[PATCH 06/15] sysfs: Fix locking and factor out sysfs_sd_setattr

Eric W. Biederman
2009-11-08T07:30:14Z

From: Eric W. Biederman <ebiederm@xmission.com>

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>
---
fs/sysfs/inode.c | 52 ++++++++++++++++++++++++++++++++--------------------
fs/sysfs/sysfs.h | 1 +
2 files changed, 33 insertions(+), 20 deletions(-)

diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index fed7a74..fccfb55 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -64,30 +64,15 @@ 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);
@@ -110,12 +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;
}

diff --git a/fs/sysfs/sysfs.h b/fs/sysfs/sysfs.h
index af4c4e7..a96d967 100644
--- a/fs/sysfs/sysfs.h
+++ b/fs/sysfs/sysfs.h
@@ -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);
--
1.6.5.2.143.g8cc62