PR-211674, fuse_vnode and fuse_msgbuf leak in fusefs-ntfs

[Mahmoud Al-Qudsi]

Hello,

Please forgive me if it is not correct form to discuss fusefs-ntfs on the FreeBSD fs mailing list.

SUMMARY

Running on FreeBSD 10.3-RELEASE-p6/i386 with fuse compiled into kernel and with fusefs-ntfs 2016.2.22 installed, there is a fuse_vnode leak (though it seems it may be more of a complete failure to reclaim vnodes) resulting in quick resource exhaustion.

REPRODUCTION

This is easily reproduced with the following:

ntfs-3g /dev/xxx /mnt/yyyy
cd /mnt/yyyy
find . -exec touch {} \;

In another virtual terminal:

vmstat | head -n1; vmstat -m | sed 1d | sort -hk 3,3

ACTUAL RESULTS

fuse_vnode will continuously balloon, and will not be reclaimed until the filesystem is unmounted.

(likewise, fuse_msgbuff also balloons but unlike fuse_vnode, it is never reclaimed. Separate PR?)

EXPECTED RESULTS

fuse_vnode entries should be reclaimed

ADDITIONAL INFORMATION

Here's a snapshot of the fuse-related vmstat entries after this process:

fuse_vnode 36020 9005K - 502349 256
fuse_msgbuf 58141 14895K - 311095 256,512,1024,2048,4096,8192

Thank you,

Mahmoud Al-Qudsi
NeoSmart Technologies