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Diffstat (limited to 'fs/tracefs/inode.c')
-rw-r--r--fs/tracefs/inode.c92
1 files changed, 89 insertions, 3 deletions
diff --git a/fs/tracefs/inode.c b/fs/tracefs/inode.c
index d65ffad4c3..e30b74228e 100644
--- a/fs/tracefs/inode.c
+++ b/fs/tracefs/inode.c
@@ -30,20 +30,47 @@ static struct vfsmount *tracefs_mount;
static int tracefs_mount_count;
static bool tracefs_registered;
+/*
+ * Keep track of all tracefs_inodes in order to update their
+ * flags if necessary on a remount.
+ */
+static DEFINE_SPINLOCK(tracefs_inode_lock);
+static LIST_HEAD(tracefs_inodes);
+
static struct inode *tracefs_alloc_inode(struct super_block *sb)
{
struct tracefs_inode *ti;
+ unsigned long flags;
ti = kmem_cache_alloc(tracefs_inode_cachep, GFP_KERNEL);
if (!ti)
return NULL;
+ spin_lock_irqsave(&tracefs_inode_lock, flags);
+ list_add_rcu(&ti->list, &tracefs_inodes);
+ spin_unlock_irqrestore(&tracefs_inode_lock, flags);
+
return &ti->vfs_inode;
}
+static void tracefs_free_inode_rcu(struct rcu_head *rcu)
+{
+ struct tracefs_inode *ti;
+
+ ti = container_of(rcu, struct tracefs_inode, rcu);
+ kmem_cache_free(tracefs_inode_cachep, ti);
+}
+
static void tracefs_free_inode(struct inode *inode)
{
- kmem_cache_free(tracefs_inode_cachep, get_tracefs(inode));
+ struct tracefs_inode *ti = get_tracefs(inode);
+ unsigned long flags;
+
+ spin_lock_irqsave(&tracefs_inode_lock, flags);
+ list_del_rcu(&ti->list);
+ spin_unlock_irqrestore(&tracefs_inode_lock, flags);
+
+ call_rcu(&ti->rcu, tracefs_free_inode_rcu);
}
static ssize_t default_read_file(struct file *file, char __user *buf,
@@ -153,16 +180,39 @@ static void set_tracefs_inode_owner(struct inode *inode)
{
struct tracefs_inode *ti = get_tracefs(inode);
struct inode *root_inode = ti->private;
+ kuid_t uid;
+ kgid_t gid;
+
+ uid = root_inode->i_uid;
+ gid = root_inode->i_gid;
+
+ /*
+ * If the root is not the mount point, then check the root's
+ * permissions. If it was never set, then default to the
+ * mount point.
+ */
+ if (root_inode != d_inode(root_inode->i_sb->s_root)) {
+ struct tracefs_inode *rti;
+
+ rti = get_tracefs(root_inode);
+ root_inode = d_inode(root_inode->i_sb->s_root);
+
+ if (!(rti->flags & TRACEFS_UID_PERM_SET))
+ uid = root_inode->i_uid;
+
+ if (!(rti->flags & TRACEFS_GID_PERM_SET))
+ gid = root_inode->i_gid;
+ }
/*
* If this inode has never been referenced, then update
* the permissions to the superblock.
*/
if (!(ti->flags & TRACEFS_UID_PERM_SET))
- inode->i_uid = root_inode->i_uid;
+ inode->i_uid = uid;
if (!(ti->flags & TRACEFS_GID_PERM_SET))
- inode->i_gid = root_inode->i_gid;
+ inode->i_gid = gid;
}
static int tracefs_permission(struct mnt_idmap *idmap,
@@ -313,6 +363,8 @@ static int tracefs_apply_options(struct super_block *sb, bool remount)
struct tracefs_fs_info *fsi = sb->s_fs_info;
struct inode *inode = d_inode(sb->s_root);
struct tracefs_mount_opts *opts = &fsi->mount_opts;
+ struct tracefs_inode *ti;
+ bool update_uid, update_gid;
umode_t tmp_mode;
/*
@@ -332,6 +384,25 @@ static int tracefs_apply_options(struct super_block *sb, bool remount)
if (!remount || opts->opts & BIT(Opt_gid))
inode->i_gid = opts->gid;
+ if (remount && (opts->opts & BIT(Opt_uid) || opts->opts & BIT(Opt_gid))) {
+
+ update_uid = opts->opts & BIT(Opt_uid);
+ update_gid = opts->opts & BIT(Opt_gid);
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(ti, &tracefs_inodes, list) {
+ if (update_uid)
+ ti->flags &= ~TRACEFS_UID_PERM_SET;
+
+ if (update_gid)
+ ti->flags &= ~TRACEFS_GID_PERM_SET;
+
+ if (ti->flags & TRACEFS_EVENT_INODE)
+ eventfs_remount(ti, update_uid, update_gid);
+ }
+ rcu_read_unlock();
+ }
+
return 0;
}
@@ -398,7 +469,22 @@ static int tracefs_d_revalidate(struct dentry *dentry, unsigned int flags)
return !(ei && ei->is_freed);
}
+static void tracefs_d_iput(struct dentry *dentry, struct inode *inode)
+{
+ struct tracefs_inode *ti = get_tracefs(inode);
+
+ /*
+ * This inode is being freed and cannot be used for
+ * eventfs. Clear the flag so that it doesn't call into
+ * eventfs during the remount flag updates. The eventfs_inode
+ * gets freed after an RCU cycle, so the content will still
+ * be safe if the iteration is going on now.
+ */
+ ti->flags &= ~TRACEFS_EVENT_INODE;
+}
+
static const struct dentry_operations tracefs_dentry_operations = {
+ .d_iput = tracefs_d_iput,
.d_revalidate = tracefs_d_revalidate,
.d_release = tracefs_d_release,
};