2022-01-17 17:05:15

by Xin Yin

[permalink] [raw]
Subject: [PATCH v3 2/2] ext4: fast commit may miss file actions

in the follow scenario:
1. jbd start transaction n
2. task A get new handle for transaction n+1
3. task A do some actions and add inode to FC_Q_MAIN fc_q
4. jbd complete transaction n and clear FC_Q_MAIN fc_q
5. task A call fsync

fast commit will lost the file actions during a full commit.

we should also add updates to staging queue during a full commit.
and in ext4_fc_cleanup(), when reset a inode's fc track range, check
it's i_sync_tid, if it bigger than current transaction tid, do not
rest it, or we will lost the track range.

And EXT4_MF_FC_COMMITTING is not needed anymore, so drop it.

Signed-off-by: Xin Yin <[email protected]>
---
v2: drop EXT4_MF_FC_COMMITTING
---
fs/ext4/ext4.h | 5 +----
fs/ext4/fast_commit.c | 11 ++++++-----
fs/ext4/super.c | 1 -
3 files changed, 7 insertions(+), 10 deletions(-)

diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index 881f480dd150..22a954fb0c20 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -1796,10 +1796,7 @@ static inline int ext4_valid_inum(struct super_block *sb, unsigned long ino)
enum {
EXT4_MF_MNTDIR_SAMPLED,
EXT4_MF_FS_ABORTED, /* Fatal error detected */
- EXT4_MF_FC_INELIGIBLE, /* Fast commit ineligible */
- EXT4_MF_FC_COMMITTING /* File system underoing a fast
- * commit.
- */
+ EXT4_MF_FC_INELIGIBLE /* Fast commit ineligible */
};

static inline void ext4_set_mount_flag(struct super_block *sb, int bit)
diff --git a/fs/ext4/fast_commit.c b/fs/ext4/fast_commit.c
index e031afee42de..ccd2b216d6ba 100644
--- a/fs/ext4/fast_commit.c
+++ b/fs/ext4/fast_commit.c
@@ -375,7 +375,8 @@ static int ext4_fc_track_template(
spin_lock(&sbi->s_fc_lock);
if (list_empty(&EXT4_I(inode)->i_fc_list))
list_add_tail(&EXT4_I(inode)->i_fc_list,
- (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_COMMITTING)) ?
+ (sbi->s_journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
+ sbi->s_journal->j_flags & JBD2_FAST_COMMIT_ONGOING) ?
&sbi->s_fc_q[FC_Q_STAGING] :
&sbi->s_fc_q[FC_Q_MAIN]);
spin_unlock(&sbi->s_fc_lock);
@@ -428,7 +429,8 @@ static int __track_dentry_update(struct inode *inode, void *arg, bool update)
node->fcd_name.len = dentry->d_name.len;

spin_lock(&sbi->s_fc_lock);
- if (ext4_test_mount_flag(inode->i_sb, EXT4_MF_FC_COMMITTING))
+ if (sbi->s_journal->j_flags & JBD2_FULL_COMMIT_ONGOING ||
+ sbi->s_journal->j_flags & JBD2_FAST_COMMIT_ONGOING)
list_add_tail(&node->fcd_list,
&sbi->s_fc_dentry_q[FC_Q_STAGING]);
else
@@ -893,7 +895,6 @@ static int ext4_fc_submit_inode_data_all(journal_t *journal)
int ret = 0;

spin_lock(&sbi->s_fc_lock);
- ext4_set_mount_flag(sb, EXT4_MF_FC_COMMITTING);
list_for_each_entry(ei, &sbi->s_fc_q[FC_Q_MAIN], i_fc_list) {
ext4_set_inode_state(&ei->vfs_inode, EXT4_STATE_FC_COMMITTING);
while (atomic_read(&ei->i_fc_updates)) {
@@ -1211,7 +1212,8 @@ static void ext4_fc_cleanup(journal_t *journal, int full, tid_t tid)
list_del_init(&iter->i_fc_list);
ext4_clear_inode_state(&iter->vfs_inode,
EXT4_STATE_FC_COMMITTING);
- ext4_fc_reset_inode(&iter->vfs_inode);
+ if (iter->i_sync_tid <= tid)
+ ext4_fc_reset_inode(&iter->vfs_inode);
/* Make sure EXT4_STATE_FC_COMMITTING bit is clear */
smp_mb();
#if (BITS_PER_LONG < 64)
@@ -1240,7 +1242,6 @@ static void ext4_fc_cleanup(journal_t *journal, int full, tid_t tid)
list_splice_init(&sbi->s_fc_q[FC_Q_STAGING],
&sbi->s_fc_q[FC_Q_MAIN]);

- ext4_clear_mount_flag(sb, EXT4_MF_FC_COMMITTING);
if (tid >= sbi->s_fc_ineligible_tid) {
sbi->s_fc_ineligible_tid = 0;
ext4_clear_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 38b496745825..2b0a7e4fa379 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -5086,7 +5086,6 @@ static int __ext4_fill_super(struct fs_context *fc, struct super_block *sb)
INIT_LIST_HEAD(&sbi->s_fc_dentry_q[FC_Q_STAGING]);
sbi->s_fc_bytes = 0;
ext4_clear_mount_flag(sb, EXT4_MF_FC_INELIGIBLE);
- ext4_clear_mount_flag(sb, EXT4_MF_FC_COMMITTING);
sbi->s_fc_ineligible_tid = 0;
spin_lock_init(&sbi->s_fc_lock);
memset(&sbi->s_fc_stats, 0, sizeof(sbi->s_fc_stats));
--
2.25.1