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Date: Mon, 26 Apr 2021 14:41:59 -0400
From: Gabriel Krisman Bertazi <krisman@...labora.com>
To: amir73il@...il.com, tytso@....edu, djwong@...nel.org
Cc: david@...morbit.com, jack@...e.com, dhowells@...hat.com,
khazhy@...gle.com, linux-fsdevel@...r.kernel.org,
linux-ext4@...r.kernel.org,
Gabriel Krisman Bertazi <krisman@...labora.com>,
kernel@...labora.com
Subject: [PATCH RFC 13/15] ext4: Send notifications on error
Send a FS_ERROR message via fsnotify to a userspace monitoring tool
whenever a ext4 error condition is triggered. This follows the existing
error conditions in ext4, so it is hooked to the ext4_error* functions.
It also follows the current dmesg reporting in the format. The
filesystem message is composed mostly by the string that would be
otherwise printed in dmesg.
A new ext4 specific record format is exposed in the uapi, such that a
monitoring tool knows what to expect when listening errors of an ext4
filesystem.
Signed-off-by: Gabriel Krisman Bertazi <krisman@...labora.com>
---
fs/ext4/super.c | 60 ++++++++++++++++++++++++--------
include/uapi/linux/ext4-notify.h | 17 +++++++++
2 files changed, 62 insertions(+), 15 deletions(-)
create mode 100644 include/uapi/linux/ext4-notify.h
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index b9693680463a..032e29e7ff6a 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -46,6 +46,8 @@
#include <linux/part_stat.h>
#include <linux/kthread.h>
#include <linux/freezer.h>
+#include <linux/fsnotify.h>
+#include <uapi/linux/ext4-notify.h>
#include "ext4.h"
#include "ext4_extents.h" /* Needed for trace points definition */
@@ -727,6 +729,22 @@ static void flush_stashed_error_work(struct work_struct *work)
ext4_commit_super(sbi->s_sb);
}
+static void ext4_fsnotify_error(int error, struct inode *inode, __u64 block,
+ const char *func, int line,
+ const char *desc, struct va_format *vaf)
+{
+ struct ext4_error_inode_report report;
+
+ if (inode->i_sb->s_fsnotify_marks) {
+ report.inode = inode ? inode->i_ino : -1L;
+ report.block = block ? block : -1L;
+
+ snprintf(report.desc, EXT4_FSN_DESC_LEN, "%s%pV\n", desc?:"", vaf);
+
+ fsnotify_error_event(error, inode, func, line, &report, sizeof(report));
+ }
+}
+
#define ext4_error_ratelimit(sb) \
___ratelimit(&(EXT4_SB(sb)->s_err_ratelimit_state), \
"EXT4-fs error")
@@ -742,15 +760,18 @@ void __ext4_error(struct super_block *sb, const char *function,
return;
trace_ext4_error(sb, function, line);
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &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);
+
}
+ ext4_fsnotify_error(error, sb->s_root->d_inode, block, function, line, NULL, &vaf);
+ va_end(args);
ext4_handle_error(sb, force_ro, error, 0, block, function, line);
}
@@ -765,10 +786,10 @@ void __ext4_error_inode(struct inode *inode, const char *function,
return;
trace_ext4_error(inode->i_sb, function, line);
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
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",
@@ -779,8 +800,11 @@ void __ext4_error_inode(struct inode *inode, const char *function,
"inode #%lu: comm %s: %pV\n",
inode->i_sb->s_id, function, line, inode->i_ino,
current->comm, &vaf);
- va_end(args);
}
+
+ ext4_fsnotify_error(error, inode, block, function, line, NULL, &vaf);
+ va_end(args);
+
ext4_handle_error(inode->i_sb, false, error, inode->i_ino, block,
function, line);
}
@@ -798,13 +822,16 @@ void __ext4_error_file(struct file *file, const char *function,
return;
trace_ext4_error(inode->i_sb, function, line);
+
+ path = file_path(file, pathname, sizeof(pathname));
+ if (IS_ERR(path))
+ path = "(unknown)";
+
+ va_start(args, fmt);
+ vaf.fmt = fmt;
+ vaf.va = &args;
+
if (ext4_error_ratelimit(inode->i_sb)) {
- path = file_path(file, 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: "
@@ -817,8 +844,10 @@ void __ext4_error_file(struct file *file, const char *function,
"comm %s: path %s: %pV\n",
inode->i_sb->s_id, function, line, inode->i_ino,
current->comm, path, &vaf);
- va_end(args);
}
+ ext4_fsnotify_error(EFSCORRUPTED, inode, block, function, line, NULL, &vaf);
+ va_end(args);
+
ext4_handle_error(inode->i_sb, false, EFSCORRUPTED, inode->i_ino, block,
function, line);
}
@@ -886,6 +915,7 @@ void __ext4_std_error(struct super_block *sb, const char *function,
printk(KERN_CRIT "EXT4-fs error (device %s) in %s:%d: %s\n",
sb->s_id, function, line, errstr);
}
+ ext4_fsnotify_error(errno, NULL, -1L, function, line, errstr, NULL);
ext4_handle_error(sb, false, -errno, 0, 0, function, line);
}
diff --git a/include/uapi/linux/ext4-notify.h b/include/uapi/linux/ext4-notify.h
new file mode 100644
index 000000000000..31a3bbcafd13
--- /dev/null
+++ b/include/uapi/linux/ext4-notify.h
@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: GPL-2.0+ WITH Linux-syscall-note */
+/*
+ * Copyright 2021, Collabora Ltd.
+ */
+
+#ifndef EXT4_NOTIFY_H
+#define EXT4_NOTIFY_H
+
+#define EXT4_FSN_DESC_LEN 256
+
+struct ext4_error_inode_report {
+ u64 inode;
+ u64 block;
+ char desc[EXT4_FSN_DESC_LEN];
+};
+
+#endif
--
2.31.0
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