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Date: Fri, 18 Oct 2013 15:08:41 +0200 (CEST)
From: Lukáš Czerner <lczerner@...hat.com>
To: "Theodore Ts'o" <tytso@....edu>
cc: Ext4 Developers List <linux-ext4@...r.kernel.org>
Subject: Re: [PATCH] ext4: add ratelimiting to ext4 messages
On Thu, 17 Oct 2013, Theodore Ts'o wrote:
> Date: Thu, 17 Oct 2013 21:28:48 -0400
> From: Theodore Ts'o <tytso@....edu>
> To: Ext4 Developers List <linux-ext4@...r.kernel.org>
> Cc: Theodore Ts'o <tytso@....edu>
> Subject: [PATCH] ext4: add ratelimiting to ext4 messages
>
> In the case of a storage device that suddenly disappears, or in the
> case of significant file system corruption, this can result in a huge
> flood of messages being sent to the console. This can overflow the
> file system containing /var/log/messages, or if a serial console is
> configured, this can slow down the system so much that a hardware
> watchdog can end up triggering forcing a system reboot.
>
> Google-Bug-Id: 7258357
Looks good. Thanks!
Reviewed-by: Lukas Czerner <lczerner@...hat.com>
However looking at what we print out from ext4 it looks like we
should revisit the code at some point and make a use of those
ext4_* helpers because there are still cases out there where we
just use printk, or combination of the ext4_* helper and printk.
Also it looks like almost every file in the fs/ext4 has it's own
debugging method, it would be nice to clean it up at some point as
well. But that's not really a priority I guess.
Thanks!
-Lukas
>
> Signed-off-by: "Theodore Ts'o" <tytso@....edu>
> ---
> fs/ext4/ext4.h | 6 +++
> fs/ext4/super.c | 152 +++++++++++++++++++++++++++++++++++---------------------
> 2 files changed, 100 insertions(+), 58 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index af815ea..65485ab 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -29,6 +29,7 @@
> #include <linux/wait.h>
> #include <linux/blockgroup_lock.h>
> #include <linux/percpu_counter.h>
> +#include <linux/ratelimit.h>
> #include <crypto/hash.h>
> #ifdef __KERNEL__
> #include <linux/compat.h>
> @@ -1314,6 +1315,11 @@ struct ext4_sb_info {
> unsigned long s_es_last_sorted;
> struct percpu_counter s_extent_cache_cnt;
> spinlock_t s_es_lru_lock ____cacheline_aligned_in_smp;
> +
> + /* Ratelimit ext4 messages. */
> + struct ratelimit_state s_err_ratelimit_state;
> + struct ratelimit_state s_warning_ratelimit_state;
> + struct ratelimit_state s_msg_ratelimit_state;
> };
>
> static inline struct ext4_sb_info *EXT4_SB(struct super_block *sb)
> diff --git a/fs/ext4/super.c b/fs/ext4/super.c
> index 2c2e6cb..d3a857b 100644
> --- a/fs/ext4/super.c
> +++ b/fs/ext4/super.c
> @@ -411,20 +411,26 @@ static void ext4_handle_error(struct super_block *sb)
> sb->s_id);
> }
>
> +#define ext4_error_ratelimit(sb) \
> + ___ratelimit(&(EXT4_SB(sb)->s_err_ratelimit_state), \
> + "EXT4-fs error")
> +
> void __ext4_error(struct super_block *sb, const char *function,
> unsigned int line, const char *fmt, ...)
> {
> struct va_format vaf;
> va_list args;
>
> - va_start(args, fmt);
> - vaf.fmt = fmt;
> - vaf.va = &args;
> - printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
> - sb->s_id, function, line, current->comm, &vaf);
> - va_end(args);
> + if (ext4_error_ratelimit(sb)) {
> + va_start(args, fmt);
> + vaf.fmt = fmt;
> + vaf.va = &args;
> + printk(KERN_CRIT
> + "EXT4-fs error (device %s): %s:%d: comm %s: %pV\n",
> + sb->s_id, function, line, current->comm, &vaf);
> + va_end(args);
> + }
> save_error_info(sb, function, line);
> -
> ext4_handle_error(sb);
> }
>
> @@ -438,22 +444,23 @@ void __ext4_error_inode(struct inode *inode, const char *function,
>
> es->s_last_error_ino = cpu_to_le32(inode->i_ino);
> es->s_last_error_block = cpu_to_le64(block);
> + if (ext4_error_ratelimit(inode->i_sb)) {
> + va_start(args, fmt);
> + vaf.fmt = fmt;
> + vaf.va = &args;
> + if (block)
> + printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
> + "inode #%lu: block %llu: comm %s: %pV\n",
> + inode->i_sb->s_id, function, line, inode->i_ino,
> + block, current->comm, &vaf);
> + else
> + printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
> + "inode #%lu: comm %s: %pV\n",
> + inode->i_sb->s_id, function, line, inode->i_ino,
> + current->comm, &vaf);
> + va_end(args);
> + }
> save_error_info(inode->i_sb, function, line);
> - va_start(args, fmt);
> - vaf.fmt = fmt;
> - vaf.va = &args;
> - if (block)
> - printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
> - "inode #%lu: block %llu: comm %s: %pV\n",
> - inode->i_sb->s_id, function, line, inode->i_ino,
> - block, current->comm, &vaf);
> - else
> - printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: "
> - "inode #%lu: comm %s: %pV\n",
> - inode->i_sb->s_id, function, line, inode->i_ino,
> - current->comm, &vaf);
> - va_end(args);
> -
> ext4_handle_error(inode->i_sb);
> }
>
> @@ -469,27 +476,28 @@ void __ext4_error_file(struct file *file, const char *function,
>
> es = EXT4_SB(inode->i_sb)->s_es;
> es->s_last_error_ino = cpu_to_le32(inode->i_ino);
> + if (ext4_error_ratelimit(inode->i_sb)) {
> + path = d_path(&(file->f_path), pathname, sizeof(pathname));
> + if (IS_ERR(path))
> + path = "(unknown)";
> + va_start(args, fmt);
> + vaf.fmt = fmt;
> + vaf.va = &args;
> + if (block)
> + printk(KERN_CRIT
> + "EXT4-fs error (device %s): %s:%d: inode #%lu: "
> + "block %llu: comm %s: path %s: %pV\n",
> + inode->i_sb->s_id, function, line, inode->i_ino,
> + block, current->comm, path, &vaf);
> + else
> + printk(KERN_CRIT
> + "EXT4-fs error (device %s): %s:%d: inode #%lu: "
> + "comm %s: path %s: %pV\n",
> + inode->i_sb->s_id, function, line, inode->i_ino,
> + current->comm, path, &vaf);
> + va_end(args);
> + }
> save_error_info(inode->i_sb, function, line);
> - path = d_path(&(file->f_path), pathname, sizeof(pathname));
> - if (IS_ERR(path))
> - path = "(unknown)";
> - va_start(args, fmt);
> - vaf.fmt = fmt;
> - vaf.va = &args;
> - if (block)
> - printk(KERN_CRIT
> - "EXT4-fs error (device %s): %s:%d: inode #%lu: "
> - "block %llu: comm %s: path %s: %pV\n",
> - inode->i_sb->s_id, function, line, inode->i_ino,
> - block, current->comm, path, &vaf);
> - else
> - printk(KERN_CRIT
> - "EXT4-fs error (device %s): %s:%d: inode #%lu: "
> - "comm %s: path %s: %pV\n",
> - inode->i_sb->s_id, function, line, inode->i_ino,
> - current->comm, path, &vaf);
> - va_end(args);
> -
> ext4_handle_error(inode->i_sb);
> }
>
> @@ -543,11 +551,13 @@ void __ext4_std_error(struct super_block *sb, const char *function,
> (sb->s_flags & MS_RDONLY))
> return;
>
> - errstr = ext4_decode_error(sb, errno, nbuf);
> - printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
> - sb->s_id, function, line, errstr);
> - save_error_info(sb, function, line);
> + if (ext4_error_ratelimit(sb)) {
> + errstr = ext4_decode_error(sb, errno, nbuf);
> + printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
> + sb->s_id, function, line, errstr);
> + }
>
> + save_error_info(sb, function, line);
> ext4_handle_error(sb);
> }
>
> @@ -597,6 +607,9 @@ void __ext4_msg(struct super_block *sb,
> struct va_format vaf;
> va_list args;
>
> + if (!___ratelimit(&(EXT4_SB(sb)->s_msg_ratelimit_state), "EXT4-fs"))
> + return;
> +
> va_start(args, fmt);
> vaf.fmt = fmt;
> vaf.va = &args;
> @@ -610,6 +623,10 @@ void __ext4_warning(struct super_block *sb, const char *function,
> struct va_format vaf;
> va_list args;
>
> + if (!___ratelimit(&(EXT4_SB(sb)->s_warning_ratelimit_state),
> + "EXT4-fs warning"))
> + return;
> +
> va_start(args, fmt);
> vaf.fmt = fmt;
> vaf.va = &args;
> @@ -633,18 +650,20 @@ __acquires(bitlock)
> es->s_last_error_block = cpu_to_le64(block);
> __save_error_info(sb, function, line);
>
> - va_start(args, fmt);
> -
> - vaf.fmt = fmt;
> - vaf.va = &args;
> - printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
> - sb->s_id, function, line, grp);
> - if (ino)
> - printk(KERN_CONT "inode %lu: ", ino);
> - if (block)
> - printk(KERN_CONT "block %llu:", (unsigned long long) block);
> - printk(KERN_CONT "%pV\n", &vaf);
> - va_end(args);
> + if (ext4_error_ratelimit(sb)) {
> + va_start(args, fmt);
> + vaf.fmt = fmt;
> + vaf.va = &args;
> + printk(KERN_CRIT "EXT4-fs error (device %s): %s:%d: group %u, ",
> + sb->s_id, function, line, grp);
> + if (ino)
> + printk(KERN_CONT "inode %lu: ", ino);
> + if (block)
> + printk(KERN_CONT "block %llu:",
> + (unsigned long long) block);
> + printk(KERN_CONT "%pV\n", &vaf);
> + va_end(args);
> + }
>
> if (test_opt(sb, ERRORS_CONT)) {
> ext4_commit_super(sb, 0);
> @@ -2606,6 +2625,12 @@ EXT4_RW_ATTR_SBI_UI(mb_group_prealloc, s_mb_group_prealloc);
> EXT4_DEPRECATED_ATTR(max_writeback_mb_bump, 128);
> EXT4_RW_ATTR_SBI_UI(extent_max_zeroout_kb, s_extent_max_zeroout_kb);
> EXT4_ATTR(trigger_fs_error, 0200, NULL, trigger_test_error);
> +EXT4_RW_ATTR_SBI_UI(err_ratelimit_interval_ms, s_err_ratelimit_state.interval);
> +EXT4_RW_ATTR_SBI_UI(err_ratelimit_burst, s_err_ratelimit_state.burst);
> +EXT4_RW_ATTR_SBI_UI(warning_ratelimit_interval_ms, s_warning_ratelimit_state.interval);
> +EXT4_RW_ATTR_SBI_UI(warning_ratelimit_burst, s_warning_ratelimit_state.burst);
> +EXT4_RW_ATTR_SBI_UI(msg_ratelimit_interval_ms, s_msg_ratelimit_state.interval);
> +EXT4_RW_ATTR_SBI_UI(msg_ratelimit_burst, s_msg_ratelimit_state.burst);
>
> static struct attribute *ext4_attrs[] = {
> ATTR_LIST(delayed_allocation_blocks),
> @@ -2623,6 +2648,12 @@ static struct attribute *ext4_attrs[] = {
> ATTR_LIST(max_writeback_mb_bump),
> ATTR_LIST(extent_max_zeroout_kb),
> ATTR_LIST(trigger_fs_error),
> + ATTR_LIST(err_ratelimit_interval_ms),
> + ATTR_LIST(err_ratelimit_burst),
> + ATTR_LIST(warning_ratelimit_interval_ms),
> + ATTR_LIST(warning_ratelimit_burst),
> + ATTR_LIST(msg_ratelimit_interval_ms),
> + ATTR_LIST(msg_ratelimit_burst),
> NULL,
> };
>
> @@ -4118,6 +4149,11 @@ no_journal:
> if (es->s_error_count)
> mod_timer(&sbi->s_err_report, jiffies + 300*HZ); /* 5 minutes */
>
> + /* Enable message ratelimiting. Default is 10 messages per 5 secs. */
> + ratelimit_state_init(&sbi->s_err_ratelimit_state, 5 * HZ, 10);
> + ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
> + ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
> +
> kfree(orig_data);
> return 0;
>
>
--
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