nilfs2: fix possible mismatch of sufile counters on recovery

On-disk counters ndirtysegs and ncleansegs of sufile, can go wrong
after roll-forward recovery because
nilfs_prepare_segment_for_recovery() function marks segments dirty
without adjusting value of these counters.

This fixes the problem by adding a function to sufile which does the
operation adjusting the counters, and by letting the recovery function
use it.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>

3 files changed, 45 insertions, 16 deletions

diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
index 6ade0963fc1d..4fc081e47d70 100644
--- a/fs/nilfs2/recovery.c
+++ b/fs/nilfs2/recovery.c
@@ -413,7 +413,6 @@ static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
         struct nilfs_segment_entry *ent, *n;
         struct inode *sufile = nilfs->ns_sufile;
         __u64 segnum[4];
-        time_t mtime;
         int err;
         int i;
 
@@ -442,24 +441,13 @@ static int nilfs_prepare_segment_for_recovery(struct the_nilfs *nilfs,
          * Collecting segments written after the latest super root.
          * These are marked dirty to avoid being reallocated in the next write.
          */
-        mtime = get_seconds();
         list_for_each_entry_safe(ent, n, head, list) {
-                if (ent->segnum == segnum[0]) {
-                        list_del(&ent->list);
-                        nilfs_free_segment_entry(ent);
-                        continue;
-                }
-                err = nilfs_open_segment_entry(ent, sufile);
-                if (unlikely(err))
-                        goto failed;
-                if (!nilfs_segment_usage_dirty(ent->raw_su)) {
-                        /* make the segment garbage */
-                        ent->raw_su->su_nblocks = cpu_to_le32(0);
-                        ent->raw_su->su_lastmod = cpu_to_le32(mtime);
-                        nilfs_segment_usage_set_dirty(ent->raw_su);
+                if (ent->segnum != segnum[0]) {
+                        err = nilfs_sufile_scrap(sufile, ent->segnum);
+                        if (unlikely(err))
+                                goto failed;
                 }
                 list_del(&ent->list);
-                nilfs_close_segment_entry(ent, sufile);
                 nilfs_free_segment_entry(ent);
         }
 
diff --git a/fs/nilfs2/sufile.c b/fs/nilfs2/sufile.c
index 07013f58dfe9..98e68677f045 100644
--- a/fs/nilfs2/sufile.c
+++ b/fs/nilfs2/sufile.c
@@ -258,6 +258,35 @@ void nilfs_sufile_do_cancel_free(struct inode *sufile, __u64 segnum,
         nilfs_mdt_mark_dirty(sufile);
 }
 
+void nilfs_sufile_do_scrap(struct inode *sufile, __u64 segnum,
+                           struct buffer_head *header_bh,
+                           struct buffer_head *su_bh)
+{
+        struct nilfs_segment_usage *su;
+        void *kaddr;
+        int clean, dirty;
+
+        kaddr = kmap_atomic(su_bh->b_page, KM_USER0);
+        su = nilfs_sufile_block_get_segment_usage(sufile, segnum, su_bh, kaddr);
+        if (su->su_flags == cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY) &&
+            su->su_nblocks == cpu_to_le32(0)) {
+                kunmap_atomic(kaddr, KM_USER0);
+                return;
+        }
+        clean = nilfs_segment_usage_clean(su);
+        dirty = nilfs_segment_usage_dirty(su);
+
+        /* make the segment garbage */
+        su->su_lastmod = cpu_to_le64(0);
+        su->su_nblocks = cpu_to_le32(0);
+        su->su_flags = cpu_to_le32(1UL << NILFS_SEGMENT_USAGE_DIRTY);
+        kunmap_atomic(kaddr, KM_USER0);
+
+        nilfs_sufile_mod_counter(header_bh, clean ? (u64)-1 : 0, dirty ? 0 : 1);
+        nilfs_mdt_mark_buffer_dirty(su_bh);
+        nilfs_mdt_mark_dirty(sufile);
+}
+
 void nilfs_sufile_do_free(struct inode *sufile, __u64 segnum,
                           struct buffer_head *header_bh,
                           struct buffer_head *su_bh)
diff --git a/fs/nilfs2/sufile.h b/fs/nilfs2/sufile.h
index 449a6e2671b0..a2e2efd4ade1 100644
--- a/fs/nilfs2/sufile.h
+++ b/fs/nilfs2/sufile.h
@@ -52,6 +52,8 @@ int nilfs_sufile_update(struct inode *, __u64, int,
                                        struct buffer_head *));
 void nilfs_sufile_do_cancel_free(struct inode *, __u64, struct buffer_head *,
                                  struct buffer_head *);
+void nilfs_sufile_do_scrap(struct inode *, __u64, struct buffer_head *,
+                           struct buffer_head *);
 void nilfs_sufile_do_free(struct inode *, __u64, struct buffer_head *,
                           struct buffer_head *);
 void nilfs_sufile_do_set_error(struct inode *, __u64, struct buffer_head *,
@@ -78,6 +80,16 @@ static inline int nilfs_sufile_cancel_free(struct inode *sufile, __u64 segnum)
 }
 
 /**
+ * nilfs_sufile_scrap - make a segment garbage
+ * @sufile: inode of segment usage file
+ * @segnum: segment number to be freed
+ */
+static inline int nilfs_sufile_scrap(struct inode *sufile, __u64 segnum)
+{
+        return nilfs_sufile_update(sufile, segnum, 1, nilfs_sufile_do_scrap);
+}
+
+/**
  * nilfs_sufile_free - free segment
  * @sufile: inode of segment usage file
  * @segnum: segment number to be freed