3740 Poor ZFS send / receive performance due to snapshot
     hold / release processing
Reviewed by: Matthew Ahrens <mahrens@delphix.com>
Approved by: Christopher Siden <christopher.siden@delphix.com>

References:
  https://www.illumos.org/issues/3740
  illumos/illumos-gate@a7a845e4bf

Ported-by: Richard Yao <ryao@gentoo.org>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
Issue #1775

Porting notes:

1. 13fe019870 introduced a merge conflict
   in dsl_dataset_user_release_tmp where some variables were moved
   outside of the preprocessor directive.

2. dea9dfefdd747534b3846845629d2200f0616dad made the previous merge
   conflict worse by switching KM_SLEEP to KM_PUSHPAGE. This is notable
   because this commit refactors the code, adding a new KM_SLEEP
   allocation. It is not clear to me whether this should be converted
   to KM_PUSHPAGE.

3. We had a merge conflict in libzfs_sendrecv.c because of copyright
   notices.

4. Several small C99 compatibility fixed were made.
This commit is contained in:
Steven Hartland
2013-05-25 02:06:23 +00:00
committed by Brian Behlendorf
parent 7bc7f25040
commit 95fd54a1c5
13 changed files with 672 additions and 505 deletions
+35 -12
View File
@@ -21,6 +21,7 @@
/*
* Copyright (c) 2012 by Delphix. All rights reserved.
* Copyright (c) 2013 Steven Hartland. All rights reserved.
*/
/*
@@ -254,8 +255,11 @@ lzc_snapshot(nvlist_t *snaps, nvlist_t *props, nvlist_t **errlist)
* marked for deferred destruction, and will be destroyed when the last hold
* or clone is removed/destroyed.
*
* The return value will be ENOENT if none of the snapshots existed.
*
* The return value will be 0 if all snapshots were destroyed (or marked for
* later destruction if 'defer' is set) or didn't exist to begin with.
* later destruction if 'defer' is set) or didn't exist to begin with and
* at least one snapshot was destroyed.
*
* Otherwise the return value will be the errno of a (unspecified) snapshot
* that failed, no snapshots will be destroyed, and the errlist will have an
@@ -286,7 +290,6 @@ lzc_destroy_snaps(nvlist_t *snaps, boolean_t defer, nvlist_t **errlist)
nvlist_free(args);
return (error);
}
int
@@ -346,11 +349,22 @@ lzc_exists(const char *dataset)
* uncleanly, the holds will be released when the pool is next opened
* or imported.
*
* The return value will be 0 if all holds were created. Otherwise the return
* value will be the errno of a (unspecified) hold that failed, no holds will
* be created, and the errlist will have an entry for each hold that
* failed (name = snapshot). The value in the errlist will be the error
* code (int32).
* Holds for snapshots which don't exist will be skipped and have an entry
* added to errlist, but will not cause an overall failure, except in the
* case that all holds where skipped.
*
* The return value will be ENOENT if none of the snapshots for the requested
* holds existed.
*
* The return value will be 0 if the nvl holds was empty or all holds, for
* snapshots that existed, were succesfully created and at least one hold
* was created.
*
* Otherwise the return value will be the errno of a (unspecified) hold that
* failed and no holds will be created.
*
* In all cases the errlist will have an entry for each hold that failed
* (name = snapshot), with its value being the error code (int32).
*/
int
lzc_hold(nvlist_t *holds, int cleanup_fd, nvlist_t **errlist)
@@ -387,11 +401,20 @@ lzc_hold(nvlist_t *holds, int cleanup_fd, nvlist_t **errlist)
* The snapshots must all be in the same pool.
* The value is a nvlist whose keys are the holds to remove.
*
* The return value will be 0 if all holds were removed.
* Otherwise the return value will be the errno of a (unspecified) release
* that failed, no holds will be released, and the errlist will have an
* entry for each snapshot that has failed releases (name = snapshot).
* The value in the errlist will be the error code (int32) of a failed release.
* Holds which failed to release because they didn't exist will have an entry
* added to errlist, but will not cause an overall failure, except in the
* case that all releases where skipped.
*
* The return value will be ENOENT if none of the specified holds existed.
*
* The return value will be 0 if the nvl holds was empty or all holds that
* existed, were successfully removed and at least one hold was removed.
*
* Otherwise the return value will be the errno of a (unspecified) hold that
* failed to release and no holds will be released.
*
* In all cases the errlist will have an entry for each hold that failed to
* to release.
*/
int
lzc_release(nvlist_t *holds, nvlist_t **errlist)