[Ocfs2-devel] [PATCH v3] ocfs2: retry on ENOSPC if sufficient space in truncate log
Joseph Qi
joseph.qi at huawei.com
Mon Jul 11 04:04:45 PDT 2016
On 2016/7/9 10:32, Eric Ren wrote:
> The testcase "mmaptruncate" in ocfs2 test suite always fails with
> ENOSPC error on small volume (say less than 10G). This testcase
> repeatedly performs "extend" and "truncate" on a file. Continuously,
> it truncates the file to 1/2 of the size, and then extends to 100% of
> the size. The main bitmap will quickly run out of space because the
> "truncate" code prevent truncate log from being flushed by
> ocfs2_schedule_truncate_log_flush(osb, 1), while truncate log may
> have cached lots of clusters.
>
> So retry to allocate after flushing truncate log when ENOSPC is
> returned. And we cannot reuse the deleted blocks before the transaction
> committed. Fortunately, we already have a function to do this -
> ocfs2_try_to_free_truncate_log(). Just need to remove the "static"
> modifier and put it into the right place.
>
> The "unlock"/"lock" code isn't elegant, but looks no better option.
>
> v3:
> 1. Also need to lock allocator inode when "= 0" is returned from
> ocfs2_schedule_truncate_log_flush(), which means no space really.
> -- spotted by Joseph Qi
>
> v2:
> 1. Lock allocator inode again if ocfs2_schedule_truncate_log_flush()
> fails. -- spotted by Joseph Qi <joseph.qi at huawei.com>
>
> Signed-off-by: Eric Ren <zren at suse.com>
Reviewed-by: Joseph Qi <joseph.qi at huawei.com>
> ---
> fs/ocfs2/alloc.c | 37 +++++++++++++++++++++++++++++++++++++
> fs/ocfs2/alloc.h | 2 ++
> fs/ocfs2/aops.c | 37 -------------------------------------
> fs/ocfs2/suballoc.c | 20 +++++++++++++++++++-
> 4 files changed, 58 insertions(+), 38 deletions(-)
>
> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
> index 460c0ce..7dabbc3 100644
> --- a/fs/ocfs2/alloc.c
> +++ b/fs/ocfs2/alloc.c
> @@ -6106,6 +6106,43 @@ void ocfs2_schedule_truncate_log_flush(struct ocfs2_super *osb,
> }
> }
>
> +/*
> + * Try to flush truncate logs if we can free enough clusters from it.
> + * As for return value, "< 0" means error, "0" no space and "1" means
> + * we have freed enough spaces and let the caller try to allocate again.
> + */
> +int ocfs2_try_to_free_truncate_log(struct ocfs2_super *osb,
> + unsigned int needed)
> +{
> + tid_t target;
> + int ret = 0;
> + unsigned int truncated_clusters;
> +
> + inode_lock(osb->osb_tl_inode);
> + truncated_clusters = osb->truncated_clusters;
> + inode_unlock(osb->osb_tl_inode);
> +
> + /*
> + * Check whether we can succeed in allocating if we free
> + * the truncate log.
> + */
> + if (truncated_clusters < needed)
> + goto out;
> +
> + ret = ocfs2_flush_truncate_log(osb);
> + if (ret) {
> + mlog_errno(ret);
> + goto out;
> + }
> +
> + if (jbd2_journal_start_commit(osb->journal->j_journal, &target)) {
> + jbd2_log_wait_commit(osb->journal->j_journal, target);
> + ret = 1;
> + }
> +out:
> + return ret;
> +}
> +
> static int ocfs2_get_truncate_log_info(struct ocfs2_super *osb,
> int slot_num,
> struct inode **tl_inode,
> diff --git a/fs/ocfs2/alloc.h b/fs/ocfs2/alloc.h
> index f3dc1b0..4a5152e 100644
> --- a/fs/ocfs2/alloc.h
> +++ b/fs/ocfs2/alloc.h
> @@ -188,6 +188,8 @@ int ocfs2_truncate_log_append(struct ocfs2_super *osb,
> u64 start_blk,
> unsigned int num_clusters);
> int __ocfs2_flush_truncate_log(struct ocfs2_super *osb);
> +int ocfs2_try_to_free_truncate_log(struct ocfs2_super *osb,
> + unsigned int needed);
>
> /*
> * Process local structure which describes the block unlinks done
> diff --git a/fs/ocfs2/aops.c b/fs/ocfs2/aops.c
> index c034edf..1802aef 100644
> --- a/fs/ocfs2/aops.c
> +++ b/fs/ocfs2/aops.c
> @@ -1645,43 +1645,6 @@ static int ocfs2_zero_tail(struct inode *inode, struct buffer_head *di_bh,
> return ret;
> }
>
> -/*
> - * Try to flush truncate logs if we can free enough clusters from it.
> - * As for return value, "< 0" means error, "0" no space and "1" means
> - * we have freed enough spaces and let the caller try to allocate again.
> - */
> -static int ocfs2_try_to_free_truncate_log(struct ocfs2_super *osb,
> - unsigned int needed)
> -{
> - tid_t target;
> - int ret = 0;
> - unsigned int truncated_clusters;
> -
> - inode_lock(osb->osb_tl_inode);
> - truncated_clusters = osb->truncated_clusters;
> - inode_unlock(osb->osb_tl_inode);
> -
> - /*
> - * Check whether we can succeed in allocating if we free
> - * the truncate log.
> - */
> - if (truncated_clusters < needed)
> - goto out;
> -
> - ret = ocfs2_flush_truncate_log(osb);
> - if (ret) {
> - mlog_errno(ret);
> - goto out;
> - }
> -
> - if (jbd2_journal_start_commit(osb->journal->j_journal, &target)) {
> - jbd2_log_wait_commit(osb->journal->j_journal, target);
> - ret = 1;
> - }
> -out:
> - return ret;
> -}
> -
> int ocfs2_write_begin_nolock(struct address_space *mapping,
> loff_t pos, unsigned len, ocfs2_write_type_t type,
> struct page **pagep, void **fsdata,
> diff --git a/fs/ocfs2/suballoc.c b/fs/ocfs2/suballoc.c
> index 2f19aee..ea47120 100644
> --- a/fs/ocfs2/suballoc.c
> +++ b/fs/ocfs2/suballoc.c
> @@ -1164,7 +1164,8 @@ static int ocfs2_reserve_clusters_with_limit(struct ocfs2_super *osb,
> int flags,
> struct ocfs2_alloc_context **ac)
> {
> - int status;
> + int status, ret = 0;
> + int retried = 0;
>
> *ac = kzalloc(sizeof(struct ocfs2_alloc_context), GFP_KERNEL);
> if (!(*ac)) {
> @@ -1189,7 +1190,24 @@ static int ocfs2_reserve_clusters_with_limit(struct ocfs2_super *osb,
> }
>
> if (status == -ENOSPC) {
> +retry:
> status = ocfs2_reserve_cluster_bitmap_bits(osb, *ac);
> + /* Retry if there is sufficient space cached in truncate log */
> + if (status == -ENOSPC && !retried) {
> + retried = 1;
> + ocfs2_inode_unlock((*ac)->ac_inode, 1);
> + inode_unlock((*ac)->ac_inode);
> +
> + ret = ocfs2_try_to_free_truncate_log(osb, bits_wanted);
> + if (ret == 1)
> + goto retry;
> +
> + if (ret < 0)
> + mlog_errno(ret);
> +
> + inode_lock((*ac)->ac_inode);
> + ocfs2_inode_lock((*ac)->ac_inode, NULL, 1);
> + }
> if (status < 0) {
> if (status != -ENOSPC)
> mlog_errno(status);
>
More information about the Ocfs2-devel
mailing list