Revert "Handle zap_add() failures in mixed ... "

This reverts commit cc63068e95ee725cce03b1b7ce50179825a6cda5.

Under certain circumstances this change can result in an ENOSPC
error when adding new files to a directory.  See #7401 for full
details.

Reviewed-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tony Hutter <[email protected]>
Issue #7401 
Cloes #7416 

5 files changed, 27 insertions, 141 deletions

diff --git a/module/zfs/zap.c b/module/zfs/zap.c
index 1c2030bda..2f6aed667 100644
--- a/module/zfs/zap.c
+++ b/module/zfs/zap.c
@@ -818,19 +818,15 @@ fzap_lookup(zap_name_t *zn,
 	return (err);
 }
 
-#define	MAX_EXPAND_RETRIES  2
-
 int
 fzap_add_cd(zap_name_t *zn,
     uint64_t integer_size, uint64_t num_integers,
     const void *val, uint32_t cd, void *tag, dmu_tx_t *tx)
 {
 	zap_leaf_t *l;
-	zap_leaf_t *prev_l = NULL;
 	int err;
 	zap_entry_handle_t zeh;
 	zap_t *zap = zn->zn_zap;
-	int expand_retries = 0;
 
 	ASSERT(RW_LOCK_HELD(&zap->zap_rwlock));
 	ASSERT(!zap->zap_ismicro);
@@ -854,29 +850,10 @@ retry:
 	if (err == 0) {
 		zap_increment_num_entries(zap, 1, tx);
 	} else if (err == EAGAIN) {
-		/*
-		 * If the last two expansions did not help, there is no point
-		 * trying to expand again
-		 */
-		if (expand_retries > MAX_EXPAND_RETRIES && prev_l == l) {
-			err = SET_ERROR(ENOSPC);
-			goto out;
-		}
-
 		err = zap_expand_leaf(zn, l, tag, tx, &l);
 		zap = zn->zn_zap;	/* zap_expand_leaf() may change zap */
-		if (err == 0) {
-			prev_l = l;
-			expand_retries++;
+		if (err == 0)
 			goto retry;
-		} else if (err == ENOSPC) {
-			/*
-			 * If we failed to expand the leaf, then bailout
-			 * as there is no point trying
-			 * zap_put_leaf_maybe_grow_ptrtbl().
-			 */
-			return (err);
-		}
 	}
 
 out:
diff --git a/module/zfs/zap_leaf.c b/module/zfs/zap_leaf.c
index 661fd747b..5341fc098 100644
--- a/module/zfs/zap_leaf.c
+++ b/module/zfs/zap_leaf.c
@@ -53,7 +53,7 @@ static uint16_t *zap_leaf_rehash_entry(zap_leaf_t *l, uint16_t entry);
 	((h) >> \
 	(64 - ZAP_LEAF_HASH_SHIFT(l) - zap_leaf_phys(l)->l_hdr.lh_prefix_len)))
 
-#define	LEAF_HASH_ENTPTR(l, h)	(&zap_leaf_phys(l)->l_hash[LEAF_HASH(l, h)])
+#define	LEAF_HASH_ENTPTR(l, h) (&zap_leaf_phys(l)->l_hash[LEAF_HASH(l, h)])
 
 extern inline zap_leaf_phys_t *zap_leaf_phys(zap_leaf_t *l);
 
diff --git a/module/zfs/zap_micro.c b/module/zfs/zap_micro.c
index ad9a62161..b81a48a0f 100644
--- a/module/zfs/zap_micro.c
+++ b/module/zfs/zap_micro.c
@@ -363,41 +363,6 @@ mze_find_unused_cd(zap_t *zap, uint64_t hash)
 	return (cd);
 }
 
-/*
- * Each mzap entry requires at max : 4 chunks
- * 3 chunks for names + 1 chunk for value.
- */
-#define	MZAP_ENT_CHUNKS	(1 + ZAP_LEAF_ARRAY_NCHUNKS(MZAP_NAME_LEN) + \
-	ZAP_LEAF_ARRAY_NCHUNKS(sizeof (uint64_t)))
-
-/*
- * Check if the current entry keeps the colliding entries under the fatzap leaf
- * size.
- */
-static boolean_t
-mze_canfit_fzap_leaf(zap_name_t *zn, uint64_t hash)
-{
-	zap_t *zap = zn->zn_zap;
-	mzap_ent_t mze_tofind;
-	mzap_ent_t *mze;
-	avl_index_t idx;
-	avl_tree_t *avl = &zap->zap_m.zap_avl;
-	uint32_t mzap_ents = 0;
-
-	mze_tofind.mze_hash = hash;
-	mze_tofind.mze_cd = 0;
-
-	for (mze = avl_find(avl, &mze_tofind, &idx);
-	    mze && mze->mze_hash == hash; mze = AVL_NEXT(avl, mze)) {
-		mzap_ents++;
-	}
-
-	/* Include the new entry being added */
-	mzap_ents++;
-
-	return (ZAP_LEAF_NUMCHUNKS_DEF > (mzap_ents * MZAP_ENT_CHUNKS));
-}
-
 static void
 mze_remove(zap_t *zap, mzap_ent_t *mze)
 {
@@ -1225,8 +1190,7 @@ zap_add_impl(zap_t *zap, const char *key,
 		err = fzap_add(zn, integer_size, num_integers, val, tag, tx);
 		zap = zn->zn_zap;	/* fzap_add() may change zap */
 	} else if (integer_size != 8 || num_integers != 1 ||
-	    strlen(key) >= MZAP_NAME_LEN ||
-	    !mze_canfit_fzap_leaf(zn, zn->zn_hash)) {
+	    strlen(key) >= MZAP_NAME_LEN) {
 		err = mzap_upgrade(&zn->zn_zap, tag, tx, 0);
 		if (err == 0) {
 			err = fzap_add(zn, integer_size, num_integers, val,
diff --git a/module/zfs/zfs_dir.c b/module/zfs/zfs_dir.c
index 7eb426b78..76f79cc11 100644
--- a/module/zfs/zfs_dir.c
+++ b/module/zfs/zfs_dir.c
@@ -742,11 +742,7 @@ zfs_dirent(znode_t *zp, uint64_t mode)
 }
 
 /*
- * Link zp into dl.  Can fail in the following cases :
- * - if zp has been unlinked.
- * - if the number of entries with the same hash (aka. colliding entries)
- *    exceed the capacity of a leaf-block of fatzap and splitting of the
- *    leaf-block does not help.
+ * Link zp into dl.  Can only fail if zp has been unlinked.
  */
 int
 zfs_link_create(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag)
@@ -780,24 +776,6 @@ zfs_link_create(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag)
 			    NULL, &links, sizeof (links));
 		}
 	}
-
-	value = zfs_dirent(zp, zp->z_mode);
-	error = zap_add(ZTOZSB(zp)->z_os, dzp->z_id, dl->dl_name, 8, 1,
-	    &value, tx);
-
-	/*
-	 * zap_add could fail to add the entry if it exceeds the capacity of the
-	 * leaf-block and zap_leaf_split() failed to help.
-	 * The caller of this routine is responsible for failing the transaction
-	 * which will rollback the SA updates done above.
-	 */
-	if (error != 0) {
-		if (!(flag & ZRENAMING) && !(flag & ZNEW))
-			drop_nlink(ZTOI(zp));
-		mutex_exit(&zp->z_lock);
-		return (error);
-	}
-
 	SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_PARENT(zfsvfs), NULL,
 	    &dzp->z_id, sizeof (dzp->z_id));
 	SA_ADD_BULK_ATTR(bulk, count, SA_ZPL_FLAGS(zfsvfs), NULL,
@@ -835,6 +813,11 @@ zfs_link_create(zfs_dirlock_t *dl, znode_t *zp, dmu_tx_t *tx, int flag)
 	ASSERT(error == 0);
 	mutex_exit(&dzp->z_lock);
 
+	value = zfs_dirent(zp, zp->z_mode);
+	error = zap_add(ZTOZSB(zp)->z_os, dzp->z_id, dl->dl_name,
+	    8, 1, &value, tx);
+	ASSERT(error == 0);
+
 	return (0);
 }
 
diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c
index 14caa80e5..fd8debdcf 100644
--- a/module/zfs/zfs_vnops.c
+++ b/module/zfs/zfs_vnops.c
@@ -1438,7 +1438,6 @@ top:
 			dmu_tx_hold_write(tx, DMU_NEW_OBJECT,
 			    0, acl_ids.z_aclp->z_acl_bytes);
 		}
-
 		error = dmu_tx_assign(tx,
 		    (waited ? TXG_NOTHROTTLE : 0) | TXG_NOWAIT);
 		if (error) {
@@ -1456,22 +1455,10 @@ top:
 		}
 		zfs_mknode(dzp, vap, tx, cr, 0, &zp, &acl_ids);
 
-		error = zfs_link_create(dl, zp, tx, ZNEW);
-		if (error != 0) {
-			/*
-			 * Since, we failed to add the directory entry for it,
-			 * delete the newly created dnode.
-			 */
-			zfs_znode_delete(zp, tx);
-			remove_inode_hash(ZTOI(zp));
-			zfs_acl_ids_free(&acl_ids);
-			dmu_tx_commit(tx);
-			goto out;
-		}
-
 		if (fuid_dirtied)
 			zfs_fuid_sync(zfsvfs, tx);
 
+		(void) zfs_link_create(dl, zp, tx, ZNEW);
 		txtype = zfs_log_create_txtype(Z_FILE, vsecp, vap);
 		if (flag & FIGNORECASE)
 			txtype |= TX_CI;
@@ -2065,18 +2052,13 @@ top:
 	 */
 	zfs_mknode(dzp, vap, tx, cr, 0, &zp, &acl_ids);
 
+	if (fuid_dirtied)
+		zfs_fuid_sync(zfsvfs, tx);
+
 	/*
 	 * Now put new name in parent dir.
 	 */
-	error = zfs_link_create(dl, zp, tx, ZNEW);
-	if (error != 0) {
-		zfs_znode_delete(zp, tx);
-		remove_inode_hash(ZTOI(zp));
-		goto out;
-	}
-
-	if (fuid_dirtied)
-		zfs_fuid_sync(zfsvfs, tx);
+	(void) zfs_link_create(dl, zp, tx, ZNEW);
 
 	*ipp = ZTOI(zp);
 
@@ -2086,7 +2068,6 @@ top:
 	zfs_log_create(zilog, tx, txtype, dzp, zp, dirname, vsecp,
 	    acl_ids.z_fuidp, vap);
 
-out:
 	zfs_acl_ids_free(&acl_ids);
 
 	dmu_tx_commit(tx);
@@ -2096,14 +2077,10 @@ out:
 	if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
 		zil_commit(zilog, 0);
 
-	if (error != 0) {
-		iput(ZTOI(zp));
-	} else {
-		zfs_inode_update(dzp);
-		zfs_inode_update(zp);
-	}
+	zfs_inode_update(dzp);
+	zfs_inode_update(zp);
 	ZFS_EXIT(zfsvfs);
-	return (error);
+	return (0);
 }
 
 /*
@@ -3961,13 +3938,6 @@ top:
 				VERIFY3U(zfs_link_destroy(tdl, szp, tx,
 				    ZRENAMING, NULL), ==, 0);
 			}
-		} else {
-			/*
-			 * If we had removed the existing target, subsequent
-			 * call to zfs_link_create() to add back the same entry
-			 * but, the new dnode (szp) should not fail.
-			 */
-			ASSERT(tzp == NULL);
 		}
 	}
 
@@ -4138,18 +4108,14 @@ top:
 	/*
 	 * Insert the new object into the directory.
 	 */
-	error = zfs_link_create(dl, zp, tx, ZNEW);
-	if (error != 0) {
-		zfs_znode_delete(zp, tx);
-		remove_inode_hash(ZTOI(zp));
-	} else {
-		if (flags & FIGNORECASE)
-			txtype |= TX_CI;
-		zfs_log_symlink(zilog, tx, txtype, dzp, zp, name, link);
+	(void) zfs_link_create(dl, zp, tx, ZNEW);
 
-		zfs_inode_update(dzp);
-		zfs_inode_update(zp);
-	}
+	if (flags & FIGNORECASE)
+		txtype |= TX_CI;
+	zfs_log_symlink(zilog, tx, txtype, dzp, zp, name, link);
+
+	zfs_inode_update(dzp);
+	zfs_inode_update(zp);
 
 	zfs_acl_ids_free(&acl_ids);
 
@@ -4157,14 +4123,10 @@ top:
 
 	zfs_dirent_unlock(dl);
 
-	if (error == 0) {
-		*ipp = ZTOI(zp);
+	*ipp = ZTOI(zp);
 
-		if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
-			zil_commit(zilog, 0);
-	} else {
-		iput(ZTOI(zp));
-	}
+	if (zfsvfs->z_os->os_sync == ZFS_SYNC_ALWAYS)
+		zil_commit(zilog, 0);
 
 	ZFS_EXIT(zfsvfs);
 	return (error);