]> git.ipfire.org Git - thirdparty/xfsprogs-dev.git/blobdiff - libxfs/xfs_attr.c
xfs: allocate xattr buffer on demand
[thirdparty/xfsprogs-dev.git] / libxfs / xfs_attr.c
index 92e445dfed2e0f60d13aaee71cc3c1cfbd1f53d4..ada1b5f40ba3523e8490ecf0008080daa90cd0b6 100644 (file)
@@ -9,17 +9,16 @@
 #include "xfs_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
-#include "xfs_bit.h"
 #include "xfs_mount.h"
 #include "xfs_defer.h"
 #include "xfs_da_format.h"
 #include "xfs_da_btree.h"
 #include "xfs_attr_sf.h"
 #include "xfs_inode.h"
-#include "xfs_alloc.h"
 #include "xfs_trans.h"
 #include "xfs_bmap.h"
 #include "xfs_bmap_btree.h"
+#include "xfs_attr.h"
 #include "xfs_attr_leaf.h"
 #include "xfs_attr_remote.h"
 #include "xfs_trans_space.h"
@@ -97,7 +96,10 @@ xfs_inode_hasattr(
  * Overall external interface routines.
  *========================================================================*/
 
-/* Retrieve an extended attribute and its value.  Must have ilock. */
+/*
+ * Retrieve an extended attribute and its value.  Must have ilock.
+ * Returns 0 on successful retrieval, otherwise an error.
+ */
 int
 xfs_attr_get_ilocked(
        struct xfs_inode        *ip,
@@ -115,12 +117,28 @@ xfs_attr_get_ilocked(
                return xfs_attr_node_get(args);
 }
 
-/* Retrieve an extended attribute by name, and its value. */
+/*
+ * Retrieve an extended attribute by name, and its value if requested.
+ *
+ * If ATTR_KERNOVAL is set in @flags, then the caller does not want the value,
+ * just an indication whether the attribute exists and the size of the value if
+ * it exists. The size is returned in @valuelenp,
+ *
+ * If the attribute is found, but exceeds the size limit set by the caller in
+ * @valuelenp, return -ERANGE with the size of the attribute that was found in
+ * @valuelenp.
+ *
+ * If ATTR_ALLOC is set in @flags, allocate the buffer for the value after
+ * existence of the attribute has been determined. On success, return that
+ * buffer to the caller and leave them to free it. On failure, free any
+ * allocated buffer and ensure the buffer pointer returned to the caller is
+ * null.
+ */
 int
 xfs_attr_get(
        struct xfs_inode        *ip,
        const unsigned char     *name,
-       unsigned char           *value,
+       unsigned char           **value,
        int                     *valuelenp,
        int                     flags)
 {
@@ -128,6 +146,8 @@ xfs_attr_get(
        uint                    lock_mode;
        int                     error;
 
+       ASSERT((flags & (ATTR_ALLOC | ATTR_KERNOVAL)) || *value);
+
        XFS_STATS_INC(ip->i_mount, xs_attr_get);
 
        if (XFS_FORCED_SHUTDOWN(ip->i_mount))
@@ -137,17 +157,29 @@ xfs_attr_get(
        if (error)
                return error;
 
-       args.value = value;
-       args.valuelen = *valuelenp;
        /* Entirely possible to look up a name which doesn't exist */
        args.op_flags = XFS_DA_OP_OKNOENT;
+       if (flags & ATTR_ALLOC)
+               args.op_flags |= XFS_DA_OP_ALLOCVAL;
+       else
+               args.value = *value;
+       args.valuelen = *valuelenp;
 
        lock_mode = xfs_ilock_attr_map_shared(ip);
        error = xfs_attr_get_ilocked(ip, &args);
        xfs_iunlock(ip, lock_mode);
-
        *valuelenp = args.valuelen;
-       return error == -EEXIST ? 0 : error;
+
+       /* on error, we have to clean up allocated value buffers */
+       if (error) {
+               if (flags & ATTR_ALLOC) {
+                       kmem_free(args.value);
+                       *value = NULL;
+               }
+               return error;
+       }
+       *value = args.value;
+       return 0;
 }
 
 /*
@@ -186,6 +218,121 @@ xfs_attr_calc_size(
        return nblks;
 }
 
+STATIC int
+xfs_attr_try_sf_addname(
+       struct xfs_inode        *dp,
+       struct xfs_da_args      *args)
+{
+
+       struct xfs_mount        *mp = dp->i_mount;
+       int                     error, error2;
+
+       error = xfs_attr_shortform_addname(args);
+       if (error == -ENOSPC)
+               return error;
+
+       /*
+        * Commit the shortform mods, and we're done.
+        * NOTE: this is also the error path (EEXIST, etc).
+        */
+       if (!error && (args->flags & ATTR_KERNOTIME) == 0)
+               xfs_trans_ichgtime(args->trans, dp, XFS_ICHGTIME_CHG);
+
+       if (mp->m_flags & XFS_MOUNT_WSYNC)
+               xfs_trans_set_sync(args->trans);
+
+       error2 = xfs_trans_commit(args->trans);
+       args->trans = NULL;
+       return error ? error : error2;
+}
+
+/*
+ * Set the attribute specified in @args.
+ */
+int
+xfs_attr_set_args(
+       struct xfs_da_args      *args)
+{
+       struct xfs_inode        *dp = args->dp;
+       struct xfs_buf          *leaf_bp = NULL;
+       int                     error;
+
+       /*
+        * If the attribute list is non-existent or a shortform list,
+        * upgrade it to a single-leaf-block attribute list.
+        */
+       if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL ||
+           (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
+            dp->i_d.di_anextents == 0)) {
+
+               /*
+                * Build initial attribute list (if required).
+                */
+               if (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS)
+                       xfs_attr_shortform_create(args);
+
+               /*
+                * Try to add the attr to the attribute list in the inode.
+                */
+               error = xfs_attr_try_sf_addname(dp, args);
+               if (error != -ENOSPC)
+                       return error;
+
+               /*
+                * It won't fit in the shortform, transform to a leaf block.
+                * GROT: another possible req'mt for a double-split btree op.
+                */
+               error = xfs_attr_shortform_to_leaf(args, &leaf_bp);
+               if (error)
+                       return error;
+
+               /*
+                * Prevent the leaf buffer from being unlocked so that a
+                * concurrent AIL push cannot grab the half-baked leaf
+                * buffer and run into problems with the write verifier.
+                * Once we're done rolling the transaction we can release
+                * the hold and add the attr to the leaf.
+                */
+               xfs_trans_bhold(args->trans, leaf_bp);
+               error = xfs_defer_finish(&args->trans);
+               xfs_trans_bhold_release(args->trans, leaf_bp);
+               if (error) {
+                       xfs_trans_brelse(args->trans, leaf_bp);
+                       return error;
+               }
+       }
+
+       if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
+               error = xfs_attr_leaf_addname(args);
+       else
+               error = xfs_attr_node_addname(args);
+       return error;
+}
+
+/*
+ * Remove the attribute specified in @args.
+ */
+int
+xfs_attr_remove_args(
+       struct xfs_da_args      *args)
+{
+       struct xfs_inode        *dp = args->dp;
+       int                     error;
+
+       if (!xfs_inode_hasattr(dp)) {
+               error = -ENOATTR;
+       } else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
+               ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
+               error = xfs_attr_shortform_remove(args);
+       } else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
+               error = xfs_attr_leaf_removename(args);
+       } else {
+               error = xfs_attr_node_removename(args);
+       }
+
+       return error;
+}
+
 int
 xfs_attr_set(
        struct xfs_inode        *dp,
@@ -195,13 +342,10 @@ xfs_attr_set(
        int                     flags)
 {
        struct xfs_mount        *mp = dp->i_mount;
-       struct xfs_buf          *leaf_bp = NULL;
        struct xfs_da_args      args;
-       struct xfs_defer_ops    dfops;
        struct xfs_trans_res    tres;
-       xfs_fsblock_t           firstblock;
        int                     rsvd = (flags & ATTR_ROOT) != 0;
-       int                     error, err2, local;
+       int                     error, local;
 
        XFS_STATS_INC(mp, xs_attr_set);
 
@@ -214,7 +358,6 @@ xfs_attr_set(
 
        args.value = value;
        args.valuelen = valuelen;
-       args.firstblock = &firstblock;
        args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
        args.total = xfs_attr_calc_size(&args, &local);
 
@@ -248,101 +391,22 @@ xfs_attr_set(
                        rsvd ? XFS_TRANS_RESERVE : 0, &args.trans);
        if (error)
                return error;
-       xfs_defer_init(args.trans, &dfops, &firstblock);
 
        xfs_ilock(dp, XFS_ILOCK_EXCL);
        error = xfs_trans_reserve_quota_nblks(args.trans, dp, args.total, 0,
                                rsvd ? XFS_QMOPT_RES_REGBLKS | XFS_QMOPT_FORCE_RES :
                                       XFS_QMOPT_RES_REGBLKS);
-       if (error) {
-               xfs_iunlock(dp, XFS_ILOCK_EXCL);
-               xfs_trans_cancel(args.trans);
-               return error;
-       }
+       if (error)
+               goto out_trans_cancel;
 
        xfs_trans_ijoin(args.trans, dp, 0);
-
-       /*
-        * If the attribute list is non-existent or a shortform list,
-        * upgrade it to a single-leaf-block attribute list.
-        */
-       if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL ||
-           (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
-            dp->i_d.di_anextents == 0)) {
-
-               /*
-                * Build initial attribute list (if required).
-                */
-               if (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS)
-                       xfs_attr_shortform_create(&args);
-
-               /*
-                * Try to add the attr to the attribute list in
-                * the inode.
-                */
-               error = xfs_attr_shortform_addname(&args);
-               if (error != -ENOSPC) {
-                       /*
-                        * Commit the shortform mods, and we're done.
-                        * NOTE: this is also the error path (EEXIST, etc).
-                        */
-                       ASSERT(args.trans != NULL);
-
-                       /*
-                        * If this is a synchronous mount, make sure that
-                        * the transaction goes to disk before returning
-                        * to the user.
-                        */
-                       if (mp->m_flags & XFS_MOUNT_WSYNC)
-                               xfs_trans_set_sync(args.trans);
-
-                       if (!error && (flags & ATTR_KERNOTIME) == 0) {
-                               xfs_trans_ichgtime(args.trans, dp,
-                                                       XFS_ICHGTIME_CHG);
-                       }
-                       err2 = xfs_trans_commit(args.trans);
-                       xfs_iunlock(dp, XFS_ILOCK_EXCL);
-
-                       return error ? error : err2;
-               }
-
-               /*
-                * It won't fit in the shortform, transform to a leaf block.
-                * GROT: another possible req'mt for a double-split btree op.
-                */
-               error = xfs_attr_shortform_to_leaf(&args, &leaf_bp);
-               if (error)
-                       goto out_defer_cancel;
-               /*
-                * Prevent the leaf buffer from being unlocked so that a
-                * concurrent AIL push cannot grab the half-baked leaf
-                * buffer and run into problems with the write verifier.
-                */
-               xfs_trans_bhold(args.trans, leaf_bp);
-               xfs_defer_bjoin(&dfops, leaf_bp);
-               xfs_defer_ijoin(&dfops, dp);
-               error = xfs_defer_finish(&args.trans, &dfops);
-               if (error)
-                       goto out_defer_cancel;
-
-               /*
-                * Commit the leaf transformation.  We'll need another (linked)
-                * transaction to add the new attribute to the leaf, which
-                * means that we have to hold & join the leaf buffer here too.
-                */
-               error = xfs_trans_roll_inode(&args.trans, dp);
-               if (error)
-                       goto out;
-               xfs_trans_bjoin(args.trans, leaf_bp);
-               leaf_bp = NULL;
-       }
-
-       if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
-               error = xfs_attr_leaf_addname(&args);
-       else
-               error = xfs_attr_node_addname(&args);
+       error = xfs_attr_set_args(&args);
        if (error)
-               goto out;
+               goto out_trans_cancel;
+       if (!args.trans) {
+               /* shortform attribute has already been committed */
+               goto out_unlock;
+       }
 
        /*
         * If this is a synchronous mount, make sure that the
@@ -359,19 +423,14 @@ xfs_attr_set(
         */
        xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
        error = xfs_trans_commit(args.trans);
+out_unlock:
        xfs_iunlock(dp, XFS_ILOCK_EXCL);
-
        return error;
 
-out_defer_cancel:
-       xfs_defer_cancel(&dfops);
-out:
-       if (leaf_bp)
-               xfs_trans_brelse(args.trans, leaf_bp);
+out_trans_cancel:
        if (args.trans)
                xfs_trans_cancel(args.trans);
-       xfs_iunlock(dp, XFS_ILOCK_EXCL);
-       return error;
+       goto out_unlock;
 }
 
 /*
@@ -386,8 +445,6 @@ xfs_attr_remove(
 {
        struct xfs_mount        *mp = dp->i_mount;
        struct xfs_da_args      args;
-       struct xfs_defer_ops    dfops;
-       xfs_fsblock_t           firstblock;
        int                     error;
 
        XFS_STATS_INC(mp, xs_attr_remove);
@@ -399,8 +456,6 @@ xfs_attr_remove(
        if (error)
                return error;
 
-       args.firstblock = &firstblock;
-
        /*
         * we have no control over the attribute names that userspace passes us
         * to remove, so we have to allow the name lookup prior to attribute
@@ -422,7 +477,6 @@ xfs_attr_remove(
                        &args.trans);
        if (error)
                return error;
-       xfs_defer_init(args.trans, &dfops, &firstblock);
 
        xfs_ilock(dp, XFS_ILOCK_EXCL);
        /*
@@ -431,17 +485,7 @@ xfs_attr_remove(
         */
        xfs_trans_ijoin(args.trans, dp, 0);
 
-       if (!xfs_inode_hasattr(dp)) {
-               error = -ENOATTR;
-       } else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
-               ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
-               error = xfs_attr_shortform_remove(&args);
-       } else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
-               error = xfs_attr_leaf_removename(&args);
-       } else {
-               error = xfs_attr_node_removename(&args);
-       }
-
+       error = xfs_attr_remove_args(&args);
        if (error)
                goto out;
 
@@ -593,14 +637,12 @@ xfs_attr_leaf_addname(
                 * Commit that transaction so that the node_addname() call
                 * can manage its own transactions.
                 */
-               xfs_defer_init(NULL, args->trans->t_dfops, args->firstblock);
                error = xfs_attr3_leaf_to_node(args);
                if (error)
-                       goto out_defer_cancel;
-               xfs_defer_ijoin(args->trans->t_dfops, dp);
-               error = xfs_defer_finish(&args->trans, args->trans->t_dfops);
+                       return error;
+               error = xfs_defer_finish(&args->trans);
                if (error)
-                       goto out_defer_cancel;
+                       return error;
 
                /*
                 * Commit the current trans (including the inode) and start
@@ -682,16 +724,13 @@ xfs_attr_leaf_addname(
                 * If the result is small enough, shrink it all into the inode.
                 */
                if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
-                       xfs_defer_init(NULL, args->trans->t_dfops,
-                                      args->firstblock);
                        error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
                        /* bp is gone due to xfs_da_shrink_inode */
                        if (error)
-                               goto out_defer_cancel;
-                       xfs_defer_ijoin(args->trans->t_dfops, dp);
-                       error = xfs_defer_finish(&args->trans, args->trans->t_dfops);
+                               return error;
+                       error = xfs_defer_finish(&args->trans);
                        if (error)
-                               goto out_defer_cancel;
+                               return error;
                }
 
                /*
@@ -706,9 +745,6 @@ xfs_attr_leaf_addname(
                error = xfs_attr3_leaf_clearflag(args);
        }
        return error;
-out_defer_cancel:
-       xfs_defer_cancel(args->trans->t_dfops);
-       return error;
 }
 
 /*
@@ -748,20 +784,15 @@ xfs_attr_leaf_removename(
         * If the result is small enough, shrink it all into the inode.
         */
        if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
-               xfs_defer_init(NULL, args->trans->t_dfops, args->firstblock);
                error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
                /* bp is gone due to xfs_da_shrink_inode */
                if (error)
-                       goto out_defer_cancel;
-               xfs_defer_ijoin(args->trans->t_dfops, dp);
-               error = xfs_defer_finish(&args->trans, args->trans->t_dfops);
+                       return error;
+               error = xfs_defer_finish(&args->trans);
                if (error)
-                       goto out_defer_cancel;
+                       return error;
        }
        return 0;
-out_defer_cancel:
-       xfs_defer_cancel(args->trans->t_dfops);
-       return error;
 }
 
 /*
@@ -769,6 +800,8 @@ out_defer_cancel:
  *
  * This leaf block cannot have a "remote" value, we only call this routine
  * if bmap_one_block() says there is only one block (ie: no remote blks).
+ *
+ * Returns 0 on successful retrieval, otherwise an error.
  */
 STATIC int
 xfs_attr_leaf_get(xfs_da_args_t *args)
@@ -790,9 +823,6 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
        }
        error = xfs_attr3_leaf_getvalue(bp, args);
        xfs_trans_brelse(args->trans, bp);
-       if (!error && (args->rmtblkno > 0) && !(args->flags & ATTR_KERNOVAL)) {
-               error = xfs_attr_rmtval_get(args);
-       }
        return error;
 }
 
@@ -877,16 +907,12 @@ restart:
                         */
                        xfs_da_state_free(state);
                        state = NULL;
-                       xfs_defer_init(NULL, args->trans->t_dfops,
-                                      args->firstblock);
                        error = xfs_attr3_leaf_to_node(args);
                        if (error)
-                               goto out_defer_cancel;
-                       xfs_defer_ijoin(args->trans->t_dfops, dp);
-                       error = xfs_defer_finish(&args->trans,
-                                                args->trans->t_dfops);
+                               goto out;
+                       error = xfs_defer_finish(&args->trans);
                        if (error)
-                               goto out_defer_cancel;
+                               goto out;
 
                        /*
                         * Commit the node conversion and start the next
@@ -905,14 +931,12 @@ restart:
                 * in the index/blkno/rmtblkno/rmtblkcnt fields and
                 * in the index2/blkno2/rmtblkno2/rmtblkcnt2 fields.
                 */
-               xfs_defer_init(NULL, args->trans->t_dfops, args->firstblock);
                error = xfs_da3_split(state);
                if (error)
-                       goto out_defer_cancel;
-               xfs_defer_ijoin(args->trans->t_dfops, dp);
-               error = xfs_defer_finish(&args->trans, args->trans->t_dfops);
+                       goto out;
+               error = xfs_defer_finish(&args->trans);
                if (error)
-                       goto out_defer_cancel;
+                       goto out;
        } else {
                /*
                 * Addition succeeded, update Btree hashvals.
@@ -1003,15 +1027,12 @@ restart:
                 * Check to see if the tree needs to be collapsed.
                 */
                if (retval && (state->path.active > 1)) {
-                       xfs_defer_init(NULL, args->trans->t_dfops,
-                                      args->firstblock);
                        error = xfs_da3_join(state);
                        if (error)
-                               goto out_defer_cancel;
-                       xfs_defer_ijoin(args->trans->t_dfops, dp);
-                       error = xfs_defer_finish(&args->trans, args->trans->t_dfops);
+                               goto out;
+                       error = xfs_defer_finish(&args->trans);
                        if (error)
-                               goto out_defer_cancel;
+                               goto out;
                }
 
                /*
@@ -1037,9 +1058,6 @@ out:
        if (error)
                return error;
        return retval;
-out_defer_cancel:
-       xfs_defer_cancel(args->trans->t_dfops);
-       goto out;
 }
 
 /*
@@ -1129,14 +1147,12 @@ xfs_attr_node_removename(
         * Check to see if the tree needs to be collapsed.
         */
        if (retval && (state->path.active > 1)) {
-               xfs_defer_init(NULL, args->trans->t_dfops, args->firstblock);
                error = xfs_da3_join(state);
                if (error)
-                       goto out_defer_cancel;
-               xfs_defer_ijoin(args->trans->t_dfops, dp);
-               error = xfs_defer_finish(&args->trans, args->trans->t_dfops);
+                       goto out;
+               error = xfs_defer_finish(&args->trans);
                if (error)
-                       goto out_defer_cancel;
+                       goto out;
                /*
                 * Commit the Btree join operation and start a new trans.
                 */
@@ -1161,16 +1177,13 @@ xfs_attr_node_removename(
                        goto out;
 
                if ((forkoff = xfs_attr_shortform_allfit(bp, dp))) {
-                       xfs_defer_init(NULL, args->trans->t_dfops,
-                                      args->firstblock);
                        error = xfs_attr3_leaf_to_shortform(bp, args, forkoff);
                        /* bp is gone due to xfs_da_shrink_inode */
                        if (error)
-                               goto out_defer_cancel;
-                       xfs_defer_ijoin(args->trans->t_dfops, dp);
-                       error = xfs_defer_finish(&args->trans, args->trans->t_dfops);
+                               goto out;
+                       error = xfs_defer_finish(&args->trans);
                        if (error)
-                               goto out_defer_cancel;
+                               goto out;
                } else
                        xfs_trans_brelse(args->trans, bp);
        }
@@ -1179,9 +1192,6 @@ xfs_attr_node_removename(
 out:
        xfs_da_state_free(state);
        return error;
-out_defer_cancel:
-       xfs_defer_cancel(args->trans->t_dfops);
-       goto out;
 }
 
 /*
@@ -1289,11 +1299,13 @@ xfs_attr_refillstate(xfs_da_state_t *state)
 }
 
 /*
- * Look up a filename in a node attribute list.
+ * Retrieve the attribute data from a node attribute list.
  *
  * This routine gets called for any attribute fork that has more than one
  * block, ie: both true Btree attr lists and for single-leaf-blocks with
  * "remote" values taking up more blocks.
+ *
+ * Returns 0 on successful retrieval, otherwise an error.
  */
 STATIC int
 xfs_attr_node_get(xfs_da_args_t *args)
@@ -1315,24 +1327,21 @@ xfs_attr_node_get(xfs_da_args_t *args)
        error = xfs_da3_node_lookup_int(state, &retval);
        if (error) {
                retval = error;
-       } else if (retval == -EEXIST) {
-               blk = &state->path.blk[ state->path.active-1 ];
-               ASSERT(blk->bp != NULL);
-               ASSERT(blk->magic == XFS_ATTR_LEAF_MAGIC);
-
-               /*
-                * Get the value, local or "remote"
-                */
-               retval = xfs_attr3_leaf_getvalue(blk->bp, args);
-               if (!retval && (args->rmtblkno > 0)
-                   && !(args->flags & ATTR_KERNOVAL)) {
-                       retval = xfs_attr_rmtval_get(args);
-               }
+               goto out_release;
        }
+       if (retval != -EEXIST)
+               goto out_release;
+
+       /*
+        * Get the value, local or "remote"
+        */
+       blk = &state->path.blk[state->path.active - 1];
+       retval = xfs_attr3_leaf_getvalue(blk->bp, args);
 
        /*
         * If not in a transaction, we have to release all the buffers.
         */
+out_release:
        for (i = 0; i < state->path.active; i++) {
                xfs_trans_brelse(args->trans, state->path.blk[i].bp);
                state->path.blk[i].bp = NULL;
@@ -1341,3 +1350,20 @@ xfs_attr_node_get(xfs_da_args_t *args)
        xfs_da_state_free(state);
        return retval;
 }
+
+/* Returns true if the attribute entry name is valid. */
+bool
+xfs_attr_namecheck(
+       const void      *name,
+       size_t          length)
+{
+       /*
+        * MAXNAMELEN includes the trailing null, but (name/length) leave it
+        * out, so use >= for the length check.
+        */
+       if (length >= MAXNAMELEN)
+               return false;
+
+       /* There shouldn't be any nulls here */
+       return !memchr(name, 0, length);
+}