Illumos 4638 - Panic in ZFS via rfs3_setattr()/rfs3_write(): dirtying snapshot!

4638 Panic in ZFS via rfs3_setattr()/rfs3_write(): dirtying snapshot!
Reviewed by: Alek Pinchuk <[email protected]>
Reviewed by: Ilya Usvyatsky <[email protected]>
Reviewed by: Dan McDonald <[email protected]>
Reviewed by: Matthew Ahrens <[email protected]>
Reviewed by: Garrett D'Amore <[email protected]>
Approved by: Garrett D'Amore <[email protected]>

References:
  https://www.illumos.org/issues/4638
  https://github.com/illumos/illumos-gate/commit/2144b12

Porting notes:
- [module/zfs/zfs_vnops.c]
  - 3558fd7 Prototype/structure update for Linux
  - 2cf7f52 Linux compat 2.6.39: mount_nodev()
  - Use zfs_is_readonly() wrapper
  - Remove first line of comment which doesn't apply

Ported-by: kernelOfTruth [email protected]
Signed-off-by: Brian Behlendorf <[email protected]>

1 files changed, 19 insertions, 0 deletions

diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index 174c918ab..64412a69d 100644
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -21,6 +21,7 @@
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
  * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright 2014 Nexenta Systems, Inc.  All rights reserved.
  * Copyright (c) 2015 by Chunwei Chen. All rights reserved.
  */
 
@@ -622,6 +623,15 @@ zfs_write(struct inode *ip, uio_t *uio, int ioflag, cred_t *cr)
 	    &zp->z_pflags, 8);
 
 	/*
+	 * Callers might not be able to detect properly that we are read-only,
+	 * so check it explicitly here.
+	 */
+	if (zfs_is_readonly(zsb)) {
+		ZFS_EXIT(zsb);
+		return (SET_ERROR(EROFS));
+	}
+
+	/*
 	 * If immutable or not appending then return EPERM
 	 */
 	if ((zp->z_pflags & (ZFS_IMMUTABLE | ZFS_READONLY)) ||
@@ -4378,6 +4388,15 @@ zfs_space(struct inode *ip, int cmd, flock64_t *bfp, int flag,
 		return (SET_ERROR(EINVAL));
 	}
 
+	/*
+	 * Callers might not be able to detect properly that we are read-only,
+	 * so check it explicitly here.
+	 */
+	if (zfs_is_readonly(zsb)) {
+		ZFS_EXIT(zsb);
+		return (SET_ERROR(EROFS));
+	}
+
 	if ((error = convoff(ip, bfp, 0, offset))) {
 		ZFS_EXIT(zsb);
 		return (error);