[PATCH 3.4 012/125] FS-Cache: Don't override netfs's primary_index if registering failed

From: lizf
Date: Wed Oct 12 2016 - 08:35:52 EST


From: Kinglong Mee <kinglongmee@xxxxxxxxx>

3.4.113-rc1 review patch. If anyone has any objections, please let me know.

------------------


commit b130ed5998e62879a66bad08931a2b5e832da95c upstream.

Only override netfs->primary_index when registering success.

Signed-off-by: Kinglong Mee <kinglongmee@xxxxxxxxx>
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
Signed-off-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
[lizf: Backported to 3.4: there are no n_active and flags in primary_index]
Signed-off-by: Zefan Li <lizefan@xxxxxxxxxx>
---
fs/fscache/netfs.c | 31 +++++++++++++++----------------
1 file changed, 15 insertions(+), 16 deletions(-)

diff --git a/fs/fscache/netfs.c b/fs/fscache/netfs.c
index 0912b90..6f4e4ed 100644
--- a/fs/fscache/netfs.c
+++ b/fs/fscache/netfs.c
@@ -22,6 +22,7 @@ static LIST_HEAD(fscache_netfs_list);
int __fscache_register_netfs(struct fscache_netfs *netfs)
{
struct fscache_netfs *ptr;
+ struct fscache_cookie *cookie;
int ret;

_enter("{%s}", netfs->name);
@@ -29,24 +30,23 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
INIT_LIST_HEAD(&netfs->link);

/* allocate a cookie for the primary index */
- netfs->primary_index =
- kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);
+ cookie = kmem_cache_zalloc(fscache_cookie_jar, GFP_KERNEL);

- if (!netfs->primary_index) {
+ if (!cookie) {
_leave(" = -ENOMEM");
return -ENOMEM;
}

/* initialise the primary index cookie */
- atomic_set(&netfs->primary_index->usage, 1);
- atomic_set(&netfs->primary_index->n_children, 0);
+ atomic_set(&cookie->usage, 1);
+ atomic_set(&cookie->n_children, 0);

- netfs->primary_index->def = &fscache_fsdef_netfs_def;
- netfs->primary_index->parent = &fscache_fsdef_index;
- netfs->primary_index->netfs_data = netfs;
+ cookie->def = &fscache_fsdef_netfs_def;
+ cookie->parent = &fscache_fsdef_index;
+ cookie->netfs_data = netfs;

- spin_lock_init(&netfs->primary_index->lock);
- INIT_HLIST_HEAD(&netfs->primary_index->backing_objects);
+ spin_lock_init(&cookie->lock);
+ INIT_HLIST_HEAD(&cookie->backing_objects);

/* check the netfs type is not already present */
down_write(&fscache_addremove_sem);
@@ -57,9 +57,10 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
goto already_registered;
}

- atomic_inc(&netfs->primary_index->parent->usage);
- atomic_inc(&netfs->primary_index->parent->n_children);
+ atomic_inc(&cookie->parent->usage);
+ atomic_inc(&cookie->parent->n_children);

+ netfs->primary_index = cookie;
list_add(&netfs->link, &fscache_netfs_list);
ret = 0;

@@ -69,10 +70,8 @@ int __fscache_register_netfs(struct fscache_netfs *netfs)
already_registered:
up_write(&fscache_addremove_sem);

- if (ret < 0) {
- kmem_cache_free(fscache_cookie_jar, netfs->primary_index);
- netfs->primary_index = NULL;
- }
+ if (ret < 0)
+ kmem_cache_free(fscache_cookie_jar, cookie);

_leave(" = %d", ret);
return ret;
--
1.9.1