From: Miklos Szeredi <mszeredi@xxxxxxx>
Keep track of vfsmounts belonging to a superblock. List is protected
by vfsmount_lock.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxx>
---
fs/namespace.c | 5 +++++
fs/super.c | 7 +++++++
include/linux/fs.h | 1 +
include/linux/mount.h | 1 +
4 files changed, 14 insertions(+)
Index: linux-2.6/include/linux/fs.h
===================================================================
--- linux-2.6.orig/include/linux/fs.h 2011-01-18 12:35:42.000000000 +0100
+++ linux-2.6/include/linux/fs.h 2011-01-18 12:36:41.000000000 +0100
@@ -1386,6 +1386,7 @@ struct super_block {
#else
struct list_head s_files;
#endif
+ struct list_head s_mounts; /* list of mounts */
/* s_dentry_lru, s_nr_dentry_unused protected by dcache.c lru locks */
struct list_head s_dentry_lru; /* unused dentry lru */
int s_nr_dentry_unused; /* # of dentry on lru */
Index: linux-2.6/include/linux/mount.h
===================================================================
--- linux-2.6.orig/include/linux/mount.h 2011-01-18 12:35:42.000000000 +0100
+++ linux-2.6/include/linux/mount.h 2011-01-18 12:36:41.000000000 +0100
@@ -67,6 +67,7 @@ struct vfsmount {
#endif
struct list_head mnt_mounts; /* list of children, anchored here */
struct list_head mnt_child; /* and going through their mnt_child */
+ struct list_head mnt_instance; /* mount instance on sb->s_mounts */
int mnt_flags;
/* 4 bytes hole on 64bits arches without fsnotify */
#ifdef CONFIG_FSNOTIFY
Index: linux-2.6/fs/namespace.c
===================================================================
--- linux-2.6.orig/fs/namespace.c 2011-01-18 12:35:42.000000000 +0100
+++ linux-2.6/fs/namespace.c 2011-01-18 12:37:27.000000000 +0100
@@ -723,6 +723,10 @@ static struct vfsmount *clone_mnt(struct
if (!list_empty(&old->mnt_expire))
list_add(&mnt->mnt_expire, &old->mnt_expire);
}
+
+ br_write_lock(vfsmount_lock);
+ list_add_tail(&mnt->mnt_instance, &mnt->mnt_sb->s_mounts);
+ br_write_unlock(vfsmount_lock);
}
return mnt;
@@ -783,6 +787,7 @@ static void mntput_no_expire(struct vfsm
acct_auto_close_mnt(mnt);
goto put_again;
}
+ list_del(&mnt->mnt_instance);
br_write_unlock(vfsmount_lock);
mntfree(mnt);
}
Index: linux-2.6/fs/super.c
===================================================================
--- linux-2.6.orig/fs/super.c 2011-01-18 12:36:02.000000000 +0100
+++ linux-2.6/fs/super.c 2011-01-18 12:36:41.000000000 +0100
@@ -75,6 +75,7 @@ static struct super_block *alloc_super(s
INIT_HLIST_BL_HEAD(&s->s_anon);
INIT_LIST_HEAD(&s->s_inodes);
INIT_LIST_HEAD(&s->s_dentry_lru);
+ INIT_LIST_HEAD(&s->s_mounts);
init_rwsem(&s->s_umount);
mutex_init(&s->s_lock);
lockdep_set_class(&s->s_umount, &type->s_umount_key);
@@ -128,6 +129,7 @@ static inline void destroy_super(struct
free_percpu(s->s_files);
#endif
security_sb_free(s);
+ WARN_ON(!list_empty(&s->s_mounts));
kfree(s->s_subtype);
kfree(s->s_options);
kfree(s);
@@ -1019,6 +1021,11 @@ vfs_kern_mount(struct file_system_type *
mnt->mnt_parent = mnt;
up_write(&mnt->mnt_sb->s_umount);
free_secdata(secdata);
+
+ br_write_lock(vfsmount_lock);
+ list_add_tail(&mnt->mnt_instance, &mnt->mnt_sb->s_mounts);
+ br_write_unlock(vfsmount_lock);
+
return mnt;
out_sb:
dput(mnt->mnt_root);
--
--
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