3 files changed, 10 insertions, 5 deletions

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 9b6ed7c9f34f..ca7e25292542 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -412,7 +412,7 @@ prototypes:
         int (*open) (struct inode *, struct file *);
         int (*flush) (struct file *);
         int (*release) (struct inode *, struct file *);
-        int (*fsync) (struct file *, int datasync);
+        int (*fsync) (struct file *, loff_t start, loff_t end, int datasync);
         int (*aio_fsync) (struct kiocb *, int datasync);
         int (*fasync) (int, struct file *, int);
         int (*lock) (struct file *, int, struct file_lock *);
@@ -438,9 +438,7 @@ prototypes:
 
 locking rules:
         All may block except for ->setlease.
-        No VFS locks held on entry except for ->fsync and ->setlease.
-
-->fsync() has i_mutex on inode.
+        No VFS locks held on entry except for ->setlease.
 
 ->setlease has the file_list_lock held and must not sleep.
 
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 6b96773e27cb..7f8861d341ea 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -421,3 +421,10 @@ data and there is a virtual hole at the end of the file.  So if the provided
 offset is less than i_size and SEEK_DATA is specified, return the same offset.
 If the above is true for the offset and you are given SEEK_HOLE, return the end
 of the file.  If the offset is i_size or greater return -ENXIO in either case.
+
+[mandatory]
+        If you have your own ->fsync() you must make sure to call
+filemap_write_and_wait_range() so that all dirty pages are synced out properly.
+You must also keep in mind that ->fsync() is not called with i_mutex held
+anymore, so if you require i_mutex locking you must make sure to take it and
+release it yourself.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 6bf85b78cfea..eff6617c9a0f 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -777,7 +777,7 @@ struct file_operations {
         int (*open) (struct inode *, struct file *);
         int (*flush) (struct file *);
         int (*release) (struct inode *, struct file *);
-        int (*fsync) (struct file *, int datasync);
+        int (*fsync) (struct file *, loff_t, loff_t, int datasync);
         int (*aio_fsync) (struct kiocb *, int datasync);
         int (*fasync) (int, struct file *, int);
         int (*lock) (struct file *, int, struct file_lock *);