OpenZFS 8930 - zfs_zinactive: do not remove the node if the filesystem is readonly

Authored by: Andriy Gapon <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>
Reviewed-by: George Melikov <[email protected]>
Approved by: Gordon Ross <[email protected]>
Ported-by: Brian Behlendorf <[email protected]>

OpenZFS-issue: https://www.illumos.org/issues/8930
OpenZFS-commit: https://github.com/openzfs/openzfs/commit/93c618e0f4
Closes #7029

1 files changed, 26 insertions, 7 deletions

diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index 3caf1bdc1..d3b68403b 100644
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -1255,7 +1255,6 @@ zfs_rezget(znode_t *zp)
 		return (SET_ERROR(EIO));
 	}
 
-	zp->z_unlinked = (ZTOI(zp)->i_nlink == 0);
 	set_nlink(ZTOI(zp), (uint32_t)links);
 	zfs_set_inode_flags(zp, ZTOI(zp));
 
@@ -1263,6 +1262,19 @@ zfs_rezget(znode_t *zp)
 	zp->z_atime_dirty = 0;
 	zfs_inode_update(zp);
 
+	/*
+	 * If the file has zero links, then it has been unlinked on the send
+	 * side and it must be in the received unlinked set.
+	 * We call zfs_znode_dmu_fini() now to prevent any accesses to the
+	 * stale data and to prevent automatical removal of the file in
+	 * zfs_zinactive().  The file will be removed either when it is removed
+	 * on the send side and the next incremental stream is received or
+	 * when the unlinked set gets processed.
+	 */
+	zp->z_unlinked = (ZTOI(zp)->i_nlink == 0);
+	if (zp->z_unlinked)
+		zfs_znode_dmu_fini(zp);
+
 	zfs_znode_hold_exit(zfsvfs, zh);
 
 	return (0);
@@ -1304,14 +1316,21 @@ zfs_zinactive(znode_t *zp)
 	mutex_enter(&zp->z_lock);
 
 	/*
-	 * If this was the last reference to a file with no links,
-	 * remove the file from the file system.
+	 * If this was the last reference to a file with no links, remove
+	 * the file from the file system unless the file system is mounted
+	 * read-only.  That can happen, for example, if the file system was
+	 * originally read-write, the file was opened, then unlinked and
+	 * the file system was made read-only before the file was finally
+	 * closed.  The file will remain in the unlinked set.
 	 */
 	if (zp->z_unlinked) {
-		mutex_exit(&zp->z_lock);
-		zfs_znode_hold_exit(zfsvfs, zh);
-		zfs_rmnode(zp);
-		return;
+		ASSERT(!zfsvfs->z_issnap);
+		if (!zfs_is_readonly(zfsvfs)) {
+			mutex_exit(&zp->z_lock);
+			zfs_znode_hold_exit(zfsvfs, zh);
+			zfs_rmnode(zp);
+			return;
+		}
 	}
 
 	mutex_exit(&zp->z_lock);