Whamcloud - gitweb
LU-5549 mdc: cl_default_mds_easize not refreshed
[fs/lustre-release.git] / lustre / llite / llite_lib.c
index 7e49c90..7d332ab 100644 (file)
@@ -27,7 +27,7 @@
  * Copyright (c) 2003, 2010, Oracle and/or its affiliates. All rights reserved.
  * Use is subject to license terms.
  *
- * Copyright (c) 2011, 2013, Intel Corporation.
+ * Copyright (c) 2011, 2014, Intel Corporation.
  */
 /*
  * This file is part of Lustre, http://www.lustre.org/
 #define DEBUG_SUBSYSTEM S_LLITE
 
 #include <linux/module.h>
+#include <linux/statfs.h>
 #include <linux/types.h>
 #include <linux/version.h>
 #include <linux/mm.h>
 
 #include <lustre_ioctl.h>
-#include <lustre_lite.h>
 #include <lustre_ha.h>
 #include <lustre_dlm.h>
 #include <lprocfs_status.h>
@@ -93,13 +93,13 @@ static struct ll_sb_info *ll_init_sbi(void)
        /* initialize ll_cache data */
        atomic_set(&sbi->ll_cache.ccc_users, 0);
        sbi->ll_cache.ccc_lru_max = lru_page_max;
-       atomic_set(&sbi->ll_cache.ccc_lru_left, lru_page_max);
+       atomic_long_set(&sbi->ll_cache.ccc_lru_left, lru_page_max);
        spin_lock_init(&sbi->ll_cache.ccc_lru_lock);
        INIT_LIST_HEAD(&sbi->ll_cache.ccc_lru);
 
        /* turn unstable check off by default as it impacts performance */
        sbi->ll_cache.ccc_unstable_check = 0;
-       atomic_set(&sbi->ll_cache.ccc_unstable_nr, 0);
+       atomic_long_set(&sbi->ll_cache.ccc_unstable_nr, 0);
        init_waitqueue_head(&sbi->ll_cache.ccc_unstable_waitq);
 
        sbi->ll_ra_info.ra_max_pages_per_file = min(pages / 32,
@@ -138,6 +138,7 @@ static struct ll_sb_info *ll_init_sbi(void)
        sbi->ll_sa_max = LL_SA_RPC_DEF;
        atomic_set(&sbi->ll_sa_total, 0);
        atomic_set(&sbi->ll_sa_wrong, 0);
+       atomic_set(&sbi->ll_sa_running, 0);
        atomic_set(&sbi->ll_agl_total, 0);
        sbi->ll_flags |= LL_SBI_AGL_ENABLED;
 
@@ -169,7 +170,7 @@ static void ll_free_sbi(struct super_block *sb)
 static int client_common_fill_super(struct super_block *sb, char *md, char *dt,
                                     struct vfsmount *mnt)
 {
-        struct inode *root = 0;
+       struct inode *root = NULL;
         struct ll_sb_info *sbi = ll_s2sbi(sb);
         struct obd_device *obd;
         struct obd_capa *oc = NULL;
@@ -179,7 +180,7 @@ static int client_common_fill_super(struct super_block *sb, char *md, char *dt,
         struct obd_uuid *uuid;
         struct md_op_data *op_data;
         struct lustre_md lmd;
-        obd_valid valid;
+       u64 valid;
         int size, err, checksum;
         ENTRY;
 
@@ -652,6 +653,17 @@ int ll_get_max_mdsize(struct ll_sb_info *sbi, int *lmmsize)
        RETURN(rc);
 }
 
+/**
+ * Get the value of the default_easize parameter.
+ *
+ * \see client_obd::cl_default_mds_easize
+ *
+ * \param[in] sbi      superblock info for this filesystem
+ * \param[out] lmmsize pointer to storage location for value
+ *
+ * \retval 0           on success
+ * \retval negative    negated errno on failure
+ */
 int ll_get_default_mdsize(struct ll_sb_info *sbi, int *lmmsize)
 {
        int size, rc;
@@ -665,6 +677,32 @@ int ll_get_default_mdsize(struct ll_sb_info *sbi, int *lmmsize)
        RETURN(rc);
 }
 
+/**
+ * Set the default_easize parameter to the given value.
+ *
+ * \see client_obd::cl_default_mds_easize
+ *
+ * \param[in] sbi      superblock info for this filesystem
+ * \param[in] lmmsize  the size to set
+ *
+ * \retval 0           on success
+ * \retval negative    negated errno on failure
+ */
+int ll_set_default_mdsize(struct ll_sb_info *sbi, int lmmsize)
+{
+       int rc;
+
+       if (lmmsize < sizeof(struct lov_mds_md) ||
+           lmmsize > OBD_MAX_DEFAULT_EA_SIZE)
+               return -EINVAL;
+
+       rc = obd_set_info_async(NULL, sbi->ll_md_exp,
+                               sizeof(KEY_DEFAULT_EASIZE), KEY_DEFAULT_EASIZE,
+                               sizeof(int), &lmmsize, NULL);
+
+       RETURN(rc);
+}
+
 int ll_get_max_cookiesize(struct ll_sb_info *sbi, int *lmmsize)
 {
        int size, rc;
@@ -722,7 +760,7 @@ void lustre_dump_dentry(struct dentry *dentry, int recur)
                " flags=0x%x, fsdata=%p, %d subdirs\n", dentry,
                dentry->d_name.len, dentry->d_name.name,
                dentry->d_parent->d_name.len, dentry->d_parent->d_name.name,
-              dentry->d_parent, dentry->d_inode, d_count(dentry),
+              dentry->d_parent, dentry->d_inode, ll_d_count(dentry),
                dentry->d_flags, dentry->d_fsdata, subdirs);
         if (dentry->d_inode != NULL)
                 ll_dump_inode(dentry->d_inode);
@@ -772,22 +810,27 @@ static void client_common_put_super(struct super_block *sb)
 
 void ll_kill_super(struct super_block *sb)
 {
-        struct ll_sb_info *sbi;
-
-        ENTRY;
+       struct ll_sb_info *sbi;
+       ENTRY;
 
         /* not init sb ?*/
-        if (!(sb->s_flags & MS_ACTIVE))
-                return;
+       if (!(sb->s_flags & MS_ACTIVE))
+               return;
 
-        sbi = ll_s2sbi(sb);
-        /* we need restore s_dev from changed for clustred NFS before put_super
-         * because new kernels have cached s_dev and change sb->s_dev in
-         * put_super not affected real removing devices */
+       sbi = ll_s2sbi(sb);
+       /* we need restore s_dev from changed for clustred NFS before put_super
+        * because new kernels have cached s_dev and change sb->s_dev in
+        * put_super not affected real removing devices */
        if (sbi) {
                sb->s_dev = sbi->ll_sdev_orig;
                sbi->ll_umounting = 1;
+
+               /* wait running statahead threads to quit */
+               while (atomic_read(&sbi->ll_sa_running) > 0)
+                       schedule_timeout_and_set_state(TASK_UNINTERRUPTIBLE,
+                               msecs_to_jiffies(MSEC_PER_SEC >> 3));
        }
+
        EXIT;
 }
 
@@ -843,30 +886,11 @@ static int ll_options(char *options, int *flags)
                         *flags &= ~tmp;
                         goto next;
                 }
-#if LUSTRE_VERSION_CODE < OBD_OCD_VERSION(2, 6, 51, 0)
-               tmp = ll_set_opt("acl", s1, LL_SBI_ACL);
-               if (tmp) {
-                       /* Ignore deprecated mount option.  The client will
-                        * always try to mount with ACL support, whether this
-                        * is used depends on whether server supports it. */
-                       LCONSOLE_ERROR_MSG(0x152, "Ignoring deprecated "
-                                                 "mount option 'acl'.\n");
-                       goto next;
-               }
-               tmp = ll_set_opt("noacl", s1, LL_SBI_ACL);
+               tmp = ll_set_opt("remote_client", s1, LL_SBI_RMT_CLIENT);
                if (tmp) {
-                       LCONSOLE_ERROR_MSG(0x152, "Ignoring deprecated "
-                                                 "mount option 'noacl'.\n");
+                       *flags |= tmp;
                        goto next;
                }
-#else
-#warning "{no}acl options have been deprecated since 1.8, please remove them"
-#endif
-                tmp = ll_set_opt("remote_client", s1, LL_SBI_RMT_CLIENT);
-                if (tmp) {
-                        *flags |= tmp;
-                        goto next;
-                }
                tmp = ll_set_opt("user_fid2path", s1, LL_SBI_USER_FID2PATH);
                if (tmp) {
                        *flags |= tmp;
@@ -983,11 +1007,13 @@ void ll_lli_init(struct ll_inode_info *lli)
                lli->lli_sai = NULL;
                spin_lock_init(&lli->lli_sa_lock);
                lli->lli_opendir_pid = 0;
+               lli->lli_sa_enabled = 0;
+               lli->lli_def_stripe_offset = -1;
        } else {
                mutex_init(&lli->lli_size_mutex);
                lli->lli_symlink_name = NULL;
                init_rwsem(&lli->lli_trunc_sem);
-               mutex_init(&lli->lli_write_mutex);
+               range_lock_tree_init(&lli->lli_write_tree);
                init_rwsem(&lli->lli_glimpse_sem);
                lli->lli_glimpse_time = 0;
                INIT_LIST_HEAD(&lli->lli_agl_list);
@@ -1110,7 +1136,8 @@ void ll_put_super(struct super_block *sb)
         struct lustre_sb_info *lsi = s2lsi(sb);
         struct ll_sb_info *sbi = ll_s2sbi(sb);
         char *profilenm = get_profile_name(sb);
-       int ccc_count, next, force = 1, rc = 0;
+       long ccc_count;
+       int next, force = 1, rc = 0;
         ENTRY;
 
         CDEBUG(D_VFSTRACE, "VFS Op: sb %p - %s\n", sb, profilenm);
@@ -1133,13 +1160,13 @@ void ll_put_super(struct super_block *sb)
        if (force == 0) {
                struct l_wait_info lwi = LWI_INTR(LWI_ON_SIGNAL_NOOP, NULL);
                rc = l_wait_event(sbi->ll_cache.ccc_unstable_waitq,
-                       atomic_read(&sbi->ll_cache.ccc_unstable_nr) == 0,
+                       atomic_long_read(&sbi->ll_cache.ccc_unstable_nr) == 0,
                        &lwi);
        }
 
-       ccc_count = atomic_read(&sbi->ll_cache.ccc_unstable_nr);
+       ccc_count = atomic_long_read(&sbi->ll_cache.ccc_unstable_nr);
        if (force == 0 && rc != -EINTR)
-               LASSERTF(ccc_count == 0, "count: %i\n", ccc_count);
+               LASSERTF(ccc_count == 0, "count: %li\n", ccc_count);
 
 
         /* We need to set force before the lov_disconnect in
@@ -1306,10 +1333,7 @@ static int ll_init_lsm_md(struct inode *inode, struct lustre_md *md)
                }
        }
 
-       /* Here is where the lsm is being initialized(fill lmo_info) after
-        * client retrieve MD stripe information from MDT. */
-       return md_update_lsm_md(ll_i2mdexp(inode), lsm, md->body,
-                               ll_md_blocking_ast);
+       return 0;
 }
 
 static inline int lli_lsm_md_eq(const struct lmv_stripe_md *lsm_md1,
@@ -1409,10 +1433,7 @@ static int ll_update_lsm_md(struct inode *inode, struct lustre_md *md)
                RETURN(-EIO);
        }
 
-       rc = md_update_lsm_md(ll_i2mdexp(inode), ll_i2info(inode)->lli_lsm_md,
-                             md->body, ll_md_blocking_ast);
-
-       RETURN(rc);
+       RETURN(0);
 }
 
 void ll_clear_inode(struct inode *inode)
@@ -1488,8 +1509,8 @@ void ll_clear_inode(struct inode *inode)
        EXIT;
 }
 
-int ll_md_setattr(struct dentry *dentry, struct md_op_data *op_data,
-                  struct md_open_data **mod)
+static int ll_md_setattr(struct dentry *dentry, struct md_op_data *op_data,
+                        struct md_open_data **mod)
 {
         struct lustre_md md;
         struct inode *inode = dentry->d_inode;
@@ -1969,7 +1990,7 @@ int ll_update_inode(struct inode *inode, struct lustre_md *md)
        if (body->mbo_valid & OBD_MD_FLATIME) {
                if (body->mbo_atime > LTIME_S(inode->i_atime))
                        LTIME_S(inode->i_atime) = body->mbo_atime;
-               lli->lli_lvb.lvb_atime = body->mbo_atime;
+               lli->lli_atime = body->mbo_atime;
        }
 
        if (body->mbo_valid & OBD_MD_FLMTIME) {
@@ -1979,13 +2000,13 @@ int ll_update_inode(struct inode *inode, struct lustre_md *md)
                               LTIME_S(inode->i_mtime), body->mbo_mtime);
                        LTIME_S(inode->i_mtime) = body->mbo_mtime;
                }
-               lli->lli_lvb.lvb_mtime = body->mbo_mtime;
+               lli->lli_mtime = body->mbo_mtime;
        }
 
        if (body->mbo_valid & OBD_MD_FLCTIME) {
                if (body->mbo_ctime > LTIME_S(inode->i_ctime))
                        LTIME_S(inode->i_ctime) = body->mbo_ctime;
-               lli->lli_lvb.lvb_ctime = body->mbo_ctime;
+               lli->lli_ctime = body->mbo_ctime;
        }
 
        if (body->mbo_valid & OBD_MD_FLMODE)
@@ -2153,28 +2174,19 @@ int ll_read_inode2(struct inode *inode, void *opaque)
 
 void ll_delete_inode(struct inode *inode)
 {
-       struct cl_inode_info *lli = cl_i2info(inode);
+       struct ll_inode_info *lli = ll_i2info(inode);
        ENTRY;
 
        if (S_ISREG(inode->i_mode) && lli->lli_clob != NULL)
-               /* discard all dirty pages before truncating them, required by
-                * osc_extent implementation at LU-1030. */
-               cl_sync_file_range(inode, 0, OBD_OBJECT_EOF,
-                                  CL_FSYNC_DISCARD, 1);
-
-        truncate_inode_pages(&inode->i_data, 0);
-
-        /* Workaround for LU-118 */
-        if (inode->i_data.nrpages) {
-               spin_lock_irq(&inode->i_data.tree_lock);
-               spin_unlock_irq(&inode->i_data.tree_lock);
-                LASSERTF(inode->i_data.nrpages == 0,
-                        "inode="DFID"(%p) nrpages=%lu, see "
-                        "http://jira.whamcloud.com/browse/LU-118\n",
-                        PFID(ll_inode2fid(inode)), inode,
-                         inode->i_data.nrpages);
-        }
-        /* Workaround end */
+               /* It is last chance to write out dirty pages,
+                * otherwise we may lose data while umount */
+               cl_sync_file_range(inode, 0, OBD_OBJECT_EOF, CL_FSYNC_LOCAL, 1);
+
+       truncate_inode_pages_final(&inode->i_data);
+
+       LASSERTF(inode->i_data.nrpages == 0, "inode="DFID"(%p) nrpages=%lu, "
+                "see https://jira.hpdd.intel.com/browse/LU-118\n",
+                PFID(ll_inode2fid(inode)), inode, inode->i_data.nrpages);
 
 #ifdef HAVE_SBOPS_EVICT_INODE
        ll_clear_inode(inode);
@@ -2219,22 +2231,22 @@ int ll_iocontrol(struct inode *inode, struct file *file,
 
                 ptlrpc_req_finished(req);
 
-                RETURN(put_user(flags, (int *)arg));
+               RETURN(put_user(flags, (int __user *)arg));
         }
         case FSFILT_IOC_SETFLAGS: {
                struct lov_stripe_md *lsm;
                 struct obd_info oinfo = { { { 0 } } };
                 struct md_op_data *op_data;
 
-                if (get_user(flags, (int *)arg))
-                        RETURN(-EFAULT);
+               if (get_user(flags, (int __user *)arg))
+                       RETURN(-EFAULT);
 
                 op_data = ll_prep_md_op_data(NULL, inode, NULL, NULL, 0, 0,
                                              LUSTRE_OPC_ANY, NULL);
                 if (IS_ERR(op_data))
                         RETURN(PTR_ERR(op_data));
 
-                ((struct ll_iattr *)&op_data->op_attr)->ia_attr_flags = flags;
+               op_data->op_attr_flags = flags;
                 op_data->op_attr.ia_valid |= ATTR_ATTR_FLAG;
                 rc = md_setattr(sbi->ll_md_exp, op_data,
                                 NULL, 0, NULL, 0, &req, NULL);
@@ -2380,7 +2392,7 @@ int ll_prep_inode(struct inode **inode, struct ptlrpc_request *req,
                  struct super_block *sb, struct lookup_intent *it)
 {
        struct ll_sb_info *sbi = NULL;
-       struct lustre_md md = { 0 };
+       struct lustre_md md = { NULL };
        int rc;
        ENTRY;
 
@@ -2456,14 +2468,14 @@ out:
        RETURN(rc);
 }
 
-int ll_obd_statfs(struct inode *inode, void *arg)
+int ll_obd_statfs(struct inode *inode, void __user *arg)
 {
         struct ll_sb_info *sbi = NULL;
         struct obd_export *exp;
         char *buf = NULL;
         struct obd_ioctl_data *data = NULL;
         __u32 type;
-       __u32 flags;
+       __u32 __user flags;     /* not user, but obd_iocontrol is abused */
         int len = 0, rc;
 
         if (!inode || !(sbi = ll_i2sbi(inode)))
@@ -2521,8 +2533,8 @@ int ll_process_config(struct lustre_cfg *lcfg)
 
        /* Note we have not called client_common_fill_super yet, so
           proc fns must be able to handle that! */
-       rc = class_process_proc_seq_param(PARAM_LLITE, lprocfs_llite_obd_vars,
-                                         lcfg, sb);
+       rc = class_process_proc_param(PARAM_LLITE, lprocfs_llite_obd_vars,
+                                     lcfg, sb);
        if (rc > 0)
                rc = 0;
        return rc;
@@ -2530,9 +2542,9 @@ int ll_process_config(struct lustre_cfg *lcfg)
 
 /* this function prepares md_op_data hint for passing ot down to MD stack. */
 struct md_op_data * ll_prep_md_op_data(struct md_op_data *op_data,
-                                       struct inode *i1, struct inode *i2,
-                                       const char *name, int namelen,
-                                       int mode, __u32 opc, void *data)
+                                      struct inode *i1, struct inode *i2,
+                                      const char *name, size_t namelen,
+                                      __u32 mode, __u32 opc, void *data)
 {
         LASSERT(i1 != NULL);
 
@@ -2557,8 +2569,12 @@ struct md_op_data * ll_prep_md_op_data(struct md_op_data *op_data,
        ll_i2gids(op_data->op_suppgids, i1, i2);
        op_data->op_fid1 = *ll_inode2fid(i1);
        op_data->op_capa1 = ll_mdscapa_get(i1);
-       if (S_ISDIR(i1->i_mode))
+       op_data->op_default_stripe_offset = -1;
+       if (S_ISDIR(i1->i_mode)) {
                op_data->op_mea1 = ll_i2info(i1)->lli_lsm_md;
+               op_data->op_default_stripe_offset =
+                          ll_i2info(i1)->lli_def_stripe_offset;
+       }
 
        if (i2) {
                op_data->op_fid2 = *ll_inode2fid(i2);
@@ -2586,9 +2602,11 @@ struct md_op_data * ll_prep_md_op_data(struct md_op_data *op_data,
        op_data->op_bias = 0;
        op_data->op_cli_flags = 0;
        if ((opc == LUSTRE_OPC_CREATE) && (name != NULL) &&
-            filename_is_volatile(name, namelen, NULL))
+            filename_is_volatile(name, namelen, &op_data->op_mds)) {
                op_data->op_bias |= MDS_CREATE_VOLATILE;
-       op_data->op_mds = 0;
+       } else {
+               op_data->op_mds = 0;
+       }
        op_data->op_data = data;
 
        /* When called by ll_setattr_raw, file is i1. */
@@ -2661,7 +2679,7 @@ int ll_get_obd_name(struct inode *inode, unsigned int cmd, unsigned long arg)
         if (!obd)
                 RETURN(-ENOENT);
 
-       if (copy_to_user((void *)arg, obd->obd_name,
+       if (copy_to_user((void __user *)arg, obd->obd_name,
                         strlen(obd->obd_name) + 1))
                RETURN(-EFAULT);
 
@@ -2719,7 +2737,7 @@ void ll_dirty_page_discard_warn(struct page *page, int ioret)
 {
        char *buf, *path = NULL;
        struct dentry *dentry = NULL;
-       struct ccc_object *obj = cl_inode2ccc(page->mapping->host);
+       struct vvp_object *obj = cl_inode2vvp(page->mapping->host);
 
        /* this can be called inside spin lock so use GFP_ATOMIC. */
        buf = (char *)__get_free_page(GFP_ATOMIC);
@@ -2733,7 +2751,7 @@ void ll_dirty_page_discard_warn(struct page *page, int ioret)
               "%s: dirty page discard: %s/fid: "DFID"/%s may get corrupted "
               "(rc %d)\n", ll_get_fsname(page->mapping->host->i_sb, NULL, 0),
               s2lsi(page->mapping->host->i_sb)->lsi_lmd->lmd_dev,
-              PFID(&obj->cob_header.coh_lu.loh_fid),
+              PFID(&obj->vob_header.coh_lu.loh_fid),
               (path && !IS_ERR(path)) ? path : "", ioret);
 
        if (dentry != NULL)
@@ -2743,6 +2761,32 @@ void ll_dirty_page_discard_warn(struct page *page, int ioret)
                free_page((unsigned long)buf);
 }
 
+ssize_t ll_copy_user_md(const struct lov_user_md __user *md,
+                       struct lov_user_md **kbuf)
+{
+       struct lov_user_md      lum;
+       ssize_t                 lum_size;
+       ENTRY;
+
+       if (copy_from_user(&lum, md, sizeof(lum)))
+               RETURN(-EFAULT);
+
+       lum_size = ll_lov_user_md_size(&lum);
+       if (lum_size < 0)
+               RETURN(lum_size);
+
+       OBD_ALLOC(*kbuf, lum_size);
+       if (*kbuf == NULL)
+               RETURN(-ENOMEM);
+
+       if (copy_from_user(*kbuf, md, lum_size) != 0) {
+               OBD_FREE(*kbuf, lum_size);
+               RETURN(-EFAULT);
+       }
+
+       RETURN(lum_size);
+}
+
 /*
  * Compute llite root squash state after a change of root squash
  * configuration setting or add/remove of a lnet nid
@@ -2779,4 +2823,120 @@ void ll_compute_rootsquash_state(struct ll_sb_info *sbi)
        up_write(&squash->rsi_sem);
 }
 
+/**
+ * Parse linkea content to extract information about a given hardlink
+ *
+ * \param[in]   ldata      - Initialized linkea data
+ * \param[in]   linkno     - Link identifier
+ * \param[out]  parent_fid - The entry's parent FID
+ * \param[out]  ln         - Entry name destination buffer
+ *
+ * \retval 0 on success
+ * \retval Appropriate negative error code on failure
+ */
+static int ll_linkea_decode(struct linkea_data *ldata, unsigned int linkno,
+                           struct lu_fid *parent_fid, struct lu_name *ln)
+{
+       unsigned int    idx;
+       int             rc;
+       ENTRY;
+
+       rc = linkea_init(ldata);
+       if (rc < 0)
+               RETURN(rc);
 
+       if (linkno >= ldata->ld_leh->leh_reccount)
+               /* beyond last link */
+               RETURN(-ENODATA);
+
+       linkea_first_entry(ldata);
+       for (idx = 0; ldata->ld_lee != NULL; idx++) {
+               linkea_entry_unpack(ldata->ld_lee, &ldata->ld_reclen, ln,
+                                   parent_fid);
+               if (idx == linkno)
+                       break;
+
+               linkea_next_entry(ldata);
+       }
+
+       if (idx < linkno)
+               RETURN(-ENODATA);
+
+       RETURN(0);
+}
+
+/**
+ * Get parent FID and name of an identified link. Operation is performed for
+ * a given link number, letting the caller iterate over linkno to list one or
+ * all links of an entry.
+ *
+ * \param[in]     file - File descriptor against which to perform the operation
+ * \param[in,out] arg  - User-filled structure containing the linkno to operate
+ *                       on and the available size. It is eventually filled with
+ *                       the requested information or left untouched on error
+ *
+ * \retval - 0 on success
+ * \retval - Appropriate negative error code on failure
+ */
+int ll_getparent(struct file *file, struct getparent __user *arg)
+{
+       struct dentry           *dentry = file->f_dentry;
+       struct inode            *inode = file->f_dentry->d_inode;
+       struct linkea_data      *ldata;
+       struct lu_buf            buf = LU_BUF_NULL;
+       struct lu_name           ln;
+       struct lu_fid            parent_fid;
+       __u32                    linkno;
+       __u32                    name_size;
+       int                      rc;
+
+       ENTRY;
+
+       if (!cfs_capable(CFS_CAP_DAC_READ_SEARCH) &&
+           !(ll_i2sbi(inode)->ll_flags & LL_SBI_USER_FID2PATH))
+               RETURN(-EPERM);
+
+       if (get_user(name_size, &arg->gp_name_size))
+               RETURN(-EFAULT);
+
+       if (get_user(linkno, &arg->gp_linkno))
+               RETURN(-EFAULT);
+
+       if (name_size > PATH_MAX)
+               RETURN(-EINVAL);
+
+       OBD_ALLOC(ldata, sizeof(*ldata));
+       if (ldata == NULL)
+               RETURN(-ENOMEM);
+
+       rc = linkea_data_new(ldata, &buf);
+       if (rc < 0)
+               GOTO(ldata_free, rc);
+
+       rc = ll_getxattr(dentry, XATTR_NAME_LINK, buf.lb_buf, buf.lb_len);
+       if (rc < 0)
+               GOTO(lb_free, rc);
+
+       rc = ll_linkea_decode(ldata, linkno, &parent_fid, &ln);
+       if (rc < 0)
+               GOTO(lb_free, rc);
+
+       if (ln.ln_namelen >= name_size)
+               GOTO(lb_free, rc = -EOVERFLOW);
+
+       if (copy_to_user(&arg->gp_fid, &parent_fid, sizeof(arg->gp_fid)))
+               GOTO(lb_free, rc = -EFAULT);
+
+       if (copy_to_user(&arg->gp_name, ln.ln_name, ln.ln_namelen))
+               GOTO(lb_free, rc = -EFAULT);
+
+       if (put_user('\0', arg->gp_name + ln.ln_namelen))
+               GOTO(lb_free, rc = -EFAULT);
+
+lb_free:
+       lu_buf_free(&buf);
+ldata_free:
+       OBD_FREE(ldata, sizeof(*ldata));
+
+       RETURN(rc);
+}