Christoph Hellwig wrote:
On Fri, Aug 04, 2006 at 09:45:52AM -0500, Eric Sandeen wrote:
Greg KH wrote:
-stable review patch. If anyone has any objections, please let us know.
------------------
From: Neil Brown <[email protected]>
The inode number out of an NFS file handle gets passed eventually to
ext3_get_inode_block() without any checking. If ext3_get_inode_block()
allows it to trigger an error, then bad filehandles can have unpleasant
effect - ext3_error() will usually cause a forced read-only remount, or a
panic if `errors=panic' was used.
So remove the call to ext3_error there and put a matching check in
ext3/namei.c where inode numbers are read off storage.
This patch and the ext2 patch (23/23) are accomplishing the same thing in 2
different ways, I think, and introducing unnecessary differences between
ext2 and ext3. I'd personally prefer to see both ext2 and ext3 handled
with the get_dentry op addition, and I'd be happy to quickly whip up the
ext3 patch to do this if there's agreement on this path.
I completly agree with Eric here. Also pushing out only the fix for one
(and today probably the lesser used) filesystems to -stable seems wrong.
so how's this? (compile tested)
Thanks,
-Eric
Signed-off-by: Eric Sandeen <[email protected]>
(tho blatantly ripped off from Neil Brown's ext2 patch)
Index: linux-2.6.17/fs/ext3/super.c
===================================================================
--- linux-2.6.17.orig/fs/ext3/super.c
+++ linux-2.6.17/fs/ext3/super.c
@@ -620,8 +620,48 @@ static struct super_operations ext3_sops
#endif
};
+static struct dentry *ext3_get_dentry(struct super_block *sb, void *vobjp)
+{
+ __u32 *objp = vobjp;
+ unsigned long ino = objp[0];
+ __u32 generation = objp[1];
+ struct inode *inode;
+ struct dentry *result;
+
+ if (ino != EXT3_ROOT_INO && ino < EXT3_FIRST_INO(sb))
+ return ERR_PTR(-ESTALE);
+ if (ino > le32_to_cpu(EXT3_SB(sb)->s_es->s_inodes_count))
+ return ERR_PTR(-ESTALE);
+
+ /* iget isn't really right if the inode is currently unallocated!!
+ * ext3_read_inode currently does appropriate checks, but
+ * it might be "neater" to call ext3_get_inode first and check
+ * if the inode is valid.....
+ */
+ inode = iget(sb, ino);
+ if (inode == NULL)
+ return ERR_PTR(-ENOMEM);
+ if (is_bad_inode(inode)
+ || (generation && inode->i_generation != generation)
+ ) {
+ /* we didn't find the right inode.. */
+ iput(inode);
+ return ERR_PTR(-ESTALE);
+ }
+ /* now to find a dentry.
+ * If possible, get a well-connected one
+ */
+ result = d_alloc_anon(inode);
+ if (!result) {
+ iput(inode);
+ return ERR_PTR(-ENOMEM);
+ }
+ return result;
+}
+
static struct export_operations ext3_export_ops = {
.get_parent = ext3_get_parent,
+ .get_dentry = ext3_get_dentry,
};
enum {
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