Hi
Thanks for your reply
Yes the sentence below should have the *if* .. sorry about the typo
The issue doesnt happen if all the writer processes/threads are killed
before the
emergency remount
Note that an emergency remount is very much an emergency. So we don't
do a graceful shutdown of any pending writes. (Normally we would
return EBUSY if there anything that would prevent a clean remount.)
In the emergency remount path, we bypass all of these checks.
And on disk we see that one of the files being written to has incorrect
ext4_inode->i_blocks_lo ( which is less than the the size of the file by
something like 2k)
When unlinking this file the vfs inode->iblocks underflows and we end up
with EFBIG if EXT4_FEATURE_RO_COMPAT_HUGE_FILE is not enabled in the
superblock.
Is this a known issue?
No, this isn't a known issue. I've never seen anything like this, but
all of the tests we do assume a forced poweroff, which we simulate
using dm-flakey. We do *not* test the blunt-force-trauma which is
inflected on the file system structures which results from doing an
emergency remount.
Off by 2k really doesn't make sense. I could see if it was off by 4k,
but 2k is really wierd.
Just to clarify when i say off by 2k .. i meant the i_blocks count not
the actual size file ( which would be 2k * 512 if i am not wrong)
For example we see fsck report
Pass 1: Checking inodes, blocks, and sizes
Inode XXX, i_blocks is 854024, should be 856072.
I would appreciate if you could point me in the right direction and any help
you can give me.
Well, what I'd do is create a new ioctl interface which simulates an
emergency ro on just the one device, and try to create a reliable
repro. Eventually we'll want to add some tests for this in xfstests.
Thanks so much for your suggestion.
I will try to see if i can reliably reproduce the issue after
implementing the ioctl as you suggested.
I have some issues getting the xfs tests to run on the device which i
have been meaning to work on .. maybe this is the time to do so.
--
Thanks
Nikhilesh Reddy
Qualcomm Innovation Center, Inc.
The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum,
a Linux Foundation Collaborative Project.
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