From: Jonathan Davies <jonathan.davies@nutanix.com>
Date: Fri, 11 Jun 2021 14:02:08 +0000 (+0000)
Subject: ext4: notify sysfs on errors_count value change
X-Git-Url: http://git.osdn.net/view?a=commitdiff_plain;h=d578b99443fde0968246cc7cbf3bc3016123c2f4;p=uclinux-h8%2Flinux.git

ext4: notify sysfs on errors_count value change

After s_error_count is incremented, signal the change in the
corresponding sysfs attribute via sysfs_notify. This allows userspace to
poll() on changes to /sys/fs/ext4/*/errors_count.

[ Moved call of ext4_notify_error_sysfs() to flush_stashed_error_work()
  to avoid BUG's caused by calling sysfs_notify trying to sleep after
  being called from an invalid context. -- TYT ]

Signed-off-by: Jonathan Davies <jonathan.davies@nutanix.com>
Link: https://lore.kernel.org/r/20210611140209.28903-1-jonathan.davies@nutanix.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
---

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 8ff4ae3b5715..3c51e243450d 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -3624,6 +3624,7 @@ extern const struct inode_operations ext4_symlink_inode_operations;
 extern const struct inode_operations ext4_fast_symlink_inode_operations;
 
 /* sysfs.c */
+extern void ext4_notify_error_sysfs(struct ext4_sb_info *sbi);
 extern int ext4_register_sysfs(struct super_block *sb);
 extern void ext4_unregister_sysfs(struct super_block *sb);
 extern int __init ext4_init_sysfs(void);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 9e0fb798b807..20344633bdd9 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -718,6 +718,7 @@ static void flush_stashed_error_work(struct work_struct *work)
 			goto write_directly;
 		}
 		jbd2_journal_stop(handle);
+		ext4_notify_error_sysfs(sbi);
 		return;
 	}
 write_directly:
@@ -726,6 +727,7 @@ write_directly:
 	 * out and hope for the best.
 	 */
 	ext4_commit_super(sbi->s_sb);
+	ext4_notify_error_sysfs(sbi);
 }
 
 #define ext4_error_ratelimit(sb)					\
diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 55fcab60a59a..2314f7446592 100644
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -506,6 +506,11 @@ static struct kobj_type ext4_feat_ktype = {
 	.release	= (void (*)(struct kobject *))kfree,
 };
 
+void ext4_notify_error_sysfs(struct ext4_sb_info *sbi)
+{
+	sysfs_notify(&sbi->s_kobj, NULL, "errors_count");
+}
+
 static struct kobject *ext4_root;
 
 static struct kobject *ext4_feat;