On Thu 30-06-16 11:00:31, Ted Tso wrote:
> If there are no pending blocks to be released after a commit, forcing
> a journal commit has no hope of helping. It's possible that a commit
> had just completed, so if there are now free blocks available for
> allocation, it's worth retrying the commit.
>
> Reported-by: Chao Yu <yuchao0@xxxxxxxxxx>
> Signed-off-by: Theodore Ts'o <tytso@xxxxxxx>
The patch looks good now. Feel free to add:
Reviewed-by: Jan Kara <jack@xxxxxxx>
I'd just remove ext4_journal_callback_add() function since it is unused now
and if Lustre uses it, it can easily replicate it.
Honza
> ---
> fs/ext4/balloc.c | 4 +++-
> fs/ext4/ext4.h | 1 +
> fs/ext4/ext4_jbd2.h | 10 +++++++++-
> fs/ext4/mballoc.c | 12 ++++++++++--
> 4 files changed, 23 insertions(+), 4 deletions(-)
>
> diff --git a/fs/ext4/balloc.c b/fs/ext4/balloc.c
> index 3020fd7..0b8105b 100644
> --- a/fs/ext4/balloc.c
> +++ b/fs/ext4/balloc.c
> @@ -610,7 +610,9 @@ int ext4_should_retry_alloc(struct super_block *sb, int *retries)
>
> jbd_debug(1, "%s: retrying operation after ENOSPC\n", sb->s_id);
>
> - jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
> + smp_mb();
> + if (EXT4_SB(sb)->s_mb_free_pending)
> + jbd2_journal_force_commit_nested(EXT4_SB(sb)->s_journal);
> return 1;
> }
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index b84aa1c..96c73e6 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -1430,6 +1430,7 @@ struct ext4_sb_info {
> unsigned short *s_mb_offsets;
> unsigned int *s_mb_maxs;
> unsigned int s_group_info_size;
> + unsigned int s_mb_free_pending;
>
> /* tunables */
> unsigned long s_stripe;
> diff --git a/fs/ext4/ext4_jbd2.h b/fs/ext4/ext4_jbd2.h
> index 09c1ef3..b1d52c1 100644
> --- a/fs/ext4/ext4_jbd2.h
> +++ b/fs/ext4/ext4_jbd2.h
> @@ -175,6 +175,13 @@ struct ext4_journal_cb_entry {
> * There is no guaranteed calling order of multiple registered callbacks on
> * the same transaction.
> */
> +static inline void _ext4_journal_callback_add(handle_t *handle,
> + struct ext4_journal_cb_entry *jce)
> +{
> + /* Add the jce to transaction's private list */
> + list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);
> +}
> +
> static inline void ext4_journal_callback_add(handle_t *handle,
> void (*func)(struct super_block *sb,
> struct ext4_journal_cb_entry *jce,
> @@ -187,10 +194,11 @@ static inline void ext4_journal_callback_add(handle_t *handle,
> /* Add the jce to transaction's private list */
> jce->jce_func = func;
> spin_lock(&sbi->s_md_lock);
> - list_add_tail(&jce->jce_list, &handle->h_transaction->t_private_list);
> + _ext4_journal_callback_add(handle, jce);
> spin_unlock(&sbi->s_md_lock);
> }
>
> +
> /**
> * ext4_journal_callback_del: delete a registered callback
> * @handle: active journal transaction handle on which callback was registered
> diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
> index c1ab3ec..77249e1 100644
> --- a/fs/ext4/mballoc.c
> +++ b/fs/ext4/mballoc.c
> @@ -2627,6 +2627,7 @@ int ext4_mb_init(struct super_block *sb)
>
> spin_lock_init(&sbi->s_md_lock);
> spin_lock_init(&sbi->s_bal_lock);
> + sbi->s_mb_free_pending = 0;
>
> sbi->s_mb_max_to_scan = MB_DEFAULT_MAX_TO_SCAN;
> sbi->s_mb_min_to_scan = MB_DEFAULT_MIN_TO_SCAN;
> @@ -2814,6 +2815,9 @@ static void ext4_free_data_callback(struct super_block *sb,
> /* we expect to find existing buddy because it's pinned */
> BUG_ON(err != 0);
>
> + spin_lock(&EXT4_SB(sb)->s_md_lock);
> + EXT4_SB(sb)->s_mb_free_pending -= entry->efd_count;
> + spin_unlock(&EXT4_SB(sb)->s_md_lock);
>
> db = e4b.bd_info;
> /* there are blocks to put in buddy to make them really free */
> @@ -4583,6 +4587,7 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
> {
> ext4_group_t group = e4b->bd_group;
> ext4_grpblk_t cluster;
> + ext4_grpblk_t clusters = new_entry->efd_count;
> struct ext4_free_data *entry;
> struct ext4_group_info *db = e4b->bd_info;
> struct super_block *sb = e4b->bd_sb;
> @@ -4649,8 +4654,11 @@ ext4_mb_free_metadata(handle_t *handle, struct ext4_buddy *e4b,
> }
> }
> /* Add the extent to transaction's private list */
> - ext4_journal_callback_add(handle, ext4_free_data_callback,
> - &new_entry->efd_jce);
> + new_entry->efd_jce.jce_func = ext4_free_data_callback;
> + spin_lock(&sbi->s_md_lock);
> + _ext4_journal_callback_add(handle, &new_entry->efd_jce);
> + sbi->s_mb_free_pending += clusters;
> + spin_unlock(&sbi->s_md_lock);
> return 0;
> }
>
> --
> 2.5.0
>
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--
Jan Kara <jack@xxxxxxxx>
SUSE Labs, CR
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