sysfs: Fix locking and factor out sysfs_sd_setattr

Cleanly separate the work that is specific to setting the
attributes of a sysfs_dirent from what is needed to update
the attributes of a vfs inode.

Additionally grab the sysfs_mutex to keep any nasties from
surprising us when updating the sysfs_dirent.

Acked-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Eric W. Biederman <ebiederm@aristanetworks.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Eric W. Biederman 2009-11-20 16:08:50 -08:00 committed by Greg Kroah-Hartman
parent 4be3df28be
commit 35df63c46c
2 changed files with 32 additions and 20 deletions

View file

@ -65,30 +65,14 @@ static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)
return attrs;
}
int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr * iattr)
{
struct inode * inode = dentry->d_inode;
struct sysfs_dirent * sd = dentry->d_fsdata;
struct sysfs_inode_attrs *sd_attrs;
struct iattr *iattrs;
unsigned int ia_valid = iattr->ia_valid;
int error;
if (!sd)
return -EINVAL;
sd_attrs = sd->s_iattr;
error = inode_change_ok(inode, iattr);
if (error)
return error;
iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */
error = inode_setattr(inode, iattr);
if (error)
return error;
if (!sd_attrs) {
/* setting attributes for the first time, allocate now */
sd_attrs = sysfs_init_inode_attrs(sd);
@ -111,12 +95,39 @@ int sysfs_setattr(struct dentry * dentry, struct iattr * iattr)
iattrs->ia_ctime = iattr->ia_ctime;
if (ia_valid & ATTR_MODE) {
umode_t mode = iattr->ia_mode;
if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
mode &= ~S_ISGID;
iattrs->ia_mode = sd->s_mode = mode;
}
}
return 0;
}
int sysfs_setattr(struct dentry *dentry, struct iattr *iattr)
{
struct inode *inode = dentry->d_inode;
struct sysfs_dirent *sd = dentry->d_fsdata;
int error;
if (!sd)
return -EINVAL;
error = inode_change_ok(inode, iattr);
if (error)
return error;
iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */
if (iattr->ia_valid & ATTR_MODE) {
if (!in_group_p(inode->i_gid) && !capable(CAP_FSETID))
iattr->ia_mode &= ~S_ISGID;
}
error = inode_setattr(inode, iattr);
if (error)
return error;
mutex_lock(&sysfs_mutex);
error = sysfs_sd_setattr(sd, iattr);
mutex_unlock(&sysfs_mutex);
return error;
}

View file

@ -155,6 +155,7 @@ static inline void __sysfs_put(struct sysfs_dirent *sd)
*/
struct inode *sysfs_get_inode(struct sysfs_dirent *sd);
void sysfs_delete_inode(struct inode *inode);
int sysfs_sd_setattr(struct sysfs_dirent *sd, struct iattr *iattr);
int sysfs_setattr(struct dentry *dentry, struct iattr *iattr);
int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
size_t size, int flags);