Patch "Clarify locking of cifs file and tcon structures and make more granular" has been added to the 4.8-stable tree

@@ -1271,7 +1271,6 @@ init_cifs(void)
 	GlobalTotalActiveXid = 0;
 	GlobalMaxActiveXid = 0;
 	spin_lock_init(&cifs_tcp_ses_lock);
-	spin_lock_init(&cifs_file_list_lock);
 	spin_lock_init(&GlobalMid_Lock);
 
 	get_random_bytes(&cifs_lock_secret, sizeof(cifs_lock_secret));

@@ -833,6 +833,7 @@ struct cifs_tcon {
 	struct list_head tcon_list;
 	int tc_count;
 	struct list_head openFileList;
+	spinlock_t open_file_lock; /* protects list above */
 	struct cifs_ses *ses;	/* pointer to session associated with */
 	char treeName[MAX_TREE_SIZE + 1]; /* UNC name of resource in ASCII */
 	char *nativeFileSystem;

@@ -889,7 +890,7 @@ struct cifs_tcon {
 #endif /* CONFIG_CIFS_STATS2 */
 	__u64    bytes_read;
 	__u64    bytes_written;
-	spinlock_t stat_lock;
+	spinlock_t stat_lock;  /* protects the two fields above */
 #endif /* CONFIG_CIFS_STATS */
 	FILE_SYSTEM_DEVICE_INFO fsDevInfo;
 	FILE_SYSTEM_ATTRIBUTE_INFO fsAttrInfo; /* ok if fs name truncated */

@@ -1040,8 +1041,10 @@ struct cifs_fid_locks {
 };
 
 struct cifsFileInfo {
+	/* following two lists are protected by tcon->open_file_lock */
 	struct list_head tlist;	/* pointer to next fid owned by tcon */
 	struct list_head flist;	/* next fid (file instance) for this inode */
+	/* lock list below protected by cifsi->lock_sem */
 	struct cifs_fid_locks *llist;	/* brlocks held by this fid */
 	kuid_t uid;		/* allows finding which FileInfo structure */
 	__u32 pid;		/* process id who opened file */

@@ -1049,11 +1052,12 @@ struct cifsFileInfo {
 	/* BB add lock scope info here if needed */ ;
 	/* lock scope id (0 if none) */
 	struct dentry *dentry;
-	unsigned int f_flags;
 	struct tcon_link *tlink;
+	unsigned int f_flags;
 	bool invalidHandle:1;	/* file closed via session abend */
 	bool oplock_break_cancelled:1;
-	int count;		/* refcount protected by cifs_file_list_lock */
+	int count;
+	spinlock_t file_info_lock; /* protects four flag/count fields above */
 	struct mutex fh_mutex; /* prevents reopen race after dead ses*/
 	struct cifs_search_info srch_inf;
 	struct work_struct oplock_break; /* work for oplock breaks */

@@ -1120,7 +1124,7 @@ struct cifs_writedata {
 
 /*
  * Take a reference on the file private data. Must be called with
- * cifs_file_list_lock held.
+ * cfile->file_info_lock held.
  */
 static inline void
 cifsFileInfo_get_locked(struct cifsFileInfo *cifs_file)

@@ -1514,8 +1518,10 @@ require use of the stronger protocol */
  *  GlobalMid_Lock protects:
  *	list operations on pending_mid_q and oplockQ
  *      updates to XID counters, multiplex id  and SMB sequence numbers
- *  cifs_file_list_lock protects:
- *	list operations on tcp and SMB session lists and tCon lists
+ *  tcp_ses_lock protects:
+ *	list operations on tcp and SMB session lists
+ *  tcon->open_file_lock protects the list of open files hanging off the tcon
+ *  cfile->file_info_lock protects counters and fields in cifs file struct
  *  f_owner.lock protects certain per file struct operations
  *  mapping->page_lock protects certain per page operations
  *

@@ -1547,18 +1553,12 @@ GLOBAL_EXTERN struct list_head		cifs_tcp
  * tcp session, and the list of tcon's per smb session. It also protects
  * the reference counters for the server, smb session, and tcon. Finally,
  * changes to the tcon->tidStatus should be done while holding this lock.
+ * generally the locks should be taken in order tcp_ses_lock before
+ * tcon->open_file_lock and that before file->file_info_lock since the
+ * structure order is cifs_socket-->cifs_ses-->cifs_tcon-->cifs_file
  */
 GLOBAL_EXTERN spinlock_t		cifs_tcp_ses_lock;
 
-/*
- * This lock protects the cifs_file->llist and cifs_file->flist
- * list operations, and updates to some flags (cifs_file->invalidHandle)
- * It will be moved to either use the tcon->stat_lock or equivalent later.
- * If cifs_tcp_ses_lock and the lock below are both needed to be held, then
- * the cifs_tcp_ses_lock must be grabbed first and released last.
- */
-GLOBAL_EXTERN spinlock_t	cifs_file_list_lock;
-
 #ifdef CONFIG_CIFS_DNOTIFY_EXPERIMENTAL /* unused temporarily */
 /* Outstanding dir notify requests */
 GLOBAL_EXTERN struct list_head GlobalDnotifyReqList;

@@ -98,13 +98,13 @@ cifs_mark_open_files_invalid(struct cifs
 	struct list_head *tmp1;
 
 	/* list all files open on tree connection and mark them invalid */
-	spin_lock(&cifs_file_list_lock);
+	spin_lock(&tcon->open_file_lock);
 	list_for_each_safe(tmp, tmp1, &tcon->openFileList) {
 		open_file = list_entry(tmp, struct cifsFileInfo, tlist);
 		open_file->invalidHandle = true;
 		open_file->oplock_break_cancelled = true;
 	}
-	spin_unlock(&cifs_file_list_lock);
+	spin_unlock(&tcon->open_file_lock);
 	/*
 	 * BB Add call to invalidate_inodes(sb) for all superblocks mounted
 	 * to this tcon.

210 lines not on this page · raw message

@@ -120,6 +120,7 @@ tconInfoAlloc(void)
 		++ret_buf->tc_count;
 		INIT_LIST_HEAD(&ret_buf->openFileList);
 		INIT_LIST_HEAD(&ret_buf->tcon_list);
+		spin_lock_init(&ret_buf->open_file_lock);
 #ifdef CONFIG_CIFS_STATS
 		spin_lock_init(&ret_buf->stat_lock);
 #endif

@@ -465,7 +466,7 @@ is_valid_oplock_break(char *buffer, stru
 				continue;
 
 			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
-			spin_lock(&cifs_file_list_lock);
+			spin_lock(&tcon->open_file_lock);
 			list_for_each(tmp2, &tcon->openFileList) {
 				netfile = list_entry(tmp2, struct cifsFileInfo,
 						     tlist);

@@ -495,11 +496,11 @@ is_valid_oplock_break(char *buffer, stru
 					   &netfile->oplock_break);
 				netfile->oplock_break_cancelled = false;
 
-				spin_unlock(&cifs_file_list_lock);
+				spin_unlock(&tcon->open_file_lock);
 				spin_unlock(&cifs_tcp_ses_lock);
 				return true;
 			}
-			spin_unlock(&cifs_file_list_lock);
+			spin_unlock(&tcon->open_file_lock);
 			spin_unlock(&cifs_tcp_ses_lock);
 			cifs_dbg(FYI, "No matching file for oplock break\n");
 			return true;

@@ -613,9 +614,9 @@ backup_cred(struct cifs_sb_info *cifs_sb
 void
 cifs_del_pending_open(struct cifs_pending_open *open)
 {
-	spin_lock(&cifs_file_list_lock);
+	spin_lock(&tlink_tcon(open->tlink)->open_file_lock);
 	list_del(&open->olist);
-	spin_unlock(&cifs_file_list_lock);
+	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 }
 
 void

@@ -635,7 +636,7 @@ void
 cifs_add_pending_open(struct cifs_fid *fid, struct tcon_link *tlink,
 		      struct cifs_pending_open *open)
 {
-	spin_lock(&cifs_file_list_lock);
+	spin_lock(&tlink_tcon(tlink)->open_file_lock);
 	cifs_add_pending_open_locked(fid, tlink, open);
-	spin_unlock(&cifs_file_list_lock);
+	spin_unlock(&tlink_tcon(open->tlink)->open_file_lock);
 }

@@ -597,14 +597,14 @@ find_cifs_entry(const unsigned int xid,
 	     is_dir_changed(file)) || (index_to_find < first_entry_in_buffer)) {
 		/* close and restart search */
 		cifs_dbg(FYI, "search backing up - close and restart search\n");
-		spin_lock(&cifs_file_list_lock);
+		spin_lock(&cfile->file_info_lock);
 		if (server->ops->dir_needs_close(cfile)) {
 			cfile->invalidHandle = true;
-			spin_unlock(&cifs_file_list_lock);
+			spin_unlock(&cfile->file_info_lock);
 			if (server->ops->close_dir)
 				server->ops->close_dir(xid, tcon, &cfile->fid);
 		} else
-			spin_unlock(&cifs_file_list_lock);
+			spin_unlock(&cfile->file_info_lock);
 		if (cfile->srch_inf.ntwrk_buf_start) {
 			cifs_dbg(FYI, "freeing SMB ff cache buf on search rewind\n");
 			if (cfile->srch_inf.smallBuf)

@@ -549,19 +549,19 @@ smb2_is_valid_lease_break(char *buffer)
 		list_for_each(tmp1, &server->smb_ses_list) {
 			ses = list_entry(tmp1, struct cifs_ses, smb_ses_list);
 
-			spin_lock(&cifs_file_list_lock);
 			list_for_each(tmp2, &ses->tcon_list) {
 				tcon = list_entry(tmp2, struct cifs_tcon,
 						  tcon_list);
+				spin_lock(&tcon->open_file_lock);
 				cifs_stats_inc(
 				    &tcon->stats.cifs_stats.num_oplock_brks);
 				if (smb2_tcon_has_lease(tcon, rsp, lw)) {
-					spin_unlock(&cifs_file_list_lock);
+					spin_unlock(&tcon->open_file_lock);
 					spin_unlock(&cifs_tcp_ses_lock);
 					return true;
 				}
+				spin_unlock(&tcon->open_file_lock);
 			}
-			spin_unlock(&cifs_file_list_lock);
 		}
 	}
 	spin_unlock(&cifs_tcp_ses_lock);

@@ -603,7 +603,7 @@ smb2_is_valid_oplock_break(char *buffer,
 			tcon = list_entry(tmp1, struct cifs_tcon, tcon_list);
 
 			cifs_stats_inc(&tcon->stats.cifs_stats.num_oplock_brks);
-			spin_lock(&cifs_file_list_lock);
+			spin_lock(&tcon->open_file_lock);
 			list_for_each(tmp2, &tcon->openFileList) {
 				cfile = list_entry(tmp2, struct cifsFileInfo,
 						     tlist);

@@ -615,7 +615,7 @@ smb2_is_valid_oplock_break(char *buffer,
 
 				cifs_dbg(FYI, "file id match, oplock break\n");
 				cinode = CIFS_I(d_inode(cfile->dentry));
-
+				spin_lock(&cfile->file_info_lock);
 				if (!CIFS_CACHE_WRITE(cinode) &&
 				    rsp->OplockLevel == SMB2_OPLOCK_LEVEL_NONE)
 					cfile->oplock_break_cancelled = true;

@@ -637,14 +637,14 @@ smb2_is_valid_oplock_break(char *buffer,
 					clear_bit(
 					   CIFS_INODE_DOWNGRADE_OPLOCK_TO_L2,
 					   &cinode->flags);
-
+				spin_unlock(&cfile->file_info_lock);
 				queue_work(cifsiod_wq, &cfile->oplock_break);
 
-				spin_unlock(&cifs_file_list_lock);
+				spin_unlock(&tcon->open_file_lock);
 				spin_unlock(&cifs_tcp_ses_lock);
 				return true;
 			}
-			spin_unlock(&cifs_file_list_lock);
+			spin_unlock(&tcon->open_file_lock);
 			spin_unlock(&cifs_tcp_ses_lock);
 			cifs_dbg(FYI, "No matching file for oplock break\n");
 			return true;