move vnode creation from zfs_znode_cache_constructor to zfs_znode_alloc
Andriy Gapon
avg at FreeBSD.org
Sun Feb 3 17:32:00 UTC 2013
Please review the following proposed change.
Thank you.
commit db54bca1cc711e5632b26da3f9591ca62a9d7c87
Author: Andriy Gapon <avg at icyb.net.ua>
Date: Fri Nov 16 11:54:04 2012 +0200
zfs: move vnode creation from zfs_znode_cache_constructor to zfs_znode_alloc
All other places where a znode is allocated do not need z_vnode at all.
These are:
- zfs_create_share_dir
- zfs_create_fs
This chnage ensures two things:
- VN_LOCK_ASHARE is not erroneously called for VFIFO vnodes
- vn_lock is called on a fully constructed vnode with correct v_ops
The change also allows to make zfs_znode_cache_constructor a normal kmem_cache
constructor again (as it is in upstream).
This allows to avoid a potential problem where zfs_znode_cache_destructor
may be called on un-constructed znodes.
With the new arrangement we can call getnewvnode after all the necessary
znode checks thus removing a need for zfs_vnode_forget.
This change required moving vnode manipulations from zfs_znode_sa_init to
zfs_znode_alloc.
diff --git a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
index 7d7b20a..c2ea9ef 100644
--- a/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
+++ b/sys/cddl/contrib/opensolaris/uts/common/fs/zfs/zfs_znode.c
@@ -113,37 +113,12 @@ extern struct vop_vector zfs_vnodeops;
extern struct vop_vector zfs_fifoops;
extern struct vop_vector zfs_shareops;
-/*
- * XXX: We cannot use this function as a cache constructor, because
- * there is one global cache for all file systems and we need
- * to pass vfsp here, which is not possible, because argument
- * 'cdrarg' is defined at kmem_cache_create() time.
- */
-/*ARGSUSED*/
static int
zfs_znode_cache_constructor(void *buf, void *arg, int kmflags)
{
znode_t *zp = buf;
- vnode_t *vp;
- vfs_t *vfsp = arg;
- int error;
POINTER_INVALIDATE(&zp->z_zfsvfs);
- ASSERT(!POINTER_IS_VALID(zp->z_zfsvfs));
-
- if (vfsp != NULL) {
- error = getnewvnode("zfs", vfsp, &zfs_vnodeops, &vp);
- if (error != 0 && (kmflags & KM_NOSLEEP))
- return (-1);
- ASSERT(error == 0);
- vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
- zp->z_vnode = vp;
- vp->v_data = (caddr_t)zp;
- VN_LOCK_AREC(vp);
- VN_LOCK_ASHARE(vp);
- } else {
- zp->z_vnode = NULL;
- }
list_link_init(&zp->z_link_node);
@@ -158,7 +133,9 @@ zfs_znode_cache_constructor(void *buf, void *arg, int kmflags)
zp->z_dirlocks = NULL;
zp->z_acl_cached = NULL;
+ zp->z_vnode = NULL;
zp->z_moved = 0;
+
return (0);
}
@@ -377,7 +354,7 @@ zfs_znode_init(void)
rw_init(&zfsvfs_lock, NULL, RW_DEFAULT, NULL);
ASSERT(znode_cache == NULL);
znode_cache = kmem_cache_create("zfs_znode_cache",
- sizeof (znode_t), 0, /* zfs_znode_cache_constructor */ NULL,
+ sizeof (znode_t), 0, zfs_znode_cache_constructor,
zfs_znode_cache_destructor, NULL, NULL, NULL, 0);
kmem_cache_set_move(znode_cache, zfs_znode_move);
}
@@ -501,7 +478,9 @@ zfs_create_share_dir(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
zfs_acl_ids_t acl_ids;
vattr_t vattr;
znode_t *sharezp;
- vnode_t *vp, vnode;
+#ifdef sun
+ vnode_t *vp;
+#endif
znode_t *zp;
int error;
@@ -512,7 +491,6 @@ zfs_create_share_dir(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
vattr.va_gid = crgetgid(kcred);
sharezp = kmem_cache_alloc(znode_cache, KM_SLEEP);
- zfs_znode_cache_constructor(sharezp, zfsvfs->z_parent->z_vfs, 0);
ASSERT(!POINTER_IS_VALID(sharezp->z_zfsvfs));
sharezp->z_moved = 0;
sharezp->z_unlinked = 0;
@@ -520,11 +498,10 @@ zfs_create_share_dir(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
sharezp->z_zfsvfs = zfsvfs;
sharezp->z_is_sa = zfsvfs->z_use_sa;
- sharezp->z_vnode = &vnode;
- vnode.v_data = sharezp;
-
+#ifdef sun
vp = ZTOV(sharezp);
vp->v_type = VDIR;
+#endif
VERIFY(0 == zfs_acl_ids_create(sharezp, IS_ROOT_NODE, &vattr,
kcred, NULL, &acl_ids));
@@ -536,12 +513,7 @@ zfs_create_share_dir(zfsvfs_t *zfsvfs, dmu_tx_t *tx)
zfsvfs->z_shares_dir = sharezp->z_id;
zfs_acl_ids_free(&acl_ids);
- ZTOV(sharezp)->v_data = NULL;
- ZTOV(sharezp)->v_count = 0;
- ZTOV(sharezp)->v_holdcnt = 0;
- zp->z_vnode = NULL;
sa_handle_destroy(sharezp->z_sa_hdl);
- sharezp->z_vnode = NULL;
kmem_cache_free(znode_cache, sharezp);
return (error);
@@ -608,11 +580,13 @@ zfs_znode_sa_init(zfsvfs_t *zfsvfs, znode_t *zp,
zp->z_is_sa = (obj_type == DMU_OT_SA) ? B_TRUE : B_FALSE;
+#ifdef sun
/*
* Slap on VROOT if we are the root znode
*/
if (zp->z_id == zfsvfs->z_root)
ZTOV(zp)->v_flag |= VROOT;
+#endif
mutex_exit(&zp->z_lock);
vn_exists(ZTOV(zp));
@@ -629,17 +603,6 @@ zfs_znode_dmu_fini(znode_t *zp)
zp->z_sa_hdl = NULL;
}
-static void
-zfs_vnode_forget(vnode_t *vp)
-{
-
- /* copied from insmntque_stddtr */
- vp->v_data = NULL;
- vp->v_op = &dead_vnodeops;
- vgone(vp);
- vput(vp);
-}
-
/*
* Construct a new znode/vnode and intialize.
*
@@ -657,9 +620,9 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
uint64_t parent;
sa_bulk_attr_t bulk[9];
int count = 0;
+ int error;
zp = kmem_cache_alloc(znode_cache, KM_SLEEP);
- zfs_znode_cache_constructor(zp, zfsvfs->z_parent->z_vfs, 0);
ASSERT(zp->z_dirlocks == NULL);
ASSERT(!POINTER_IS_VALID(zp->z_zfsvfs));
@@ -678,8 +641,6 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
zp->z_seq = 0x7A4653;
zp->z_sync_cnt = 0;
- vp = ZTOV(zp);
-
zfs_znode_sa_init(zfsvfs, zp, db, obj_type, hdl);
SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_MODE(zfsvfs), NULL, &mode, 8);
@@ -701,12 +662,27 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
if (sa_bulk_lookup(zp->z_sa_hdl, bulk, count) != 0 || zp->z_gen == 0) {
if (hdl == NULL)
sa_handle_destroy(zp->z_sa_hdl);
- zfs_vnode_forget(vp);
- zp->z_vnode = NULL;
kmem_cache_free(znode_cache, zp);
return (NULL);
}
+ error = getnewvnode("zfs", zfsvfs->z_parent->z_vfs, &zfs_vnodeops, &vp);
+ ASSERT(error == 0);
+ if (error != 0) { /* hm, just in case */
+ kmem_cache_free(znode_cache, zp);
+ return (NULL);
+ }
+ zp->z_vnode = vp;
+ vp->v_data = zp;
+
+#ifdef sun
+ /*
+ * Slap on VROOT if we are the root znode
+ */
+ if (zp->z_id == zfsvfs->z_root)
+ vp->v_flag |= VROOT;
+#endif
+
zp->z_mode = mode;
vp->v_type = IFTOVT((mode_t)mode);
@@ -749,8 +725,6 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
break;
#endif /* sun */
}
- if (vp->v_type != VFIFO)
- VN_LOCK_ASHARE(vp);
mutex_enter(&zfsvfs->z_znodes_lock);
list_insert_tail(&zfsvfs->z_all_znodes, zp);
@@ -762,6 +736,14 @@ zfs_znode_alloc(zfsvfs_t *zfsvfs, dmu_buf_t *db, int blksz,
zp->z_zfsvfs = zfsvfs;
mutex_exit(&zfsvfs->z_znodes_lock);
+ /*
+ * Acquire vnode lock before making it available to the world.
+ */
+ vn_lock(vp, LK_EXCLUSIVE | LK_RETRY);
+ VN_LOCK_AREC(vp);
+ if (vp->v_type != VFIFO)
+ VN_LOCK_ASHARE(vp);
+
VFS_HOLD(zfsvfs->z_vfs);
return (zp);
}
@@ -1839,7 +1821,9 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t
*zplprops, dmu_tx_t *tx)
int error;
int i;
znode_t *rootzp = NULL;
- vnode_t vnode;
+#ifdef sun
+ vnode_t *vp;
+#endif
vattr_t vattr;
znode_t *zp;
zfs_acl_ids_t acl_ids;
@@ -1918,16 +1902,17 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t
*zplprops, dmu_tx_t *tx)
bzero(&zfsvfs, sizeof (zfsvfs_t));
rootzp = kmem_cache_alloc(znode_cache, KM_SLEEP);
- zfs_znode_cache_constructor(rootzp, NULL, 0);
ASSERT(!POINTER_IS_VALID(rootzp->z_zfsvfs));
rootzp->z_moved = 0;
rootzp->z_unlinked = 0;
rootzp->z_atime_dirty = 0;
rootzp->z_is_sa = USE_SA(version, os);
- vnode.v_type = VDIR;
- vnode.v_data = rootzp;
- rootzp->z_vnode = &vnode;
+#ifdef sun
+ vp = ZTOV(rootzp);
+ vn_reinit(vp);
+ vp->v_type = VDIR;
+#endif
zfsvfs.z_os = os;
zfsvfs.z_parent = &zfsvfs;
@@ -1966,7 +1951,6 @@ zfs_create_fs(objset_t *os, cred_t *cr, nvlist_t
*zplprops, dmu_tx_t *tx)
POINTER_INVALIDATE(&rootzp->z_zfsvfs);
sa_handle_destroy(rootzp->z_sa_hdl);
- rootzp->z_vnode = NULL;
kmem_cache_free(znode_cache, rootzp);
/*
--
Andriy Gapon
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