ext4 crypto: fix memory leaks in ext4_encrypted_zeroout

ext4_encrypted_zeroout() could end up leaking a bio and bounce page.
Fortunately it's not used much.  While we're fixing things up,
refactor out common code into the static function alloc_bounce_page()
and fix up error handling if mempool_alloc() fails.

Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index c3a9b08309db193cbcbbc44cd5962a57c3f134b8..1c9a8c499369f43d12c3e49c6e48a10319143532 100644 (file)
--- a/fs/ext4/crypto.c
+++ b/fs/ext4/crypto.c
@@ -314,6 +314,26 @@ static int ext4_page_crypto(struct ext4_crypto_ctx *ctx,
        return 0;
 }
 
+static struct page *alloc_bounce_page(struct ext4_crypto_ctx *ctx)
+{
+       struct page *ciphertext_page = alloc_page(GFP_NOFS);
+
+       if (!ciphertext_page) {
+               /* This is a potential bottleneck, but at least we'll have
+                * forward progress. */
+               ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
+                                                GFP_NOFS);
+               if (ciphertext_page == NULL)
+                       return ERR_PTR(-ENOMEM);
+               ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
+       } else {
+               ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
+       }
+       ctx->flags |= EXT4_WRITE_PATH_FL;
+       ctx->w.bounce_page = ciphertext_page;
+       return ciphertext_page;
+}
+
 /**
  * ext4_encrypt() - Encrypts a page
  * @inode:          The inode for which the encryption should take place
@@ -343,28 +363,17 @@ struct page *ext4_encrypt(struct inode *inode,
                return (struct page *) ctx;
 
        /* The encryption operation will require a bounce page. */
-       ciphertext_page = alloc_page(GFP_NOFS);
-       if (!ciphertext_page) {
-               /* This is a potential bottleneck, but at least we'll have
-                * forward progress. */
-               ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
-                                                GFP_NOFS);
-               if (WARN_ON_ONCE(!ciphertext_page)) {
-                       ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
-                                                        GFP_NOFS | __GFP_WAIT);
-               }
-               ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
-       } else {
-               ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
-       }
-       ctx->flags |= EXT4_WRITE_PATH_FL;
-       ctx->w.bounce_page = ciphertext_page;
+       ciphertext_page = alloc_bounce_page(ctx);
+       if (IS_ERR(ciphertext_page))
+               goto errout;
        ctx->w.control_page = plaintext_page;
        err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, plaintext_page->index,
                               plaintext_page, ciphertext_page);
        if (err) {
+               ciphertext_page = ERR_PTR(err);
+       errout:
                ext4_release_crypto_ctx(ctx);
-               return ERR_PTR(err);
+               return ciphertext_page;
        }
        SetPagePrivate(ciphertext_page);
        set_page_private(ciphertext_page, (unsigned long)ctx);
@@ -424,21 +433,11 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
        if (IS_ERR(ctx))
                return PTR_ERR(ctx);
 
-       ciphertext_page = alloc_page(GFP_NOFS);
-       if (!ciphertext_page) {
-               /* This is a potential bottleneck, but at least we'll have
-                * forward progress. */
-               ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
-                                                GFP_NOFS);
-               if (WARN_ON_ONCE(!ciphertext_page)) {
-                       ciphertext_page = mempool_alloc(ext4_bounce_page_pool,
-                                                        GFP_NOFS | __GFP_WAIT);
-               }
-               ctx->flags &= ~EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
-       } else {
-               ctx->flags |= EXT4_BOUNCE_PAGE_REQUIRES_FREE_ENCRYPT_FL;
+       ciphertext_page = alloc_bounce_page(ctx);
+       if (IS_ERR(ciphertext_page)) {
+               err = PTR_ERR(ciphertext_page);
+               goto errout;
        }
-       ctx->w.bounce_page = ciphertext_page;
 
        while (len--) {
                err = ext4_page_crypto(ctx, inode, EXT4_ENCRYPT, lblk,
@@ -460,6 +459,7 @@ int ext4_encrypted_zeroout(struct inode *inode, struct ext4_extent *ex)
                        goto errout;
                }
                err = submit_bio_wait(WRITE, bio);
+               bio_put(bio);
                if (err)
                        goto errout;
        }