Fix issue when reading directory with many entries

[greenboxal]

By some reason reading a directory with many entries(1000+) caused an EIO(-5) error.

Letting libfuse manage the readdir offsets fixed the issue.

[mpartel]

Hmm, I can't reproduce this. I tried writing a test like this but it passed. This is on Ubuntu 14.04.

• Does that test pass or fail for you, if you add it to tests/test_bindfs.rb?
• What OS and version of FUSE are you using?
• Does the problem only occur with specific flags?
• Which program is failing to read the directory? (does ls fail?)

[chrisenytc]

👍 I have the same problem

[greenboxal]

Maybe this only occurs with specific backing filesystems.

I'm using bindfs to mount a path inside an AFS mount. I can access everything in AFS, including the same directory that gives me problems when mounted with bindfs.

Is there any harm in letting FUSE manage readdir offsets? If not, even this is a extreme edge case with specific filesystems, I don't see any harm in merging it.

[mpartel]

Ok, that's strange.

Assuming FUSE works the way the API suggests it does, and given that bindfs is single-threaded by default, the downside of this change is that it makes the entire directory scan an O(n) blocking operation that prevents other simultaneous operations from going through. I don't think most users would notice a difference, but it might well be a nontrivial regression for some users with huge directories.

Sorry, I'm hesitant to merge this without additional information, since it sounds like the bug might really be in AFS or FUSE. If you can't find any additional information but still want to upstream this change, I'm open to adding it as an optional flag.

[ghostwheel]

I had a similar problem, in android running debian linux in chroot, and mounting a fat32 mounted dir
again mapped user. bindfs wouldn't read the whole dir, and the hack above fixed the problem.

[mpartel]

Ok, I suppose this affects enough people to be worth changing, although I still can't reproduce this, even on fat32 :/

Merged and released as 1.13.1.

Thanks all for reporting!