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Commit c3b1b1cb authored by Wu Fengguang's avatar Wu Fengguang Committed by Linus Torvalds
Browse files

ramfs: add support for "mode=" mount option 

Addresses http://bugzilla.kernel.org/show_bug.cgi?id=12843



"I use ramfs instead of tmpfs for /tmp because I don't use swap on my
laptop.  Some apps need 1777 mode for /tmp directory, but ramfs does not
support 'mode=' mount option."

Reported-by: default avatarAvan Anishchuk <matimatik@gmail.com>
Signed-off-by: default avatarWu Fengguang <fengguang.wu@intel.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent bb233fdf

fs/ramfs/inode.c

+86 −8
Original line number Diff line number Diff line
@@ -33,12 +33,15 @@ 
#include <linux/backing-dev.h>

#include <linux/ramfs.h>

#include <linux/sched.h>

#include <linux/parser.h>

#include <asm/uaccess.h>

#include "internal.h"



/* some random number */

#define RAMFS_MAGIC	0x858458f6



#define RAMFS_DEFAULT_MODE	0755



static const struct super_operations ramfs_ops;

static const struct inode_operations ramfs_dir_inode_operations;
@@ -158,12 +161,75 @@ static const struct inode_operations ramfs_dir_inode_operations = { 
static const struct super_operations ramfs_ops = {

	.statfs		= simple_statfs,

	.drop_inode	= generic_delete_inode,

	.show_options	= generic_show_options,

};



struct ramfs_mount_opts {

	umode_t mode;

};



enum {

	Opt_mode,

	Opt_err

};



static const match_table_t tokens = {

	{Opt_mode, "mode=%o"},

	{Opt_err, NULL}

};



struct ramfs_fs_info {

	struct ramfs_mount_opts mount_opts;

};



static int ramfs_parse_options(char *data, struct ramfs_mount_opts *opts)

{

	substring_t args[MAX_OPT_ARGS];

	int option;

	int token;

	char *p;



	opts->mode = RAMFS_DEFAULT_MODE;



	while ((p = strsep(&data, ",")) != NULL) {

		if (!*p)

			continue;



		token = match_token(p, tokens, args);

		switch (token) {

		case Opt_mode:

			if (match_octal(&args[0], &option))

				return -EINVAL;

			opts->mode = option & S_IALLUGO;

			break;

		default:

			printk(KERN_ERR "ramfs: bad mount option: %s\n", p);

			return -EINVAL;

		}

	}



	return 0;

}



static int ramfs_fill_super(struct super_block * sb, void * data, int silent)

{

	struct inode * inode;

	struct ramfs_fs_info *fsi;

	struct inode *inode = NULL;

	struct dentry *root;

	int err;



	save_mount_options(sb, data);



	fsi = kzalloc(sizeof(struct ramfs_fs_info), GFP_KERNEL);

	if (!fsi) {

		err = -ENOMEM;

		goto fail;

	}

	sb->s_fs_info = fsi;



	err = ramfs_parse_options(data, &fsi->mount_opts);

	if (err)

		goto fail;



	sb->s_maxbytes = MAX_LFS_FILESIZE;

	sb->s_blocksize = PAGE_CACHE_SIZE;
@@ -171,17 +237,23 @@ static int ramfs_fill_super(struct super_block * sb, void * data, int silent) 
	sb->s_magic = RAMFS_MAGIC;

	sb->s_op = &ramfs_ops;

	sb->s_time_gran = 1;

	inode = ramfs_get_inode(sb, S_IFDIR | 0755, 0);

	if (!inode)

		return -ENOMEM;

	inode = ramfs_get_inode(sb, S_IFDIR | fsi->mount_opts.mode, 0);

	if (!inode) {

		err = -ENOMEM;

		goto fail;

	}



	root = d_alloc_root(inode);

	if (!root) {

		iput(inode);

		return -ENOMEM;

		err = -ENOMEM;

		goto fail;

	}

	sb->s_root = root;

	return 0;

fail:

	kfree(fsi);

	iput(inode);

	return err;

}



int ramfs_get_sb(struct file_system_type *fs_type,
@@ -197,10 +269,16 @@ static int rootfs_get_sb(struct file_system_type *fs_type, 
			    mnt);

}



static void ramfs_kill_sb(struct super_block *sb)

{

	kfree(sb->s_fs_info);

	kill_litter_super(sb);

}



static struct file_system_type ramfs_fs_type = {

	.name		= "ramfs",

	.get_sb		= ramfs_get_sb,

	.kill_sb	= kill_litter_super,

	.kill_sb	= ramfs_kill_sb,

};

static struct file_system_type rootfs_fs_type = {

	.name		= "rootfs",