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

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 <sandeen@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dave Chinner <david@fromorbit.com>
This commit is contained in:
Eric Sandeen 2016-04-06 07:57:18 +10:00 committed by Dave Chinner
parent f55532a0c0
commit 2a6fba6d23
3 changed files with 14 additions and 9 deletions
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1
fs/xfs/xfs_attr.h
View File

@ -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 *);

8
fs/xfs/xfs_attr_list.c
View File

@ -108,16 +108,14 @@ xfs_attr_shortform_list(xfs_attr_list_context_t *context)
(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];

14
fs/xfs/xfs_xattr.c
View File

@ -146,7 +146,7 @@ __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, prefix, prefix_len);
@ -221,11 +221,15 @@ xfs_xattr_put_listent(
}
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);
struct inode *inode = d_inode(dentry);
int error;
/*
* First read the regular on-disk attributes.
@ -239,7 +243,9 @@ xfs_vn_listxattr(struct dentry *dentry, char *data, size_t size)
context.firstu = context.bufsize;
context.put_listent = xfs_xattr_put_listent;
xfs_attr_list_int(&context);
error = xfs_attr_list_int(&context);
if (error)
return error;
if (context.count < 0)
return -ERANGE;