Merge branch 'linux-2.6' into for-2.6.24

[linux-2.6-omap-h63xx.git] / Documentation / filesystems / Locking

diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 59c14159cc47ddce04a19ae48d559fabedcf6902..f0f825808ca463023d815b3d38679851b55a6ff6 100644 (file)
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -54,7 +54,7 @@ ata *);
 
 locking rules:
        all may block, none have BKL
-               i_sem(inode)
+               i_mutex(inode)
 lookup:                yes
 create:                yes
 link:          yes (both)
@@ -74,7 +74,7 @@ setxattr:     yes
 getxattr:      no
 listxattr:     no
 removexattr:   yes
-       Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_sem on
+       Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on
 victim.
        cross-directory ->rename() has (per-superblock) ->s_vfs_rename_sem.
        ->truncate() is never called directly - it's a callback, not a
@@ -461,7 +461,7 @@ doesn't take the BKL.
 ->read on directories probably must go away - we should just enforce -EISDIR
 in sys_read() and friends.
 
-->fsync() has i_sem on inode.
+->fsync() has i_mutex on inode.
 
 --------------------------- dquot_operations -------------------------------
 prototypes:
@@ -510,13 +510,24 @@ More details about quota locking can be found in fs/dquot.c.
 prototypes:
        void (*open)(struct vm_area_struct*);
        void (*close)(struct vm_area_struct*);
+       int (*fault)(struct vm_area_struct*, struct vm_fault *);
        struct page *(*nopage)(struct vm_area_struct*, unsigned long, int *);
+       int (*page_mkwrite)(struct vm_area_struct *, struct page *);
 
 locking rules:
-               BKL     mmap_sem
+               BKL     mmap_sem        PageLocked(page)
 open:          no      yes
 close:         no      yes
+fault:         no      yes
 nopage:                no      yes
+page_mkwrite:  no      yes             no
+
+       ->page_mkwrite() is called when a previously read-only page is
+about to become writeable. The file system is responsible for
+protecting against truncate races. Once appropriate action has been
+taking to lock out truncate, the page range should be verified to be
+within i_size. The page mapping should also be checked that it is not
+NULL.
 
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                        Dubious stuff