Re: [PATCH] erofs: simplify erofs_read_inode()
From: Yue Hu
Date: Wed Nov 08 2023 - 03:45:00 EST
On Mon, 6 Nov 2023 19:01:41 +0800
Ferry Meng <mengferry@xxxxxxxxxxxxxxxxx> wrote:
> After commit 1c7f49a76773 ("erofs: tidy up EROFS on-disk naming"),
> there is a unique `union erofs_inode_i_u` so that we could parse
> the union directly.
>
> Besides, it also replaces `inode->i_sb` with `sb` for simplicity.
>
> Signed-off-by: Ferry Meng <mengferry@xxxxxxxxxxxxxxxxx>
> ---
> fs/erofs/inode.c | 98 +++++++++++++++++-------------------------------
> 1 file changed, 35 insertions(+), 63 deletions(-)
>
> diff --git a/fs/erofs/inode.c b/fs/erofs/inode.c
> index edc8ec7581b8..99535c8c53b5 100644
> --- a/fs/erofs/inode.c
> +++ b/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);
may cause use-after-free for acrossing block boundary case due to kfree(copied) before?
> + 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;
> @@ -190,10 +166,6 @@ 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);