* Rich Felker: > An issue was reported today on the Alpine Linux tracker at > https://gitlab.alpinelinux.org/alpine/aports/issues/10960 regarding > readdir results from SMB/NFS shares with musl libc. > > After a good deal of analysis, we determined the root cause to be that > the second and subsequent calls to getdents64 are dropping/skipping > direntries (that have not yet been deleted) when some entries were > deleted following the previous call. The issue appears to happen only > when the buffer size passed to getdents64 is below some threshold > greater than 2k (the size musl uses) but less than 32k (the size glibc > uses, with which we were unable to reproduce the issue). >From the Gitlab issue: while ((dp = readdir(dir)) != NULL) { unlink(dp->d_name); ++file_cnt; } I'm not sure that this is valid code to delete the contents of a directory. It's true that POSIX says this: | If a file is removed from or added to the directory after the most | recent call to opendir() or rewinddir(), whether a subsequent call | to readdir() returns an entry for that file is unspecified. But many file systems simply provide not the necessary on-disk data structures which are need to ensure stable iteration in the face of modification of the directory. There are hacks, of course, such as compacting the on-disk directory only on file creation, which solves the file removal case. For deleting an entire directory, that is not really a problem because you can stick another loop around this while loop which re-reads the directory after rewinddir. Eventually, it will become empty.
