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mtdchar: kill persistently held vfsmount

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... and mtdchar_notifier along with it; just have ->drop_inode() that
will unconditionally get evict them instead of dances on mtd device
removal and use simple_pin_fs() instead of kern_mount()

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro 2012-03-23 13:47:52 -04:00
parent 22a71c3055
commit 00292bbf76
1 changed files with 16 additions and 37 deletions
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53
drivers/mtd/mtdchar.c
View file

@ -39,7 +39,6 @@
#include <asm/uaccess.h> #include <asm/uaccess.h>
static DEFINE_MUTEX(mtd_mutex); static DEFINE_MUTEX(mtd_mutex);
static struct vfsmount *mtd_inode_mnt __read_mostly;
/* /*
* Data structure to hold the pointer to the mtd device as well * Data structure to hold the pointer to the mtd device as well
@ -75,7 +74,9 @@ static loff_t mtdchar_lseek(struct file *file, loff_t offset, int orig)
return -EINVAL; return -EINVAL;
} }
static int count;
static struct vfsmount *mnt;
static struct file_system_type mtd_inodefs_type;
static int mtdchar_open(struct inode *inode, struct file *file) static int mtdchar_open(struct inode *inode, struct file *file)
{ {
@ -92,6 +93,10 @@ static int mtdchar_open(struct inode *inode, struct file *file)
if ((file->f_mode & FMODE_WRITE) && (minor & 1)) if ((file->f_mode & FMODE_WRITE) && (minor & 1))
return -EACCES; return -EACCES;
ret = simple_pin_fs(&mtd_inodefs_type, &mnt, &count);
if (ret)
return ret;
mutex_lock(&mtd_mutex); mutex_lock(&mtd_mutex);
mtd = get_mtd_device(NULL, devnum); mtd = get_mtd_device(NULL, devnum);
@ -106,7 +111,7 @@ static int mtdchar_open(struct inode *inode, struct file *file)
goto out; goto out;
} }
mtd_ino = iget_locked(mtd_inode_mnt->mnt_sb, devnum); mtd_ino = iget_locked(mnt->mnt_sb, devnum);
if (!mtd_ino) { if (!mtd_ino) {
put_mtd_device(mtd); put_mtd_device(mtd);
ret = -ENOMEM; ret = -ENOMEM;
@ -141,6 +146,7 @@ static int mtdchar_open(struct inode *inode, struct file *file)
out: out:
mutex_unlock(&mtd_mutex); mutex_unlock(&mtd_mutex);
simple_release_fs(&mnt, &count);
return ret; return ret;
} /* mtdchar_open */ } /* mtdchar_open */
@ -162,6 +168,7 @@ static int mtdchar_close(struct inode *inode, struct file *file)
put_mtd_device(mtd); put_mtd_device(mtd);
file->private_data = NULL; file->private_data = NULL;
kfree(mfi); kfree(mfi);
simple_release_fs(&mnt, &count);
return 0; return 0;
} /* mtdchar_close */ } /* mtdchar_close */
@ -1175,10 +1182,15 @@ static const struct file_operations mtd_fops = {
#endif #endif
}; };
static const struct super_operations mtd_ops = {
.drop_inode = generic_delete_inode,
.statfs = simple_statfs,
};
static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type, static struct dentry *mtd_inodefs_mount(struct file_system_type *fs_type,
int flags, const char *dev_name, void *data) int flags, const char *dev_name, void *data)
{ {
return mount_pseudo(fs_type, "mtd_inode:", NULL, NULL, MTD_INODE_FS_MAGIC); return mount_pseudo(fs_type, "mtd_inode:", &mtd_ops, NULL, MTD_INODE_FS_MAGIC);
} }
static struct file_system_type mtd_inodefs_type = { static struct file_system_type mtd_inodefs_type = {
@ -1187,26 +1199,6 @@ static struct file_system_type mtd_inodefs_type = {
.kill_sb = kill_anon_super, .kill_sb = kill_anon_super,
}; };
static void mtdchar_notify_add(struct mtd_info *mtd)
{
}
static void mtdchar_notify_remove(struct mtd_info *mtd)
{
struct inode *mtd_ino = ilookup(mtd_inode_mnt->mnt_sb, mtd->index);
if (mtd_ino) {
/* Destroy the inode if it exists */
clear_nlink(mtd_ino);
iput(mtd_ino);
}
}
static struct mtd_notifier mtdchar_notifier = {
.add = mtdchar_notify_add,
.remove = mtdchar_notify_remove,
};
static int __init init_mtdchar(void) static int __init init_mtdchar(void)
{ {
int ret; int ret;
@ -1224,19 +1216,8 @@ static int __init init_mtdchar(void)
pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret); pr_notice("Can't register mtd_inodefs filesystem: %d\n", ret);
goto err_unregister_chdev; goto err_unregister_chdev;
} }
mtd_inode_mnt = kern_mount(&mtd_inodefs_type);
if (IS_ERR(mtd_inode_mnt)) {
ret = PTR_ERR(mtd_inode_mnt);
pr_notice("Error mounting mtd_inodefs filesystem: %d\n", ret);
goto err_unregister_filesystem;
}
register_mtd_user(&mtdchar_notifier);
return ret; return ret;
err_unregister_filesystem:
unregister_filesystem(&mtd_inodefs_type);
err_unregister_chdev: err_unregister_chdev:
__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd"); __unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
return ret; return ret;
@ -1244,8 +1225,6 @@ static int __init init_mtdchar(void)
static void __exit cleanup_mtdchar(void) static void __exit cleanup_mtdchar(void)
{ {
unregister_mtd_user(&mtdchar_notifier);
kern_unmount(mtd_inode_mnt);
unregister_filesystem(&mtd_inodefs_type); unregister_filesystem(&mtd_inodefs_type);
__unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd"); __unregister_chrdev(MTD_CHAR_MAJOR, 0, 1 << MINORBITS, "mtd");
} }