ifp;
+ int whichfork = xfs_bmapi_whichfork(flags);
+ struct xfs_ifork *ifp = XFS_IFORK_PTR(ip, whichfork);
struct xfs_bmbt_irec got;
xfs_fileoff_t obno;
xfs_fileoff_t end;
@@ -3899,12 +3900,14 @@ xfs_bmapi_read(
int error;
bool eof = false;
int n = 0;
- int whichfork = xfs_bmapi_whichfork(flags);

ASSERT(*nmap >= 1);
ASSERT(!(flags & ~(XFS_BMAPI_ATTRFORK | XFS_BMAPI_ENTIRE)));
ASSERT(xfs_isilocked(ip, XFS_ILOCK_SHARED|XFS_ILOCK_EXCL));

+ if (WARN_ON_ONCE(!ifp))
+ return -EFSCORRUPTED;
+
if (XFS_IS_CORRUPT(mp, !xfs_ifork_has_extents(ip, whichfork)) ||
XFS_TEST_ERROR(false, mp, XFS_ERRTAG_BMAPIFORMAT)) {
return -EFSCORRUPTED;
@@ -3915,21 +3918,6 @@ xfs_bmapi_read(

XFS_STATS_INC(mp, xs_blk_mapr);

- ifp = XFS_IFORK_PTR(ip, whichfork);
- if (!ifp) {
- /*
- * A missing attr ifork implies that the inode says we're in
- * extents or btree format but failed to pass the inode fork
- * verifier while trying to load it. Treat that as a file
- * corruption too.
- */
-#ifdef DEBUG
- xfs_alert(mp, "%s: inode %llu missing fork %d",
- __func__, ip->i_ino, whichfork);
-#endif /* DEBUG */
- return -EFSCORRUPTED;
- }
-
if (!(ifp->if_flags & XFS_IFEXTENTS)) {
error = xfs_iread_extents(NULL, ip, whichfork);
if (error)
--
2.26.2