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>

1 files changed, 29 insertions, 0 deletions

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)