Hi, On Sat, Dec 14, 2013 at 12:09:19AM +0000, bugzilla-daemon@xxxxxxxxxxxxxxxxxxx wrote: > https://bugzilla.kernel.org/show_bug.cgi?id=66951 > > Bug ID: 66951 > Summary: filesystems should reserve inodes for root as they do > disk space > Product: File System > Version: 2.5 > Kernel Version: 3.11.10 > Hardware: All > OS: Linux > Tree: Mainline > Status: NEW > Severity: enhancement > Priority: P1 > Component: ext4 > Assignee: fs_ext4@xxxxxxxxxxxxxxxxxxxx > Reporter: kernelbugs@xxxxxxxxxxxxx > Regression: No > > I had a runaway non-root user process (Opera browser actually) exhaust all of > the inodes on my / (root) filesystem (ext4) by creating millions of 10 to 50 > byte cache files in /home (which is not a separate partition on my system). > Linux & ext4 happily allowed this program to cripple the whole system until I > figured out a) inodes were exhausted and b) what app was causing it and where > they all were, and c) rm -rf them all. > > We all know filesystems like ext2/3/4 reserve a (tunable) amount of space for > root use only if a disk fills beyond a certain threshold. I find it shocking > that a similar mechanism does not exist for inodes. Most *NIX geeks I know > also can't believe it. Do you find it shocking too? > Yes, having an inode amount reserved for root might be good to avoid these cases. > One could argue I should have /home on a separate partition, but this is a > non-solution because all it takes is one user-writable directory in / (root) > such as /var/tmp. Sure, then you could say /var should be a separate > partition, but let's be realistic: 95%+ of systems out there will not have a > separate /home or /var partition (let alone both). Also, no distros by default > create separate partitions for all of these. > Sorry, but you're wrong here. Almost all good system administrators knows the importance of keep directories like /home and /var in different filesystems, for simply 2 reasons: - Keep system data separated from user data - /var will store logs, and this might be HUGE in some cases. And also, most distros I know of keeps /var and /home separated in their default installations. So, there is no excuse to keep /home and /var in different filesystems. Even if you have just a single user, keep a separate /home filesystem is always recommended. > One could argue you should have your inode capacity be set so large it would be > impossible to exhaust it before you run out of disk space. That point is moot > because a program could create 0 byte files, thus allowing exhaustion of inodes > before free space (which would remain unchanged). Besides, one should be > allowed to tune their inodes at fs creation time to suit their usage habits as > monitored over the years (such as looking at their usual NBPI and adding a 2 or > 4X safety margin). > I agree that change the inode capacity wouldn't make the system behave any better. > One could argue you could use quotas, but that seems unreasonable for the > average guy (like myself) to do on their home desktop computer that only they > use. > Agreed indeed. > Can ext2/3/4 and the kernel be modified to reserve a (tunable) number of inodes > for root just as it does for disk space? > I'm not sure how feasible it is or if is there any kind of job being done or already done in this area, but is a good idea and I just added it to my TODO list. In the meantime, this isn't just a matter of how ext4 behaves regarding the amount of inode, but looks like a BUG in your browser, or maybe you're accessing a site which creates thousands of inodes? -- Carlos -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
