ocfs2: fix the application IO timeout when fstrim is running

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.

Link: http://lkml.kernel.org/r/20190111090014.31645-1-ghe@suse.com
Signed-off-by: Gang He <ghe@suse.com>
Reviewed-by: Changwei Ge <ge.changwei@h3c.com>
Cc: Mark Fasheh <mfasheh@versity.com>
Cc: Joel Becker <jlbec@evilplan.org>
Cc: Junxiao Bi <junxiao.bi@oracle.com>
Cc: Joseph Qi <joseph.qi@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/fs/ocfs2/alloc.c b/fs/ocfs2/alloc.c
index d1cbb27808e27597592538a176d99e388a5d2705..6f0999015a44e536b89fec658bf931437558a9aa 100644 (file)
--- 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 7c835824247eb7a64446467b03080f07f67aa90e..af405586c5b111f5ddb4612728131e28d597f8fe 100644 (file)
--- 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 4f86ac0027b5ba376495e3bf859c8e8f57ccf452..1f029fbe8b8d1d210ee7ebe70294246c87885fe9 100644 (file)
--- 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 2ee76a90ba8f7406548da0b15bcc8624a332ae73..dc4bce1649c1bc36563499d1da8d84a862257782 100644 (file)
--- 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 3415e0b09398fb50a813499f14596db104cd414c..96ae7cedd487931ca8d1af33270763c9e186931b 100644 (file)
--- 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);