Commit 23135982 authored by Al Viro's avatar Al Viro
Browse files

convert ramfs and tmpfs 



Quite a bit is already done by infrastructure changes (simple_link(),
simple_unlink()) - all that is left is replacing d_instantiate() +
pinning dget() (in ->symlink() and ->mknod()) with d_make_persistent(),
and, in case of shmem, using simple_unlink() and simple_link() in
->unlink() and ->link() resp., instead of open-coding those there.
Since d_make_persistent() accepts (and hashes) unhashed ones, shmem
situation gets simpler - we no longer care whether ->lookup() has hashed
the sucker.

With that done, we don't need kill_litter_super() for these filesystems
anymore - by the umount time all remaining dentries will be marked
persistent and kill_litter_super() will boil down to call of
kill_anon_super().

The same goes for devtmpfs and rootfs - they are handled by
ramfs or by shmem, depending upon config.

NB: strictly speaking, both devtmpfs and rootfs ought to use
ramfs_kill_sb() if they end up using ramfs; that's a separate
story and the only impact of "just use kill_{litter,anon}_super()"
is that we fail to free their sb->s_fs_info... on reboot.
That's orthogonal to the changes in this series - kill_litter_super()
is identical to kill_anon_super() for those at this point.

Signed-off-by: default avatarAl Viro <viro@zeniv.linux.org.uk>
parent e49ce258

drivers/base/devtmpfs.c

+1 −1
Original line number Diff line number Diff line
@@ -70,7 +70,7 @@ static struct file_system_type internal_fs_type = { 
#else

	.init_fs_context = ramfs_init_fs_context,

#endif

	.kill_sb = kill_litter_super,

	.kill_sb = kill_anon_super,

};



/* Simply take a ref on the existing mount */

fs/ramfs/inode.c

+3 −5
Original line number Diff line number Diff line
@@ -110,8 +110,7 @@ ramfs_mknod(struct mnt_idmap *idmap, struct inode *dir, 
			goto out;

		}



		d_instantiate(dentry, inode);

		dget(dentry);	/* Extra count - pin the dentry in core */

		d_make_persistent(dentry, inode);

		error = 0;

		inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));

	}
@@ -154,8 +153,7 @@ static int ramfs_symlink(struct mnt_idmap *idmap, struct inode *dir, 


		error = page_symlink(inode, symname, l);

		if (!error) {

			d_instantiate(dentry, inode);

			dget(dentry);

			d_make_persistent(dentry, inode);

			inode_set_mtime_to_ts(dir,

					      inode_set_ctime_current(dir));

		} else
@@ -313,7 +311,7 @@ int ramfs_init_fs_context(struct fs_context *fc) 
void ramfs_kill_sb(struct super_block *sb)

{

	kfree(sb->s_fs_info);

	kill_litter_super(sb);

	kill_anon_super(sb);

}



static struct file_system_type ramfs_fs_type = {

init/do_mounts.c

+1 −1
Original line number Diff line number Diff line
@@ -507,7 +507,7 @@ static int rootfs_init_fs_context(struct fs_context *fc) 
struct file_system_type rootfs_fs_type = {

	.name		= "rootfs",

	.init_fs_context = rootfs_init_fs_context,

	.kill_sb	= kill_litter_super,

	.kill_sb	= kill_anon_super,

};



void __init init_rootfs(void)

mm/shmem.c

+8 −30
Original line number Diff line number Diff line
@@ -3858,12 +3858,7 @@ shmem_mknod(struct mnt_idmap *idmap, struct inode *dir, 
	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));

	inode_inc_iversion(dir);



	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))

		d_add(dentry, inode);

	else

		d_instantiate(dentry, inode);



	dget(dentry); /* Extra count - pin the dentry in core */

	d_make_persistent(dentry, inode);

	return error;



out_iput:
@@ -3924,7 +3919,7 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, 
		      struct dentry *dentry)

{

	struct inode *inode = d_inode(old_dentry);

	int ret = 0;

	int ret;



	/*

	 * No ordinary (disk based) filesystem counts links as inodes;
@@ -3936,29 +3931,19 @@ static int shmem_link(struct dentry *old_dentry, struct inode *dir, 
	if (inode->i_nlink) {

		ret = shmem_reserve_inode(inode->i_sb, NULL);

		if (ret)

			goto out;

			return ret;

	}



	ret = simple_offset_add(shmem_get_offset_ctx(dir), dentry);

	if (ret) {

		if (inode->i_nlink)

			shmem_free_inode(inode->i_sb, 0);

		goto out;

		return ret;

	}



	dir->i_size += BOGO_DIRENT_SIZE;

	inode_set_mtime_to_ts(dir,

			      inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode)));

	inode_inc_iversion(dir);

	inc_nlink(inode);

	ihold(inode);	/* New dentry reference */

	dget(dentry);	/* Extra pinning count for the created dentry */

	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))

		d_add(dentry, inode);

	else

		d_instantiate(dentry, inode);

out:

	return ret;

	return simple_link(old_dentry, dir, dentry);

}



static int shmem_unlink(struct inode *dir, struct dentry *dentry)
@@ -3971,11 +3956,8 @@ static int shmem_unlink(struct inode *dir, struct dentry *dentry) 
	simple_offset_remove(shmem_get_offset_ctx(dir), dentry);



	dir->i_size -= BOGO_DIRENT_SIZE;

	inode_set_mtime_to_ts(dir,

			      inode_set_ctime_to_ts(dir, inode_set_ctime_current(inode)));

	inode_inc_iversion(dir);

	drop_nlink(inode);

	dput(dentry);	/* Undo the count from "create" - does all the work */

	simple_unlink(dir, dentry);



	/*

	 * For now, VFS can't deal with case-insensitive negative dentries, so
@@ -4130,11 +4112,7 @@ static int shmem_symlink(struct mnt_idmap *idmap, struct inode *dir, 
	dir->i_size += BOGO_DIRENT_SIZE;

	inode_set_mtime_to_ts(dir, inode_set_ctime_current(dir));

	inode_inc_iversion(dir);

	if (IS_ENABLED(CONFIG_UNICODE) && IS_CASEFOLDED(dir))

		d_add(dentry, inode);

	else

		d_instantiate(dentry, inode);

	dget(dentry);

	d_make_persistent(dentry, inode);

	return 0;



out_remove_offset:
@@ -5334,7 +5312,7 @@ static struct file_system_type shmem_fs_type = { 
#ifdef CONFIG_TMPFS

	.parameters	= shmem_fs_parameters,

#endif

	.kill_sb	= kill_litter_super,

	.kill_sb	= kill_anon_super,

	.fs_flags	= FS_USERNS_MOUNT | FS_ALLOW_IDMAP | FS_MGTIME,

};