xfs: atomic drop extent entries when inactiving attr

Offering: HULK
hulk inclusion
category: bugfix
bugzilla: https://gitee.com/openeuler/kernel/issues/I76JSK

--------------------------------

When inactiving an unlinked inode and it's attrs, if xlog is shutdown
either during or just after the process of recurse deleting attribute
nodes/leafs in xfs_attr3_root_inactive(), the log will records some
buffer cancel items, but doesn't contain the corresponding extent
entries and inode updates, this is incomplete and inconsistent. Because
of the inactiving process is not completed and the unlinked inode is
still in the agi_unlinked table, it will continue to be inactived after
replaying the log on the next mount, the attr node/leaf blocks' created
record before the cancel items could not be replayed but the inode
does. So we could get corrupted data when reading the canceled blocks.

 XFS (pmem0): Metadata corruption detected at
 xfs_da3_node_read_verify+0x53/0x220, xfs_da3_node block 0x78
 XFS (pmem0): Unmount and run xfs_repair
 XFS (pmem0): First 128 bytes of corrupted metadata buffer:
 00000000: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
 00000010: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
 00000020: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
 00000030: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
 00000040: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
 00000050: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
 00000060: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
 00000070: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
 XFS (pmem0): metadata I/O error in "xfs_da_read_buf+0x104/0x190" at daddr 0x78 len 8 error 117

In order to fix the issue, we need to remove the extent entries, update
inode and attr btree atomically when staling attr node/leaf blocks. And
note that we may also need to log and update the parent attr node
entry when removing child or leaf attr block. Fortunately, it doesn't
have to be so complicated, we could leave the removed entres as
holes and skip them if we need to do re-inactiving, the whole node tree
will be removed completely in the end.

Cc: stable@vger.kernel.org
Signed-off-by: NZhang Yi <yi.zhang@huawei.com>
Signed-off-by: NLong Li <leo.lilong@huawei.com>

fs/xfs/xfs_attr_inactive.c

@@ -23,6 +23,7 @@
 #include "xfs_quota.h"
 #include "xfs_dir2.h"
 #include "xfs_error.h"
+#include "xfs_defer.h"
 
 /*
  * Invalidate any incore buffers associated with this remote attribute value
@@ -139,7 +140,8 @@ xfs_attr3_node_inactive(
 	xfs_daddr_t		parent_blkno, child_blkno;
 	struct xfs_buf		*child_bp;
 	struct xfs_da3_icnode_hdr ichdr;
-	int			error, i;
+	int			error, i, done;
+	xfs_filblks_t		count = mp->m_attr_geo->fsbcount;
 
 	/*
 	 * Since this code is recursive (gasp!) we must protect ourselves.
@@ -172,10 +174,13 @@ xfs_attr3_node_inactive(
 		 * traversal of the tree so we may deal with many blocks
 		 * before we come back to this one.
 		 */
-		error = xfs_da3_node_read(*trans, dp, child_fsb, &child_bp,
-					  XFS_ATTR_FORK);
+		error = __xfs_da3_node_read(*trans, dp, child_fsb,
+					    XFS_DABUF_MAP_HOLE_OK, &child_bp,
+					    XFS_ATTR_FORK);
 		if (error)
 			return error;
+		if (!child_bp)
+			goto next_entry;
 
 		/* save for re-read later */
 		child_blkno = xfs_buf_daddr(child_bp);
@@ -207,14 +212,32 @@ xfs_attr3_node_inactive(
 		 * Remove the subsidiary block from the cache and from the log.
 		 */
 		error = xfs_trans_get_buf(*trans, mp->m_ddev_targp,
-				child_blkno,
-				XFS_FSB_TO_BB(mp, mp->m_attr_geo->fsbcount), 0,
-				&child_bp);
+					  child_blkno, XFS_FSB_TO_BB(mp, count),
+					  0, &child_bp);
 		if (error)
 			return error;
+
+		error = xfs_bunmapi(*trans, dp, child_fsb, count,
+				    XFS_BMAPI_ATTRFORK, 0, &done);
+		if (error) {
+			xfs_trans_brelse(*trans, child_bp);
+			return error;
+		}
 		xfs_trans_binval(*trans, child_bp);
+
+		error = xfs_defer_finish(trans);
+		if (error)
+			return error;
 		child_bp = NULL;
 
+		/*
+		 * Atomically commit the whole invalidate stuff.
+		 */
+		error = xfs_trans_roll_inode(trans, dp);
+		if (error)
+			return  error;
+
+next_entry:
 		/*
 		 * If we're not done, re-read the parent to get the next
 		 * child block number.
@@ -232,12 +255,6 @@ xfs_attr3_node_inactive(
 			xfs_trans_brelse(*trans, bp);
 			bp = NULL;
 		}
-		/*
-		 * Atomically commit the whole invalidate stuff.
-		 */
-		error = xfs_trans_roll_inode(trans, dp);
-		if (error)
-			return  error;
 	}
 
 	return 0;
@@ -258,7 +275,8 @@ xfs_attr3_root_inactive(
 	struct xfs_da_blkinfo	*info;
 	struct xfs_buf		*bp;
 	xfs_daddr_t		blkno;
-	int			error;
+	xfs_filblks_t		count = mp->m_attr_geo->fsbcount;
+	int			error, done;
 
 	/*
 	 * Read block 0 to see what we have to work with.
@@ -266,8 +284,9 @@ xfs_attr3_root_inactive(
 	 * the extents in reverse order the extent containing
 	 * block 0 must still be there.
 	 */
-	error = xfs_da3_node_read(*trans, dp, 0, &bp, XFS_ATTR_FORK);
-	if (error)
+	error = __xfs_da3_node_read(*trans, dp, 0, XFS_DABUF_MAP_HOLE_OK,
+				    &bp, XFS_ATTR_FORK);
+	if (error || !bp)
 		return error;
 	blkno = bp->b_bn;
 
@@ -298,7 +317,7 @@ xfs_attr3_root_inactive(
 	 * Invalidate the incore copy of the root block.
 	 */
 	error = xfs_trans_get_buf(*trans, mp->m_ddev_targp, blkno,
-			XFS_FSB_TO_BB(mp, mp->m_attr_geo->fsbcount), 0, &bp);
+				  XFS_FSB_TO_BB(mp, count), 0, &bp);
 	if (error)
 		return error;
 	error = bp->b_error;
@@ -306,7 +325,17 @@ xfs_attr3_root_inactive(
 		xfs_trans_brelse(*trans, bp);
 		return error;
 	}
+
+	error = xfs_bunmapi(*trans, dp, 0, count, XFS_BMAPI_ATTRFORK, 0, &done);
+	if (error) {
+		xfs_trans_brelse(*trans, bp);
+		return error;
+	}
 	xfs_trans_binval(*trans, bp);	/* remove from cache */
+
+	error = xfs_defer_finish(trans);
+	if (error)
+		return error;
 	/*
 	 * Commit the invalidate and start the next transaction.
 	 */
@@ -369,6 +398,7 @@ xfs_attr_inactive(
 		if (error)
 			goto out_shutdown;
 
+		/* Remove the potential leftover remote attr blocks. */
 		error = xfs_itruncate_extents(&trans, dp, XFS_ATTR_FORK, 0);
 		if (error)
 			goto out_cancel;