xfs: consolidate attribute value copying

The same code is used to copy do the attribute copying in three
different places. Consolidate them into a single function in
preparation from on-demand buffer allocation.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

1 files changed, 49 insertions, 39 deletions

diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
index 8085c4f0e5a0..f6a595e76343 100644
--- a/fs/xfs/libxfs/xfs_attr_leaf.c
+++ b/fs/xfs/libxfs/xfs_attr_leaf.c
@@ -393,6 +393,44 @@ xfs_attr_namesp_match(int arg_flags, int ondisk_flags)
         return XFS_ATTR_NSP_ONDISK(ondisk_flags) == XFS_ATTR_NSP_ARGS_TO_ONDISK(arg_flags);
 }
 
+static int
+xfs_attr_copy_value(
+        struct xfs_da_args      *args,
+        unsigned char           *value,
+        int                     valuelen)
+{
+        /*
+         * No copy if all we have to do is get the length
+         */
+        if (args->flags & ATTR_KERNOVAL) {
+                args->valuelen = valuelen;
+                return 0;
+        }
+
+        /*
+         * No copy if the length of the existing buffer is too small
+         */
+        if (args->valuelen < valuelen) {
+                args->valuelen = valuelen;
+                return -ERANGE;
+        }
+        args->valuelen = valuelen;
+
+        /* remote block xattr requires IO for copy-in */
+        if (args->rmtblkno)
+                return xfs_attr_rmtval_get(args);
+
+        /*
+         * This is to prevent a GCC warning because the remote xattr case
+         * doesn't have a value to pass in. In that case, we never reach here,
+         * but GCC can't work that out and so throws a "passing NULL to
+         * memcpy" warning.
+         */
+        if (!value)
+                return -EINVAL;
+        memcpy(args->value, value, valuelen);
+        return 0;
+}
 
 /*========================================================================
  * External routines when attribute fork size < XFS_LITINO(mp).
@@ -727,11 +765,12 @@ xfs_attr_shortform_lookup(xfs_da_args_t *args)
  * exist or we can't retrieve the value.
  */
 int
-xfs_attr_shortform_getvalue(xfs_da_args_t *args)
+xfs_attr_shortform_getvalue(
+        struct xfs_da_args      *args)
 {
-        xfs_attr_shortform_t *sf;
-        xfs_attr_sf_entry_t *sfe;
-        int i;
+        struct xfs_attr_shortform *sf;
+        struct xfs_attr_sf_entry *sfe;
+        int                     i;
 
         ASSERT(args->dp->i_afp->if_flags == XFS_IFINLINE);
         sf = (xfs_attr_shortform_t *)args->dp->i_afp->if_u1.if_data;
@@ -744,18 +783,8 @@ xfs_attr_shortform_getvalue(xfs_da_args_t *args)
                         continue;
                 if (!xfs_attr_namesp_match(args->flags, sfe->flags))
                         continue;
-                if (args->flags & ATTR_KERNOVAL) {
-                        args->valuelen = sfe->valuelen;
-                        return 0;
-                }
-                if (args->valuelen < sfe->valuelen) {
-                        args->valuelen = sfe->valuelen;
-                        return -ERANGE;
-                }
-                args->valuelen = sfe->valuelen;
-                memcpy(args->value, &sfe->nameval[args->namelen],
-                                                    args->valuelen);
-                return 0;
+                return xfs_attr_copy_value(args, &sfe->nameval[args->namelen],
+                                                sfe->valuelen);
         }
         return -ENOATTR;
 }
@@ -2368,7 +2397,6 @@ xfs_attr3_leaf_getvalue(
         struct xfs_attr_leaf_entry *entry;
         struct xfs_attr_leaf_name_local *name_loc;
         struct xfs_attr_leaf_name_remote *name_rmt;
-        int                     valuelen;
 
         leaf = bp->b_addr;
         xfs_attr3_leaf_hdr_from_disk(args->geo, &ichdr, leaf);
@@ -2380,18 +2408,9 @@ xfs_attr3_leaf_getvalue(
                 name_loc = xfs_attr3_leaf_name_local(leaf, args->index);
                 ASSERT(name_loc->namelen == args->namelen);
                 ASSERT(memcmp(args->name, name_loc->nameval, args->namelen) == 0);
-                valuelen = be16_to_cpu(name_loc->valuelen);
-                if (args->flags & ATTR_KERNOVAL) {
-                        args->valuelen = valuelen;
-                        return 0;
-                }
-                if (args->valuelen < valuelen) {
-                        args->valuelen = valuelen;
-                        return -ERANGE;
-                }
-                args->valuelen = valuelen;
-                memcpy(args->value, &name_loc->nameval[args->namelen], valuelen);
-                return 0;
+                return xfs_attr_copy_value(args,
+                                        &name_loc->nameval[args->namelen],
+                                        be16_to_cpu(name_loc->valuelen));
         }
 
         name_rmt = xfs_attr3_leaf_name_remote(leaf, args->index);
@@ -2401,16 +2420,7 @@ xfs_attr3_leaf_getvalue(
         args->rmtblkno = be32_to_cpu(name_rmt->valueblk);
         args->rmtblkcnt = xfs_attr3_rmt_blocks(args->dp->i_mount,
                                                args->rmtvaluelen);
-        if (args->flags & ATTR_KERNOVAL) {
-                args->valuelen = args->rmtvaluelen;
-                return 0;
-        }
-        if (args->valuelen < args->rmtvaluelen) {
-                args->valuelen = args->rmtvaluelen;
-                return -ERANGE;
-        }
-        args->valuelen = args->rmtvaluelen;
-        return xfs_attr_rmtval_get(args);
+        return xfs_attr_copy_value(args, NULL, args->rmtvaluelen);
 }
 
 /*========================================================================