1 files changed, 24 insertions, 19 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 75d2d57e2c44..15853d522941 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -69,31 +69,31 @@ prototypes:
 
 locking rules:
         all may block
-                i_mutex(inode)
-lookup:         yes
-create:         yes
-link:           yes (both)
-mknod:          yes
-symlink:        yes
-mkdir:          yes
-unlink:         yes (both)
-rmdir:          yes (both)      (see below)
-rename: yes (all)       (see below)
+                i_rwsem(inode)
+lookup:         shared
+create:         exclusive
+link:           exclusive (both)
+mknod:          exclusive
+symlink:        exclusive
+mkdir:          exclusive
+unlink:         exclusive (both)
+rmdir:          exclusive (both)(see below)
+rename:         exclusive (all) (see below)
 readlink:       no
 get_link:       no
-setattr:        yes
+setattr:        exclusive
 permission:     no (may not block if called in rcu-walk mode)
 get_acl:        no
 getattr:        no
 listxattr:      no
 fiemap:         no
 update_time:    no
-atomic_open:    yes
+atomic_open:    exclusive
 tmpfile:        no
 
 
-        Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
-victim.
+        Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_rwsem
+        exclusive on victim.
         cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem.
 
 See Documentation/filesystems/directory-locking for more detailed discussion
@@ -111,10 +111,10 @@ prototypes:
 
 locking rules:
         all may block
-                i_mutex(inode)
+                i_rwsem(inode)
 list:           no
 get:            no
-set:            yes
+set:            exclusive
 
 --------------------------- super_operations ---------------------------
 prototypes:
@@ -217,14 +217,14 @@ prototypes:
 locking rules:
         All except set_page_dirty and freepage may block
 
-                        PageLocked(page)        i_mutex
+                        PageLocked(page)        i_rwsem
 writepage:              yes, unlocks (see below)
 readpage:               yes, unlocks
 writepages:
 set_page_dirty          no
 readpages:
-write_begin:            locks the page          yes
-write_end:              yes, unlocks            yes
+write_begin:            locks the page          exclusive
+write_end:              yes, unlocks            exclusive
 bmap:
 invalidatepage:         yes
 releasepage:            yes
@@ -439,6 +439,7 @@ prototypes:
         ssize_t (*read_iter) (struct kiocb *, struct iov_iter *);
         ssize_t (*write_iter) (struct kiocb *, struct iov_iter *);
         int (*iterate) (struct file *, struct dir_context *);
+        int (*iterate_shared) (struct file *, struct dir_context *);
         unsigned int (*poll) (struct file *, struct poll_table_struct *);
         long (*unlocked_ioctl) (struct file *, unsigned int, unsigned long);
         long (*compat_ioctl) (struct file *, unsigned int, unsigned long);
@@ -480,6 +481,10 @@ mutex or just to use i_size_read() instead.
 Note: this does not protect the file->f_pos against concurrent modifications
 since this is something the userspace has to take care about.
 
+->iterate() is called with i_rwsem exclusive.
+
+->iterate_shared() is called with i_rwsem at least shared.
+
 ->fasync() is responsible for maintaining the FASYNC bit in filp->f_flags.
 Most instances call fasync_helper(), which does that maintenance, so it's
 not normally something one needs to worry about.  Return values > 0 will be