(2011/02/12 20:17), Yoshinori Sano wrote:
> 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@xxxxxxxxx>
> ---
> 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));
alloc_extent_map() returns only the address or NULL.
Therefore, I think that check by IS_ERR() is unnecessary.
Regards,
Itoh
> + }
> + 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;
--
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