On Tue 08-03-22 02:51:10, Harshad Shirwadkar wrote:
> From: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
>
> If the inode that's being requested to track using ext4_fc_track_inode
> is being committed, then wait until the inode finishes the commit.
>
> Signed-off-by: Harshad Shirwadkar <harshadshirwadkar@xxxxxxxxx>
Looks mostly good. Just some notes below.
> diff --git a/fs/ext4/ext4_jbd2.c b/fs/ext4/ext4_jbd2.c
> index 3477a16d08ae..7fa301b0a35a 100644
> --- a/fs/ext4/ext4_jbd2.c
> +++ b/fs/ext4/ext4_jbd2.c
> @@ -106,6 +106,18 @@ handle_t *__ext4_journal_start_sb(struct super_block *sb, unsigned int line,
> GFP_NOFS, type, line);
> }
>
> +handle_t *__ext4_journal_start(struct inode *inode, unsigned int line,
> + int type, int blocks, int rsv_blocks,
> + int revoke_creds)
> +{
> + handle_t *handle = __ext4_journal_start_sb(inode->i_sb, line,
> + type, blocks, rsv_blocks,
> + revoke_creds);
> + if (ext4_handle_valid(handle) && !IS_ERR(handle))
> + ext4_fc_track_inode(handle, inode);
Why do you need to call ext4_fc_track_inode() here? Calls in
ext4_map_blocks() and ext4_mark_iloc_dirty() should be enough, shouldn't
they?
> + return handle;
> +}
> +
> int __ext4_journal_stop(const char *where, unsigned int line, handle_t *handle)
> {
> struct super_block *sb;
...
> @@ -519,6 +525,33 @@ void ext4_fc_track_inode(handle_t *handle, struct inode *inode)
> return;
> }
>
> + if (!test_opt2(inode->i_sb, JOURNAL_FAST_COMMIT) ||
> + (EXT4_SB(inode->i_sb)->s_mount_state & EXT4_FC_REPLAY))
> + return;
> +
> + spin_lock(&ei->i_fc_lock);
> + while (ext4_test_inode_state(inode, EXT4_STATE_FC_COMMITTING)) {
> +#if (BITS_PER_LONG < 64)
> + DEFINE_WAIT_BIT(wait, &ei->i_state_flags,
> + EXT4_STATE_FC_COMMITTING);
> + wq = bit_waitqueue(&ei->i_state_flags,
> + EXT4_STATE_FC_COMMITTING);
> +#else
> + DEFINE_WAIT_BIT(wait, &ei->i_flags,
> + EXT4_STATE_FC_COMMITTING);
> + wq = bit_waitqueue(&ei->i_flags,
> + EXT4_STATE_FC_COMMITTING);
> +#endif
> +
> + prepare_to_wait(wq, &wait.wq_entry, TASK_UNINTERRUPTIBLE);
> + spin_unlock(&ei->i_fc_lock);
> +
> + schedule();
> + finish_wait(wq, &wait.wq_entry);
> + spin_lock(&ei->i_fc_lock);
> + }
> + spin_unlock(&ei->i_fc_lock);
Hum, we operate inode state with atomic bitops. So I think there's no real
need for ei->i_fc_lock here. You just need to be careful and check inode
state again after prepare_to_wait() call.
Honza
--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
