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>

1 files changed, 31 insertions, 31 deletions

diff --git a/fs/ext4/crypto.c b/fs/ext4/crypto.c
index c3a9b08309db..1c9a8c499369 100644
--- 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;
         }