hfs: fix memory leak when unmounting

When an HFS filesystem is unmounted, it leaks a 2-page bitmap.  Also,
under extreme memory pressure, it's possible that hfs_releasepage() may
use a tree pointer that has not been initialized, and if so, the release
request should just be rejected.

[akpm@linux-foundation.org: free_pages(0) is legal, remove obvious comment]
Signed-off-by: Dave Anderson <anderson@redhat.com>
Tested-by: Eugene Teo <eugeneteo@kernel.sg>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 5 insertions, 0 deletions

diff --git a/fs/hfs/inode.c b/fs/hfs/inode.c
index 9435dda8f1e0..a1cbff2b4d99 100644
--- a/fs/hfs/inode.c
+++ b/fs/hfs/inode.c
@@ -70,6 +70,10 @@ static int hfs_releasepage(struct page *page, gfp_t mask)
                 BUG();
                 return 0;
         }
+
+        if (!tree)
+                return 0;
+
         if (tree->node_size >= PAGE_CACHE_SIZE) {
                 nidx = page->index >> (tree->node_size_shift - PAGE_CACHE_SHIFT);
                 spin_lock(&tree->hash_lock);
diff --git a/fs/hfs/mdb.c b/fs/hfs/mdb.c
index 36ca2e1a4fa3..7b6165f25fbe 100644
--- a/fs/hfs/mdb.c
+++ b/fs/hfs/mdb.c
@@ -349,6 +349,7 @@ void hfs_mdb_put(struct super_block *sb)
         if (HFS_SB(sb)->nls_disk)
                 unload_nls(HFS_SB(sb)->nls_disk);
 
+        free_pages((unsigned long)HFS_SB(sb)->bitmap, PAGE_SIZE < 8192 ? 1 : 0);
         kfree(HFS_SB(sb));
         sb->s_fs_info = NULL;
 }