From: Darrick J. Wong <darrick.wong@oracle.com>
Date: Sat, 14 Mar 2020 03:00:22 +0000 (-0400)
Subject: xfs: refactor remote attr value buffer invalidation
X-Git-Tag: v5.6.0-rc0~18
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=5867837a4b2ef2a1eabb946fe53e08ae8b18f3b0;p=users%2Fhch%2Fxfsprogs.git

xfs: refactor remote attr value buffer invalidation

Source kernel commit: 8edbb26b06023de31ad7d4c9b984d99f66577929

Hoist the code that invalidates remote extended attribute value buffers
into a separate helper function.  This prepares us for a memory
corruption fix in the next patch.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Eric Sandeen <sandeen@sandeen.net>
---

diff --git a/libxfs/libxfs_priv.h b/libxfs/libxfs_priv.h
index 5d6dd0633..763880134 100644
--- a/libxfs/libxfs_priv.h
+++ b/libxfs/libxfs_priv.h
@@ -370,13 +370,7 @@ roundup_64(uint64_t x, uint32_t y)
 #define XFS_BUF_SET_BDSTRAT_FUNC(a,b)	((void) 0)
 
 /* avoid gcc warning */
-#define xfs_buf_incore(bt,blkno,len,lockit) ({		\
-	typeof(blkno) __foo = (blkno);			\
-	typeof(len) __bar = (len);			\
-	(blkno) = __foo;				\
-	(len) = __bar; /* no set-but-unused warning */	\
-	NULL;						\
-})
+#define xfs_buf_incore(bt,blkno,len,lockit)	NULL
 #define xfs_buf_oneshot(bp)		((void) 0)
 
 #define XBRW_READ			LIBXFS_BREAD
diff --git a/libxfs/xfs_attr_remote.c b/libxfs/xfs_attr_remote.c
index 958f8f616..8a409f21b 100644
--- a/libxfs/xfs_attr_remote.c
+++ b/libxfs/xfs_attr_remote.c
@@ -551,6 +551,33 @@ xfs_attr_rmtval_set(
 	return 0;
 }
 
+/* Mark stale any incore buffers for the remote value. */
+int
+xfs_attr_rmtval_stale(
+	struct xfs_inode	*ip,
+	struct xfs_bmbt_irec	*map,
+	xfs_buf_flags_t		incore_flags)
+{
+	struct xfs_mount	*mp = ip->i_mount;
+	struct xfs_buf		*bp;
+
+	ASSERT(xfs_isilocked(ip, XFS_ILOCK_EXCL));
+
+	if (XFS_IS_CORRUPT(mp, map->br_startblock == DELAYSTARTBLOCK) ||
+	    XFS_IS_CORRUPT(mp, map->br_startblock == HOLESTARTBLOCK))
+		return -EFSCORRUPTED;
+
+	bp = xfs_buf_incore(mp->m_ddev_targp,
+			XFS_FSB_TO_DADDR(mp, map->br_startblock),
+			XFS_FSB_TO_BB(mp, map->br_blockcount), incore_flags);
+	if (bp) {
+		xfs_buf_stale(bp);
+		xfs_buf_relse(bp);
+	}
+
+	return 0;
+}
+
 /*
  * Remove the value associated with an attribute by deleting the
  * out-of-line buffer that it is stored on.
@@ -559,7 +586,6 @@ int
 xfs_attr_rmtval_remove(
 	struct xfs_da_args	*args)
 {
-	struct xfs_mount	*mp = args->dp->i_mount;
 	xfs_dablk_t		lblkno;
 	int			blkcnt;
 	int			error;
@@ -574,9 +600,6 @@ xfs_attr_rmtval_remove(
 	blkcnt = args->rmtblkcnt;
 	while (blkcnt > 0) {
 		struct xfs_bmbt_irec	map;
-		struct xfs_buf		*bp;
-		xfs_daddr_t		dblkno;
-		int			dblkcnt;
 		int			nmap;
 
 		/*
@@ -587,22 +610,11 @@ xfs_attr_rmtval_remove(
 				       blkcnt, &map, &nmap, XFS_BMAPI_ATTRFORK);
 		if (error)
 			return error;
-		ASSERT(nmap == 1);
-		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
-		       (map.br_startblock != HOLESTARTBLOCK));
-
-		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
-		dblkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
-
-		/*
-		 * If the "remote" value is in the cache, remove it.
-		 */
-		bp = xfs_buf_incore(mp->m_ddev_targp, dblkno, dblkcnt, XBF_TRYLOCK);
-		if (bp) {
-			xfs_buf_stale(bp);
-			xfs_buf_relse(bp);
-			bp = NULL;
-		}
+		if (XFS_IS_CORRUPT(args->dp->i_mount, nmap != 1))
+			return -EFSCORRUPTED;
+		error = xfs_attr_rmtval_stale(args->dp, &map, XBF_TRYLOCK);
+		if (error)
+			return error;
 
 		lblkno += map.br_blockcount;
 		blkcnt -= map.br_blockcount;
diff --git a/libxfs/xfs_attr_remote.h b/libxfs/xfs_attr_remote.h
index 9d20b66ad..6fb457284 100644
--- a/libxfs/xfs_attr_remote.h
+++ b/libxfs/xfs_attr_remote.h
@@ -11,5 +11,7 @@ int xfs_attr3_rmt_blocks(struct xfs_mount *mp, int attrlen);
 int xfs_attr_rmtval_get(struct xfs_da_args *args);
 int xfs_attr_rmtval_set(struct xfs_da_args *args);
 int xfs_attr_rmtval_remove(struct xfs_da_args *args);
+int xfs_attr_rmtval_stale(struct xfs_inode *ip, struct xfs_bmbt_irec *map,
+		xfs_buf_flags_t incore_flags);
 
 #endif /* __XFS_ATTR_REMOTE_H__ */