Re: [PATCH] f2fs: compress: do sanity check on cluster

Chao Yu
2021-08-04T00:48:21Z

On 2021/8/4 2:26, Jaegeuk Kim wrote:
> On 08/03, Chao Yu wrote:
>> This patch adds f2fs_sanity_check_cluster() to support doing
>> sanity check on cluster of compressed file, it will be triggered
>> from below two paths:
>>
>> - __f2fs_cluster_blocks()
>> - f2fs_map_blocks(F2FS_GET_BLOCK_FIEMAP)
>>
>> And it can detect below three kind of cluster insanity status.
>>
>> C: COMPRESS_ADDR
>> N: NULL_ADDR or NEW_ADDR
>> V: valid blkaddr
>> *: any value
>>
>> 1. [*|C|*|*]
>> 2. [C|*|C|*]
>> 3. [C|N|N|V]
>>
>> Signed-off-by: Chao Yu <chao@kernel.org>
>> ---
>> fs/f2fs/compress.c | 53 ++++++++++++++++++++++++++++++++++++++++++++++
>> fs/f2fs/data.c | 21 ++++++++++++------
>> fs/f2fs/f2fs.h | 1 +
>> 3 files changed, 68 insertions(+), 7 deletions(-)
>>
>> diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
>> index 455561826c7d..4aa166d3d9bf 100644
>> --- a/fs/f2fs/compress.c
>> +++ b/fs/f2fs/compress.c
>> @@ -898,6 +898,54 @@ static bool cluster_has_invalid_data(struct compress_ctx *cc)
>> return false;
>> }
>>
>> +bool f2fs_sanity_check_cluster(struct dnode_of_data *dn)
>> +{
>> + struct f2fs_sb_info *sbi = F2FS_I_SB(dn->inode);
>> + unsigned int cluster_size = F2FS_I(dn->inode)->i_cluster_size;
>> + bool compressed = dn->data_blkaddr == COMPRESS_ADDR;
>> + int cluster_end = 0;
>> + int i;
>> + char *reason = "";
>> +
>> + if (!compressed)
>> + return false;
>> +
>> + /* [..., COMPR_ADDR, ...] */
>> + if (dn->ofs_in_node % cluster_size) {
>> + reason = "[*|C|*|*]";
>> + goto out;
>> + }
>> +
>> + for (i = 1; i < cluster_size; i++) {
>> + block_t blkaddr = data_blkaddr(dn->inode, dn->node_page,
>> + dn->ofs_in_node + i);
>> +
>> + /* [COMPR_ADDR, ..., COMPR_ADDR] */
>> + if (blkaddr == COMPRESS_ADDR) {
>> + reason = "[C|*|C|*]";
>> + goto out;
>> + }
>> + if (compressed) {
>> + if (!__is_valid_data_blkaddr(blkaddr)) {
>> + if (!cluster_end)
>> + cluster_end = i;
>> + continue;
>> + }
>> + /* [COMPR_ADDR, NULL_ADDR or NEW_ADDR, valid_blkaddr] */
>> + if (cluster_end) {
>> + reason = "[C|N|N|V]";
>> + goto out;
>> + }
>> + }
>> + }
>> + return false;
>> +out:
>> + f2fs_warn(sbi, "access invalid cluster, ino:%lu, nid:%u, ofs_in_node:%u, reason:%s",
>> + dn->inode->i_ino, dn->nid, dn->ofs_in_node, reason);
>> + set_sbi_flag(sbi, SBI_NEED_FSCK);
>> + return true;
>> +}
>> +
>> static int __f2fs_cluster_blocks(struct inode *inode,
>> unsigned int cluster_idx, bool compr)
>> {
>> @@ -915,6 +963,11 @@ static int __f2fs_cluster_blocks(struct inode *inode,
>> goto fail;
>> }
>>
>> + if (f2fs_sanity_check_cluster(&dn)) {
>> + ret = -EFSCORRUPTED;
>> + goto fail;
>> + }
>> +
>> if (dn.data_blkaddr == COMPRESS_ADDR) {
>> int i;
>>
>> diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
>> index 948083c88d17..75dda2035f68 100644
>> --- a/fs/f2fs/data.c
>> +++ b/fs/f2fs/data.c
>> @@ -1558,13 +1558,20 @@ int f2fs_map_blocks(struct inode *inode, struct f2fs_map_blocks *map,
>> }
>> if (flag == F2FS_GET_BLOCK_PRECACHE)
>> goto sync_out;
>> - if (flag == F2FS_GET_BLOCK_FIEMAP &&
>> - blkaddr == NULL_ADDR) {
>> - if (map->m_next_pgofs)
>> - *map->m_next_pgofs = pgofs + 1;
>> - goto sync_out;
>> - }
>> - if (flag != F2FS_GET_BLOCK_FIEMAP) {
>> + if (flag == ) {
>> + if (blkaddr == NULL_ADDR) {
>> + if (map->m_next_pgofs)
>> + *map->m_next_pgofs = pgofs + 1;
>> + goto sync_out;
>> + }
>> +#ifdef CONFIG_F2FS_FS_COMPRESSION
>> + if (f2fs_compressed_file(inode) &&
>> + f2fs_sanity_check_cluster(&dn)) {
>> + err = -EFSCORRUPTED;
>
> I prefer to give the block map as is instead of giving an error, since this\

It looks the policy is not consistent with the one we did in
f2fs_is_valid_blkaddr().

> takes away to debug the problem from user-land.

We can debug through "dump.f2fs -i" command? also once f2fs_sanity_check_cluster()
fails, it will print kernel message for further debuging.

Thanks,

>
>> + goto sync_out;
>> + }
>> +#endif
>> + } else {
>> /* for defragment case */
>> if (map->m_next_pgofs)
>> *map->m_next_pgofs = pgofs + 1;
>> diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
>> index 20389b9b3eac..86d416ffad61 100644
>> --- a/fs/f2fs/f2fs.h
>> +++ b/fs/f2fs/f2fs.h
>> @@ -4060,6 +4060,7 @@ void f2fs_end_read_compressed_page(struct page *page, bool failed,
>> block_t blkaddr);
>> bool f2fs_cluster_is_empty(struct compress_ctx *cc);
>> bool f2fs_cluster_can_merge_page(struct compress_ctx *cc, pgoff_t index);
>> +bool f2fs_sanity_check_cluster(struct dnode_of_data *dn);
>> void f2fs_compress_ctx_add_page(struct compress_ctx *cc, struct page *page);
>> int f2fs_write_multi_pages(struct compress_ctx *cc,
>> int *submitted,
>> --
>> 2.22.1