9c4a5c75a6
Pass updated i_size in fscache_unuse_cookie() when called
from nfs_fscache_release_file(), which ensures the size of
an fscache object gets written to the cache storage. Failing
to do so results in unnessary reads from the NFS server, even
when the data is cached, due to a cachefiles object coherency
check failing with a trace similar to the following:
cachefiles_coherency: o=0000000e BAD osiz B=afbb3 c=0
This problem can be reproduced as follows:
#!/bin/bash
v=4.2; NFS_SERVER=127.0.0.1
set -e; trap cleanup EXIT; rc=1
function cleanup {
umount /mnt/nfs > /dev/null 2>&1
RC_STR="TEST PASS"
[ $rc -eq 1 ] && RC_STR="TEST FAIL"
echo "$RC_STR on $(uname -r) with NFSv$v and server $NFS_SERVER"
}
mount -o vers=$v,fsc $NFS_SERVER:/export /mnt/nfs
rm -f /mnt/nfs/file1.bin > /dev/null 2>&1
dd if=/dev/zero of=/mnt/nfs/file1.bin bs=4096 count=1 > /dev/null 2>&1
echo 3 > /proc/sys/vm/drop_caches
echo Read file 1st time from NFS server into fscache
dd if=/mnt/nfs/file1.bin of=/dev/null > /dev/null 2>&1
umount /mnt/nfs && mount -o vers=$v,fsc $NFS_SERVER:/export /mnt/nfs
echo 3 > /proc/sys/vm/drop_caches
echo Read file 2nd time from fscache
dd if=/mnt/nfs/file1.bin of=/dev/null > /dev/null 2>&1
echo Check mountstats for NFS read
grep -q "READ: 0" /proc/self/mountstats # (1st number) == 0
[ $? -eq 0 ] && rc=0
Fixes: a6b5a28eb56c "nfs: Convert to new fscache volume/cookie API"
Signed-off-by: Dave Wysochanski <dwysocha@redhat.com>
Tested-by: Daire Byrne <daire@dneg.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.