Re: [Ocfs2-devel] [PATCH] ocfs2: fix the application IO timeout when fstrim is running

From: Changwei Ge
Date: Fri Jan 11 2019 - 04:56:02 EST


Hi Gang,

On 2019/1/11 17:01, Gang He wrote:
> The user reported this problem, the upper application IO was
> timeout when fstrim was running on this ocfs2 partition. the
> application monitoring resource agent considered that this
> application did not work, then this node was fenced by the cluster
> brain (e.g. pacemaker).
> The root cause is that fstrim thread always holds main_bm meta-file
> related locks until all the cluster groups are trimmed.
> This patch will make fstrim thread release main_bm meta-file
> related locks when each cluster group is trimmed, this will let
> the current application IO has a chance to claim the clusters from
> main_bm meta-file.

Sounds a good idea, I will look into this.

Thanks,
Changwei

>
> Signed-off-by: Gang He <ghe@xxxxxxxx>
> ---
> fs/ocfs2/alloc.c | 159 +++++++++++++++++++++++++----------------
> fs/ocfs2/dlmglue.c | 5 ++
> fs/ocfs2/ocfs2.h | 1 +
> fs/ocfs2/ocfs2_trace.h | 2 +
> fs/ocfs2/super.c | 2 +
> 5 files changed, 106 insertions(+), 63 deletions(-)
>
> diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
> index d1cbb27808e2..6f0999015a44 100644
> --- a/fs/ocfs2/alloc.c
> +++ b/fs/ocfs2/alloc.c
> @@ -7532,10 +7532,11 @@ static int ocfs2_trim_group(struct super_block *sb,
> return count;
> }
>
> -int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
> +static
> +int ocfs2_trim_mainbm(struct super_block *sb, struct fstrim_range *range)
> {
> struct ocfs2_super *osb = OCFS2_SB(sb);
> - u64 start, len, trimmed, first_group, last_group, group;
> + u64 start, len, trimmed = 0, first_group, last_group = 0, group = 0;
> int ret, cnt;
> u32 first_bit, last_bit, minlen;
> struct buffer_head *main_bm_bh = NULL;
> @@ -7543,7 +7544,6 @@ int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
> struct buffer_head *gd_bh = NULL;
> struct ocfs2_dinode *main_bm;
> struct ocfs2_group_desc *gd = NULL;
> - struct ocfs2_trim_fs_info info, *pinfo = NULL;
>
> start = range->start >> osb->s_clustersize_bits;
> len = range->len >> osb->s_clustersize_bits;
> @@ -7552,6 +7552,9 @@ int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
> if (minlen >= osb->bitmap_cpg || range->len < sb->s_blocksize)
> return -EINVAL;
>
> + trace_ocfs2_trim_mainbm(start, len, minlen);
> +
> +next_group:
> main_bm_inode = ocfs2_get_system_file_inode(osb,
> GLOBAL_BITMAP_SYSTEM_INODE,
> OCFS2_INVALID_SLOT);
> @@ -7570,64 +7573,34 @@ int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
> }
> main_bm = (struct ocfs2_dinode *)main_bm_bh->b_data;
>
> - if (start >= le32_to_cpu(main_bm->i_clusters)) {
> - ret = -EINVAL;
> - goto out_unlock;
> - }
> -
> - len = range->len >> osb->s_clustersize_bits;
> - if (start + len > le32_to_cpu(main_bm->i_clusters))
> - len = le32_to_cpu(main_bm->i_clusters) - start;
> -
> - trace_ocfs2_trim_fs(start, len, minlen);
> -
> - ocfs2_trim_fs_lock_res_init(osb);
> - ret = ocfs2_trim_fs_lock(osb, NULL, 1);
> - if (ret < 0) {
> - if (ret != -EAGAIN) {
> - mlog_errno(ret);
> - ocfs2_trim_fs_lock_res_uninit(osb);
> + /*
> + * Do some check before trim the first group.
> + */
> + if (!group) {
> + if (start >= le32_to_cpu(main_bm->i_clusters)) {
> + ret = -EINVAL;
> goto out_unlock;
> }
>
> - mlog(ML_NOTICE, "Wait for trim on device (%s) to "
> - "finish, which is running from another node.\n",
> - osb->dev_str);
> - ret = ocfs2_trim_fs_lock(osb, &info, 0);
> - if (ret < 0) {
> - mlog_errno(ret);
> - ocfs2_trim_fs_lock_res_uninit(osb);
> - goto out_unlock;
> - }
> + if (start + len > le32_to_cpu(main_bm->i_clusters))
> + len = le32_to_cpu(main_bm->i_clusters) - start;
>
> - if (info.tf_valid && info.tf_success &&
> - info.tf_start == start && info.tf_len == len &&
> - info.tf_minlen == minlen) {
> - /* Avoid sending duplicated trim to a shared device */
> - mlog(ML_NOTICE, "The same trim on device (%s) was "
> - "just done from node (%u), return.\n",
> - osb->dev_str, info.tf_nodenum);
> - range->len = info.tf_trimlen;
> - goto out_trimunlock;
> - }
> + /*
> + * Determine first and last group to examine based on
> + * start and len
> + */
> + first_group = ocfs2_which_cluster_group(main_bm_inode, start);
> + if (first_group == osb->first_cluster_group_blkno)
> + first_bit = start;
> + else
> + first_bit = start - ocfs2_blocks_to_clusters(sb,
> + first_group);
> + last_group = ocfs2_which_cluster_group(main_bm_inode,
> + start + len - 1);
> + group = first_group;
> }
>
> - info.tf_nodenum = osb->node_num;
> - info.tf_start = start;
> - info.tf_len = len;
> - info.tf_minlen = minlen;
> -
> - /* Determine first and last group to examine based on start and len */
> - first_group = ocfs2_which_cluster_group(main_bm_inode, start);
> - if (first_group == osb->first_cluster_group_blkno)
> - first_bit = start;
> - else
> - first_bit = start - ocfs2_blocks_to_clusters(sb, first_group);
> - last_group = ocfs2_which_cluster_group(main_bm_inode, start + len - 1);
> - last_bit = osb->bitmap_cpg;
> -
> - trimmed = 0;
> - for (group = first_group; group <= last_group;) {
> + do {
> if (first_bit + len >= osb->bitmap_cpg)
> last_bit = osb->bitmap_cpg;
> else
> @@ -7659,21 +7632,81 @@ int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
> group = ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
> else
> group += ocfs2_clusters_to_blocks(sb, osb->bitmap_cpg);
> - }
> - range->len = trimmed * sb->s_blocksize;
> + } while (0);
>
> - info.tf_trimlen = range->len;
> - info.tf_success = (ret ? 0 : 1);
> - pinfo = &info;
> -out_trimunlock:
> - ocfs2_trim_fs_unlock(osb, pinfo);
> - ocfs2_trim_fs_lock_res_uninit(osb);
> out_unlock:
> ocfs2_inode_unlock(main_bm_inode, 0);
> brelse(main_bm_bh);
> + main_bm_bh = NULL;
> out_mutex:
> inode_unlock(main_bm_inode);
> iput(main_bm_inode);
> +
> + /*
> + * If all the groups trim are not done or failed, but we should release
> + * main_bm related locks for avoiding the current IO starve, then go to
> + * trim the next group
> + */
> + if (ret >= 0 && group <= last_group)
> + goto next_group;
> out:
> + range->len = trimmed * sb->s_blocksize;
> + return ret;
> +}
> +
> +int ocfs2_trim_fs(struct super_block *sb, struct fstrim_range *range)
> +{
> + int ret;
> + struct ocfs2_super *osb = OCFS2_SB(sb);
> + struct ocfs2_trim_fs_info info, *pinfo = NULL;
> +
> + ocfs2_trim_fs_lock_res_init(osb);
> +
> + trace_ocfs2_trim_fs(range->start, range->len, range->minlen);
> +
> + ret = ocfs2_trim_fs_lock(osb, NULL, 1);
> + if (ret < 0) {
> + if (ret != -EAGAIN) {
> + mlog_errno(ret);
> + ocfs2_trim_fs_lock_res_uninit(osb);
> + return ret;
> + }
> +
> + mlog(ML_NOTICE, "Wait for trim on device (%s) to "
> + "finish, which is running from another node.\n",
> + osb->dev_str);
> + ret = ocfs2_trim_fs_lock(osb, &info, 0);
> + if (ret < 0) {
> + mlog_errno(ret);
> + ocfs2_trim_fs_lock_res_uninit(osb);
> + return ret;
> + }
> +
> + if (info.tf_valid && info.tf_success &&
> + info.tf_start == range->start &&
> + info.tf_len == range->len &&
> + info.tf_minlen == range->minlen) {
> + /* Avoid sending duplicated trim to a shared device */
> + mlog(ML_NOTICE, "The same trim on device (%s) was "
> + "just done from node (%u), return.\n",
> + osb->dev_str, info.tf_nodenum);
> + range->len = info.tf_trimlen;
> + goto out;
> + }
> + }
> +
> + info.tf_nodenum = osb->node_num;
> + info.tf_start = range->start;
> + info.tf_len = range->len;
> + info.tf_minlen = range->minlen;
> +
> + ret = ocfs2_trim_mainbm(sb, range);
> +
> + info.tf_trimlen = range->len;
> + info.tf_success = (ret < 0 ? 0 : 1);
> + pinfo = &info;
> +out:
> + ocfs2_trim_fs_unlock(osb, pinfo);
> + ocfs2_trim_fs_lock_res_uninit(osb);
> return ret;
> }
> diff --git a/fs/ocfs2/dlmglue.c b/fs/ocfs2/dlmglue.c
> index 7c835824247e..af405586c5b1 100644
> --- a/fs/ocfs2/dlmglue.c
> +++ b/fs/ocfs2/dlmglue.c
> @@ -686,6 +686,9 @@ void ocfs2_trim_fs_lock_res_init(struct ocfs2_super *osb)
> {
> struct ocfs2_lock_res *lockres = &osb->osb_trim_fs_lockres;
>
> + /* Only one trimfs thread are allowed to work at the same time. */
> + mutex_lock(&osb->obs_trim_fs_mutex);
> +
> ocfs2_lock_res_init_once(lockres);
> ocfs2_build_lock_name(OCFS2_LOCK_TYPE_TRIM_FS, 0, 0, lockres->l_name);
> ocfs2_lock_res_init_common(osb, lockres, OCFS2_LOCK_TYPE_TRIM_FS,
> @@ -698,6 +701,8 @@ void ocfs2_trim_fs_lock_res_uninit(struct ocfs2_super *osb)
>
> ocfs2_simple_drop_lockres(osb, lockres);
> ocfs2_lock_res_free(lockres);
> +
> + mutex_unlock(&osb->obs_trim_fs_mutex);
> }
>
> static void ocfs2_orphan_scan_lock_res_init(struct ocfs2_lock_res *res,
> diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
> index 4f86ac0027b5..1f029fbe8b8d 100644
> --- a/fs/ocfs2/ocfs2.h
> +++ b/fs/ocfs2/ocfs2.h
> @@ -407,6 +407,7 @@ struct ocfs2_super
> struct ocfs2_lock_res osb_rename_lockres;
> struct ocfs2_lock_res osb_nfs_sync_lockres;
> struct ocfs2_lock_res osb_trim_fs_lockres;
> + struct mutex obs_trim_fs_mutex;
> struct ocfs2_dlm_debug *osb_dlm_debug;
>
> struct dentry *osb_debug_root;
> diff --git a/fs/ocfs2/ocfs2_trace.h b/fs/ocfs2/ocfs2_trace.h
> index 2ee76a90ba8f..dc4bce1649c1 100644
> --- a/fs/ocfs2/ocfs2_trace.h
> +++ b/fs/ocfs2/ocfs2_trace.h
> @@ -712,6 +712,8 @@ TRACE_EVENT(ocfs2_trim_extent,
>
> DEFINE_OCFS2_ULL_UINT_UINT_UINT_EVENT(ocfs2_trim_group);
>
> +DEFINE_OCFS2_ULL_ULL_ULL_EVENT(ocfs2_trim_mainbm);
> +
> DEFINE_OCFS2_ULL_ULL_ULL_EVENT(ocfs2_trim_fs);
>
> /* End of trace events for fs/ocfs2/alloc.c. */
> diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
> index 3415e0b09398..96ae7cedd487 100644
> --- a/fs/ocfs2/super.c
> +++ b/fs/ocfs2/super.c
> @@ -1847,6 +1847,8 @@ static int ocfs2_mount_volume(struct super_block *sb)
> if (ocfs2_is_hard_readonly(osb))
> goto leave;
>
> + mutex_init(&osb->obs_trim_fs_mutex);
> +
> status = ocfs2_dlm_init(osb);
> if (status < 0) {
> mlog_errno(status);
>