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| author | Ingo Molnar <mingo@elte.hu> | 2009-05-18 07:37:44 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-05-18 07:37:49 +0200 |
| commit | dc3f81b129b5439ba7bac265bbc6a51a39275dae (patch) | |
| tree | 216030731d911249496d2e97206cd61431e31c89 /Documentation/filesystems/Locking | |
| parent | d2517a49d55536b38c7a87e5289550cfedaa4dcc (diff) | |
| parent | 1406de8e11eb043681297adf86d6892ff8efc27a (diff) | |
| download | op-kernel-dev-dc3f81b129b5439ba7bac265bbc6a51a39275dae.zip op-kernel-dev-dc3f81b129b5439ba7bac265bbc6a51a39275dae.tar.gz | |
Merge commit 'v2.6.30-rc6' into perfcounters/core
Merge reason: this branch was on an -rc4 base, merge it up to -rc6
to get the latest upstream fixes.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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 76efe5b..3120f8d 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 |
