btrfs: fix uncheck memory allocation in btrfs_submit_compressed_read

btrfs_submit_compressed_read() is lack of memory allocation checks and
corresponding error route.

After this fix, if it comes to "no memory" case, errno will be returned
to userland step by step, and tell users this operation cannot go on.

Signed-off-by: Liu Bo <liubo2009@cn.fujitsu.com>
Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 23 insertions, 2 deletions

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index f745287..3a932f1 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -562,7 +562,7 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 	u64 em_len;
 	u64 em_start;
 	struct extent_map *em;
-	int ret;
+	int ret = -ENOMEM;
 	u32 *sums;
 
 	tree = &BTRFS_I(inode)->io_tree;
@@ -577,6 +577,9 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 
 	compressed_len = em->block_len;
 	cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
+	if (!cb)
+		goto out;
+
 	atomic_set(&cb->pending_bios, 0);
 	cb->errors = 0;
 	cb->inode = inode;
@@ -597,13 +600,18 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 
 	nr_pages = (compressed_len + PAGE_CACHE_SIZE - 1) /
 				 PAGE_CACHE_SIZE;
-	cb->compressed_pages = kmalloc(sizeof(struct page *) * nr_pages,
+	cb->compressed_pages = kzalloc(sizeof(struct page *) * nr_pages,
 				       GFP_NOFS);
+	if (!cb->compressed_pages)
+		goto fail1;
+
 	bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 
 	for (page_index = 0; page_index < nr_pages; page_index++) {
 		cb->compressed_pages[page_index] = alloc_page(GFP_NOFS |
 							      __GFP_HIGHMEM);
+		if (!cb->compressed_pages[page_index])
+			goto fail2;
 	}
 	cb->nr_pages = nr_pages;
 
@@ -614,6 +622,8 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 	cb->len = uncompressed_len;
 
 	comp_bio = compressed_bio_alloc(bdev, cur_disk_byte, GFP_NOFS);
+	if (!comp_bio)
+		goto fail2;
 	comp_bio->bi_private = cb;
 	comp_bio->bi_end_io = end_compressed_bio_read;
 	atomic_inc(&cb->pending_bios);
@@ -681,6 +691,17 @@ int btrfs_submit_compressed_read(struct inode *inode, struct bio *bio,
 
 	bio_put(comp_bio);
 	return 0;
+
+fail2:
+	for (page_index = 0; page_index < nr_pages; page_index++)
+		free_page((unsigned long)cb->compressed_pages[page_index]);
+
+	kfree(cb->compressed_pages);
+fail1:
+	kfree(cb);
+out:
+	free_extent_map(em);
+	return ret;
 }
 
 static struct list_head comp_idle_workspace[BTRFS_COMPRESS_TYPES];