Fix iput() calls within a tx

As explicitly stated in section 2 of the 'Programming rules'
comments at the top of zfs_vnops.c.

  If you must call iput() within a tx then use zfs_iput_async().

Move iput() calls after dmu_tx_commit() / dmu_tx_abort when
possible.  When not possible convert the iput() calls to
zfs_iput_async().

Reviewed-by: Don Brady <don.brady@intel.com>
Reviewed-by: Chunwei Chen <david.chen@osnexus.com>
Reviewed-by: George Melikov <mail@gmelikov.ru>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Closes #5758

diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index b55445e0a08eb8ded4f6622ae82e8984c0e6b803..41572d34f2decae4f9c10af19da8f712e2e4ae5a 100644 (file)
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -1778,18 +1778,21 @@ top:
        error = dmu_tx_assign(tx, waited ? TXG_WAITED : TXG_NOWAIT);
        if (error) {
                zfs_dirent_unlock(dl);
-               iput(ip);
-               if (xzp)
-                       iput(ZTOI(xzp));
                if (error == ERESTART) {
                        waited = B_TRUE;
                        dmu_tx_wait(tx);
                        dmu_tx_abort(tx);
+                       iput(ip);
+                       if (xzp)
+                               iput(ZTOI(xzp));
                        goto top;
                }
                if (realnmp)
                        pn_free(realnmp);
                dmu_tx_abort(tx);
+               iput(ip);
+               if (xzp)
+                       iput(ZTOI(xzp));
                ZFS_EXIT(zsb);
                return (error);
        }
@@ -1847,8 +1850,6 @@ top:
                 */
                zfs_unlinked_add(zp, tx);
                mutex_exit(&zp->z_lock);
-               zfs_inode_update(zp);
-               iput(ip);
        } else if (unlinked) {
                mutex_exit(&zp->z_lock);
                zfs_unlinked_add(zp, tx);
@@ -1866,11 +1867,12 @@ out:
 
        zfs_dirent_unlock(dl);
        zfs_inode_update(dzp);
+       zfs_inode_update(zp);
 
-       if (!delete_now) {
-               zfs_inode_update(zp);
+       if (delete_now)
+               iput(ip);
+       else
                zfs_iput_async(ip);
-       }
 
        if (xzp) {
                zfs_inode_update(xzp);
@@ -2161,14 +2163,15 @@ top:
                rw_exit(&zp->z_parent_lock);
                rw_exit(&zp->z_name_lock);
                zfs_dirent_unlock(dl);
-               iput(ip);
                if (error == ERESTART) {
                        waited = B_TRUE;
                        dmu_tx_wait(tx);
                        dmu_tx_abort(tx);
+                       iput(ip);
                        goto top;
                }
                dmu_tx_abort(tx);
+               iput(ip);
                ZFS_EXIT(zsb);
                return (error);
        }
@@ -3242,8 +3245,6 @@ out:
                ASSERT(err2 == 0);
        }
 
-       if (attrzp)
-               iput(ZTOI(attrzp));
        if (aclp)
                zfs_acl_free(aclp);
 
@@ -3254,11 +3255,15 @@ out:
 
        if (err) {
                dmu_tx_abort(tx);
+               if (attrzp)
+                       iput(ZTOI(attrzp));
                if (err == ERESTART)
                        goto top;
        } else {
                err2 = sa_bulk_update(zp->z_sa_hdl, bulk, count, tx);
                dmu_tx_commit(tx);
+               if (attrzp)
+                       iput(ZTOI(attrzp));
                zfs_inode_update(zp);
        }
 
@@ -3291,7 +3296,7 @@ zfs_rename_unlock(zfs_zlock_t **zlpp)
 
        while ((zl = *zlpp) != NULL) {
                if (zl->zl_znode != NULL)
-                       iput(ZTOI(zl->zl_znode));
+                       zfs_iput_async(ZTOI(zl->zl_znode));
                rw_exit(zl->zl_rwlock);
                *zlpp = zl->zl_next;
                kmem_free(zl, sizeof (*zl));
@@ -3636,16 +3641,19 @@ top:
                if (sdzp == tdzp)
                        rw_exit(&sdzp->z_name_lock);
 
-               iput(ZTOI(szp));
-               if (tzp)
-                       iput(ZTOI(tzp));
                if (error == ERESTART) {
                        waited = B_TRUE;
                        dmu_tx_wait(tx);
                        dmu_tx_abort(tx);
+                       iput(ZTOI(szp));
+                       if (tzp)
+                               iput(ZTOI(tzp));
                        goto top;
                }
                dmu_tx_abort(tx);
+               iput(ZTOI(szp));
+               if (tzp)
+                       iput(ZTOI(tzp));
                ZFS_EXIT(zsb);
                return (error);
        }