Re: [PATCH 2/3] btrfs-progs: check/original: Add checks for compressed extent without csum

[Su Yue <suy.fnst@cn.fujitsu.com>]

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On 05/14/2018 03:03 PM, Qu Wenruo wrote:
> There is one report of compressed extent happens in btrfs, but has no
> csum and then leads to possible decompress error screwing up kernel
> memory.
> 
> Although it's a kernel bug, and won't cause problem until compressed
> data get corrupted, let's catch such problem in advance.
> 
> This patch will catch any unexpected compressed extent with:
> 
> 1) 0 or less than expected csum
> 
> 2) nodatasum flag set in the inode item
> 
> This is for original mode.
> 
> Reported-by: James Harvey <jamespharvey20@gmail.com>
> Issue: #134
> Signed-off-by: Qu Wenruo <wqu@suse.com>

Reviewed-by: Su Yue <suy.fnst@cn.fujitsu.com>

> ---
>  check/main.c | 10 ++++++++--
>  1 file changed, 8 insertions(+), 2 deletions(-)
> 
> diff --git a/check/main.c b/check/main.c
> index 891a6d797756..db064b27e84b 100644
> --- a/check/main.c
> +++ b/check/main.c
> @@ -1437,6 +1437,7 @@ static int process_file_extent(struct btrfs_root *root,
>  	u64 mask = root->fs_info->sectorsize - 1;
>  	u32 max_inline_size = min_t(u32, mask,
>  				BTRFS_MAX_INLINE_DATA_SIZE(root->fs_info));
> +	u8 compression;
>  	int extent_type;
>  	int ret;
>  
> @@ -1460,9 +1461,9 @@ static int process_file_extent(struct btrfs_root *root,
>  
>  	fi = btrfs_item_ptr(eb, slot, struct btrfs_file_extent_item);
>  	extent_type = btrfs_file_extent_type(eb, fi);
> +	compression = btrfs_file_extent_compression(eb, fi);
>  
>  	if (extent_type == BTRFS_FILE_EXTENT_INLINE) {
> -		u8 compression = btrfs_file_extent_compression(eb, fi);
>  		struct btrfs_item *item = btrfs_item_nr(slot);
>  
>  		num_bytes = btrfs_file_extent_inline_len(eb, slot, fi);
> @@ -1494,6 +1495,8 @@ static int process_file_extent(struct btrfs_root *root,
>  		     btrfs_file_extent_encryption(eb, fi) ||
>  		     btrfs_file_extent_other_encoding(eb, fi)))
>  			rec->errors |= I_ERR_BAD_FILE_EXTENT;
> +		if (compression && rec->nodatasum)
> +			rec->errors |= I_ERR_BAD_FILE_EXTENT;
>  		if (disk_bytenr > 0)
>  			rec->found_size += num_bytes;
>  	} else {
> @@ -1512,7 +1515,8 @@ static int process_file_extent(struct btrfs_root *root,
>  	if (disk_bytenr > 0 &&
>  	    btrfs_header_owner(eb) != BTRFS_DATA_RELOC_TREE_OBJECTID) {
>  		u64 found;
> -		if (btrfs_file_extent_compression(eb, fi))
> +
> +		if (compression)
>  			num_bytes = btrfs_file_extent_disk_num_bytes(eb, fi);
>  		else
>  			disk_bytenr += extent_offset;
> @@ -1526,6 +1530,8 @@ static int process_file_extent(struct btrfs_root *root,
>  				rec->found_csum_item = 1;
>  			if (found < num_bytes)
>  				rec->some_csum_missing = 1;
> +			if (compression && found < num_bytes)
> +				rec->errors |= I_ERR_SOME_CSUM_MISSING;
>  		} else if (extent_type == BTRFS_FILE_EXTENT_PREALLOC) {
>  			if (found > 0) {
>  				ret = check_prealloc_extent_written(root->fs_info,
> 



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