f2fs: compress: do sanity check on cluster

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>
[Nathan Chancellor: fix missing inline warning]
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

1 files changed, 53 insertions, 0 deletions

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index afb79480c6a3..ec70a0a32327 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -899,6 +899,54 @@ 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)
 {
@@ -916,6 +964,11 @@ 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;