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Illumos 5056 - ZFS deadlock on db_mtx and dn_holds

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5056 ZFS deadlock on db_mtx and dn_holds
Author: Justin Gibbs <justing@spectralogic.com>
Reviewed by: Will Andrews <willa@spectralogic.com>
Reviewed by: Matt Ahrens <mahrens@delphix.com>
Reviewed by: George Wilson <george.wilson@delphix.com>
Approved by: Dan McDonald <danmcd@omniti.com>

References:
  https://www.illumos.org/issues/5056
  https://github.com/illumos/illumos-gate/commit/bc9014e

Porting Notes:

sa_handle_get_from_db():
  - the original patch includes an otherwise unmentioned fix for a
    possible usage of an uninitialised variable

dmu_objset_open_impl():
  - Under Illumos list_link_init() is the same as filling a list_node_t
    with NULLs, so they don't notice if they miss doing list_link_init()
    on a zero'd containing structure (e.g. allocated with kmem_zalloc as
    here). Under Linux, not so much: an uninitialised list_node_t goes
    "Boom!" some time later when it's used or destroyed.

dmu_objset_evict_dbufs():
  - reduce stack usage using kmem_alloc()

Ported-by: Chris Dunlop <chris@onthe.net.au>
Signed-off-by: Brian Behlendorf <behlendorf1@llnl.gov>
This commit is contained in:
Justin T. Gibbs
2015-04-02 14:44:32 +11:00
committed by Brian Behlendorf
parent d683ddbb72
commit 0c66c32d1d
35 changed files with 645 additions and 316 deletions
Download Patch File Download Diff File Expand all files Collapse all files
module/zfs/sa.c
+22 -21
View File
@@ -22,6 +22,7 @@
/*
* Copyright (c) 2010, Oracle and/or its affiliates. All rights reserved.
* Copyright (c) 2013 by Delphix. All rights reserved.
* Copyright (c) 2014 Spectra Logic Corporation, All rights reserved.
*/
#include <sys/zfs_context.h>
@@ -209,6 +210,7 @@ sa_cache_constructor(void *buf, void *unused, int kmflag)
{
sa_handle_t *hdl = buf;
hdl->sa_dbu.dbu_evict_func = NULL;
hdl->sa_bonus_tab = NULL;
hdl->sa_spill_tab = NULL;
hdl->sa_os = NULL;
@@ -224,6 +226,7 @@ static void
sa_cache_destructor(void *buf, void *unused)
{
sa_handle_t *hdl = buf;
hdl->sa_dbu.dbu_evict_func = NULL;
mutex_destroy(&hdl->sa_lock);
}
@@ -1306,10 +1309,10 @@ sa_build_index(sa_handle_t *hdl, sa_buf_type_t buftype)
}
/*ARGSUSED*/
void
sa_evict(dmu_buf_t *db, void *sap)
static void
sa_evict(void *dbu)
{
panic("evicting sa dbuf %p\n", (void *)db);
panic("evicting sa dbuf\n");
}
static void
@@ -1361,9 +1364,10 @@ sa_spill_rele(sa_handle_t *hdl)
void
sa_handle_destroy(sa_handle_t *hdl)
{
dmu_buf_t *db = hdl->sa_bonus;
mutex_enter(&hdl->sa_lock);
(void) dmu_buf_update_user((dmu_buf_t *)hdl->sa_bonus, hdl,
NULL, NULL);
(void) dmu_buf_remove_user(db, &hdl->sa_dbu);
if (hdl->sa_bonus_tab) {
sa_idx_tab_rele(hdl->sa_os, hdl->sa_bonus_tab);
@@ -1388,7 +1392,7 @@ sa_handle_get_from_db(objset_t *os, dmu_buf_t *db, void *userp,
sa_handle_type_t hdl_type, sa_handle_t **handlepp)
{
int error = 0;
sa_handle_t *handle;
sa_handle_t *handle = NULL;
#ifdef ZFS_DEBUG
dmu_object_info_t doi;
@@ -1399,9 +1403,12 @@ sa_handle_get_from_db(objset_t *os, dmu_buf_t *db, void *userp,
/* find handle, if it exists */
/* if one doesn't exist then create a new one, and initialize it */
handle = (hdl_type == SA_HDL_SHARED) ? dmu_buf_get_user(db) : NULL;
if (hdl_type == SA_HDL_SHARED)
handle = dmu_buf_get_user(db);
if (handle == NULL) {
sa_handle_t *newhandle;
sa_handle_t *winner = NULL;
handle = kmem_cache_alloc(sa_cache, KM_SLEEP);
handle->sa_userp = userp;
handle->sa_bonus = db;
@@ -1409,12 +1416,15 @@ sa_handle_get_from_db(objset_t *os, dmu_buf_t *db, void *userp,
handle->sa_spill = NULL;
error = sa_build_index(handle, SA_BONUS);
newhandle = (hdl_type == SA_HDL_SHARED) ?
dmu_buf_set_user_ie(db, handle, sa_evict) : NULL;
if (newhandle != NULL) {
if (hdl_type == SA_HDL_SHARED) {
dmu_buf_init_user(&handle->sa_dbu, sa_evict, NULL);
winner = dmu_buf_set_user_ie(db, &handle->sa_dbu);
}
if (winner != NULL) {
kmem_cache_free(sa_cache, handle);
handle = newhandle;
handle = winner;
}
}
*handlepp = handle;
@@ -1946,14 +1956,6 @@ sa_object_size(sa_handle_t *hdl, uint32_t *blksize, u_longlong_t *nblocks)
blksize, nblocks);
}
void
sa_update_user(sa_handle_t *newhdl, sa_handle_t *oldhdl)
{
(void) dmu_buf_update_user((dmu_buf_t *)newhdl->sa_bonus,
oldhdl, newhdl, sa_evict);
oldhdl->sa_bonus = NULL;
}
void
sa_set_userp(sa_handle_t *hdl, void *ptr)
{
@@ -2052,7 +2054,6 @@ EXPORT_SYMBOL(sa_size);
EXPORT_SYMBOL(sa_update_from_cb);
EXPORT_SYMBOL(sa_object_info);
EXPORT_SYMBOL(sa_object_size);
EXPORT_SYMBOL(sa_update_user);
EXPORT_SYMBOL(sa_get_userdata);
EXPORT_SYMBOL(sa_set_userp);
EXPORT_SYMBOL(sa_get_db);