[PATCH 4.4 057/115] afs: Fix page leak in afs_write_begin()

Greg Kroah-Hartman
2017-12-18T17:56:16Z

From: David Howells <dhowells@redhat.com>

[ Upstream commit 6d06b0d25209c80e99c1e89700f1e09694a3766b ]

afs_write_begin() leaks a ref and a lock on a page if afs_fill_page()
fails. Fix the leak by unlocking and releasing the page in the error path.

Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
fs/afs/write.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

--- a/fs/afs/write.c
+++ b/fs/afs/write.c
@@ -148,12 +148,12 @@ int afs_write_begin(struct file *file, s
kfree(candidate);
return -ENOMEM;
}
- *pagep = page;
- /* page won't leak in error case: it eventually gets cleaned off LRU */

if (!PageUptodate(page) && len != PAGE_CACHE_SIZE) {
ret = afs_fill_page(vnode, key, index << PAGE_CACHE_SHIFT, page);
if (ret < 0) {
+ unlock_page(page);
+ put_page(page);
kfree(candidate);
_leave(" = %d [prep]", ret);
return ret;
@@ -161,6 +161,9 @@ int afs_write_begin(struct file *file, s
SetPageUptodate(page);
}

+ /* page won't leak in error case: it eventually gets cleaned off LRU */
+ *pagep = page;
+
try_again:
spin_lock(&vnode->writeback_lock);