[External Mail]Re: [PATCH v5] erofs-utils: fsck: introduce exporting xattrs

[Gao Xiang]

On 2024/9/6 10:46, Huang Jianan via Linux-erofs wrote:
> On 2024/9/6 10:31, Gao Xiang wrote:
>>
>> Hi Jianan,
>>
>> On 2024/9/6 10:22, Hongzhen Luo wrote:
>>> The current `fsck --extract` does not support exporting the extended
>>> attributes of files. This patch adds `--xattrs` option to dump the
>>> extended attributes, as well as the `--no-xattrs` option to not dump
>>> the extended attributes.
>>>
>>> Signed-off-by: Hongzhen Luo <hongzhen at linux.alibaba.com>
>>
>> Could you confirm this version?
>>
>> Thanks,
>> Gao Xiang
>>
> 
> LGTM.
> 
> Reviewed-by: Jianan Huang <huangjianan at xiaomi.com>
> Thanks,
> 
>>> ---
>>> v5: Adjust the help information.
>>> v4: https://lore.kernel.org/all/20240905113723.1937634-1-
>>> hongzhen at linux.alibaba.com/
>>> v3: https://lore.kernel.org/all/20240903113729.3539578-1-
>>> hongzhen at linux.alibaba.com/
>>> v2: https://lore.kernel.org/all/20240903085643.3393012-1-
>>> hongzhen at linux.alibaba.com/
>>> v1: https://lore.kernel.org/all/20240903073517.3311407-1-
>>> hongzhen at linux.alibaba.com/
>>> ---
>>>    fsck/main.c | 82 ++++++++++++++++++++++++++++++++++++++++++++++++++---
>>>    1 file changed, 78 insertions(+), 4 deletions(-)
>>>
>>> diff --git a/fsck/main.c b/fsck/main.c
>>> index 28f1e7e..d110cdb 100644
>>> --- a/fsck/main.c
>>> +++ b/fsck/main.c
>>> @@ -9,6 +9,7 @@
>>>    #include <utime.h>
>>>    #include <unistd.h>
>>>    #include <sys/stat.h>
>>> +#include <sys/xattr.h>
>>>    #include "erofs/print.h"
>>>    #include "erofs/compress.h"
>>>    #include "erofs/decompress.h"
>>> @@ -31,6 +32,7 @@ struct erofsfsck_cfg {
>>>        bool overwrite;
>>>        bool preserve_owner;
>>>        bool preserve_perms;
>>> +     bool dump_xattrs;
>>>    };
>>>    static struct erofsfsck_cfg fsckcfg;
>>>
>>> @@ -48,6 +50,8 @@ static struct option long_options[] = {
>>>        {"no-preserve-owner", no_argument, 0, 10},
>>>        {"no-preserve-perms", no_argument, 0, 11},
>>>        {"offset", required_argument, 0, 12},
>>> +     {"xattrs", no_argument, 0, 13},
>>> +     {"no-xattrs", no_argument, 0, 14},
>>>        {0, 0, 0, 0},
>>>    };
>>>
>>> @@ -98,6 +102,7 @@ static void usage(int argc, char **argv)
>>>                " --extract[=X]          check if all files are well
>>> encoded, optionally\n"
>>>                "                        extract to X\n"
>>>                " --offset=#             skip # bytes at the beginning
>>> of IMAGE\n"
>>> +             " --[no-]xattrs          whether to dump extended
>>> attributes (default on)\n"
>>>                "\n"
>>>                " -a, -A, -y             no-op, for compatibility with
>>> fsck of other filesystems\n"
>>>                "\n"
>>> @@ -225,6 +230,12 @@ static int erofsfsck_parse_options_cfg(int argc,
>>> char **argv)
>>>                                return -EINVAL;
>>>                        }
>>>                        break;
>>> +             case 13:
>>> +                     fsckcfg.dump_xattrs = true;
>>> +                     break;
>>> +             case 14:
>>> +                     fsckcfg.dump_xattrs = false;
>>> +                     break;
>>>                default:
>>>                        return -EINVAL;
>>>                }
>>> @@ -411,6 +422,60 @@ out:
>>>        return ret;
>>>    }
>>>
>>> +static int erofsfsck_dump_xattrs(struct erofs_inode *inode)
>>> +{
>>> +     char *keylst, *key;
>>> +     ssize_t kllen;
>>> +     int ret;
>>> +
>>> +     kllen = erofs_listxattr(inode, NULL, 0);
>>> +     if (kllen <= 0)
>>> +             return kllen;
>>> +     keylst = malloc(kllen);
>>> +     if (!keylst)
>>> +             return -ENOMEM;
>>> +     ret = erofs_listxattr(inode, keylst, kllen);
>>> +     if (ret < 0)
>>> +             goto out;
>>> +     for (key = keylst; key < keylst + kllen; key += strlen(key) + 1) {
>>> +             void *value = NULL;
>>> +             size_t size = 0;
>>> +
>>> +             ret = erofs_getxattr(inode, key, NULL, 0);
>>> +             if (ret < 0)
>>> +                     break;
>>> +             if (ret) {
>>> +                     size = ret;
>>> +                     value = malloc(size);
>>> +                     if (!value) {
>>> +                             ret = -ENOMEM;
>>> +                             break;
>>> +                     }
>>> +                     ret = erofs_getxattr(inode, key, value, size);
>>> +                     if (ret < 0) {
>>> +                             erofs_err("fail to get xattr %s @ nid
>>> %llu",
>>> +                                       key, inode->nid | 0ULL);
>>> +                             free(value);
>>> +                             break;
>>> +                     }
>>> +                     if (fsckcfg.extract_path)
>>> +                             ret = setxattr(fsckcfg.extract_path,
>>> key, value,
>>> +                                            size, 0);

I still have some comments,

  - need to update fsck manpages together;

  - If `erofsfsck.superuser` is false, I guess we need to ignore
    non-`user.` namespace xattrs.
    If `erofsfsck.superuser` is true, we could dump all xattrs then.

  - you should use lsetxattr instead of setxattr.

Thanks,
Gao Xiang