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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: Avan Anishchuk <matimatik@gmail.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Wu Fengguang 2009-03-31 15:24:34 -07:00 committed by Linus Torvalds
parent bb233fdfc7
commit c3b1b1cbf0
1 changed files with 86 additions and 8 deletions
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94
fs/ramfs/inode.c
View File

@ -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 dentry * root;
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",