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

Jaegeuk Kim
2021-08-03T18:26:13Z

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 == F2FS_GET_BLOCK_FIEMAP) {
> + 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
takes away to debug the problem from user-land.

> + 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