diff mbox series

[04/14] xfs: fix a sloppy memory handling bug in xfs_iroot_realloc

Message ID 167243865165.708933.12401569768700467243.stgit@magnolia (mailing list archive)
State Superseded, archived
Headers show
Series xfs: refactor btrees to support records in inode root | expand

Commit Message

Darrick J. Wong Dec. 30, 2022, 10:17 p.m. UTC 
From: Darrick J. Wong <djwong@kernel.org>

While refactoring code, I noticed that when xfs_iroot_realloc tries to
shrink a bmbt root block, it allocates a smaller new block and then
copies "records" and pointers to the new block.  However, bmbt root
blocks cannot ever be leaves, which means that it's not technically
correct to copy records.  We /should/ be copying keys.

Note that this has never resulted in actual memory corruption because
sizeof(bmbt_rec) == (sizeof(bmbt_key) + sizeof(bmbt_ptr)).  However,
this will no longer be true when we start adding realtime rmap stuff,
so fix this now.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
 fs/xfs/libxfs/xfs_inode_fork.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)
diff mbox series

Patch

diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c
index 0f220f100069..b73b971b83cd 100644
--- a/fs/xfs/libxfs/xfs_inode_fork.c
+++ b/fs/xfs/libxfs/xfs_inode_fork.c
@@ -466,15 +466,15 @@  xfs_iroot_realloc(
 	memcpy(new_broot, ifp->if_broot, xfs_bmbt_block_len(ip->i_mount));
 
 	/*
-	 * Only copy the records and pointers if there are any.
+	 * Only copy the keys and pointers if there are any.
 	 */
 	if (new_max > 0) {
 		/*
-		 * First copy the records.
+		 * First copy the keys.
 		 */
-		op = (char *)xfs_bmbt_rec_addr(mp, ifp->if_broot, 1);
-		np = (char *)xfs_bmbt_rec_addr(mp, new_broot, 1);
-		memcpy(np, op, new_max * (uint)sizeof(xfs_bmbt_rec_t));
+		op = (char *)xfs_bmbt_key_addr(mp, ifp->if_broot, 1);
+		np = (char *)xfs_bmbt_key_addr(mp, new_broot, 1);
+		memcpy(np, op, new_max * (uint)sizeof(xfs_bmbt_key_t));
 
 		/*
 		 * Then copy the pointers.