Illumos 4950 - files sometimes can't be removed from a full filesystem

4950 files sometimes can't be removed from a full filesystem
Reviewed by: Adam Leventhal <[email protected]>
Reviewed by: George Wilson <[email protected]>
Reviewed by: Sebastien Roy <[email protected]>
Reviewed by: Boris Protopopov <[email protected]>
Approved by: Dan McDonald <[email protected]>

References:
  https://www.illumos.org/issues/4950
  https://github.com/illumos/illumos-gate/commit/4bb7380

Porting notes:
- ZoL currently does not log discards to zvols, so the portion of
  this patch that modifies the discard logging to mark it as
  freeing space has been discarded.

2. may_delete_now had been removed from zfs_remove() in ZoL.
   It has been reintroduced.

3. We do not try to emulate vnodes, so the following lines are
   not valid on Linux:

	mutex_enter(&vp->v_lock);
	may_delete_now = vp->v_count == 1 && !vn_has_cached_data(vp);
	mutex_exit(&vp->v_lock);

  This has been replaced with:

	mutex_enter(&zp->z_lock);
	may_delete_now = atomic_read(&ip->i_count) == 1 && !(zp->z_is_mapped);
	mutex_exit(&zp->z_lock);

Ported-by: Richard Yao <[email protected]>
Signed-off-by: Brian Behlendorf <[email protected]>

1 files changed, 6 insertions, 5 deletions

diff --git a/module/zfs/zfs_znode.c b/module/zfs/zfs_znode.c
index e4bd62fd2..7ebe54384 100644
--- a/module/zfs/zfs_znode.c
+++ b/module/zfs/zfs_znode.c
@@ -20,7 +20,7 @@
  */
 /*
  * Copyright (c) 2005, 2010, Oracle and/or its affiliates. All rights reserved.
- * Copyright (c) 2013 by Delphix. All rights reserved.
+ * Copyright (c) 2012, 2014 by Delphix. All rights reserved.
  */
 
 /* Portions Copyright 2007 Jeremy Teo */
@@ -1425,7 +1425,7 @@ zfs_grow_blocksize(znode_t *zp, uint64_t size, dmu_tx_t *tx)
  *	IN:	zp	- znode of file to free data in.
  *		end	- new end-of-file
  *
- * 	RETURN:	0 on success, error code on failure
+ *	RETURN:	0 on success, error code on failure
  */
 static int
 zfs_extend(znode_t *zp, uint64_t end)
@@ -1545,7 +1545,7 @@ zfs_zero_partial_page(znode_t *zp, uint64_t start, uint64_t len)
  *		off	- start of section to free.
  *		len	- length of section to free.
  *
- * 	RETURN:	0 on success, error code on failure
+ *	RETURN:	0 on success, error code on failure
  */
 static int
 zfs_free_range(znode_t *zp, uint64_t off, uint64_t len)
@@ -1624,7 +1624,7 @@ zfs_free_range(znode_t *zp, uint64_t off, uint64_t len)
  *	IN:	zp	- znode of file to free data in.
  *		end	- new end-of-file.
  *
- * 	RETURN:	0 on success, error code on failure
+ *	RETURN:	0 on success, error code on failure
  */
 static int
 zfs_trunc(znode_t *zp, uint64_t end)
@@ -1657,6 +1657,7 @@ zfs_trunc(znode_t *zp, uint64_t end)
 	tx = dmu_tx_create(zsb->z_os);
 	dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE);
 	zfs_sa_upgrade_txholds(tx, zp);
+	dmu_tx_mark_netfree(tx);
 	error = dmu_tx_assign(tx, TXG_WAIT);
 	if (error) {
 		dmu_tx_abort(tx);
@@ -1691,7 +1692,7 @@ zfs_trunc(znode_t *zp, uint64_t end)
  *		flag	- current file open mode flags.
  *		log	- TRUE if this action should be logged
  *
- * 	RETURN:	0 on success, error code on failure
+ *	RETURN:	0 on success, error code on failure
  */
 int
 zfs_freesp(znode_t *zp, uint64_t off, uint64_t len, int flag, boolean_t log)