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Message-ID: <4cd613cd-eea3-e6b7-e35e-f94dc1ae5a71@linux.alibaba.com>
Date: Wed, 8 Nov 2023 18:13:44 +0800
From: Gao Xiang <hsiangkao@...ux.alibaba.com>
To: Yue Hu <zbestahu@...il.com>,
Ferry Meng <mengferry@...ux.alibaba.com>
Cc: huyue2@...lpad.com, linux-erofs@...ts.ozlabs.org,
LKML <linux-kernel@...r.kernel.org>, zhangwen@...lpad.com
Subject: Re: [PATCH] erofs: simplify erofs_read_inode()
On 2023/11/8 16:44, Yue Hu wrote:
> On Mon, 6 Nov 2023 19:01:41 +0800
> Ferry Meng <mengferry@...ux.alibaba.com> 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@...ux.alibaba.com>
>> ---
>> 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?
Yeah, good catch, I think we could just make a copy instead.
Thanks,
Gao Xiang
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