NFS: Fix dentry revalidation on NFSv4 lookup

BugLink: https://bugs.launchpad.net/bugs/1839213
commit be189f7e7f03de35887e5a85ddcf39b91b5d7fc1 upstream.

We need to ensure that inode and dentry revalidation occurs correctly
on reopen of a file that is already open. Currently, we can end up
not revalidating either in the case of NFSv4.0, due to the 'cached open'
path.
Let's fix that by ensuring that we only do cached open for the special
cases of open recovery and delegation return.

Reported-by: Stan Hu <stanhu@gmail.com>
Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: Qian Lu <luqia@amazon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Khalid Elmously <khalid.elmously@canonical.com>

diff --git a/fs/nfs/nfs4proc.c b/fs/nfs/nfs4proc.c
index 8e1580f85edf0621bee072e810590be56975ef70..ec037a1ba36ea9ee5d2dc6adf3cabebe9158383b 100644 (file)
--- a/fs/nfs/nfs4proc.c
+++ b/fs/nfs/nfs4proc.c
@@ -1319,12 +1319,20 @@ static bool nfs4_mode_match_open_stateid(struct nfs4_state *state,
        return false;
 }
 
-static int can_open_cached(struct nfs4_state *state, fmode_t mode, int open_mode)
+static int can_open_cached(struct nfs4_state *state, fmode_t mode,
+               int open_mode, enum open_claim_type4 claim)
 {
        int ret = 0;
 
        if (open_mode & (O_EXCL|O_TRUNC))
                goto out;
+       switch (claim) {
+       case NFS4_OPEN_CLAIM_NULL:
+       case NFS4_OPEN_CLAIM_FH:
+               goto out;
+       default:
+               break;
+       }
        switch (mode & (FMODE_READ|FMODE_WRITE)) {
                case FMODE_READ:
                        ret |= test_bit(NFS_O_RDONLY_STATE, &state->flags) != 0
@@ -1707,7 +1715,7 @@ static struct nfs4_state *nfs4_try_open_cached(struct nfs4_opendata *opendata)
 
        for (;;) {
                spin_lock(&state->owner->so_lock);
-               if (can_open_cached(state, fmode, open_mode)) {
+               if (can_open_cached(state, fmode, open_mode, claim)) {
                        update_open_stateflags(state, fmode);
                        spin_unlock(&state->owner->so_lock);
                        goto out_return_state;
@@ -2231,7 +2239,8 @@ static void nfs4_open_prepare(struct rpc_task *task, void *calldata)
        if (data->state != NULL) {
                struct nfs_delegation *delegation;
 
-               if (can_open_cached(data->state, data->o_arg.fmode, data->o_arg.open_flags))
+               if (can_open_cached(data->state, data->o_arg.fmode,
+                                       data->o_arg.open_flags, claim))
                        goto out_no_action;
                rcu_read_lock();
                delegation = rcu_dereference(NFS_I(data->state->inode)->delegation);