From: amir73il@users.sourceforge.net Subject: [PATCH v1 02/36] ext4: snapshot debugging support Date: Tue, 7 Jun 2011 18:07:29 +0300 Message-ID: <1307459283-22130-3-git-send-email-amir73il@users.sourceforge.net> References: <1307459283-22130-1-git-send-email-amir73il@users.sourceforge.net> Cc: tytso@mit.edu, lczerner@redhat.com, Amir Goldstein , Yongqiang Yang To: linux-ext4@vger.kernel.org Return-path: Received: from mail-wy0-f174.google.com ([74.125.82.174]:60303 "EHLO mail-wy0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752832Ab1FGPJB (ORCPT ); Tue, 7 Jun 2011 11:09:01 -0400 Received: by mail-wy0-f174.google.com with SMTP id 21so3629480wya.19 for ; Tue, 07 Jun 2011 08:09:00 -0700 (PDT) In-Reply-To: <1307459283-22130-1-git-send-email-amir73il@users.sourceforge.net> Sender: linux-ext4-owner@vger.kernel.org List-ID: From: Amir Goldstein Control snapshot debug level via debugfs entry /ext4/snapshot-debug and induce delay tests via debugfs entries /ext4/test-XXX-delay-msec. Signed-off-by: Amir Goldstein Signed-off-by: Yongqiang Yang --- fs/ext4/Makefile | 1 + fs/ext4/mballoc.c | 3 + fs/ext4/snapshot.h | 9 ++++ fs/ext4/snapshot_debug.c | 100 +++++++++++++++++++++++++++++++++++++++++++ fs/ext4/snapshot_debug.h | 105 ++++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 218 insertions(+), 0 deletions(-) diff --git a/fs/ext4/Makefile b/fs/ext4/Makefile index a471c2e..1d947ef 100644 --- a/fs/ext4/Makefile +++ b/fs/ext4/Makefile @@ -13,3 +13,4 @@ ext4-$(CONFIG_EXT4_FS_POSIX_ACL) += acl.o ext4-$(CONFIG_EXT4_FS_SECURITY) += xattr_security.o ext4-$(CONFIG_EXT4_FS_SNAPSHOT) += snapshot.o snapshot_ctl.o ext4-$(CONFIG_EXT4_FS_SNAPSHOT) += snapshot_inode.o snapshot_buffer.o +ext4-$(CONFIG_EXT4_FS_SNAPSHOT) += snapshot_debug.o diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c index 5a930d6..54ea8c8 100644 --- a/fs/ext4/mballoc.c +++ b/fs/ext4/mballoc.c @@ -2658,10 +2658,13 @@ static void __init ext4_create_debugfs_entry(void) S_IRUGO | S_IWUSR, debugfs_dir, &mb_enable_debug); + if (debugfs_dir) + ext4_snapshot_create_debugfs_entry(debugfs_dir); } static void ext4_remove_debugfs_entry(void) { + ext4_snapshot_remove_debugfs_entry(); debugfs_remove(debugfs_debug); debugfs_remove(debugfs_dir); } diff --git a/fs/ext4/snapshot.h b/fs/ext4/snapshot.h index 8a60ae1..d0c985b 100644 --- a/fs/ext4/snapshot.h +++ b/fs/ext4/snapshot.h @@ -18,6 +18,7 @@ #include #include #include "ext4.h" +#include "snapshot_debug.h" /* @@ -109,6 +110,14 @@ static inline void snapshot_size_extend(struct inode *inode, ext4_fsblk_t blocks) { +#ifdef CONFIG_EXT4_DEBUG + ext4_fsblk_t old_blocks = SNAPSHOT_PROGRESS(inode); + ext4_fsblk_t max_blocks = SNAPSHOT_BLOCKS(inode); + + /* sleep total of tunable delay unit over 100% progress */ + snapshot_test_delay_progress(SNAPTEST_DELETE, + old_blocks, blocks, max_blocks); +#endif i_size_write((inode), (loff_t)(blocks) << SNAPSHOT_BLOCK_SIZE_BITS); } diff --git a/fs/ext4/snapshot_debug.c b/fs/ext4/snapshot_debug.c index e69de29..35f552a 100644 --- a/fs/ext4/snapshot_debug.c +++ b/fs/ext4/snapshot_debug.c @@ -0,0 +1,100 @@ +/* + * linux/fs/ext4/snapshot_debug.c + * + * Written by Amir Goldstein , 2008 + * + * Copyright (C) 2008-2011 CTERA Networks + * + * This file is part of the Linux kernel and is made available under + * the terms of the GNU General Public License, version 2, or at your + * option, any later version, incorporated herein by reference. + * + * Ext4 snapshot debugging. + */ + + +#include +#include +#include +#include "snapshot.h" + +#if defined(CONFIG_EXT4_FS_SNAPSHOT) && defined(CONFIG_EXT4_DEBUG) +/* + * debugfs tunables + */ + +const char *snapshot_indent = SNAPSHOT_INDENT_STR + SNAPSHOT_INDENT_MAX; + +/* + * Tunable delay values per snapshot operation for testing of + * COW race conditions and master snapshot_mutex lock + */ +static const char *snapshot_test_names[SNAPSHOT_TESTS_NUM] = { + /* delay completion of snapshot create|take */ + "test-take-delay-msec", + /* delay completion of snapshot shrink|cleanup */ + "test-delete-delay-msec", + /* delay completion of COW operation */ + "test-cow-delay-msec", + /* delay submission of tracked read */ + "test-read-delay-msec", + /* delay completion of COW bitmap operation */ + "test-bitmap-delay-msec", +}; + +#define SNAPSHOT_TEST_NAMES (sizeof(snapshot_test_names) / \ + sizeof(snapshot_test_names[0])) + +u16 snapshot_enable_test[SNAPSHOT_TESTS_NUM] __read_mostly = {0}; +u8 snapshot_enable_debug __read_mostly = 1; + +static struct dentry *snapshot_debug; +static struct dentry *snapshot_version; +static struct dentry *snapshot_test[SNAPSHOT_TESTS_NUM]; + +static char snapshot_version_str[] = EXT4_SNAPSHOT_VERSION; +static struct debugfs_blob_wrapper snapshot_version_blob = { + .data = snapshot_version_str, + .size = sizeof(snapshot_version_str) +}; + + +/* + * ext4_snapshot_create_debugfs_entry - register ext4 snapshot debug hooks + * Void function doesn't return error if debug hooks are not registered. + */ +void ext4_snapshot_create_debugfs_entry(struct dentry *debugfs_dir) +{ + int i; + + BUG_ON(!debugfs_dir); + snapshot_debug = debugfs_create_u8("snapshot-debug", S_IRUGO|S_IWUSR, + debugfs_dir, + &snapshot_enable_debug); + snapshot_version = debugfs_create_blob("snapshot-version", S_IRUGO, + debugfs_dir, + &snapshot_version_blob); + for (i = 0; i < SNAPSHOT_TESTS_NUM && i < SNAPSHOT_TEST_NAMES; i++) + snapshot_test[i] = debugfs_create_u16(snapshot_test_names[i], + S_IRUGO|S_IWUSR, + debugfs_dir, + &snapshot_enable_test[i]); +} + +/* + * ext4_snapshot_remove_debugfs_entry - unregister ext4 snapshot debug hooks + * checks if the hooks have been registered before unregistering them. + */ +void ext4_snapshot_remove_debugfs_entry(void) +{ + int i; + + for (i = 0; i < SNAPSHOT_TESTS_NUM && i < SNAPSHOT_TEST_NAMES; i++) + if (snapshot_test[i]) + debugfs_remove(snapshot_test[i]); + if (snapshot_version) + debugfs_remove(snapshot_version); + if (snapshot_debug) + debugfs_remove(snapshot_debug); +} +#endif diff --git a/fs/ext4/snapshot_debug.h b/fs/ext4/snapshot_debug.h index e69de29..f893eb1 100644 --- a/fs/ext4/snapshot_debug.h +++ b/fs/ext4/snapshot_debug.h @@ -0,0 +1,105 @@ +/* + * linux/fs/ext4/snapshot_debug.h + * + * Written by Amir Goldstein , 2008 + * + * Copyright (C) 2008-2011 CTERA Networks + * + * This file is part of the Linux kernel and is made available under + * the terms of the GNU General Public License, version 2, or at your + * option, any later version, incorporated herein by reference. + * + * Ext4 snapshot debugging. + */ + +#ifndef _LINUX_EXT4_SNAPSHOT_DEBUG_H +#define _LINUX_EXT4_SNAPSHOT_DEBUG_H + +#if defined(CONFIG_EXT4_FS_SNAPSHOT) && defined(CONFIG_EXT4_DEBUG) +#include + +#define SNAPSHOT_INDENT_MAX 4 +#define SNAPSHOT_INDENT_STR "\t\t\t\t" + +#define SNAPTEST_TAKE 0 +#define SNAPTEST_DELETE 1 +#define SNAPTEST_COW 2 +#define SNAPTEST_READ 3 +#define SNAPTEST_BITMAP 4 +#define SNAPSHOT_TESTS_NUM 5 + +extern const char *snapshot_indent; +extern u8 snapshot_enable_debug; +extern u16 snapshot_enable_test[SNAPSHOT_TESTS_NUM]; +extern u8 cow_cache_enabled; + +#define snapshot_test_delay(i) \ + do { \ + if (snapshot_enable_test[i]) \ + msleep_interruptible(snapshot_enable_test[i]); \ + } while (0) + +/* + * Sleep 1ms every 'blocks_per_ms', amounting to the total test delay + * over 100% of progress (when 'to' reaches 'max'). + * snapshot_enable_test[i] (msec) is limited to 64K and max (blocks_count) + * is likely much more than 64K, so 'blocks_per_ms' is likely non zero. + */ +#define snapshot_test_delay_progress(i, from, to, max) \ + do { \ + if (snapshot_enable_test[i] && \ + (max) > snapshot_enable_test[i] && \ + (from) <= (to) && (to) <= (max)) { \ + unsigned long blocks_per_ms = \ + do_div((max), snapshot_enable_test[i]); \ + unsigned long x = do_div((from), blocks_per_ms);\ + unsigned long y = do_div((to), blocks_per_ms); \ + if (y > x) \ + msleep_interruptible(y - x); \ + } \ + } while (0) + +#define snapshot_debug_l(n, l, f, a...) \ + do { \ + if ((n) <= snapshot_enable_debug && \ + (l) <= SNAPSHOT_INDENT_MAX) { \ + printk(KERN_DEBUG "snapshot: %s" f, \ + snapshot_indent - (l), \ + ## a); \ + } \ + } while (0) + +#define snapshot_debug(n, f, a...) snapshot_debug_l(n, 0, f, ## a) + +#define snapshot_debug_once(n, f, a...) \ + do { \ + static bool __once; \ + if (!__once) { \ + snapshot_debug(n, f, ## a); \ + __once = true; \ + } \ + } while (0) + +extern void ext4_snapshot_create_debugfs_entry(struct dentry *debugfs_dir); +extern void ext4_snapshot_remove_debugfs_entry(void); + +#else +#define snapshot_enable_debug (0) +#define snapshot_test_delay(i) +#define snapshot_test_delay_progress(i, from, to, max) +#define snapshot_debug(n, f, a...) +#define snapshot_debug_l(n, l, f, a...) +#define snapshot_debug_once(n, f, a...) +#define ext4_snapshot_create_debugfs_entry(d) +#define ext4_snapshot_remove_debugfs_entry() +#endif + + +/* debug levels */ +#define SNAP_ERR 1 /* errors and summary */ +#define SNAP_WARN 2 /* warnings */ +#define SNAP_INFO 3 /* info */ +#define SNAP_DEBUG 4 /* debug */ +#define SNAP_DUMP 5 /* dump snapshot file */ + +#endif /* _LINUX_EXT4_SNAPSHOT_DEBUG_H */ -- 1.7.4.1