Re: [f2fs-dev] [RFC PATCH v2 13/32] inject.f2fs: add member `filename' in inject_dentry

[Sheng Yong <shengyong2021@gmail.com>]

On 6/13/25 15:55, Chao Yu wrote:
> On 2025/6/10 20:37, Sheng Yong wrote:
>> From: Sheng Yong <shengyong1@xiaomi.com>
>>
>> This patch adds a new member `filename' in inject_dentry to inject
>> dentry filename. The dentry is specified by nid option.
>>
>> Note that '.' and '..' dentries are special, because they are not in the
>> parent directory of nid. So this patch also adds a new option `--dots'
>> to inject these two dentries.
>>
>> Signed-off-by: Sheng Yong <shengyong1@xiaomi.com>
>> ---
>>   fsck/inject.c     | 94 ++++++++++++++++++++++++++++++++++++++++-------
>>   fsck/inject.h     |  1 +
>>   man/inject.f2fs.8 | 12 +++++-
>>   3 files changed, 92 insertions(+), 15 deletions(-)
>>
>> diff --git a/fsck/inject.c b/fsck/inject.c
>> index 8c2f8c5dc332..5eb913fefad7 100644
>> --- a/fsck/inject.c
>> +++ b/fsck/inject.c
[...]
>> @@ -1265,6 +1301,36 @@ static int inject_dentry(struct f2fs_sb_info *sbi, struct inject_option *opt)
>>               "%d -> %d\n", opt->nid, dent->file_type,
>>               (u8)opt->val);
>>           dent->file_type = (u8)opt->val;
>> +    } else if (!strcmp(opt->mb, "filename")) {
>> +        if (!opt->str) {
>> +            ERR_MSG("option str is needed\n");
>> +            ret = -EINVAL;
>> +            goto out;
>> +        }
>> +        namecap = ALIGN_UP(le16_to_cpu(dent->name_len), F2FS_SLOT_LEN);
>> +        namelen = strlen(opt->str);
>> +        if (namelen > namecap || namelen > F2FS_NAME_LEN) {
>> +            ERR_MSG("option str too long\n");
>> +            ret = -EINVAL;
>> +            goto out;
>> +        }
>> +        name = (char *)d.filename[slot];
>> +        MSG(0, "Info: inject dentry filename of nid %u: "
>> +            "%.*s -> %s\n", opt->nid, le16_to_cpu(dent->name_len),
>> +            name, opt->str);
>> +        memcpy(name, opt->str, namelen);
>> +        MSG(0, "Info: inject dentry namelen of nid %u: "
>> +            "%d -> %d\n", opt->nid, le16_to_cpu(dent->name_len),
>> +            namelen);
>> +        dent->name_len = cpu_to_le16(namelen);
>> +        dentry_hash = f2fs_dentry_hash(get_encoding(sbi),
>> +                        IS_CASEFOLDED(inode),
>> +                        (unsigned char *)name,
>> +                        namelen);
>> +        MSG(0, "Info: inject dentry d_hash of nid %u: "
>> +            "0x%x -> 0x%x\n", opt->nid, le32_to_cpu(dent->hash_code),
>> +            dentry_hash);
>> +        dent->hash_code = cpu_to_le32(dentry_hash);
> 
> Yong,
> 
> Out of curiosity, if we inject filename in target dirent, according new
> filename's hash, it may be located in dentry block which belongs to another
> bucket, can fsck repair it?

Hi, Chao,

Yes, I think fsck can repair it, but it removes the entry directly instead of
"reordering" it (`f2fs_check_dirent_position`). I can add a test for this case.

Thanks,
shengyong
> 
> Thanks,
> 
>>       } else {
>>           ERR_MSG("unknown or unsupported member \"%s\"\n", opt->mb);
>>           ret = -EINVAL;
>> diff --git a/fsck/inject.h b/fsck/inject.h
>> index 43c21b56a7eb..706a211bc645 100644
>> --- a/fsck/inject.h
>> +++ b/fsck/inject.h
>> @@ -30,6 +30,7 @@ struct inject_option {
>>       int cp;            /* which cp */
>>       int nat;        /* which nat pack */
>>       int sit;        /* which sit pack */
>> +    int dots;        /* . or .. dentry */
>>       bool ssa;
>>       bool node;
>>       bool dent;
>> diff --git a/man/inject.f2fs.8 b/man/inject.f2fs.8
>> index 72d1c90f7ce4..27b66f59b77d 100644
>> --- a/man/inject.f2fs.8
>> +++ b/man/inject.f2fs.8
>> @@ -214,7 +214,14 @@ inode i_nid array specified by \fIidx\fP.
>>   .RE
>>   .TP
>>   .BI \-\-dent
>> -Inject dentry block or dir entry specified \fInid\fP.
>> +Inject dentry block or dir entry specified by \fInid\fP.
>> +.RS 1.2i
>> +.TP
>> +.BI \-\-dots " 1 or 2"
>> +The option means the "." or ".." directory entry of \fInid\fP is going to be injected.
>> +.RE
>> +.TP
>> +.BI ""
>>   The available \fImb\fP of \fIdent\fP are:
>>   .RS 1.2i
>>   .TP
>> @@ -229,6 +236,9 @@ dentry ino.
>>   .TP
>>   .BI d_ftype
>>   dentry ftype.
>> +.TP
>> +.BI filename
>> +dentry filename, and corresponding d_hash and namelen are updated implicitly.
>>   .RE
>>   .TP
>>   .BI \-\-dry\-run
> 



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