Currently these fields are protected with the state_lock, but that
doesn't really make a lot of sense. These fields are "private" to the
nfs4_file, and can be protected with the more granular fi_lock.
The fi_lock is already held when setting these fields. Make the code
hold the fp->fi_lock when clearing the lease-related fields in the
nfs4_file, and no longer require that the state_lock be held when
calling into this function.
To prevent lock inversion with the i_lock, we also move the vfs_setlease
and fput calls outside of the fi_lock. This also sets us up for allowing
vfs_setlease calls to block in the future.
Finally, remove a redundant NULL pointer check. unhash_delegation_locked
locks the fp->fi_lock prior to that check, so fp in that function must
never be NULL.
Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxxxxxxx>
---
fs/nfsd/nfs4state.c | 22 +++++++++++++---------
1 file changed, 13 insertions(+), 9 deletions(-)
diff --git a/fs/nfsd/nfs4state.c b/fs/nfsd/nfs4state.c
index 2e80a59e7e91..309ec3b1090a 100644
--- a/fs/nfsd/nfs4state.c
+++ b/fs/nfsd/nfs4state.c
@@ -673,15 +673,20 @@ nfs4_put_stid(struct nfs4_stid *s)
static void nfs4_put_deleg_lease(struct nfs4_file *fp)
{
- lockdep_assert_held(&state_lock);
+ struct file *filp = NULL;
+ struct file_lock *fl;
- if (!fp->fi_lease)
- return;
- if (atomic_dec_and_test(&fp->fi_delegees)) {
- vfs_setlease(fp->fi_deleg_file, F_UNLCK, &fp->fi_lease);
+ spin_lock(&fp->fi_lock);
+ if (fp->fi_lease && atomic_dec_and_test(&fp->fi_delegees)) {
+ swap(filp, fp->fi_deleg_file);
+ fl = fp->fi_lease;
fp->fi_lease = NULL;
- fput(fp->fi_deleg_file);
- fp->fi_deleg_file = NULL;
+ }
+ spin_unlock(&fp->fi_lock);
+
+ if (filp) {
+ vfs_setlease(filp, F_UNLCK, &fl);
+ fput(filp);
}
}
@@ -717,8 +722,7 @@ unhash_delegation_locked(struct nfs4_delegation *dp)
list_del_init(&dp->dl_recall_lru);
list_del_init(&dp->dl_perfile);
spin_unlock(&fp->fi_lock);
- if (fp)
- nfs4_put_deleg_lease(fp);
+ nfs4_put_deleg_lease(fp);
}
static void destroy_delegation(struct nfs4_delegation *dp)
--
1.9.3
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