Bug 2229529

Hello!
I was able to reproduce this issue on my machine.  Unfortunately, this seems to be a bug in the kernel.  find internally uses the fts* functions from glibc to traverse the filesystem and it tries to minimise the number of (l)stat(2) calls by reusing as much information it already has acquired before.  For fts to work, glibc internally calls readdir(3) which is implemented using the getdents64(2) syscall.  The structure forwarded by readdir(3) from getdents64(2) for every directory entry also contains file type information which seems to be incorrect for symlinks on NTFS volumes as witnessed by the following experiment:

$mount
...
/dev/sda1 on /mnt/ntfs type ntfs3 (rw,relatime,uid=0,gid=0,iocharset=utf8)
$ cat ~/tmp/readdir_test.c
#include <dirent.h>
#include <stdio.h>
#include <sys/types.h>

int main(int argc, char* argv[])
{
    DIR* dp = opendir(argv[1]);
    if (dp == NULL) {
        perror("opendir");
        return 1;
    }

    struct dirent* dent;
    while ((dent = readdir(dp)) != NULL) {
        const char* type;
        switch (dent->d_type) {
            case DT_BLK:
                type = "block dev"; break;
            case DT_CHR:
                type = "char dev"; break;
            case DT_DIR:
                type = "dir"; break;
            case DT_FIFO:
                type = "pipe"; break;
            case DT_LNK:
                type = "symlink"; break;
            case DT_REG:
                type = "regular file"; break;
            case DT_SOCK:
                type = "socket"; break;
            case DT_UNKNOWN:
                type = "unknown"; break;
        }
        printf("name: %s, type: %s\n", dent->d_name, type);
    }

    closedir(dp);
}
$ cc ~/tmp/readdir_test.c
$ ./a.out /mnt/ntfs
name: ., type: dir
name: .., type: dir
name: a, type: regular file
name: b, type: regular file  <-- WRONG!


I've checked ls and while it also uses readdir(3), it always issues an explicit (l)stat(2) so that's the reason why the final displayed information are correct.

I forgot to mention that I've used the enclosed reproducer for the experiment above.