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-rw-r--r--fs/super.c72
1 files changed, 47 insertions, 25 deletions
diff --git a/fs/super.c b/fs/super.c
index afd0f1ad45e..6015c02296b 100644
--- a/fs/super.c
+++ b/fs/super.c
@@ -136,12 +136,13 @@ static struct super_block *alloc_super(struct file_system_type *type)
INIT_LIST_HEAD(&s->s_files);
#endif
s->s_bdi = &default_backing_dev_info;
- INIT_LIST_HEAD(&s->s_instances);
+ INIT_HLIST_NODE(&s->s_instances);
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_inode_lru);
spin_lock_init(&s->s_inode_lru_lock);
+ 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);
@@ -200,6 +201,7 @@ static inline void destroy_super(struct super_block *s)
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);
@@ -210,7 +212,7 @@ static inline void destroy_super(struct super_block *s)
/*
* Drop a superblock's refcount. The caller must hold sb_lock.
*/
-void __put_super(struct super_block *sb)
+static void __put_super(struct super_block *sb)
{
if (!--sb->s_count) {
list_del_init(&sb->s_list);
@@ -225,7 +227,7 @@ void __put_super(struct super_block *sb)
* Drops a temporary reference, frees superblock if there's no
* references left.
*/
-void put_super(struct super_block *sb)
+static void put_super(struct super_block *sb)
{
spin_lock(&sb_lock);
__put_super(sb);
@@ -328,7 +330,7 @@ static int grab_super(struct super_block *s) __releases(sb_lock)
bool grab_super_passive(struct super_block *sb)
{
spin_lock(&sb_lock);
- if (list_empty(&sb->s_instances)) {
+ if (hlist_unhashed(&sb->s_instances)) {
spin_unlock(&sb_lock);
return false;
}
@@ -337,7 +339,7 @@ bool grab_super_passive(struct super_block *sb)
spin_unlock(&sb_lock);
if (down_read_trylock(&sb->s_umount)) {
- if (sb->s_root)
+ if (sb->s_root && (sb->s_flags & MS_BORN))
return true;
up_read(&sb->s_umount);
}
@@ -400,7 +402,7 @@ void generic_shutdown_super(struct super_block *sb)
}
spin_lock(&sb_lock);
/* should be initialized for __put_super_and_need_restart() */
- list_del_init(&sb->s_instances);
+ hlist_del_init(&sb->s_instances);
spin_unlock(&sb_lock);
up_write(&sb->s_umount);
}
@@ -420,13 +422,14 @@ struct super_block *sget(struct file_system_type *type,
void *data)
{
struct super_block *s = NULL;
+ struct hlist_node *node;
struct super_block *old;
int err;
retry:
spin_lock(&sb_lock);
if (test) {
- list_for_each_entry(old, &type->fs_supers, s_instances) {
+ hlist_for_each_entry(old, node, &type->fs_supers, s_instances) {
if (!test(old, data))
continue;
if (!grab_super(old))
@@ -462,7 +465,7 @@ retry:
s->s_type = type;
strlcpy(s->s_id, type->name, sizeof(s->s_id));
list_add_tail(&s->s_list, &super_blocks);
- list_add(&s->s_instances, &type->fs_supers);
+ hlist_add_head(&s->s_instances, &type->fs_supers);
spin_unlock(&sb_lock);
get_filesystem(type);
register_shrinker(&s->s_shrink);
@@ -497,14 +500,14 @@ void sync_supers(void)
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
- if (list_empty(&sb->s_instances))
+ if (hlist_unhashed(&sb->s_instances))
continue;
if (sb->s_op->write_super && sb->s_dirt) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
- if (sb->s_root && sb->s_dirt)
+ if (sb->s_root && sb->s_dirt && (sb->s_flags & MS_BORN))
sb->s_op->write_super(sb);
up_read(&sb->s_umount);
@@ -533,13 +536,13 @@ void iterate_supers(void (*f)(struct super_block *, void *), void *arg)
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
- if (list_empty(&sb->s_instances))
+ if (hlist_unhashed(&sb->s_instances))
continue;
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
- if (sb->s_root)
+ if (sb->s_root && (sb->s_flags & MS_BORN))
f(sb, arg);
up_read(&sb->s_umount);
@@ -566,14 +569,15 @@ void iterate_supers_type(struct file_system_type *type,
void (*f)(struct super_block *, void *), void *arg)
{
struct super_block *sb, *p = NULL;
+ struct hlist_node *node;
spin_lock(&sb_lock);
- list_for_each_entry(sb, &type->fs_supers, s_instances) {
+ hlist_for_each_entry(sb, node, &type->fs_supers, s_instances) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
- if (sb->s_root)
+ if (sb->s_root && (sb->s_flags & MS_BORN))
f(sb, arg);
up_read(&sb->s_umount);
@@ -607,14 +611,14 @@ struct super_block *get_super(struct block_device *bdev)
spin_lock(&sb_lock);
rescan:
list_for_each_entry(sb, &super_blocks, s_list) {
- if (list_empty(&sb->s_instances))
+ if (hlist_unhashed(&sb->s_instances))
continue;
if (sb->s_bdev == bdev) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
/* still alive? */
- if (sb->s_root)
+ if (sb->s_root && (sb->s_flags & MS_BORN))
return sb;
up_read(&sb->s_umount);
/* nope, got unmounted */
@@ -647,7 +651,7 @@ struct super_block *get_active_super(struct block_device *bdev)
restart:
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
- if (list_empty(&sb->s_instances))
+ if (hlist_unhashed(&sb->s_instances))
continue;
if (sb->s_bdev == bdev) {
if (grab_super(sb)) /* drops sb_lock */
@@ -667,14 +671,14 @@ struct super_block *user_get_super(dev_t dev)
spin_lock(&sb_lock);
rescan:
list_for_each_entry(sb, &super_blocks, s_list) {
- if (list_empty(&sb->s_instances))
+ if (hlist_unhashed(&sb->s_instances))
continue;
if (sb->s_dev == dev) {
sb->s_count++;
spin_unlock(&sb_lock);
down_read(&sb->s_umount);
/* still alive? */
- if (sb->s_root)
+ if (sb->s_root && (sb->s_flags & MS_BORN))
return sb;
up_read(&sb->s_umount);
/* nope, got unmounted */
@@ -719,23 +723,29 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
/* If we are remounting RDONLY and current sb is read/write,
make sure there are no rw files opened */
if (remount_ro) {
- if (force)
+ if (force) {
mark_files_ro(sb);
- else if (!fs_may_remount_ro(sb))
- return -EBUSY;
+ } else {
+ retval = sb_prepare_remount_readonly(sb);
+ if (retval)
+ return retval;
+ }
}
if (sb->s_op->remount_fs) {
retval = sb->s_op->remount_fs(sb, &flags, data);
if (retval) {
if (!force)
- return retval;
+ goto cancel_readonly;
/* If forced remount, go ahead despite any errors */
WARN(1, "forced remount of a %s fs returned %i\n",
sb->s_type->name, retval);
}
}
sb->s_flags = (sb->s_flags & ~MS_RMT_MASK) | (flags & MS_RMT_MASK);
+ /* Needs to be ordered wrt mnt_is_readonly() */
+ smp_wmb();
+ sb->s_readonly_remount = 0;
/*
* Some filesystems modify their metadata via some other path than the
@@ -748,6 +758,10 @@ int do_remount_sb(struct super_block *sb, int flags, void *data, int force)
if (remount_ro && sb->s_bdev)
invalidate_bdev(sb->s_bdev);
return 0;
+
+cancel_readonly:
+ sb->s_readonly_remount = 0;
+ return retval;
}
static void do_emergency_remount(struct work_struct *work)
@@ -756,12 +770,13 @@ static void do_emergency_remount(struct work_struct *work)
spin_lock(&sb_lock);
list_for_each_entry(sb, &super_blocks, s_list) {
- if (list_empty(&sb->s_instances))
+ if (hlist_unhashed(&sb->s_instances))
continue;
sb->s_count++;
spin_unlock(&sb_lock);
down_write(&sb->s_umount);
- if (sb->s_root && sb->s_bdev && !(sb->s_flags & MS_RDONLY)) {
+ if (sb->s_root && sb->s_bdev && (sb->s_flags & MS_BORN) &&
+ !(sb->s_flags & MS_RDONLY)) {
/*
* What lock protects sb->s_flags??
*/
@@ -1144,6 +1159,11 @@ int freeze_super(struct super_block *sb)
return -EBUSY;
}
+ if (!(sb->s_flags & MS_BORN)) {
+ up_write(&sb->s_umount);
+ return 0; /* sic - it's "nothing to do" */
+ }
+
if (sb->s_flags & MS_RDONLY) {
sb->s_frozen = SB_FREEZE_TRANS;
smp_wmb();
@@ -1166,6 +1186,8 @@ int freeze_super(struct super_block *sb)
printk(KERN_ERR
"VFS:Filesystem freeze failed\n");
sb->s_frozen = SB_UNFROZEN;
+ smp_wmb();
+ wake_up(&sb->s_wait_unfrozen);
deactivate_locked_super(sb);
return ret;
}
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-23 14:41:26 +0000