[PATCH] fix uncheck memory allocations

[Yoshinori Sano <yoshinori.sano@gmail.com>]

To make Btrfs code more robust, several return value checks where memory
allocation can fail are introduced.  I use BUG_ON where I don't know how
to handle the error properly, which increases the number of using the
notorious BUG_ON, though.

Signed-off-by: Yoshinori Sano <yoshinori.sano@gmail.com>
---
 fs/btrfs/compression.c |    6 ++++++
 fs/btrfs/extent-tree.c |    2 ++
 fs/btrfs/file.c        |    8 ++++++--
 fs/btrfs/inode.c       |    5 +++++
 4 files changed, 19 insertions(+), 2 deletions(-)

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index 4d2110e..f596554 100644
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -340,6 +340,8 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
 
 	WARN_ON(start & ((u64)PAGE_CACHE_SIZE - 1));
 	cb = kmalloc(compressed_bio_size(root, compressed_len), GFP_NOFS);
+	if (!cb)
+		return -ENOMEM;
 	atomic_set(&cb->pending_bios, 0);
 	cb->errors = 0;
 	cb->inode = inode;
@@ -354,6 +356,10 @@ int btrfs_submit_compressed_write(struct inode *inode, u64 start,
 	bdev = BTRFS_I(inode)->root->fs_info->fs_devices->latest_bdev;
 
 	bio = compressed_bio_alloc(bdev, first_byte, GFP_NOFS);
+	if (!bio) {
+		kfree(cb);
+		return -ENOMEM;
+	}
 	bio->bi_private = cb;
 	bio->bi_end_io = end_compressed_bio_write;
 	atomic_inc(&cb->pending_bios);
diff --git a/fs/btrfs/extent-tree.c b/fs/btrfs/extent-tree.c
index 565e22d..aed16f4 100644
--- a/fs/btrfs/extent-tree.c
+++ b/fs/btrfs/extent-tree.c
@@ -6931,6 +6931,8 @@ static noinline int get_new_locations(struct inode *reloc_inode,
 			struct disk_extent *old = exts;
 			max *= 2;
 			exts = kzalloc(sizeof(*exts) * max, GFP_NOFS);
+			if (!exts)
+				goto out;
 			memcpy(exts, old, sizeof(*exts) * nr);
 			if (old != *extents)
 				kfree(old);
diff --git a/fs/btrfs/file.c b/fs/btrfs/file.c
index b0ff34b..4895ad2 100644
--- a/fs/btrfs/file.c
+++ b/fs/btrfs/file.c
@@ -181,10 +181,14 @@ int btrfs_drop_extent_cache(struct inode *inode, u64 start, u64 end,
 		testend = 0;
 	}
 	while (1) {
-		if (!split)
+		if (!split) {
 			split = alloc_extent_map(GFP_NOFS);
-		if (!split2)
+			BUG_ON(!split || IS_ERR(split));
+		}
+		if (!split2) {
 			split2 = alloc_extent_map(GFP_NOFS);
+			BUG_ON(!split2 || IS_ERR(split2));
+		}
 
 		write_lock(&em_tree->lock);
 		em = lookup_extent_mapping(em_tree, start, len);
diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index c9bc0af..40bbe00 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -287,6 +287,7 @@ static noinline int add_async_extent(struct async_cow *cow,
 	struct async_extent *async_extent;
 
 	async_extent = kmalloc(sizeof(*async_extent), GFP_NOFS);
+	BUG_ON(!async_extent);
 	async_extent->start = start;
 	async_extent->ram_size = ram_size;
 	async_extent->compressed_size = compressed_size;
@@ -384,6 +385,7 @@ again:
 	     (BTRFS_I(inode)->force_compress))) {
 		WARN_ON(pages);
 		pages = kzalloc(sizeof(struct page *) * nr_pages, GFP_NOFS);
+		BUG_ON(!pages);
 
 		if (BTRFS_I(inode)->force_compress)
 			compress_type = BTRFS_I(inode)->force_compress;
@@ -644,6 +646,7 @@ retry:
 					async_extent->ram_size - 1, 0);
 
 		em = alloc_extent_map(GFP_NOFS);
+		BUG_ON(!em || IS_ERR(em));
 		em->start = async_extent->start;
 		em->len = async_extent->ram_size;
 		em->orig_start = em->start;
@@ -820,6 +823,7 @@ static noinline int cow_file_range(struct inode *inode,
 		BUG_ON(ret);
 
 		em = alloc_extent_map(GFP_NOFS);
+		BUG_ON(!em || IS_ERR(em));
 		em->start = start;
 		em->orig_start = em->start;
 		ram_size = ins.offset;
@@ -1169,6 +1173,7 @@ out_check:
 			struct extent_map_tree *em_tree;
 			em_tree = &BTRFS_I(inode)->extent_tree;
 			em = alloc_extent_map(GFP_NOFS);
+			BUG_ON(!em || IS_ERR(em));
 			em->start = cur_offset;
 			em->orig_start = em->start;
 			em->len = num_bytes;
-- 
1.7.1