This is a note to let you know that I've just added the patch titled NFS: Pass i_size to fscache_unuse_cookie() when a file is released to the 5.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: nfs-pass-i_size-to-fscache_unuse_cookie-when-a-file-.patch and it can be found in the queue-5.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. commit b3c92047280fe8c6e25e04388f6b7456d60efa06 Author: Dave Wysochanski <dwysocha@xxxxxxxxxx> Date: Wed May 4 09:21:06 2022 -0400 NFS: Pass i_size to fscache_unuse_cookie() when a file is released [ Upstream commit 9c4a5c75a62e83963083efd4eea5d5bd1583193c ] 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@xxxxxxxxxx> Tested-by: Daire Byrne <daire@xxxxxxxx> Signed-off-by: Anna Schumaker <Anna.Schumaker@xxxxxxxxxx> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx> diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c index f73c09a9cf0a..e861d7bae305 100644 --- a/fs/nfs/fscache.c +++ b/fs/nfs/fscache.c @@ -231,11 +231,10 @@ void nfs_fscache_release_file(struct inode *inode, struct file *filp) { struct nfs_fscache_inode_auxdata auxdata; struct fscache_cookie *cookie = nfs_i_fscache(inode); + loff_t i_size = i_size_read(inode); - if (fscache_cookie_valid(cookie)) { - nfs_fscache_update_auxdata(&auxdata, inode); - fscache_unuse_cookie(cookie, &auxdata, NULL); - } + nfs_fscache_update_auxdata(&auxdata, inode); + fscache_unuse_cookie(cookie, &auxdata, &i_size); } /*