nilfs2: get rid of GCDAT inode

This applies prepared rollback function and redirect function of
metadata file to DAT file, and eliminates GCDAT inode.

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

1 files changed, 29 insertions, 1 deletions

diff --git a/fs/nilfs2/dat.c b/fs/nilfs2/dat.c
index 013146755683..7091c4e0f042 100644
--- a/fs/nilfs2/dat.c
+++ b/fs/nilfs2/dat.c
@@ -36,6 +36,7 @@
 struct nilfs_dat_info {
         struct nilfs_mdt_info mi;
         struct nilfs_palloc_cache palloc_cache;
+        struct nilfs_shadow_map shadow;
 };
 
 static inline struct nilfs_dat_info *NILFS_DAT_I(struct inode *dat)
@@ -327,6 +328,23 @@ int nilfs_dat_move(struct inode *dat, __u64 vblocknr, sector_t blocknr)
         ret = nilfs_palloc_get_entry_block(dat, vblocknr, 0, &entry_bh);
         if (ret < 0)
                 return ret;
+
+        /*
+         * The given disk block number (blocknr) is not yet written to
+         * the device at this point.
+         *
+         * To prevent nilfs_dat_translate() from returning the
+         * uncommited block number, this makes a copy of the entry
+         * buffer and redirects nilfs_dat_translate() to the copy.
+         */
+        if (!buffer_nilfs_redirected(entry_bh)) {
+                ret = nilfs_mdt_freeze_buffer(dat, entry_bh);
+                if (ret) {
+                        brelse(entry_bh);
+                        return ret;
+                }
+        }
+
         kaddr = kmap_atomic(entry_bh->b_page, KM_USER0);
         entry = nilfs_palloc_block_get_entry(dat, vblocknr, entry_bh, kaddr);
         if (unlikely(entry->de_blocknr == cpu_to_le64(0))) {
@@ -371,7 +389,7 @@ int nilfs_dat_move(struct inode *dat, __u64 vblocknr, sector_t blocknr)
  */
 int nilfs_dat_translate(struct inode *dat, __u64 vblocknr, sector_t *blocknrp)
 {
-        struct buffer_head *entry_bh;
+        struct buffer_head *entry_bh, *bh;
         struct nilfs_dat_entry *entry;
         sector_t blocknr;
         void *kaddr;
@@ -381,6 +399,15 @@ int nilfs_dat_translate(struct inode *dat, __u64 vblocknr, sector_t *blocknrp)
         if (ret < 0)
                 return ret;
 
+        if (!nilfs_doing_gc() && buffer_nilfs_redirected(entry_bh)) {
+                bh = nilfs_mdt_get_frozen_buffer(dat, entry_bh);
+                if (bh) {
+                        WARN_ON(!buffer_uptodate(bh));
+                        brelse(entry_bh);
+                        entry_bh = bh;
+                }
+        }
+
         kaddr = kmap_atomic(entry_bh->b_page, KM_USER0);
         entry = nilfs_palloc_block_get_entry(dat, vblocknr, entry_bh, kaddr);
         blocknr = le64_to_cpu(entry->de_blocknr);
@@ -468,6 +495,7 @@ struct inode *nilfs_dat_new(struct the_nilfs *nilfs, size_t entry_size)
                 di = NILFS_DAT_I(dat);
                 lockdep_set_class(&di->mi.mi_sem, &dat_lock_key);
                 nilfs_palloc_setup_cache(dat, &di->palloc_cache);
+                nilfs_mdt_setup_shadow_map(dat, &di->shadow);
         }
         return dat;
 }