NFSv4: Fix problem with OPEN_DOWNGRADE
RFC 3530 states that for OPEN_DOWNGRADE "The share_access and share_deny
bits specified must be exactly equal to the union of the share_access and
share_deny bits specified for some subset of the OPENs in effect for
current openowner on the current file.
Setattr is currently violating the NFSv4 rules for OPEN_DOWNGRADE in that
it may cause a downgrade from OPEN4_SHARE_ACCESS_BOTH to
OPEN4_SHARE_ACCESS_WRITE despite the fact that there exists no open file
with O_WRONLY access mode.
Fix the problem by replacing nfs4_find_state() with a modified version of
nfs_find_open_context().
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
diff --git a/fs/nfs/read.c b/fs/nfs/read.c
index 43b03b1..5f20eaf 100644
--- a/fs/nfs/read.c
+++ b/fs/nfs/read.c
@@ -507,7 +507,7 @@
goto out_error;
if (file == NULL) {
- ctx = nfs_find_open_context(inode, FMODE_READ);
+ ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
if (ctx == NULL)
return -EBADF;
} else
@@ -576,7 +576,7 @@
nr_pages);
if (filp == NULL) {
- desc.ctx = nfs_find_open_context(inode, FMODE_READ);
+ desc.ctx = nfs_find_open_context(inode, NULL, FMODE_READ);
if (desc.ctx == NULL)
return -EBADF;
} else