nilfs2: get rid of nilfs_sb_info structure

This directly uses sb->s_fs_info to keep a nilfs filesystem object and
fully removes the intermediate nilfs_sb_info structure.  With this
change, the hierarchy of on-memory structures of nilfs will be
simplified as follows:

Before:
  super_block
       -> nilfs_sb_info
             -> the_nilfs
                   -> cptree --+-> nilfs_root (current file system)
                               +-> nilfs_root (snapshot A)
                               +-> nilfs_root (snapshot B)
                               :
             -> nilfs_sc_info (log writer structure)
After:
  super_block
       -> the_nilfs
             -> cptree --+-> nilfs_root (current file system)
                         +-> nilfs_root (snapshot A)
                         +-> nilfs_root (snapshot B)
                         :
             -> nilfs_sc_info (log writer structure)

The reason why we didn't design so from the beginning is because the
initial shape also differed from the above.  The early hierachy was
composed of "per-mount-point" super_block -> nilfs_sb_info pairs and a
shared nilfs object.  On the kernel 2.6.37, it was changed to the
current shape in order to unify super block instances into one per
device, and this cleanup became applicable as the result.

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

1 files changed, 24 insertions, 23 deletions

diff --git a/fs/nilfs2/segment.c b/fs/nilfs2/segment.c
index 90e3130..afe4f21 100644
--- a/fs/nilfs2/segment.c
+++ b/fs/nilfs2/segment.c
@@ -191,7 +191,7 @@ int nilfs_transaction_begin(struct super_block *sb,
 
 	vfs_check_frozen(sb, SB_FREEZE_WRITE);
 
-	nilfs = NILFS_SB(sb)->s_nilfs;
+	nilfs = sb->s_fs_info;
 	down_read(&nilfs->ns_segctor_sem);
 	if (vacancy_check && nilfs_near_disk_full(nilfs)) {
 		up_read(&nilfs->ns_segctor_sem);
@@ -222,7 +222,7 @@ int nilfs_transaction_begin(struct super_block *sb,
 int nilfs_transaction_commit(struct super_block *sb)
 {
 	struct nilfs_transaction_info *ti = current->journal_info;
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	int err = 0;
 
 	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
@@ -252,13 +252,14 @@ int nilfs_transaction_commit(struct super_block *sb)
 void nilfs_transaction_abort(struct super_block *sb)
 {
 	struct nilfs_transaction_info *ti = current->journal_info;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 
 	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 	if (ti->ti_count > 0) {
 		ti->ti_count--;
 		return;
 	}
-	up_read(&NILFS_SB(sb)->s_nilfs->ns_segctor_sem);
+	up_read(&nilfs->ns_segctor_sem);
 
 	current->journal_info = ti->ti_save;
 	if (ti->ti_flags & NILFS_TI_DYNAMIC_ALLOC)
@@ -267,7 +268,7 @@ void nilfs_transaction_abort(struct super_block *sb)
 
 void nilfs_relax_pressure_in_lock(struct super_block *sb)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct nilfs_sc_info *sci = nilfs->ns_writer;
 
 	if (!sci || !sci->sc_flush_request)
@@ -293,7 +294,7 @@ static void nilfs_transaction_lock(struct super_block *sb,
 				   int gcflag)
 {
 	struct nilfs_transaction_info *cur_ti = current->journal_info;
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct nilfs_sc_info *sci = nilfs->ns_writer;
 
 	WARN_ON(cur_ti);
@@ -321,7 +322,7 @@ static void nilfs_transaction_lock(struct super_block *sb,
 static void nilfs_transaction_unlock(struct super_block *sb)
 {
 	struct nilfs_transaction_info *ti = current->journal_info;
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 
 	BUG_ON(ti == NULL || ti->ti_magic != NILFS_TI_MAGIC);
 	BUG_ON(ti->ti_count > 0);
@@ -770,7 +771,7 @@ static int nilfs_segctor_clean(struct nilfs_sc_info *sci)
 
 static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	int ret = 0;
 
 	if (nilfs_test_metadata_dirty(nilfs, sci->sc_root))
@@ -786,7 +787,7 @@ static int nilfs_segctor_confirm(struct nilfs_sc_info *sci)
 
 static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 
 	nilfs_mdt_clear_dirty(sci->sc_root->ifile);
 	nilfs_mdt_clear_dirty(nilfs->ns_cpfile);
@@ -796,7 +797,7 @@ static void nilfs_segctor_clear_metadata_dirty(struct nilfs_sc_info *sci)
 
 static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	struct buffer_head *bh_cp;
 	struct nilfs_checkpoint *raw_cp;
 	int err;
@@ -820,7 +821,7 @@ static int nilfs_segctor_create_checkpoint(struct nilfs_sc_info *sci)
 
 static int nilfs_segctor_fill_in_checkpoint(struct nilfs_sc_info *sci)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	struct buffer_head *bh_cp;
 	struct nilfs_checkpoint *raw_cp;
 	int err;
@@ -1044,7 +1045,7 @@ static int nilfs_segctor_scan_file_dsync(struct nilfs_sc_info *sci,
 
 static int nilfs_segctor_collect_blocks(struct nilfs_sc_info *sci, int mode)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	struct list_head *head;
 	struct nilfs_inode_info *ii;
 	size_t ndone;
@@ -1853,7 +1854,7 @@ static void nilfs_segctor_complete_write(struct nilfs_sc_info *sci)
 {
 	struct nilfs_segment_buffer *segbuf;
 	struct page *bd_page = NULL, *fs_page = NULL;
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	int update_sr = false;
 
 	list_for_each_entry(segbuf, &sci->sc_write_logs, sb_list) {
@@ -2024,7 +2025,7 @@ static void nilfs_segctor_drop_written_files(struct nilfs_sc_info *sci,
  */
 static int nilfs_segctor_do_construct(struct nilfs_sc_info *sci, int mode)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	struct page *failed_page;
 	int err;
 
@@ -2162,7 +2163,7 @@ static void nilfs_segctor_do_flush(struct nilfs_sc_info *sci, int bn)
  */
 void nilfs_flush_segment(struct super_block *sb, ino_t ino)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct nilfs_sc_info *sci = nilfs->ns_writer;
 
 	if (!sci || nilfs_doing_construction())
@@ -2252,7 +2253,7 @@ static void nilfs_segctor_wakeup(struct nilfs_sc_info *sci, int err)
  */
 int nilfs_construct_segment(struct super_block *sb)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct nilfs_sc_info *sci = nilfs->ns_writer;
 	struct nilfs_transaction_info *ti;
 	int err;
@@ -2290,7 +2291,7 @@ int nilfs_construct_segment(struct super_block *sb)
 int nilfs_construct_dsync_segment(struct super_block *sb, struct inode *inode,
 				  loff_t start, loff_t end)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct nilfs_sc_info *sci = nilfs->ns_writer;
 	struct nilfs_inode_info *ii;
 	struct nilfs_transaction_info ti;
@@ -2381,7 +2382,7 @@ static void nilfs_segctor_notify(struct nilfs_sc_info *sci, int mode, int err)
  */
 static int nilfs_segctor_construct(struct nilfs_sc_info *sci, int mode)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	struct nilfs_super_block **sbp;
 	int err = 0;
 
@@ -2436,7 +2437,7 @@ nilfs_remove_written_gcinodes(struct the_nilfs *nilfs, struct list_head *head)
 int nilfs_clean_segments(struct super_block *sb, struct nilfs_argv *argv,
 			 void **kbufs)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct nilfs_sc_info *sci = nilfs->ns_writer;
 	struct nilfs_transaction_info ti;
 	int err;
@@ -2552,7 +2553,7 @@ static int nilfs_segctor_flush_mode(struct nilfs_sc_info *sci)
 static int nilfs_segctor_thread(void *arg)
 {
 	struct nilfs_sc_info *sci = (struct nilfs_sc_info *)arg;
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	int timeout = 0;
 
 	sci->sc_timer.data = (unsigned long)current;
@@ -2666,7 +2667,7 @@ static void nilfs_segctor_kill_thread(struct nilfs_sc_info *sci)
 static struct nilfs_sc_info *nilfs_segctor_new(struct super_block *sb,
 					       struct nilfs_root *root)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct nilfs_sc_info *sci;
 
 	sci = kzalloc(sizeof(*sci), GFP_KERNEL);
@@ -2726,7 +2727,7 @@ static void nilfs_segctor_write_out(struct nilfs_sc_info *sci)
  */
 static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sci->sc_super)->s_nilfs;
+	struct the_nilfs *nilfs = sci->sc_super->s_fs_info;
 	int flag;
 
 	up_write(&nilfs->ns_segctor_sem);
@@ -2774,7 +2775,7 @@ static void nilfs_segctor_destroy(struct nilfs_sc_info *sci)
  */
 int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	int err;
 
 	if (nilfs->ns_writer) {
@@ -2807,7 +2808,7 @@ int nilfs_attach_log_writer(struct super_block *sb, struct nilfs_root *root)
  */
 void nilfs_detach_log_writer(struct super_block *sb)
 {
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	LIST_HEAD(garbage_list);
 
 	down_write(&nilfs->ns_segctor_sem);