nfs: per-name sillyunlink exclusion

use d_alloc_parallel() for sillyunlink/lookup exclusion and
explicit rwsem (nfs_rmdir() being a writer and nfs_call_unlink() -
a reader) for rmdir/sillyunlink one.

That ought to make lookup/readdir/!O_CREAT atomic_open really
parallel on NFS.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1 files changed, 3 insertions, 8 deletions

diff --git a/include/linux/nfs_fs.h b/include/linux/nfs_fs.h
index 67300f8e5f2f..fa167f25465d 100644
--- a/include/linux/nfs_fs.h
+++ b/include/linux/nfs_fs.h
@@ -163,11 +163,9 @@ struct nfs_inode {
         /* Open contexts for shared mmap writes */
         struct list_head        open_files;
 
-        /* Number of in-flight sillydelete RPC calls */
-        atomic_t                silly_count;
-        /* List of deferred sillydelete requests */
-        struct hlist_head       silly_list;
-        wait_queue_head_t       waitqueue;
+        /* Readers: in-flight sillydelete RPC calls */
+        /* Writers: rmdir */
+        struct rw_semaphore     rmdir_sem;
 
 #if IS_ENABLED(CONFIG_NFS_V4)
         struct nfs4_cached_acl  *nfs4_acl;
@@ -492,9 +490,6 @@ extern void nfs_release_automount_timer(void);
  * linux/fs/nfs/unlink.c
  */
 extern void nfs_complete_unlink(struct dentry *dentry, struct inode *);
-extern void nfs_wait_on_sillyrename(struct dentry *dentry);
-extern void nfs_block_sillyrename(struct dentry *dentry);
-extern void nfs_unblock_sillyrename(struct dentry *dentry);
 
 /*
  * linux/fs/nfs/write.c