Bug 195663
| Summary: | Not all files from a 9P mounted directory/subdirectory are shown | ||
|---|---|---|---|
| Product: | File System | Reporter: | Dinu-Razvan Chis-Serban (justcsdr) |
| Component: | v9fs | Assignee: | Eric Van Hensbergen (ericvh) |
| Status: | NEW --- | ||
| Severity: | high | CC: | asmadeus, justcsdr |
| Priority: | P1 | ||
| Hardware: | All | ||
| OS: | Linux | ||
| Kernel Version: | 4 | Subsystem: | |
| Regression: | No | Bisected commit-id: | |
| Attachments: |
Patch
Patch for fs/9p/vfs_dir.c |
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Created attachment 256479 [details]
Patch for fs/9p/vfs_dir.c
Same patch but this time I have sent -p to diff command.
Hi Razvan, thanks for the bug report and the patch (and for linking to this bugzilla on a recent diod issue, I was just browsing by chance when I stumbled on this). I agree with the problem and can definitely imagine that scenario you're describing happen even if I never experienced it myself - I think the common pattern is that the previous iteration would cleanly finish eating the buffer so it would usually work but I guess samba's buffer is too small maybe?.. I don't really like the long line with double cast like this though so I'll send an equivalent patch to the v9fs-developer list for upstream to pick up around 4.20; since you did the debugging though I've love to have your sign-off. Please reply to the mail when it comes later today! Actually I spoke too fast, the buffer isn't cleared on purpose so the readdir continues from where it was left off: imagine a readdir with a user buffer of two entries but a "on-the-wire" buffer of 100 entries. The readdir syscall would get 100 entries from the server but only return two to userspace, then on next call would get the next two etc. I think we need more info here, I don't have time to set up a samba share in the near future but this bug has been around forever... So since you said you're not using 9p anymore I assume you're not too interested in debugging further? Anyway, thanks for the report, I'll finish looking at other open bugs and dig further into this one when time permits. |
Created attachment 256207 [details] Patch Description of problem: When browsing the directories mounted over 9P filesystem, if there are lots of sub-directories and files, not all of them are shown. How reproducible: mount a 9p share and re-share it with samba, if there are a few hundred of files and sub-directories, not all of them are sown Actual results: 4xy (x, y are digits) files Expected results: 7xy (x, y are digits) files Additional info: in kernel source: 'fs/9p/vfs_dir.c' the inside the function 'v9fs_alloc_rdir_buf' the 'head' and 'tail' members of the structure 'struct p9_rdir *rdir' aren't initialized and after at a second call by the same process they retain the last value and in v9fs_dir_readdir/v9fs_dir_readdir_dotl the test (rdir->tail == rdir->head) is not executed. Patch: --- vfs_dir.c 2017-05-02 12:09:10.165100579 +0300 +++ vfs_dir.c 2017-05-02 12:13:04.305450584 +0300 @@ -97,6 +97,7 @@ struct p9_fid *fid = filp->private_data; if (!fid->rdir) fid->rdir = kzalloc(sizeof(struct p9_rdir) + buflen, GFP_KERNEL); + ((struct p9_rdir *)fid->rdir)->tail = ((struct p9_rdir *)fid->rdir)->head = 0; return fid->rdir; }