1 files changed, 123 insertions, 82 deletions

diff --git a/fs/sysfs/inode.c b/fs/sysfs/inode.c
index e28cecf179f5..a4a0a9419711 100644
--- a/fs/sysfs/inode.c
+++ b/fs/sysfs/inode.c
@@ -18,6 +18,7 @@
 #include <linux/capability.h>
 #include <linux/errno.h>
 #include <linux/sched.h>
+#include <linux/slab.h>
 #include <linux/xattr.h>
 #include <linux/security.h>
 #include "sysfs.h"
@@ -37,7 +38,9 @@ static struct backing_dev_info sysfs_backing_dev_info = {
 };
 
 static const struct inode_operations sysfs_inode_operations ={
+        .permission     = sysfs_permission,
         .setattr        = sysfs_setattr,
+        .getattr        = sysfs_getattr,
         .setxattr       = sysfs_setxattr,
 };
 
@@ -46,7 +49,7 @@ int __init sysfs_inode_init(void)
         return bdi_init(&sysfs_backing_dev_info);
 }
 
-struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)
+static struct sysfs_inode_attrs *sysfs_init_inode_attrs(struct sysfs_dirent *sd)
 {
         struct sysfs_inode_attrs *attrs;
         struct iattr *iattrs;
@@ -64,81 +67,101 @@ 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;
+
+        sd_attrs = sd->s_iattr;
+
+        if (!sd_attrs) {
+                /* setting attributes for the first time, allocate now */
+                sd_attrs = sysfs_init_inode_attrs(sd);
+                if (!sd_attrs)
+                        return -ENOMEM;
+                sd->s_iattr = sd_attrs;
+        }
+        /* attributes were changed at least once in past */
+        iattrs = &sd_attrs->ia_iattr;
+
+        if (ia_valid & ATTR_UID)
+                iattrs->ia_uid = iattr->ia_uid;
+        if (ia_valid & ATTR_GID)
+                iattrs->ia_gid = iattr->ia_gid;
+        if (ia_valid & ATTR_ATIME)
+                iattrs->ia_atime = iattr->ia_atime;
+        if (ia_valid & ATTR_MTIME)
+                iattrs->ia_mtime = iattr->ia_mtime;
+        if (ia_valid & ATTR_CTIME)
+                iattrs->ia_ctime = iattr->ia_ctime;
+        if (ia_valid & ATTR_MODE) {
+                umode_t mode = iattr->ia_mode;
+                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;
 
-        sd_attrs = sd->s_iattr;
-
+        mutex_lock(&sysfs_mutex);
         error = inode_change_ok(inode, iattr);
         if (error)
-                return error;
+                goto out;
 
         iattr->ia_valid &= ~ATTR_SIZE; /* ignore size changes */
 
         error = inode_setattr(inode, iattr);
         if (error)
-                return error;
+                goto out;
 
-        if (!sd_attrs) {
-                /* setting attributes for the first time, allocate now */
-                sd_attrs = sysfs_init_inode_attrs(sd);
-                if (!sd_attrs)
-                        return -ENOMEM;
-                sd->s_iattr = sd_attrs;
-        } else {
-                /* attributes were changed at least once in past */
-                iattrs = &sd_attrs->ia_iattr;
-
-                if (ia_valid & ATTR_UID)
-                        iattrs->ia_uid = iattr->ia_uid;
-                if (ia_valid & ATTR_GID)
-                        iattrs->ia_gid = iattr->ia_gid;
-                if (ia_valid & ATTR_ATIME)
-                        iattrs->ia_atime = timespec_trunc(iattr->ia_atime,
-                                        inode->i_sb->s_time_gran);
-                if (ia_valid & ATTR_MTIME)
-                        iattrs->ia_mtime = timespec_trunc(iattr->ia_mtime,
-                                        inode->i_sb->s_time_gran);
-                if (ia_valid & ATTR_CTIME)
-                        iattrs->ia_ctime = timespec_trunc(iattr->ia_ctime,
-                                        inode->i_sb->s_time_gran);
-                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;
-                }
-        }
+        error = sysfs_sd_setattr(sd, iattr);
+out:
+        mutex_unlock(&sysfs_mutex);
         return error;
 }
 
+static int sysfs_sd_setsecdata(struct sysfs_dirent *sd, void **secdata, u32 *secdata_len)
+{
+        struct sysfs_inode_attrs *iattrs;
+        void *old_secdata;
+        size_t old_secdata_len;
+
+        iattrs = sd->s_iattr;
+        if (!iattrs)
+                iattrs = sysfs_init_inode_attrs(sd);
+        if (!iattrs)
+                return -ENOMEM;
+
+        old_secdata = iattrs->ia_secdata;
+        old_secdata_len = iattrs->ia_secdata_len;
+
+        iattrs->ia_secdata = *secdata;
+        iattrs->ia_secdata_len = *secdata_len;
+
+        *secdata = old_secdata;
+        *secdata_len = old_secdata_len;
+        return 0;
+}
+
 int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
                 size_t size, int flags)
 {
         struct sysfs_dirent *sd = dentry->d_fsdata;
-        struct sysfs_inode_attrs *iattrs;
         void *secdata;
         int error;
         u32 secdata_len = 0;
 
         if (!sd)
                 return -EINVAL;
-        if (!sd->s_iattr)
-                sd->s_iattr = sysfs_init_inode_attrs(sd);
-        if (!sd->s_iattr)
-                return -ENOMEM;
-
-        iattrs = sd->s_iattr;
 
         if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) {
                 const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
@@ -150,12 +173,13 @@ int sysfs_setxattr(struct dentry *dentry, const char *name, const void *value,
                                                 &secdata, &secdata_len);
                 if (error)
                         goto out;
-                if (iattrs->ia_secdata)
-                        security_release_secctx(iattrs->ia_secdata,
-                                                iattrs->ia_secdata_len);
-                iattrs->ia_secdata = secdata;
-                iattrs->ia_secdata_len = secdata_len;
 
+                mutex_lock(&sysfs_mutex);
+                error = sysfs_sd_setsecdata(sd, &secdata, &secdata_len);
+                mutex_unlock(&sysfs_mutex);
+
+                if (secdata)
+                        security_release_secctx(secdata, secdata_len);
         } else
                 return -EINVAL;
 out:
@@ -170,7 +194,6 @@ static inline void set_default_inode_attr(struct inode * inode, mode_t mode)
 
 static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
 {
-        inode->i_mode = iattr->ia_mode;
         inode->i_uid = iattr->ia_uid;
         inode->i_gid = iattr->ia_gid;
         inode->i_atime = iattr->ia_atime;
@@ -178,17 +201,6 @@ static inline void set_inode_attr(struct inode * inode, struct iattr * iattr)
         inode->i_ctime = iattr->ia_ctime;
 }
 
-
-/*
- * sysfs has a different i_mutex lock order behavior for i_mutex than other
- * filesystems; sysfs i_mutex is called in many places with subsystem locks
- * held. At the same time, many of the VFS locking rules do not apply to
- * sysfs at all (cross directory rename for example). To untangle this mess
- * (which gives false positives in lockdep), we're giving sysfs inodes their
- * own class for i_mutex.
- */
-static struct lock_class_key sysfs_inode_imutex_key;
-
 static int sysfs_count_nlink(struct sysfs_dirent *sd)
 {
         struct sysfs_dirent *child;
@@ -201,38 +213,55 @@ static int sysfs_count_nlink(struct sysfs_dirent *sd)
         return nr + 2;
 }
 
+static void sysfs_refresh_inode(struct sysfs_dirent *sd, struct inode *inode)
+{
+        struct sysfs_inode_attrs *iattrs = sd->s_iattr;
+
+        inode->i_mode = sd->s_mode;
+        if (iattrs) {
+                /* sysfs_dirent has non-default attributes
+                 * get them from persistent copy in sysfs_dirent
+                 */
+                set_inode_attr(inode, &iattrs->ia_iattr);
+                security_inode_notifysecctx(inode,
+                                            iattrs->ia_secdata,
+                                            iattrs->ia_secdata_len);
+        }
+
+        if (sysfs_type(sd) == SYSFS_DIR)
+                inode->i_nlink = sysfs_count_nlink(sd);
+}
+
+int sysfs_getattr(struct vfsmount *mnt, struct dentry *dentry, struct kstat *stat)
+{
+        struct sysfs_dirent *sd = dentry->d_fsdata;
+        struct inode *inode = dentry->d_inode;
+
+        mutex_lock(&sysfs_mutex);
+        sysfs_refresh_inode(sd, inode);
+        mutex_unlock(&sysfs_mutex);
+
+        generic_fillattr(inode, stat);
+        return 0;
+}
+
 static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
 {
         struct bin_attribute *bin_attr;
-        struct sysfs_inode_attrs *iattrs;
 
         inode->i_private = sysfs_get(sd);
         inode->i_mapping->a_ops = &sysfs_aops;
         inode->i_mapping->backing_dev_info = &sysfs_backing_dev_info;
         inode->i_op = &sysfs_inode_operations;
-        inode->i_ino = sd->s_ino;
-        lockdep_set_class(&inode->i_mutex, &sysfs_inode_imutex_key);
 
-        iattrs = sd->s_iattr;
-        if (iattrs) {
-                /* sysfs_dirent has non-default attributes
-                 * get them for the new inode from persistent copy
-                 * in sysfs_dirent
-                 */
-                set_inode_attr(inode, &iattrs->ia_iattr);
-                if (iattrs->ia_secdata)
-                        security_inode_notifysecctx(inode,
-                                                iattrs->ia_secdata,
-                                                iattrs->ia_secdata_len);
-        } else
-                set_default_inode_attr(inode, sd->s_mode);
+        set_default_inode_attr(inode, sd->s_mode);
+        sysfs_refresh_inode(sd, inode);
 
         /* initialize inode according to type */
         switch (sysfs_type(sd)) {
         case SYSFS_DIR:
                 inode->i_op = &sysfs_dir_inode_operations;
                 inode->i_fop = &sysfs_dir_operations;
-                inode->i_nlink = sysfs_count_nlink(sd);
                 break;
         case SYSFS_KOBJ_ATTR:
                 inode->i_size = PAGE_SIZE;
@@ -255,6 +284,7 @@ static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
 
 /**
  *      sysfs_get_inode - get inode for sysfs_dirent
+ *      @sb: super block
  *      @sd: sysfs_dirent to allocate inode for
  *
  *      Get inode for @sd.  If such inode doesn't exist, a new inode
@@ -267,11 +297,11 @@ static void sysfs_init_inode(struct sysfs_dirent *sd, struct inode *inode)
  *      RETURNS:
  *      Pointer to allocated inode on success, NULL on failure.
  */
-struct inode * sysfs_get_inode(struct sysfs_dirent *sd)
+struct inode * sysfs_get_inode(struct super_block *sb, struct sysfs_dirent *sd)
 {
         struct inode *inode;
 
-        inode = iget_locked(sysfs_sb, sd->s_ino);
+        inode = iget_locked(sb, sd->s_ino);
         if (inode && (inode->i_state & I_NEW))
                 sysfs_init_inode(sd, inode);
 
@@ -315,3 +345,14 @@ int sysfs_hash_and_remove(struct sysfs_dirent *dir_sd, const char *name)
         else
                 return -ENOENT;
 }
+
+int sysfs_permission(struct inode *inode, int mask)
+{
+        struct sysfs_dirent *sd = inode->i_private;
+
+        mutex_lock(&sysfs_mutex);
+        sysfs_refresh_inode(sd, inode);
+        mutex_unlock(&sysfs_mutex);
+
+        return generic_permission(inode, mask, NULL);
+}