Linux 2.6.29 compat, credentials

[zfs.git] / module / zfs / zfs_znode.c

diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index 1017414..f9ea2a0 100644 (file)
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -322,7 +322,8 @@ zfs_inode_set_ops(zfs_sb_t *zsb, struct inode *ip)
  */
 static znode_t *
 zfs_znode_alloc(zfs_sb_t *zsb, dmu_buf_t *db, int blksz,
-    dmu_object_type_t obj_type, uint64_t obj, sa_handle_t *hdl)
+    dmu_object_type_t obj_type, uint64_t obj, sa_handle_t *hdl,
+    struct dentry *dentry)
 {
        znode_t *zp;
        struct inode *ip;
@@ -379,6 +380,9 @@ zfs_znode_alloc(zfs_sb_t *zsb, dmu_buf_t *db, int blksz,
        if (insert_inode_locked(ip))
                goto error;
 
+       if (dentry)
+               d_instantiate(dentry, ip);
+
        mutex_enter(&zsb->z_znodes_lock);
        list_insert_tail(&zsb->z_all_znodes, zp);
        membar_producer();
@@ -675,7 +679,8 @@ zfs_mknode(znode_t *dzp, vattr_t *vap, dmu_tx_t *tx, cred_t *cr,
        VERIFY(sa_replace_all_by_template(sa_hdl, sa_attrs, cnt, tx) == 0);
 
        if (!(flag & IS_ROOT_NODE)) {
-               *zpp = zfs_znode_alloc(zsb, db, 0, obj_type, obj, sa_hdl);
+               *zpp = zfs_znode_alloc(zsb, db, 0, obj_type, obj, sa_hdl,
+                   vap->va_dentry);
                ASSERT(*zpp != NULL);
                ASSERT(dzp != NULL);
                err = zpl_xattr_security_init(ZTOI(*zpp), ZTOI(dzp));
@@ -866,7 +871,7 @@ zfs_zget(zfs_sb_t *zsb, uint64_t obj_num, znode_t **zpp)
         * bonus buffer.
         */
        zp = zfs_znode_alloc(zsb, db, doi.doi_data_block_size,
-           doi.doi_bonus_type, obj_num, NULL);
+           doi.doi_bonus_type, obj_num, NULL, NULL);
        if (zp == NULL) {
                err = ENOENT;
        } else {
@@ -980,13 +985,24 @@ zfs_zinactive(znode_t *zp)
 {
        zfs_sb_t *zsb = ZTOZSB(zp);
        uint64_t z_id = zp->z_id;
+       boolean_t drop_mutex = 0;
 
        ASSERT(zp->z_sa_hdl);
 
        /*
-        * Don't allow a zfs_zget() while were trying to release this znode
+        * Don't allow a zfs_zget() while were trying to release this znode.
+        *
+        * Linux allows direct memory reclaim which means that any KM_SLEEP
+        * allocation may trigger inode eviction.  This can lead to a deadlock
+        * through the ->shrink_icache_memory()->evict()->zfs_inactive()->
+        * zfs_zinactive() call path.  To avoid this deadlock the process
+        * must not reacquire the mutex when it is already holding it.
         */
-       ZFS_OBJ_HOLD_ENTER(zsb, z_id);
+       if (!ZFS_OBJ_HOLD_OWNED(zsb, z_id)) {
+               ZFS_OBJ_HOLD_ENTER(zsb, z_id);
+               drop_mutex = 1;
+       }
+
        mutex_enter(&zp->z_lock);
 
        /*
@@ -995,14 +1011,19 @@ zfs_zinactive(znode_t *zp)
         */
        if (zp->z_unlinked) {
                mutex_exit(&zp->z_lock);
-               ZFS_OBJ_HOLD_EXIT(zsb, z_id);
+
+               if (drop_mutex)
+                       ZFS_OBJ_HOLD_EXIT(zsb, z_id);
+
                zfs_rmnode(zp);
                return;
        }
 
        mutex_exit(&zp->z_lock);
        zfs_znode_dmu_fini(zp);
-       ZFS_OBJ_HOLD_EXIT(zsb, z_id);
+
+       if (drop_mutex)
+               ZFS_OBJ_HOLD_EXIT(zsb, z_id);
 }
 
 void