Conserve stack in zfs_sa_upgrade()

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

diff --git a/module/zfs/zfs_sa.c b/module/zfs/zfs_sa.c
index 73a40aa..68bce0a 100644 (file)
--- a/module/zfs/zfs_sa.c
+++ b/module/zfs/zfs_sa.c
@@ -67,7 +67,6 @@ sa_attr_reg_t zfs_attr_table[ZPL_END+1] = {
 };
 
 #ifdef _KERNEL
-
 int
 zfs_sa_readlink(znode_t *zp, uio_t *uio)
 {
@@ -119,12 +118,14 @@ zfs_sa_symlink(znode_t *zp, char *link, int len, dmu_tx_t *tx)
        }
 }
 
+#ifdef HAVE_SCANSTAMP
 void
 zfs_sa_get_scanstamp(znode_t *zp, xvattr_t *xvap)
 {
        zfsvfs_t *zfsvfs = zp->z_zfsvfs;
        xoptattr_t *xoap;
 
+       ASSERT(MUTEX_HELD(&zp->z_lock));
        VERIFY((xoap = xva_getxoptattr(xvap)) != NULL);
        if (zp->z_is_sa) {
                if (sa_lookup(zp->z_sa_hdl, SA_ZPL_SCANSTAMP(zfsvfs),
@@ -158,6 +159,7 @@ zfs_sa_set_scanstamp(znode_t *zp, xvattr_t *xvap, dmu_tx_t *tx)
        zfsvfs_t *zfsvfs = zp->z_zfsvfs;
        xoptattr_t *xoap;
 
+       ASSERT(MUTEX_HELD(&zp->z_lock));
        VERIFY((xoap = xva_getxoptattr(xvap)) != NULL);
        if (zp->z_is_sa)
                VERIFY(0 == sa_update(zp->z_sa_hdl, SA_ZPL_SCANSTAMP(zfsvfs),
@@ -181,6 +183,7 @@ zfs_sa_set_scanstamp(znode_t *zp, xvattr_t *xvap, dmu_tx_t *tx)
                    &zp->z_pflags, sizeof (uint64_t), tx));
        }
 }
+#endif /* HAVE_SCANSTAMP */
 
 /*
  * I'm not convinced we should do any of this upgrade.
@@ -196,14 +199,16 @@ zfs_sa_upgrade(sa_handle_t *hdl, dmu_tx_t *tx)
        dmu_buf_t *db = sa_get_db(hdl);
        znode_t *zp = sa_get_userdata(hdl);
        zfsvfs_t *zfsvfs = zp->z_zfsvfs;
-       sa_bulk_attr_t bulk[20];
        int count = 0;
-       sa_bulk_attr_t sa_attrs[20] = { 0 };
+       sa_bulk_attr_t *bulk, *sa_attrs;
        zfs_acl_locator_cb_t locate = { 0 };
        uint64_t uid, gid, mode, rdev, xattr, parent;
        uint64_t crtime[2], mtime[2], ctime[2];
        zfs_acl_phys_t znode_acl;
+#ifdef HAVE_SCANSTAMP
        char scanstamp[AV_SCANSTAMP_SZ];
+#endif /* HAVE_SCANSTAMP */
+       boolean_t drop_lock = B_FALSE;
 
        /*
         * No upgrade if ACL isn't cached
@@ -214,7 +219,24 @@ zfs_sa_upgrade(sa_handle_t *hdl, dmu_tx_t *tx)
        if (zp->z_acl_cached == NULL || ZTOV(zp)->v_type == VLNK)
                return;
 
+       /*
+        * If the z_lock is held and we aren't the owner
+        * the just return since we don't want to deadlock
+        * trying to update the status of z_is_sa.  This
+        * file can then be upgraded at a later time.
+        *
+        * Otherwise, we know we are doing the
+        * sa_update() that caused us to enter this function.
+        */
+       if (mutex_owner(&zp->z_lock) != curthread) {
+               if (mutex_tryenter(&zp->z_lock) == 0)
+                       return;
+               else
+                       drop_lock = B_TRUE;
+       }
+
        /* First do a bulk query of the attributes that aren't cached */
+       bulk = kmem_alloc(sizeof(sa_bulk_attr_t) * 20, KM_SLEEP);
        SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MTIME(zfsvfs), NULL, &mtime, 16);
        SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CTIME(zfsvfs), NULL, &ctime, 16);
        SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_CRTIME(zfsvfs), NULL, &crtime, 16);
@@ -227,15 +249,17 @@ zfs_sa_upgrade(sa_handle_t *hdl, dmu_tx_t *tx)
        SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_ZNODE_ACL(zfsvfs), NULL,
            &znode_acl, 88);
 
-       if (sa_bulk_lookup_locked(hdl, bulk, count) != 0)
-               return;
-
+       if (sa_bulk_lookup_locked(hdl, bulk, count) != 0) {
+               kmem_free(bulk, sizeof(sa_bulk_attr_t) * 20);
+               goto done;
+       }
 
        /*
         * While the order here doesn't matter its best to try and organize
         * it is such a way to pick up an already existing layout number
         */
        count = 0;
+       sa_attrs = kmem_zalloc(sizeof(sa_bulk_attr_t) * 20, KM_SLEEP);
        SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_MODE(zfsvfs), NULL, &mode, 8);
        SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_SIZE(zfsvfs), NULL,
            &zp->z_size, 8);
@@ -269,10 +293,12 @@ zfs_sa_upgrade(sa_handle_t *hdl, dmu_tx_t *tx)
        locate.cb_aclp = zp->z_acl_cached;
        SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_DACL_ACES(zfsvfs),
            zfs_acl_data_locator, &locate, zp->z_acl_cached->z_acl_bytes);
+
        if (xattr)
-               SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_RDEV(zfsvfs),
-                   NULL, &rdev, 8);
+               SA_ADD_BULK_ATTR(sa_attrs, count, SA_ZPL_XATTR(zfsvfs),
+                   NULL, &xattr, 8);
 
+#ifdef HAVE_SCANSTAMP
        /* if scanstamp then add scanstamp */
 
        if (zp->z_pflags & ZFS_BONUS_SCANSTAMP) {
@@ -282,6 +308,7 @@ zfs_sa_upgrade(sa_handle_t *hdl, dmu_tx_t *tx)
                    NULL, scanstamp, AV_SCANSTAMP_SZ);
                zp->z_pflags &= ~ZFS_BONUS_SCANSTAMP;
        }
+#endif /* HAVE_SCANSTAMP */
 
        VERIFY(dmu_set_bonustype(db, DMU_OT_SA, tx) == 0);
        VERIFY(sa_replace_all_by_template_locked(hdl, sa_attrs,
@@ -291,6 +318,11 @@ zfs_sa_upgrade(sa_handle_t *hdl, dmu_tx_t *tx)
                    znode_acl.z_acl_extern_obj, tx));
 
        zp->z_is_sa = B_TRUE;
+       kmem_free(sa_attrs, sizeof(sa_bulk_attr_t) * 20);
+       kmem_free(bulk, sizeof(sa_bulk_attr_t) * 20);
+done:
+       if (drop_lock)
+               mutex_exit(&zp->z_lock);
 }
 
 void
@@ -299,12 +331,11 @@ zfs_sa_upgrade_txholds(dmu_tx_t *tx, znode_t *zp)
        if (!zp->z_zfsvfs->z_use_sa || zp->z_is_sa)
                return;
 
-       ASSERT(!zp->z_is_sa);
 
        dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_TRUE);
 
-       if (ZFS_EXTERNAL_ACL(zp)) {
-               dmu_tx_hold_free(tx, ZFS_EXTERNAL_ACL(zp), 0,
+       if (zfs_external_acl(zp)) {
+               dmu_tx_hold_free(tx, zfs_external_acl(zp), 0,
                    DMU_OBJECT_END);
        }
 }