+ ext4-return-eio-not-estale-on-directory-traversal-through-deleted-inode.patch added to -mm tree
diff mbox

Message ID 200902180008.n1I08BZF020006@imap1.linux-foundation.org
State Accepted, archived
Headers show

Commit Message

Andrew Morton Feb. 18, 2009, 12:08 a.m. UTC
The patch titled
     ext4: return -EIO not -ESTALE on directory traversal through deleted inode
has been added to the -mm tree.  Its filename is
     ext4-return-eio-not-estale-on-directory-traversal-through-deleted-inode.patch

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------------------------------------------------------
Subject: ext4: return -EIO not -ESTALE on directory traversal through deleted inode
From: Bryan Donlan <bdonlan@gmail.com>

ext4_iget() returns -ESTALE if invoked on a deleted inode, in order to
report errors to NFS properly.  However, in ext[234]_lookup(), this
-ESTALE can be propagated to userspace if the filesystem is corrupted such
that a directory entry references a deleted inode.  This leads to a
misleading error message - "Stale NFS file handle" - and confusion on the
part of the admin.

The bug can be easily reproduced by creating a new filesystem, making a
link to an unused inode using debugfs, then mounting and attempting to ls
-l said link.

This patch thus changes ext4_lookup to return -EIO if it receives -ESTALE
from ext4_iget(), as ext4 does for other filesystem metadata corruption;
and also invokes the appropriate ext*_error functions when this case is
detected.

Signed-off-by: Bryan Donlan <bdonlan@gmail.com>
Cc: <linux-ext4@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/ext4/namei.c |   12 ++++++++++--
 1 file changed, 10 insertions(+), 2 deletions(-)

Patch
diff mbox

diff -puN fs/ext4/namei.c~ext4-return-eio-not-estale-on-directory-traversal-through-deleted-inode fs/ext4/namei.c
--- a/fs/ext4/namei.c~ext4-return-eio-not-estale-on-directory-traversal-through-deleted-inode
+++ a/fs/ext4/namei.c
@@ -1051,8 +1051,16 @@  static struct dentry *ext4_lookup(struct
 			return ERR_PTR(-EIO);
 		}
 		inode = ext4_iget(dir->i_sb, ino);
-		if (IS_ERR(inode))
-			return ERR_CAST(inode);
+		if (unlikely(IS_ERR(inode))) {
+			if (PTR_ERR(inode) == -ESTALE) {
+				ext4_error(dir->i_sb, "ext2_lookup",
+						"deleted inode referenced: %u",
+						ino);
+				return ERR_PTR(-EIO);
+			} else {
+				return ERR_CAST(inode);
+			}
+		}
 	}
 	return d_splice_alias(inode, dentry);
 }