*Purpose:
It is reasonable to annaunce fs related events via uevent infrastructure.
This patch implement only ext4'th part, but IMHO this should be usefull for
any generic filesystem.
Example: Runtime fs-error is pure async event. Currently there is no good
way to handle this situation and inform user-space about this.
*Implementation:
Add uevent infrastructure similar to dm uevent
FS_ACTION = {MOUNT|UMOUNT|REMOUNT|ERROR|FREEZE|UNFREEZE}
FS_UUID
FS_NAME
FS_TYPE
*Open questions:
- Is it worth to add mount option to event fields?
Please let me know what you think about this idea.
Signed-off-by: Dmitry Monakhov <dmonakhov@xxxxxxxxxx>
---
fs/ext4/ext4.h | 9 +++++
fs/ext4/super.c | 90 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 97 insertions(+), 2 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 2238e60..78cf2e6 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2790,6 +2790,15 @@ enum ext4_state_bits {
* allocated cluster. */
};
+enum ext4_event_type {
+ EXT4_UA_MOUNT,
+ EXT4_UA_UMOUNT,
+ EXT4_UA_REMOUNT,
+ EXT4_UA_ERROR,
+ EXT4_UA_FREEZE,
+ EXT4_UA_UNFREEZE,
+};
+
/*
* Add new method to test whether block and inode bitmaps are properly
* initialized. With uninit_bg reading the block from disk is not enough
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index c977f4e..1113ba2 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -370,6 +370,82 @@ static void ext4_journal_commit_callback(journal_t *journal, transaction_t *txn)
spin_unlock(&sbi->s_md_lock);
}
+static int ext4_uuid_valid(const u8 *uuid)
+{
+ int i;
+
+ for (i = 0; i < 16; i++) {
+ if (uuid[i])
+ return 1;
+ }
+ return 0;
+}
+
+/**
+ * ext4_send_uevent - prepare and send uevent
+ *
+ * @sb: super_block
+ * @action: action type
+ *
+ */
+int ext4_send_uevent(struct super_block *sb, enum ext4_event_type action)
+{
+ int ret;
+ struct kobj_uevent_env *env;
+ const u8 *uuid = sb->s_uuid;
+ enum kobject_action kaction = KOBJ_CHANGE;
+
+ env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
+ if (!env)
+ return -ENOMEM;
+
+ ret = add_uevent_var(env, "FS_TYPE=%s", sb->s_type->name);
+ if (ret)
+ goto out;
+ ret = add_uevent_var(env, "FS_NAME=%s", sb->s_id);
+ if (ret)
+ goto out;
+
+ if (ext4_uuid_valid(uuid)) {
+ ret = add_uevent_var(env, "UUID=%pUB", uuid);
+ if (ret)
+ goto out;
+ }
+
+ switch (action) {
+ case EXT4_UA_MOUNT:
+ kaction = KOBJ_ONLINE;
+ ret = add_uevent_var(env, "FS_ACTION=%s", "MOUNT");
+ break;
+ case EXT4_UA_UMOUNT:
+ kaction = KOBJ_OFFLINE;
+ ret = add_uevent_var(env, "FS_ACTION=%s", "UMOUNT");
+ break;
+ case EXT4_UA_REMOUNT:
+ ret = add_uevent_var(env, "FS_ACTION=%s", "REMOUNT");
+ break;
+ case EXT4_UA_ERROR:
+ ret = add_uevent_var(env, "FS_ACTION=%s", "ERROR");
+ break;
+ case EXT4_UA_FREEZE:
+ ret = add_uevent_var(env, "FS_ACTION=%s", "FREEZE");
+ break;
+ case EXT4_UA_UNFREEZE:
+ ret = add_uevent_var(env, "FS_ACTION=%s", "UNFREEZE");
+ break;
+
+ default:
+ ret = -EINVAL;
+ }
+ if (ret)
+ goto out;
+
+ ret = kobject_uevent_env(&(EXT4_SB(sb)->s_kobj), kaction, env->envp);
+out:
+ kfree(env);
+ return ret;
+}
+
/* Deal with the reporting of failure conditions on a filesystem such as
* inconsistencies detected or read IO failures.
*
@@ -409,6 +485,8 @@ static void ext4_handle_error(struct super_block *sb)
if (test_opt(sb, ERRORS_PANIC))
panic("EXT4-fs (device %s): panic forced after error\n",
sb->s_id);
+
+ ext4_send_uevent(sb, EXT4_UA_ERROR);
}
#define ext4_error_ratelimit(sb) \
@@ -778,6 +856,7 @@ static void ext4_put_super(struct super_block *sb)
struct ext4_super_block *es = sbi->s_es;
int i, err;
+ ext4_send_uevent(sb, EXT4_UA_UMOUNT);
ext4_unregister_li_request(sb);
dquot_disable(sb, -1, DQUOT_USAGE_ENABLED | DQUOT_LIMITS_ENABLED);
@@ -4151,6 +4230,7 @@ no_journal:
ratelimit_state_init(&sbi->s_warning_ratelimit_state, 5 * HZ, 10);
ratelimit_state_init(&sbi->s_msg_ratelimit_state, 5 * HZ, 10);
+ ext4_send_uevent(sb, EXT4_UA_MOUNT);
kfree(orig_data);
return 0;
@@ -4679,9 +4759,10 @@ static int ext4_freeze(struct super_block *sb)
int error = 0;
journal_t *journal;
- if (sb->s_flags & MS_RDONLY)
+ if (sb->s_flags & MS_RDONLY) {
+ ext4_send_uevent(sb, EXT4_UA_FREEZE);
return 0;
-
+ }
journal = EXT4_SB(sb)->s_journal;
/* Now we set up the journal barrier. */
@@ -4701,6 +4782,8 @@ static int ext4_freeze(struct super_block *sb)
out:
/* we rely on upper layer to stop further updates */
jbd2_journal_unlock_updates(EXT4_SB(sb)->s_journal);
+ if (!error)
+ ext4_send_uevent(sb, EXT4_UA_FREEZE);
return error;
}
@@ -4710,6 +4793,8 @@ out:
*/
static int ext4_unfreeze(struct super_block *sb)
{
+ ext4_send_uevent(sb, EXT4_UA_UNFREEZE);
+
if (sb->s_flags & MS_RDONLY)
return 0;
@@ -4934,6 +5019,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
#endif
ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
+ ext4_send_uevent(sb, EXT4_UA_REMOUNT);
kfree(orig_data);
return 0;
--
1.7.1
--
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