Patch "xfs: only return -errno or success from attr ->put_listent" has been added to the 4.4-stable tree

PATCH [email protected] 1 participant 1 message Jun 5, 2017

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2017-06-05 15:10 UTC #0 lore raw

This is a note to let you know that I've just added the patch titled

    xfs: only return -errno or success from attr ->put_listent

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
xfs-only-return-errno-or-success-from-attr-put_listent.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

Quoted 1 line

From 2a6fba6d2311151598abaa1e7c9abd5f8d024a43 Mon Sep 17 00:00:00 2001

From: Eric Sandeen <[email protected]>
Date: Wed, 6 Apr 2016 07:57:18 +1000
Subject: xfs: only return -errno or success from attr ->put_listent

From: Eric Sandeen <[email protected]>

commit 2a6fba6d2311151598abaa1e7c9abd5f8d024a43 upstream.

Today, the put_listent formatters return either 1 or 0; if they return 1, some callers treat this as an error and return it up the stack, despite "1" not being a valid (negative) error code.

The intent seems to be that if the input buffer is full, we set seen_enough or set count = -1, and return 1; but some callers check the return before checking the seen_enough or count fields of the context.

Fix this by only returning non-zero for actual errors encountered, and rely on the caller to first check the return value, then check the values in the context to decide what to do.

Signed-off-by Eric Sandeen <[email protected]>

Reviewed-by Christoph Hellwig <[email protected]>

Signed-off-by Dave Chinner <[email protected]>

Signed-off-by Nikolay Borisov <[email protected]>

Signed-off-by Greg Kroah-Hartman <[email protected]>

---
 fs/xfs/xfs_attr.h      |    1 +
 fs/xfs/xfs_attr_list.c |    8 +++-----
 fs/xfs/xfs_xattr.c     |   15 ++++++++++-----
 3 files changed, 14 insertions(+), 10 deletions(-)

fs/xfs/xfs_attr.h +1 -0

@@ -112,6 +112,7 @@ typedef struct attrlist_cursor_kern {
  *========================================================================*/
 
 
+/* Return 0 on success, or -errno; other state communicated via *context */
 typedef int (*put_listent_func_t)(struct xfs_attr_list_context *, int,
 			      unsigned char *, int, int, unsigned char *);

fs/xfs/xfs_attr_list.c +3 -5

@@ -108,16 +108,14 @@ xfs_attr_shortform_list(xfs_attr_list_co
 					   (int)sfe->namelen,
 					   (int)sfe->valuelen,
 					   &sfe->nameval[sfe->namelen]);
-
+			if (error)
+				return error;
 			/*
 			 * Either search callback finished early or
 			 * didn't fit it all in the buffer after all.
 			 */
 			if (context->seen_enough)
 				break;
-
-			if (error)
-				return error;
 			sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
 		}
 		trace_xfs_attr_list_sf_all(context);

@@ -581,7 +579,7 @@ xfs_attr_put_listent(
 		trace_xfs_attr_list_full(context);
 		alist->al_more = 1;
 		context->seen_enough = 1;
-		return 1;
+		return 0;
 	}
 
 	aep = (attrlist_ent_t *)&context->alist[context->firstu];

fs/xfs/xfs_xattr.c +10 -5

@@ -180,7 +180,7 @@ xfs_xattr_put_listent(
 	arraytop = context->count + prefix_len + namelen + 1;
 	if (arraytop > context->firstu) {
 		context->count = -1;	/* insufficient space */
-		return 1;
+		return 0;
 	}
 	offset = (char *)context->alist + context->count;
 	strncpy(offset, xfs_xattr_prefix(flags), prefix_len);

@@ -222,12 +222,15 @@ list_one_attr(const char *name, const si
 }
 
 ssize_t
-xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size)
+xfs_vn_listxattr(
+	struct dentry	*dentry,
+	char		*data,
+	size_t		size)
 {
 	struct xfs_attr_list_context context;
 	struct attrlist_cursor_kern cursor = { 0 };
-	struct inode		*inode = d_inode(dentry);
-	int			error;
+	struct inode	*inode = d_inode(dentry);
+	int		error;
 
 	/*
 	 * First read the regular on-disk attributes.

@@ -245,7 +248,9 @@ xfs_vn_listxattr(struct dentry *dentry,
 	else
 		context.put_listent = xfs_xattr_put_listent_sizes;
 
-	xfs_attr_list_int(&context);
+	error = xfs_attr_list_int(&context);
+	if (error)
+		return error;
 	if (context.count < 0)
 		return -ERANGE;

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/xfs-only-return-errno-or-success-from-attr-put_listent.patch queue-4.4/xfs-fix-unaligned-access-in-xfs_btree_visit_blocks.patch