*
* You should have received a copy of the GNU General Public License
* version 2 along with this program; If not, see
- * http://www.sun.com/software/products/lustre/docs/GPLv2.pdf
- *
- * Please contact Sun Microsystems, Inc., 4150 Network Circle, Santa Clara,
- * CA 95054 USA or visit www.sun.com if you need additional information or
- * have any questions.
+ * http://www.gnu.org/licenses/gpl-2.0.html
*
* GPL HEADER END
*/
* Copyright (c) 2009, 2010, Oracle and/or its affiliates. All rights reserved.
* Use is subject to license terms.
*
- * Copyright (c) 2012, 2015, Intel Corporation.
+ * Copyright (c) 2012, 2016, Intel Corporation.
*/
/*
* This file is part of Lustre, http://www.lustre.org/
* LOHA_EXISTs is supposed to be the last step in the
* initialization */
- /* declare possible size change. notice we can't check
- * current size here as another thread can change it */
-
- if (dt_object_exists(dt)) {
- LASSERT(obj->oo_db);
+ /* size change (in dnode) will be declared by dmu_tx_hold_write() */
+ if (dt_object_exists(dt))
oid = obj->oo_db->db_object;
-
- dmu_tx_hold_sa(oh->ot_tx, obj->oo_sa_hdl, 0);
- } else {
+ else
oid = DMU_NEW_OBJECT;
- dmu_tx_hold_sa_create(oh->ot_tx, ZFS_SA_BASE_ATTR_SIZE);
- }
/* XXX: we still miss for append declaration support in ZFS
* -1 means append which is used by llog mostly, llog
LASSERT(th != NULL);
oh = container_of0(th, struct osd_thandle, ot_super);
- record_start_io(osd, WRITE, 0);
-
dmu_write(osd->od_os, obj->oo_db->db_object, offset,
(uint64_t)buf->lb_len, buf->lb_buf, oh->ot_tx);
write_lock(&obj->oo_attr_lock);
rc = buf->lb_len;
out:
- record_end_io(osd, WRITE, 0, buf->lb_len,
- buf->lb_len >> PAGE_SHIFT);
-
RETURN(rc);
}
* copies */
space *= osd->od_os->os_copies;
space = toqb(space);
- CDEBUG(D_QUOTA, "writing %d pages, reserving "LPD64"K of quota space\n",
+ CDEBUG(D_QUOTA, "writing %d pages, reserving %lldK of quota space\n",
npages, space);
record_start_io(osd, WRITE, discont_pages);
(void)osd_grow_blocksize(obj, oh, lnb[0].lnb_file_offset,
lnb[npages - 1].lnb_file_offset +
lnb[npages - 1].lnb_len);
+
+ /* LU-8791: take oo_guard to avoid the deadlock that changing block
+ * size and assigning arcbuf take place at the same time.
+ *
+ * Thread 1:
+ * osd_write_commit()
+ * -> osd_grow_blocksize() with osd_object::oo_guard held
+ * -> dmu_object_set_blocksize()
+ * -> dnode_set_blksz(), with dnode_t::dn_struct_rwlock
+ * write lock held
+ * -> dbuf_new_size()
+ * -> dmu_buf_will_dirty()
+ * -> dbuf_read()
+ * -> wait for the dbuf state to change
+ * Thread 2:
+ * osd_write_commit()
+ * -> dmu_assign_arcbuf()
+ * -> dbuf_assign_arcbuf(), set dbuf state to DB_FILL
+ * -> dbuf_dirty()
+ * -> try to hold the read lock of dnode_t::dn_struct_rwlock
+ *
+ * By taking the read lock, it can avoid thread 2 to enter into the
+ * critical section of assigning the arcbuf, while thread 1 is
+ * changing the block size.
+ */
+ down_read(&obj->oo_guard);
for (i = 0; i < npages; i++) {
CDEBUG(D_INODE, "write %u bytes at %u\n",
(unsigned) lnb[i].lnb_len,
new_size = lnb[i].lnb_file_offset + lnb[i].lnb_len;
iosize += lnb[i].lnb_len;
}
+ up_read(&obj->oo_guard);
if (unlikely(new_size == 0)) {
/* no pages to write, no transno is needed */