[Devel] [PATCH RHEL8 COMMIT] ext4: add generic uevent infrastructure
Konstantin Khorenko
khorenko at virtuozzo.com
Fri Nov 6 17:15:48 MSK 2020
The commit is pushed to "work" and will appear at https://src.openvz.org/scm/ovz/vzkernel.git
after rh8-4.18.0-193.6.3.vz8.4.16
------>
commit 0d32b8d103590d87315a24d2a56ac8c732c3a92d
Author: Dmitry Monakhov <dmonakhov at openvz.org>
Date: Fri Nov 6 17:15:48 2020 +0300
ext4: add generic uevent infrastructure
*Purpose:
It is reasonable to announce 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
Signed-off-by: Dmitry Monakhov <dmonakhov at openvz.org>
[aryabinin: add error event, rh8 rebase]
Signed-off-by: Andrey Ryabinin <aryabinin at virtuozzo.com>
---
fs/ext4/ext4.h | 11 +++++
fs/ext4/super.c | 128 +++++++++++++++++++++++++++++++++++++++++++++++++++++++-
2 files changed, 138 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 028832d858fc..228492c9518f 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1498,6 +1498,8 @@ struct ext4_sb_info {
/* Precomputed FS UUID checksum for seeding other checksums */
__u32 s_csum_seed;
+ bool s_err_event_sent;
+
/* Reclaim extents from extent status tree */
struct shrinker s_es_shrinker;
struct list_head s_es_list; /* List of inodes with reclaimable extents */
@@ -3119,6 +3121,15 @@ extern int ext4_check_blockref(const char *, unsigned int,
struct ext4_ext_path;
struct ext4_extent;
+enum ext4_event_type {
+ EXT4_UA_MOUNT,
+ EXT4_UA_UMOUNT,
+ EXT4_UA_REMOUNT,
+ EXT4_UA_ERROR,
+ EXT4_UA_FREEZE,
+ EXT4_UA_UNFREEZE,
+};
+
/*
* Maximum number of logical blocks in a file; ext4_extent's ee_block is
* __le32.
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 7fc5ad243953..3cc979825ec8 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -354,6 +354,117 @@ static time64_t __ext4_get_tstamp(__le32 *lo, __u8 *hi)
#define ext4_get_tstamp(es, tstamp) \
__ext4_get_tstamp(&(es)->tstamp, &(es)->tstamp ## _hi)
+static int ext4_uuid_valid(const u8 *uuid)
+{
+ int i;
+
+ for (i = 0; i < 16; i++) {
+ if (uuid[i])
+ return 1;
+ }
+ return 0;
+}
+
+struct ext4_uevent {
+ struct super_block *sb;
+ enum ext4_event_type action;
+ struct work_struct work;
+};
+
+/**
+ * ext4_send_uevent - prepare and send uevent
+ *
+ * @sb: super_block
+ * @action: action type
+ *
+ */
+static void ext4_send_uevent_work(struct work_struct *w)
+{
+ struct ext4_uevent *e = container_of(w, struct ext4_uevent, work);
+ struct super_block *sb = e->sb;
+ struct kobj_uevent_env *env;
+ const u8 *uuid = EXT4_SB(sb)->s_es->s_uuid;
+ enum kobject_action kaction = KOBJ_CHANGE;
+ int ret;
+
+ env = kzalloc(sizeof(struct kobj_uevent_env), GFP_KERNEL);
+ if (!env){
+ kfree(e);
+ return;
+ }
+ 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 (e->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);
+ kfree(e);
+}
+
+/**
+ * ext4_send_uevent - prepare and schedule event submission
+ *
+ * @sb: super_block
+ * @action: action type
+ *
+ */
+void ext4_send_uevent(struct super_block *sb, enum ext4_event_type action)
+{
+ struct ext4_uevent *e;
+
+ /*
+ * May happen if called from ext4_put_super() -> __ext4_abort()
+ * -> ext4_send_uevent()
+ */
+ if (!EXT4_SB(sb)->rsv_conversion_wq)
+ return;
+
+ e = kzalloc(sizeof(*e), GFP_NOIO);
+ if (!e)
+ return;
+
+ e->sb = sb;
+ e->action = action;
+ INIT_WORK(&e->work, ext4_send_uevent_work);
+ queue_work(EXT4_SB(sb)->rsv_conversion_wq, &e->work);
+}
+
static void __save_error_info(struct super_block *sb, const char *func,
unsigned int line)
{
@@ -453,6 +564,9 @@ static bool system_going_down(void)
static void ext4_handle_error(struct super_block *sb)
{
+ if (!xchg(&EXT4_SB(sb)->s_err_event_sent, 1))
+ ext4_send_uevent(sb, EXT4_UA_ERROR);
+
if (test_opt(sb, WARN_ON_ERROR))
WARN_ON_ONCE(1);
@@ -972,10 +1086,12 @@ static void ext4_put_super(struct super_block *sb)
int aborted = 0;
int i, err;
+ ext4_send_uevent(sb, EXT4_UA_UMOUNT);
ext4_unregister_li_request(sb);
ext4_quota_off_umount(sb);
destroy_workqueue(sbi->rsv_conversion_wq);
+ sbi->rsv_conversion_wq = NULL;
if (sbi->s_journal) {
aborted = is_journal_aborted(sbi->s_journal);
@@ -4523,6 +4639,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
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;
@@ -5081,8 +5198,10 @@ static int ext4_freeze(struct super_block *sb)
int error = 0;
journal_t *journal;
- if (sb_rdonly(sb))
+ if (sb_rdonly(sb)) {
+ ext4_send_uevent(sb, EXT4_UA_FREEZE);
return 0;
+ }
journal = EXT4_SB(sb)->s_journal;
@@ -5107,6 +5226,10 @@ static int ext4_freeze(struct super_block *sb)
if (journal)
/* we rely on upper layer to stop further updates */
jbd2_journal_unlock_updates(journal);
+
+ if (!error)
+ ext4_send_uevent(sb, EXT4_UA_FREEZE);
+
return error;
}
@@ -5116,6 +5239,8 @@ static int ext4_freeze(struct super_block *sb)
*/
static int ext4_unfreeze(struct super_block *sb)
{
+ ext4_send_uevent(sb, EXT4_UA_UNFREEZE);
+
if (sb_rdonly(sb) || ext4_forced_shutdown(EXT4_SB(sb)))
return 0;
@@ -5394,6 +5519,7 @@ static int ext4_remount(struct super_block *sb, int *flags, char *data)
*flags = (*flags & ~SB_LAZYTIME) | (sb->s_flags & SB_LAZYTIME);
ext4_msg(sb, KERN_INFO, "re-mounted. Opts: %s", orig_data);
+ ext4_send_uevent(sb, EXT4_UA_REMOUNT);
kfree(orig_data);
return 0;
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