1 files changed, 21 insertions, 6 deletions

diff --git a/fs/smb/client/file.c b/fs/smb/client/file.c
index d2df10b8e6fd..1421bde045c2 100644
--- a/fs/smb/client/file.c
+++ b/fs/smb/client/file.c
@@ -52,6 +52,7 @@ static void cifs_prepare_write(struct netfs_io_subrequest *subreq)
 	struct netfs_io_stream *stream = &req->rreq.io_streams[subreq->stream_nr];
 	struct TCP_Server_Info *server;
 	struct cifsFileInfo *open_file = req->cfile;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(wdata->rreq->inode->i_sb);
 	size_t wsize = req->rreq.wsize;
 	int rc;
 
@@ -63,6 +64,10 @@ static void cifs_prepare_write(struct netfs_io_subrequest *subreq)
 	server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
 	wdata->server = server;
 
+	if (cifs_sb->ctx->wsize == 0)
+		cifs_negotiate_wsize(server, cifs_sb->ctx,
+				     tlink_tcon(req->cfile->tlink));
+
 retry:
 	if (open_file->invalidHandle) {
 		rc = cifs_reopen_file(open_file, false);
@@ -160,10 +165,9 @@ static int cifs_prepare_read(struct netfs_io_subrequest *subreq)
 	server = cifs_pick_channel(tlink_tcon(req->cfile->tlink)->ses);
 	rdata->server = server;
 
-	if (cifs_sb->ctx->rsize == 0) {
+	if (cifs_sb->ctx->rsize == 0)
 		cifs_negotiate_rsize(server, cifs_sb->ctx,
 				     tlink_tcon(req->cfile->tlink));
-	}
 
 	rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->rsize,
 					   &size, &rdata->credits);
@@ -999,15 +1003,18 @@ int cifs_open(struct inode *inode, struct file *file)
 		rc = cifs_get_readable_path(tcon, full_path, &cfile);
 	}
 	if (rc == 0) {
-		if (file->f_flags == cfile->f_flags) {
+		unsigned int oflags = file->f_flags & ~(O_CREAT|O_EXCL|O_TRUNC);
+		unsigned int cflags = cfile->f_flags & ~(O_CREAT|O_EXCL|O_TRUNC);
+
+		if (cifs_convert_flags(oflags, 0) == cifs_convert_flags(cflags, 0) &&
+		    (oflags & (O_SYNC|O_DIRECT)) == (cflags & (O_SYNC|O_DIRECT))) {
 			file->private_data = cfile;
 			spin_lock(&CIFS_I(inode)->deferred_lock);
 			cifs_del_deferred_close(cfile);
 			spin_unlock(&CIFS_I(inode)->deferred_lock);
 			goto use_cache;
-		} else {
-			_cifsFileInfo_put(cfile, true, false);
 		}
+		_cifsFileInfo_put(cfile, true, false);
 	} else {
 		/* hard link on the defeered close file */
 		rc = cifs_get_hardlink_path(tcon, inode, file);
@@ -3081,7 +3088,8 @@ void cifs_oplock_break(struct work_struct *work)
 	struct cifsFileInfo *cfile = container_of(work, struct cifsFileInfo,
 						  oplock_break);
 	struct inode *inode = d_inode(cfile->dentry);
-	struct cifs_sb_info *cifs_sb = CIFS_SB(inode->i_sb);
+	struct super_block *sb = inode->i_sb;
+	struct cifs_sb_info *cifs_sb = CIFS_SB(sb);
 	struct cifsInodeInfo *cinode = CIFS_I(inode);
 	struct cifs_tcon *tcon;
 	struct TCP_Server_Info *server;
@@ -3091,6 +3099,12 @@ void cifs_oplock_break(struct work_struct *work)
 	__u64 persistent_fid, volatile_fid;
 	__u16 net_fid;
 
+	/*
+	 * Hold a reference to the superblock to prevent it and its inodes from
+	 * being freed while we are accessing cinode. Otherwise, _cifsFileInfo_put()
+	 * may release the last reference to the sb and trigger inode eviction.
+	 */
+	cifs_sb_active(sb);
 	wait_on_bit(&cinode->flags, CIFS_INODE_PENDING_WRITERS,
 			TASK_UNINTERRUPTIBLE);
 
@@ -3163,6 +3177,7 @@ oplock_break_ack:
 	cifs_put_tlink(tlink);
 out:
 	cifs_done_oplock_break(cinode);
+	cifs_sb_deactive(sb);
 }
 
 static int cifs_swap_activate(struct swap_info_struct *sis,