nilfs2: set pointer to root object in inodes

This puts a pointer to nilfs_root object in the private part of
on-memory inode, and makes nilfs_iget function pick up the inode with
the same root object.

Non-root inodes inherit its nilfs_root object from parent inode.  That
of the root inode is allocated through nilfs_attach_checkpoint()
function.

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

5 files changed, 68 insertions, 20 deletions

diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c
index 82cfdbc43e1c..7306fc7c4962 100644
--- a/fs/nilfs2/inode.c
+++ b/fs/nilfs2/inode.c
@@ -37,6 +37,7 @@
 struct nilfs_iget_args {
         u64 ino;
         __u64 cno;
+        struct nilfs_root *root;
         int for_gc;
 };
 
@@ -284,6 +285,7 @@ struct inode *nilfs_new_inode(struct inode *dir, int mode)
         struct nilfs_sb_info *sbi = NILFS_SB(sb);
         struct inode *inode;
         struct nilfs_inode_info *ii;
+        struct nilfs_root *root;
         int err = -ENOMEM;
         ino_t ino;
 
@@ -294,8 +296,10 @@ struct inode *nilfs_new_inode(struct inode *dir, int mode)
         mapping_set_gfp_mask(inode->i_mapping,
                              mapping_gfp_mask(inode->i_mapping) & ~__GFP_FS);
 
+        root = NILFS_I(dir)->i_root;
         ii = NILFS_I(inode);
         ii->i_state = 1 << NILFS_I_NEW;
+        ii->i_root = root;
 
         err = nilfs_ifile_create_inode(sbi->s_ifile, &ino, &ii->i_bh);
         if (unlikely(err))
@@ -484,7 +488,7 @@ static int nilfs_iget_test(struct inode *inode, void *opaque)
         struct nilfs_iget_args *args = opaque;
         struct nilfs_inode_info *ii;
 
-        if (args->ino != inode->i_ino)
+        if (args->ino != inode->i_ino || args->root != NILFS_I(inode)->i_root)
                 return 0;
 
         ii = NILFS_I(inode);
@@ -502,13 +506,21 @@ static int nilfs_iget_set(struct inode *inode, void *opaque)
         if (args->for_gc) {
                 NILFS_I(inode)->i_state = 1 << NILFS_I_GCINODE;
                 NILFS_I(inode)->i_cno = args->cno;
+                NILFS_I(inode)->i_root = NULL;
+        } else {
+                if (args->root && args->ino == NILFS_ROOT_INO)
+                        nilfs_get_root(args->root);
+                NILFS_I(inode)->i_root = args->root;
         }
         return 0;
 }
 
-struct inode *nilfs_iget(struct super_block *sb, unsigned long ino)
+struct inode *nilfs_iget(struct super_block *sb, struct nilfs_root *root,
+                         unsigned long ino)
 {
-        struct nilfs_iget_args args = { .ino = ino, .cno = 0, .for_gc = 0 };
+        struct nilfs_iget_args args = {
+                .ino = ino, .root = root, .cno = 0, .for_gc = 0
+        };
         struct inode *inode;
         int err;
 
@@ -530,7 +542,9 @@ struct inode *nilfs_iget(struct super_block *sb, unsigned long ino)
 struct inode *nilfs_iget_for_gc(struct super_block *sb, unsigned long ino,
                                 __u64 cno)
 {
-        struct nilfs_iget_args args = { .ino = ino, .cno = cno, .for_gc = 1 };
+        struct nilfs_iget_args args = {
+                .ino = ino, .root = NULL, .cno = cno, .for_gc = 1
+        };
         struct inode *inode;
         int err;
 
@@ -682,6 +696,9 @@ static void nilfs_clear_inode(struct inode *inode)
                 nilfs_bmap_clear(ii->i_bmap);
 
         nilfs_btnode_cache_clear(&ii->i_btnode_cache);
+
+        if (ii->i_root && inode->i_ino == NILFS_ROOT_INO)
+                nilfs_put_root(ii->i_root);
 }
 
 void nilfs_evict_inode(struct inode *inode)
@@ -690,7 +707,7 @@ void nilfs_evict_inode(struct inode *inode)
         struct super_block *sb = inode->i_sb;
         struct nilfs_inode_info *ii = NILFS_I(inode);
 
-        if (inode->i_nlink || unlikely(is_bad_inode(inode))) {
+        if (inode->i_nlink || !ii->i_root || unlikely(is_bad_inode(inode))) {
                 if (inode->i_data.nrpages)
                         truncate_inode_pages(&inode->i_data, 0);
                 end_writeback(inode);
diff --git a/fs/nilfs2/namei.c b/fs/nilfs2/namei.c
index ad6ed2cf19b4..1110d56a23f5 100644
--- a/fs/nilfs2/namei.c
+++ b/fs/nilfs2/namei.c
@@ -70,7 +70,7 @@ nilfs_lookup(struct inode *dir, struct dentry *dentry, struct nameidata *nd)
         ino = nilfs_inode_by_name(dir, &dentry->d_name);
         inode = NULL;
         if (ino) {
-                inode = nilfs_iget(dir->i_sb, ino);
+                inode = nilfs_iget(dir->i_sb, NILFS_I(dir)->i_root, ino);
                 if (IS_ERR(inode))
                         return ERR_CAST(inode);
         }
@@ -87,7 +87,8 @@ struct dentry *nilfs_get_parent(struct dentry *child)
         if (!ino)
                 return ERR_PTR(-ENOENT);
 
-        inode = nilfs_iget(child->d_inode->i_sb, ino);
+        inode = nilfs_iget(child->d_inode->i_sb,
+                           NILFS_I(child->d_inode)->i_root, ino);
         if (IS_ERR(inode))
                 return ERR_CAST(inode);
         return d_obtain_alias(inode);
diff --git a/fs/nilfs2/nilfs.h b/fs/nilfs2/nilfs.h
index 797cd437970e..21d90c4b4e2d 100644
--- a/fs/nilfs2/nilfs.h
+++ b/fs/nilfs2/nilfs.h
@@ -59,6 +59,7 @@ struct nilfs_inode_info {
 #endif
         struct buffer_head *i_bh;       /* i_bh contains a new or dirty
                                            disk inode */
+        struct nilfs_root *i_root;
         struct inode vfs_inode;
 };
 
@@ -247,7 +248,8 @@ extern int nilfs_get_block(struct inode *, sector_t, struct buffer_head *, int);
 extern void nilfs_set_inode_flags(struct inode *);
 extern int nilfs_read_inode_common(struct inode *, struct nilfs_inode *);
 extern void nilfs_write_inode_common(struct inode *, struct nilfs_inode *, int);
-extern struct inode *nilfs_iget(struct super_block *, unsigned long);
+struct inode *nilfs_iget(struct super_block *sb, struct nilfs_root *root,
+                         unsigned long ino);
 extern struct inode *nilfs_iget_for_gc(struct super_block *sb,
                                        unsigned long ino, __u64 cno);
 extern void nilfs_update_inode(struct inode *, struct buffer_head *);
@@ -285,7 +287,8 @@ extern struct nilfs_super_block **nilfs_prepare_super(struct nilfs_sb_info *,
                                                       int flip);
 extern int nilfs_commit_super(struct nilfs_sb_info *, int);
 extern int nilfs_cleanup_super(struct nilfs_sb_info *);
-extern int nilfs_attach_checkpoint(struct nilfs_sb_info *, __u64);
+int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
+                            struct nilfs_root **root);
 extern void nilfs_detach_checkpoint(struct nilfs_sb_info *);
 
 /* gcinode.c */
diff --git a/fs/nilfs2/recovery.c b/fs/nilfs2/recovery.c
index d0c35ef39f6a..a9a5ba8f57d5 100644
--- a/fs/nilfs2/recovery.c
+++ b/fs/nilfs2/recovery.c
@@ -504,6 +504,7 @@ static int nilfs_recovery_copy_block(struct the_nilfs *nilfs,
 
 static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs,
                                       struct nilfs_sb_info *sbi,
+                                      struct nilfs_root *root,
                                       struct list_head *head,
                                       unsigned long *nr_salvaged_blocks)
 {
@@ -515,7 +516,7 @@ static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs,
         int err = 0, err2 = 0;
 
         list_for_each_entry_safe(rb, n, head, list) {
-                inode = nilfs_iget(sbi->s_super, rb->ino);
+                inode = nilfs_iget(sbi->s_super, root, rb->ino);
                 if (IS_ERR(inode)) {
                         err = PTR_ERR(inode);
                         inode = NULL;
@@ -578,6 +579,7 @@ static int nilfs_recover_dsync_blocks(struct the_nilfs *nilfs,
  */
 static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
                                  struct nilfs_sb_info *sbi,
+                                 struct nilfs_root *root,
                                  struct nilfs_recovery_info *ri)
 {
         struct buffer_head *bh_sum = NULL;
@@ -649,7 +651,7 @@ static int nilfs_do_roll_forward(struct the_nilfs *nilfs,
                                 goto failed;
                         if (flags & NILFS_SS_LOGEND) {
                                 err = nilfs_recover_dsync_blocks(
-                                        nilfs, sbi, &dsync_blocks,
+                                        nilfs, sbi, root, &dsync_blocks,
                                         &nsalvaged_blocks);
                                 if (unlikely(err))
                                         goto failed;
@@ -746,19 +748,20 @@ int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
                               struct nilfs_sb_info *sbi,
                               struct nilfs_recovery_info *ri)
 {
+        struct nilfs_root *root;
         int err;
 
         if (ri->ri_lsegs_start == 0 || ri->ri_lsegs_end == 0)
                 return 0;
 
-        err = nilfs_attach_checkpoint(sbi, ri->ri_cno);
+        err = nilfs_attach_checkpoint(sbi, ri->ri_cno, true, &root);
         if (unlikely(err)) {
                 printk(KERN_ERR
                        "NILFS: error loading the latest checkpoint.\n");
                 return err;
         }
 
-        err = nilfs_do_roll_forward(nilfs, sbi, ri);
+        err = nilfs_do_roll_forward(nilfs, sbi, root, ri);
         if (unlikely(err))
                 goto failed;
 
@@ -789,6 +792,7 @@ int nilfs_salvage_orphan_logs(struct the_nilfs *nilfs,
 
  failed:
         nilfs_detach_checkpoint(sbi);
+        nilfs_put_root(root);
         return err;
 }
 
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index f3a00a3b2a03..a1c0e38a7706 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -391,18 +391,24 @@ static int nilfs_sync_fs(struct super_block *sb, int wait)
         return err;
 }
 
-int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
+int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno, int curr_mnt,
+                            struct nilfs_root **rootp)
 {
         struct the_nilfs *nilfs = sbi->s_nilfs;
+        struct nilfs_root *root;
         struct nilfs_checkpoint *raw_cp;
         struct buffer_head *bh_cp;
-        int err;
+        int err = -ENOMEM;
+
+        root = nilfs_find_or_create_root(
+                nilfs, curr_mnt ? NILFS_CPTREE_CURRENT_CNO : cno);
+        if (!root)
+                return err;
 
         down_write(&nilfs->ns_super_sem);
         list_add(&sbi->s_list, &nilfs->ns_supers);
         up_write(&nilfs->ns_super_sem);
 
-        err = -ENOMEM;
         sbi->s_ifile = nilfs_ifile_new(sbi, nilfs->ns_inode_size);
         if (!sbi->s_ifile)
                 goto delist;
@@ -428,6 +434,8 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
         atomic_set(&sbi->s_blocks_count, le64_to_cpu(raw_cp->cp_blocks_count));
 
         nilfs_cpfile_put_checkpoint(nilfs->ns_cpfile, cno, bh_cp);
+
+        *rootp = root;
         return 0;
 
  failed_bh:
@@ -440,6 +448,7 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
         down_write(&nilfs->ns_super_sem);
         list_del_init(&sbi->s_list);
         up_write(&nilfs->ns_super_sem);
+        nilfs_put_root(root);
 
         return err;
 }
@@ -551,12 +560,20 @@ static struct inode *
 nilfs_nfs_get_inode(struct super_block *sb, u64 ino, u32 generation)
 {
         struct inode *inode;
+        struct nilfs_root *root;
 
         if (ino < NILFS_FIRST_INO(sb) && ino != NILFS_ROOT_INO &&
             ino != NILFS_SKETCH_INO)
                 return ERR_PTR(-ESTALE);
 
-        inode = nilfs_iget(sb, ino);
+        root = nilfs_lookup_root(NILFS_SB(sb)->s_nilfs,
+                                 NILFS_CPTREE_CURRENT_CNO);
+        if (!root)
+                return ERR_PTR(-ESTALE);
+
+        /* new file handle type is required to export snapshots */
+        inode = nilfs_iget(sb, root, ino);
+        nilfs_put_root(root);
         if (IS_ERR(inode))
                 return ERR_CAST(inode);
         if (generation && inode->i_generation != generation) {
@@ -815,9 +832,10 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
                  struct the_nilfs *nilfs)
 {
         struct nilfs_sb_info *sbi;
+        struct nilfs_root *fsroot;
         struct inode *root;
         __u64 cno;
-        int err;
+        int err, curr_mnt;
 
         sbi = kzalloc(sizeof(*sbi), GFP_KERNEL);
         if (!sbi)
@@ -859,6 +877,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
                 goto failed_sbi;
 
         cno = nilfs_last_cno(nilfs);
+        curr_mnt = true;
 
         if (sb->s_flags & MS_RDONLY) {
                 if (nilfs_test_opt(sbi, SNAPSHOT)) {
@@ -881,10 +900,11 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
                                 goto failed_sbi;
                         }
                         cno = sbi->s_snapshot_cno;
+                        curr_mnt = false;
                 }
         }
 
-        err = nilfs_attach_checkpoint(sbi, cno);
+        err = nilfs_attach_checkpoint(sbi, cno, curr_mnt, &fsroot);
         if (err) {
                 printk(KERN_ERR "NILFS: error loading a checkpoint"
                        " (checkpoint number=%llu).\n", (unsigned long long)cno);
@@ -897,7 +917,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
                         goto failed_checkpoint;
         }
 
-        root = nilfs_iget(sb, NILFS_ROOT_INO);
+        root = nilfs_iget(sb, fsroot, NILFS_ROOT_INO);
         if (IS_ERR(root)) {
                 printk(KERN_ERR "NILFS: get root inode failed\n");
                 err = PTR_ERR(root);
@@ -917,6 +937,8 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
                 goto failed_segctor;
         }
 
+        nilfs_put_root(fsroot);
+
         if (!(sb->s_flags & MS_RDONLY)) {
                 down_write(&nilfs->ns_sem);
                 nilfs_setup_super(sbi);
@@ -935,6 +957,7 @@ nilfs_fill_super(struct super_block *sb, void *data, int silent,
 
  failed_checkpoint:
         nilfs_detach_checkpoint(sbi);
+        nilfs_put_root(fsroot);
 
  failed_sbi:
         put_nilfs(nilfs);