Merge branch 'upstream-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jgarzi...

[pandora-kernel.git] / Documentation / filesystems / Locking

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 06bbbed..61c98f0 100644 (file)
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -178,7 +178,7 @@ prototypes:
 locking rules:
        All except set_page_dirty may block
 
-                       BKL     PageLocked(page)        i_sem
+                       BKL     PageLocked(page)        i_mutex
 writepage:             no      yes, unlocks (see below)
 readpage:              no      yes, unlocks
 sync_page:             no      maybe
@@ -429,8 +429,9 @@ check_flags:                no
 implementations.  If your fs is not using generic_file_llseek, you
 need to acquire and release the appropriate locks in your ->llseek().
 For many filesystems, it is probably safe to acquire the inode
-semaphore.  Note some filesystems (i.e. remote ones) provide no
-protection for i_size so you will need to use the BKL.
+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.
 
 Note: ext2_release() was *the* source of contention on fs-intensive
 loads and dropping BKL on ->release() helps to get rid of that (we still