Merge tag 'erofs-for-6.7-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs

Pull erofs fixes from Gao Xiang:

 - Tidy up erofs_read_inode() for simplicity

 - Fix broken fscache mode due to NULL dereference of dif->bdev_handle

 - Add the EROFS webpage to MAINTAINERS, documentation, and Kconfig

* tag 'erofs-for-6.7-rc3-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs:
  MAINTAINERS: erofs: add EROFS webpage
  erofs: fix NULL dereference of dif->bdev_handle in fscache mode
  erofs: simplify erofs_read_inode()

Documentation/filesystems/erofs.rst

@@ -91,6 +91,10 @@ compatibility checking tool (fsck.erofs), and a debugging tool (dump.erofs):
 
 - git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs-utils.git
 
+For more information, please also refer to the documentation site:
+
+- https://erofs.docs.kernel.org
+
 Bugs and patches are welcome, please kindly help us and send to the following
 linux-erofs mailing list:
 

MAINTAINERS

@@ -7855,6 +7855,7 @@ R:	Yue Hu <huyue2@coolpad.com>
 R:	Jeffle Xu <jefflexu@linux.alibaba.com>
 L:	linux-erofs@lists.ozlabs.org
 S:	Maintained
+W:	https://erofs.docs.kernel.org
 T:	git git://git.kernel.org/pub/scm/linux/kernel/git/xiang/erofs.git
 F:	Documentation/ABI/testing/sysfs-fs-erofs
 F:	Documentation/filesystems/erofs.rst

fs/erofs/Kconfig

@@ -21,7 +21,7 @@ config EROFS_FS
 	  performance under extremely memory pressure without extra cost.
 
 	  See the documentation at <file:Documentation/filesystems/erofs.rst>
-	  for more details.
+	  and the web pages at <https://erofs.docs.kernel.org> for more details.
 
 	  If unsure, say N.
 

fs/erofs/data.c

@@ -220,7 +220,7 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 			up_read(&devs->rwsem);
 			return 0;
 		}
-		map->m_bdev = dif->bdev_handle->bdev;
+		map->m_bdev = dif->bdev_handle ? dif->bdev_handle->bdev : NULL;
 		map->m_daxdev = dif->dax_dev;
 		map->m_dax_part_off = dif->dax_part_off;
 		map->m_fscache = dif->fscache;
@@ -238,7 +238,8 @@ int erofs_map_dev(struct super_block *sb, struct erofs_map_dev *map)
 			if (map->m_pa >= startoff &&
 			    map->m_pa < startoff + length) {
 				map->m_pa -= startoff;
-				map->m_bdev = dif->bdev_handle->bdev;
+				map->m_bdev = dif->bdev_handle ?
+					      dif->bdev_handle->bdev : NULL;
 				map->m_daxdev = dif->dax_dev;
 				map->m_dax_part_off = dif->dax_part_off;
 				map->m_fscache = dif->fscache;

fs/erofs/inode.c

@@ -15,11 +15,11 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 	struct erofs_sb_info *sbi = EROFS_SB(sb);
 	struct erofs_inode *vi = EROFS_I(inode);
 	const erofs_off_t inode_loc = erofs_iloc(inode);
-
 	erofs_blk_t blkaddr, nblks = 0;
 	void *kaddr;
 	struct erofs_inode_compact *dic;
 	struct erofs_inode_extended *die, *copied = NULL;
+	union erofs_inode_i_u iu;
 	unsigned int ifmt;
 	int err;
 
@@ -35,9 +35,8 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 
 	dic = kaddr + *ofs;
 	ifmt = le16_to_cpu(dic->i_format);
-
 	if (ifmt & ~EROFS_I_ALL) {
-		erofs_err(inode->i_sb, "unsupported i_format %u of nid %llu",
+		erofs_err(sb, "unsupported i_format %u of nid %llu",
 			  ifmt, vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
@@ -45,7 +44,7 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 
 	vi->datalayout = erofs_inode_datalayout(ifmt);
 	if (vi->datalayout >= EROFS_INODE_DATALAYOUT_MAX) {
-		erofs_err(inode->i_sb, "unsupported datalayout %u of nid %llu",
+		erofs_err(sb, "unsupported datalayout %u of nid %llu",
 			  vi->datalayout, vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
@@ -82,40 +81,15 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 		vi->xattr_isize = erofs_xattr_ibody_size(die->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(die->i_mode);
-		switch (inode->i_mode & S_IFMT) {
-		case S_IFREG:
-		case S_IFDIR:
-		case S_IFLNK:
-			vi->raw_blkaddr = le32_to_cpu(die->i_u.raw_blkaddr);
-			break;
-		case S_IFCHR:
-		case S_IFBLK:
-			inode->i_rdev =
-				new_decode_dev(le32_to_cpu(die->i_u.rdev));
-			break;
-		case S_IFIFO:
-		case S_IFSOCK:
-			inode->i_rdev = 0;
-			break;
-		default:
-			goto bogusimode;
-		}
+		iu = die->i_u;
 		i_uid_write(inode, le32_to_cpu(die->i_uid));
 		i_gid_write(inode, le32_to_cpu(die->i_gid));
 		set_nlink(inode, le32_to_cpu(die->i_nlink));
-
-		/* extended inode has its own timestamp */
+		/* each extended inode has its own timestamp */
 		inode_set_ctime(inode, le64_to_cpu(die->i_mtime),
 				le32_to_cpu(die->i_mtime_nsec));
 
 		inode->i_size = le64_to_cpu(die->i_size);
-
-		/* total blocks for compressed files */
-		if (erofs_inode_is_data_compressed(vi->datalayout))
-			nblks = le32_to_cpu(die->i_u.compressed_blocks);
-		else if (vi->datalayout == EROFS_INODE_CHUNK_BASED)
-			/* fill chunked inode summary info */
-			vi->chunkformat = le16_to_cpu(die->i_u.c.format);
 		kfree(copied);
 		copied = NULL;
 		break;
@@ -125,49 +99,51 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 		vi->xattr_isize = erofs_xattr_ibody_size(dic->i_xattr_icount);
 
 		inode->i_mode = le16_to_cpu(dic->i_mode);
-		switch (inode->i_mode & S_IFMT) {
-		case S_IFREG:
-		case S_IFDIR:
-		case S_IFLNK:
-			vi->raw_blkaddr = le32_to_cpu(dic->i_u.raw_blkaddr);
-			break;
-		case S_IFCHR:
-		case S_IFBLK:
-			inode->i_rdev =
-				new_decode_dev(le32_to_cpu(dic->i_u.rdev));
-			break;
-		case S_IFIFO:
-		case S_IFSOCK:
-			inode->i_rdev = 0;
-			break;
-		default:
-			goto bogusimode;
-		}
+		iu = dic->i_u;
 		i_uid_write(inode, le16_to_cpu(dic->i_uid));
 		i_gid_write(inode, le16_to_cpu(dic->i_gid));
 		set_nlink(inode, le16_to_cpu(dic->i_nlink));
-
 		/* use build time for compact inodes */
 		inode_set_ctime(inode, sbi->build_time, sbi->build_time_nsec);
 
 		inode->i_size = le32_to_cpu(dic->i_size);
-		if (erofs_inode_is_data_compressed(vi->datalayout))
-			nblks = le32_to_cpu(dic->i_u.compressed_blocks);
-		else if (vi->datalayout == EROFS_INODE_CHUNK_BASED)
-			vi->chunkformat = le16_to_cpu(dic->i_u.c.format);
 		break;
 	default:
-		erofs_err(inode->i_sb,
-			  "unsupported on-disk inode version %u of nid %llu",
+		erofs_err(sb, "unsupported on-disk inode version %u of nid %llu",
 			  erofs_inode_version(ifmt), vi->nid);
 		err = -EOPNOTSUPP;
 		goto err_out;
 	}
 
-	if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
+	switch (inode->i_mode & S_IFMT) {
+	case S_IFREG:
+	case S_IFDIR:
+	case S_IFLNK:
+		vi->raw_blkaddr = le32_to_cpu(iu.raw_blkaddr);
+		break;
+	case S_IFCHR:
+	case S_IFBLK:
+		inode->i_rdev = new_decode_dev(le32_to_cpu(iu.rdev));
+		break;
+	case S_IFIFO:
+	case S_IFSOCK:
+		inode->i_rdev = 0;
+		break;
+	default:
+		erofs_err(sb, "bogus i_mode (%o) @ nid %llu", inode->i_mode,
+			  vi->nid);
+		err = -EFSCORRUPTED;
+		goto err_out;
+	}
+
+	/* total blocks for compressed files */
+	if (erofs_inode_is_data_compressed(vi->datalayout)) {
+		nblks = le32_to_cpu(iu.compressed_blocks);
+	} else if (vi->datalayout == EROFS_INODE_CHUNK_BASED) {
+		/* fill chunked inode summary info */
+		vi->chunkformat = le16_to_cpu(iu.c.format);
 		if (vi->chunkformat & ~EROFS_CHUNK_FORMAT_ALL) {
-			erofs_err(inode->i_sb,
-				  "unsupported chunk format %x of nid %llu",
+			erofs_err(sb, "unsupported chunk format %x of nid %llu",
 				  vi->chunkformat, vi->nid);
 			err = -EOPNOTSUPP;
 			goto err_out;
@@ -191,10 +167,6 @@ static void *erofs_read_inode(struct erofs_buf *buf,
 		inode->i_blocks = nblks << (sb->s_blocksize_bits - 9);
 	return kaddr;
 
-bogusimode:
-	erofs_err(inode->i_sb, "bogus i_mode (%o) @ nid %llu",
-		  inode->i_mode, vi->nid);
-	err = -EFSCORRUPTED;
 err_out:
 	DBG_BUGON(1);
 	kfree(copied);