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, 11 insertions, 12 deletions

diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c
index 5471eed..95c04c2 100644
--- a/fs/nilfs2/ioctl.c
+++ b/fs/nilfs2/ioctl.c
@@ -166,8 +166,7 @@ static int nilfs_ioctl_getversion(struct inode *inode, void __user *argp)
 static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
 				     unsigned int cmd, void __user *argp)
 {
-	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
-	struct inode *cpfile = nilfs->ns_cpfile;
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
 	struct nilfs_transaction_info ti;
 	struct nilfs_cpmode cpmode;
 	int ret;
@@ -187,7 +186,7 @@ static int nilfs_ioctl_change_cpmode(struct inode *inode, struct file *filp,
 
 	nilfs_transaction_begin(inode->i_sb, &ti, 0);
 	ret = nilfs_cpfile_change_cpmode(
-		cpfile, cpmode.cm_cno, cpmode.cm_mode);
+		nilfs->ns_cpfile, cpmode.cm_cno, cpmode.cm_mode);
 	if (unlikely(ret < 0))
 		nilfs_transaction_abort(inode->i_sb);
 	else
@@ -203,7 +202,7 @@ static int
 nilfs_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
 			      unsigned int cmd, void __user *argp)
 {
-	struct inode *cpfile = NILFS_SB(inode->i_sb)->s_nilfs->ns_cpfile;
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
 	struct nilfs_transaction_info ti;
 	__u64 cno;
 	int ret;
@@ -220,7 +219,7 @@ nilfs_ioctl_delete_checkpoint(struct inode *inode, struct file *filp,
 		goto out;
 
 	nilfs_transaction_begin(inode->i_sb, &ti, 0);
-	ret = nilfs_cpfile_delete_checkpoint(cpfile, cno);
+	ret = nilfs_cpfile_delete_checkpoint(nilfs->ns_cpfile, cno);
 	if (unlikely(ret < 0))
 		nilfs_transaction_abort(inode->i_sb);
 	else
@@ -246,7 +245,7 @@ nilfs_ioctl_do_get_cpinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
 static int nilfs_ioctl_get_cpstat(struct inode *inode, struct file *filp,
 				  unsigned int cmd, void __user *argp)
 {
-	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
 	struct nilfs_cpstat cpstat;
 	int ret;
 
@@ -277,7 +276,7 @@ nilfs_ioctl_do_get_suinfo(struct the_nilfs *nilfs, __u64 *posp, int flags,
 static int nilfs_ioctl_get_sustat(struct inode *inode, struct file *filp,
 				  unsigned int cmd, void __user *argp)
 {
-	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
 	struct nilfs_sustat sustat;
 	int ret;
 
@@ -333,7 +332,7 @@ nilfs_ioctl_do_get_bdescs(struct the_nilfs *nilfs, __u64 *posp, int flags,
 static int nilfs_ioctl_get_bdescs(struct inode *inode, struct file *filp,
 				  unsigned int cmd, void __user *argp)
 {
-	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
 	struct nilfs_argv argv;
 	int ret;
 
@@ -402,7 +401,7 @@ static int nilfs_ioctl_move_blocks(struct super_block *sb,
 				   struct nilfs_argv *argv, void *buf)
 {
 	size_t nmembs = argv->v_nmembs;
-	struct the_nilfs *nilfs = NILFS_SB(sb)->s_nilfs;
+	struct the_nilfs *nilfs = sb->s_fs_info;
 	struct inode *inode;
 	struct nilfs_vdesc *vdesc;
 	struct buffer_head *bh, *n;
@@ -616,7 +615,7 @@ static int nilfs_ioctl_clean_segments(struct inode *inode, struct file *filp,
 		ret = PTR_ERR(kbufs[4]);
 		goto out;
 	}
-	nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	nilfs = inode->i_sb->s_fs_info;
 
 	for (n = 0; n < 4; n++) {
 		ret = -EINVAL;
@@ -689,7 +688,7 @@ static int nilfs_ioctl_sync(struct inode *inode, struct file *filp,
 		return ret;
 
 	if (argp != NULL) {
-		nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+		nilfs = inode->i_sb->s_fs_info;
 		down_read(&nilfs->ns_segctor_sem);
 		cno = nilfs->ns_cno - 1;
 		up_read(&nilfs->ns_segctor_sem);
@@ -707,7 +706,7 @@ static int nilfs_ioctl_get_info(struct inode *inode, struct file *filp,
 						  void *, size_t, size_t))
 
 {
-	struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs;
+	struct the_nilfs *nilfs = inode->i_sb->s_fs_info;
 	struct nilfs_argv argv;
 	int ret;