diff options
| author | Russell King <rmk@dyn-67.arm.linux.org.uk> | 2009-05-23 20:57:31 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2009-05-23 20:57:31 +0100 |
| commit | a2ab67fae1ab9226679495a8d260f4e6555efc5f (patch) | |
| tree | f7de683c9c8ff0869a7e11f1d40802145d05f5b4 /Documentation/filesystems/Locking | |
| parent | 6d0485a99366d4e0e7e725f14995c74cb7ca4499 (diff) | |
| parent | 135cad366b4e7d6a79f6369f6cb5b721985aa62f (diff) | |
Merge branch 'for-rmk-devel' of git://git.pengutronix.de/git/imx/linux-2.6 into devel
Conflicts:
arch/arm/Kconfig
arch/arm/Makefile
Diffstat (limited to 'Documentation/filesystems/Locking')
| -rw-r--r-- | Documentation/filesystems/Locking | 24 |
1 files changed, 16 insertions, 8 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 76efe5b71d7..3120f8dd2c3 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -512,16 +512,24 @@ locking rules: BKL mmap_sem PageLocked(page) open: no yes close: no yes -fault: no yes -page_mkwrite: no yes no +fault: no yes can return with page locked +page_mkwrite: no yes can return with page locked access: no yes - ->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. + ->fault() is called when a previously not present pte is about +to be faulted in. The filesystem must find and return the page associated +with the passed in "pgoff" in the vm_fault structure. If it is possible that +the page may be truncated and/or invalidated, then the filesystem must lock +the page, then ensure it is not already truncated (the page lock will block +subsequent truncate), and then return with VM_FAULT_LOCKED, and the page +locked. The VM will unlock the page. + + ->page_mkwrite() is called when a previously read-only pte is +about to become writeable. The filesystem again must ensure that there are +no truncate/invalidate races, and then return with the page locked. If +the page has been truncated, the filesystem should not look up a new page +like the ->fault() handler, but simply return with VM_FAULT_NOPAGE, which +will cause the VM to retry the fault. ->access() is called when get_user_pages() fails in acces_process_vm(), typically used to debug a process through |