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Message-Id: <1488451397-3365-5-git-send-email-elena.reshetova@intel.com>
Date: Thu, 2 Mar 2017 12:43:11 +0200
From: Elena Reshetova <elena.reshetova@...el.com>
To: linux-kernel@...r.kernel.org
Cc: linux-fsdevel@...r.kernel.org, linux-nilfs@...r.kernel.org,
linux-cachefs@...hat.com, linux-cifs@...r.kernel.org,
peterz@...radead.org, gregkh@...uxfoundation.org,
viro@...iv.linux.org.uk, dhowells@...hat.com, sfrench@...ba.org,
eparis@...isplace.org, konishi.ryusuke@....ntt.co.jp,
john@...nmccutchan.com, rlove@...ve.org, paul@...l-moore.com,
Elena Reshetova <elena.reshetova@...el.com>,
Hans Liljestrand <ishkamiel@...il.com>,
Kees Cook <keescook@...omium.org>,
David Windsor <dwindsor@...il.com>
Subject: [PATCH 04/10] fs, nilfs: convert nilfs_root.count from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@...el.com>
Signed-off-by: Hans Liljestrand <ishkamiel@...il.com>
Signed-off-by: Kees Cook <keescook@...omium.org>
Signed-off-by: David Windsor <dwindsor@...il.com>
---
fs/nilfs2/the_nilfs.c | 8 ++++----
fs/nilfs2/the_nilfs.h | 5 +++--
2 files changed, 7 insertions(+), 6 deletions(-)
diff --git a/fs/nilfs2/the_nilfs.c b/fs/nilfs2/the_nilfs.c
index 2dd75bf..afebb50 100644
--- a/fs/nilfs2/the_nilfs.c
+++ b/fs/nilfs2/the_nilfs.c
@@ -737,7 +737,7 @@ struct nilfs_root *nilfs_lookup_root(struct the_nilfs *nilfs, __u64 cno)
} else if (cno > root->cno) {
n = n->rb_right;
} else {
- atomic_inc(&root->count);
+ refcount_inc(&root->count);
spin_unlock(&nilfs->ns_cptree_lock);
return root;
}
@@ -776,7 +776,7 @@ nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
} else if (cno > root->cno) {
p = &(*p)->rb_right;
} else {
- atomic_inc(&root->count);
+ refcount_inc(&root->count);
spin_unlock(&nilfs->ns_cptree_lock);
kfree(new);
return root;
@@ -786,7 +786,7 @@ nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
new->cno = cno;
new->ifile = NULL;
new->nilfs = nilfs;
- atomic_set(&new->count, 1);
+ refcount_set(&new->count, 1);
atomic64_set(&new->inodes_count, 0);
atomic64_set(&new->blocks_count, 0);
@@ -806,7 +806,7 @@ nilfs_find_or_create_root(struct the_nilfs *nilfs, __u64 cno)
void nilfs_put_root(struct nilfs_root *root)
{
- if (atomic_dec_and_test(&root->count)) {
+ if (refcount_dec_and_test(&root->count)) {
struct the_nilfs *nilfs = root->nilfs;
nilfs_sysfs_delete_snapshot_group(root);
diff --git a/fs/nilfs2/the_nilfs.h b/fs/nilfs2/the_nilfs.h
index b305c6f..883d732 100644
--- a/fs/nilfs2/the_nilfs.h
+++ b/fs/nilfs2/the_nilfs.h
@@ -27,6 +27,7 @@
#include <linux/blkdev.h>
#include <linux/backing-dev.h>
#include <linux/slab.h>
+#include <linux/refcount.h>
struct nilfs_sc_info;
struct nilfs_sysfs_dev_subgroups;
@@ -246,7 +247,7 @@ struct nilfs_root {
__u64 cno;
struct rb_node rb_node;
- atomic_t count;
+ refcount_t count;
struct the_nilfs *nilfs;
struct inode *ifile;
@@ -299,7 +300,7 @@ void nilfs_swap_super_block(struct the_nilfs *);
static inline void nilfs_get_root(struct nilfs_root *root)
{
- atomic_inc(&root->count);
+ refcount_inc(&root->count);
}
static inline int nilfs_valid_fs(struct the_nilfs *nilfs)
--
2.7.4
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