2020-07-29 14:13:28

by David Wysochanski

Subject: [RFC PATCH v2 09/14] NFS: Only use and unuse an fscache cookie a single time based on NFS_INO_FSCACHE

For NFS, we only want to make a decision whether to "use" a inode based
fscache cookie one time, not multiple times, and based on whether the
inode is open for write by any process. Achieve this by gating the
call to fscache_use_cookie / fscache_unuse_cookie by the NFS_INO_FSCACHE
flag on the nfs_inode.

Signed-off-by: Dave Wysochanski <[email protected]>
---
fs/nfs/fscache.c | 21 ++++++++++++++-------
1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/fs/nfs/fscache.c b/fs/nfs/fscache.c
index 1c4ced273fb7..00bb720cccfa 100644
--- a/fs/nfs/fscache.c
+++ b/fs/nfs/fscache.c
@@ -285,8 +285,10 @@ void nfs_fscache_clear_inode(struct inode *inode)

dfprintk(FSCACHE, "NFS: clear cookie (0x%p/0x%p)\n", nfsi, cookie);

- nfs_fscache_update_auxdata(&auxdata, nfsi);
- fscache_unuse_cookie(cookie, &auxdata, NULL);
+ if (test_and_clear_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags)) {
+ nfs_fscache_update_auxdata(&auxdata, nfsi);
+ fscache_unuse_cookie(cookie, &auxdata, NULL);
+ }
fscache_relinquish_cookie(cookie, false);
nfsi->fscache = NULL;
}
@@ -321,18 +323,23 @@ void nfs_fscache_open_file(struct inode *inode, struct file *filp)
{
struct nfs_inode *nfsi = NFS_I(inode);
struct fscache_cookie *cookie = nfs_i_fscache(inode);
+ struct nfs_fscache_inode_auxdata auxdata;

if (!fscache_cookie_valid(cookie))
return;

if (inode_is_open_for_write(inode)) {
- dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
- clear_bit(NFS_INO_FSCACHE, &nfsi->flags);
+ if (test_and_clear_bit(NFS_INO_FSCACHE, &nfsi->flags)) {
+ dfprintk(FSCACHE, "NFS: nfsi 0x%p disabling cache\n", nfsi);
+ nfs_fscache_update_auxdata(&auxdata, nfsi);
+ fscache_unuse_cookie(cookie, &auxdata, NULL);
+ }
} else {
- dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
- set_bit(NFS_INO_FSCACHE, &NFS_I(inode)->flags);
+ if (!test_and_set_bit(NFS_INO_FSCACHE, &nfsi->flags)) {
+ dfprintk(FSCACHE, "NFS: nfsi 0x%p enabling cache\n", nfsi);
+ fscache_use_cookie(cookie, false);
+ }
}
- fscache_use_cookie(cookie, false);
}
EXPORT_SYMBOL_GPL(nfs_fscache_open_file);

--
1.8.3.1