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ubi: Don't bypass ->getattr()

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Directly accessing inode fields bypasses ->getattr()
and can cause problems when the underlying filesystem
does not have the default ->getattr() implementation.

So instead of obtaining the backing inode via d_backing_inode()
use vfs_getattr() and obtain what we need from the kstat struct.

Cc: Al Viro <viro@zeniv.linux.org.uk>
Reported-by: Al Viro <viro@zeniv.linux.org.uk>
Signed-off-by: Richard Weinberger <richard@nod.at>
This commit is contained in:
Richard Weinberger 2016-06-13 00:49:04 +02:00
parent 1a498ec45e
commit 61edc3f3b5
2 changed files with 20 additions and 13 deletions
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16
drivers/mtd/ubi/build.c
View File

@ -1147,22 +1147,26 @@ int ubi_detach_mtd_dev(int ubi_num, int anyway)
*/ */
static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev) static struct mtd_info * __init open_mtd_by_chdev(const char *mtd_dev)
{ {
int err, major, minor, mode; int err, minor;
struct path path; struct path path;
struct kstat stat;
/* Probably this is an MTD character device node path */ /* Probably this is an MTD character device node path */
err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path); err = kern_path(mtd_dev, LOOKUP_FOLLOW, &path);
if (err) if (err)
return ERR_PTR(err); return ERR_PTR(err);
/* MTD device number is defined by the major / minor numbers */ err = vfs_getattr(&path, &stat);
major = imajor(d_backing_inode(path.dentry));
minor = iminor(d_backing_inode(path.dentry));
mode = d_backing_inode(path.dentry)->i_mode;
path_put(&path); path_put(&path);
if (major != MTD_CHAR_MAJOR || !S_ISCHR(mode)) if (err)
return ERR_PTR(err);
/* MTD device number is defined by the major / minor numbers */
if (MAJOR(stat.rdev) != MTD_CHAR_MAJOR || !S_ISCHR(stat.mode))
return ERR_PTR(-EINVAL); return ERR_PTR(-EINVAL);
minor = MINOR(stat.rdev);
if (minor & 1) if (minor & 1)
/* /*
* Just do not think the "/dev/mtdrX" devices support is need, * Just do not think the "/dev/mtdrX" devices support is need,

17
drivers/mtd/ubi/kapi.c
View File

@ -301,9 +301,9 @@ EXPORT_SYMBOL_GPL(ubi_open_volume_nm);
*/ */
struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode) struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
{ {
int error, ubi_num, vol_id, mod; int error, ubi_num, vol_id;
struct inode *inode;
struct path path; struct path path;
struct kstat stat;
dbg_gen("open volume %s, mode %d", pathname, mode); dbg_gen("open volume %s, mode %d", pathname, mode);
@ -314,14 +314,17 @@ struct ubi_volume_desc *ubi_open_volume_path(const char *pathname, int mode)
if (error) if (error)
return ERR_PTR(error); return ERR_PTR(error);
inode = d_backing_inode(path.dentry); error = vfs_getattr(&path, &stat);
mod = inode->i_mode;
ubi_num = ubi_major2num(imajor(inode));
vol_id = iminor(inode) - 1;
path_put(&path); path_put(&path);
if (error)
return ERR_PTR(error);
if (!S_ISCHR(mod)) if (!S_ISCHR(stat.mode))
return ERR_PTR(-EINVAL); return ERR_PTR(-EINVAL);
ubi_num = ubi_major2num(MAJOR(stat.rdev));
vol_id = MINOR(stat.rdev) - 1;
if (vol_id >= 0 && ubi_num >= 0) if (vol_id >= 0 && ubi_num >= 0)
return ubi_open_volume(ubi_num, vol_id, mode); return ubi_open_volume(ubi_num, vol_id, mode);
return ERR_PTR(-ENODEV); return ERR_PTR(-ENODEV);