[PATCH 05/10] sysfs: sysfs_chmod_file handle multiple superblocks

From: Benjamin Thery
Date: Tue Apr 29 2008 - 13:38:24 EST


sysfs: sysfs_chmod_file handle multiple superblocks

Teach sysfs_chmod_file how to handle multiple sysfs
superblocks.

Signed-off-by: Eric W. Biederman <ebiederm@xxxxxxxxxxxx>
Acked-by: Benjamin Thery <benjamin.thery@xxxxxxxx>
---
fs/sysfs/file.c | 53 +++++++++++++++++++++++++++++------------------------
1 file changed, 29 insertions(+), 24 deletions(-)

Index: linux-mm/fs/sysfs/file.c
===================================================================
--- linux-mm.orig/fs/sysfs/file.c
+++ linux-mm/fs/sysfs/file.c
@@ -567,7 +567,8 @@ EXPORT_SYMBOL_GPL(sysfs_add_file_to_grou
int sysfs_chmod_file(struct kobject *kobj, struct attribute *attr, mode_t mode)
{
struct sysfs_dirent *victim_sd = NULL;
- struct dentry *victim = NULL;
+ struct super_block *sb;
+ struct dentry *victim;
struct inode * inode;
struct iattr newattrs;
int rc;
@@ -578,31 +579,35 @@ int sysfs_chmod_file(struct kobject *kob
goto out;

mutex_lock(&sysfs_rename_mutex);
- victim = sysfs_get_dentry(sysfs_sb, victim_sd);
- mutex_unlock(&sysfs_rename_mutex);
- if (IS_ERR(victim)) {
- rc = PTR_ERR(victim);
- victim = NULL;
- goto out;
- }
-
- inode = victim->d_inode;
+ sysfs_grab_supers();
+ list_for_each_entry(sb, &sysfs_fs_type.fs_supers, s_instances) {
+ victim = sysfs_get_dentry(sb, victim_sd);
+ if (victim == ERR_PTR(-EXDEV))
+ continue;
+ if (IS_ERR(victim)) {
+ rc = PTR_ERR(victim);
+ victim = NULL;
+ goto out_unlock;
+ }
+
+ inode = victim->d_inode;
+ mutex_lock(&inode->i_mutex);
+ newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
+ newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
+ rc = notify_change(victim, &newattrs);
+ if (rc == 0) {
+ mutex_lock(&sysfs_mutex);
+ victim_sd->s_mode = newattrs.ia_mode;
+ mutex_unlock(&sysfs_mutex);
+ }
+ mutex_unlock(&inode->i_mutex);

- mutex_lock(&inode->i_mutex);
-
- newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
- newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
- rc = notify_change(victim, &newattrs);
-
- if (rc == 0) {
- mutex_lock(&sysfs_mutex);
- victim_sd->s_mode = newattrs.ia_mode;
- mutex_unlock(&sysfs_mutex);
+ dput(victim);
}
-
- mutex_unlock(&inode->i_mutex);
- out:
- dput(victim);
+out_unlock:
+ sysfs_release_supers();
+ mutex_unlock(&sysfs_rename_mutex);
+out:
sysfs_put(victim_sd);
return rc;
}

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