The patch titled
r-o-bind-mounts: make access() use mnt check
has been added to the -mm tree. Its filename is
r-o-bind-mounts-make-access-use-mnt-check.patch
*** Remember to use Documentation/SubmitChecklist when testing your code ***
See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this
------------------------------------------------------
Subject: r-o-bind-mounts: make access() use mnt check
From: Dave Hansen <haveblue@xxxxxxxxxx>
It is OK to let access() go without using a mnt_want/drop_write() pair because
it doesn't actually do writes to the filesystem, and it is inherently racy
anyway. This is a rare case when it is OK to use __mnt_is_readonly()
directly.
Acked-by: Christoph Hellwig <hch@xxxxxxxxxxxxx>
Signed-off-by: Dave Hansen <haveblue@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
fs/open.c | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)
diff -puN fs/open.c~r-o-bind-mounts-make-access-use-mnt-check fs/open.c
--- a/fs/open.c~r-o-bind-mounts-make-access-use-mnt-check
+++ a/fs/open.c
@@ -459,8 +459,17 @@ asmlinkage long sys_faccessat(int dfd, c
if(res || !(mode & S_IWOTH) ||
special_file(nd.dentry->d_inode->i_mode))
goto out_path_release;
-
- if(IS_RDONLY(nd.dentry->d_inode))
+ /*
+ * This is a rare case where using __mnt_is_readonly()
+ * is OK without a mnt_want/drop_write() pair. Since
+ * no actual write to the fs is performed here, we do
+ * not need to telegraph to that to anyone.
+ *
+ * By doing this, we accept that this access is
+ * inherently racy and know that the fs may change
+ * state before we even see this result.
+ */
+ if (__mnt_is_readonly(nd.mnt))
res = -EROFS;
out_path_release:
_
Patches currently in -mm which might be from haveblue@xxxxxxxxxx are
markers-fix-warnings.patch
maps4-add-proportional-set-size-accounting-in-smaps.patch
maps4-rework-task_size-macros.patch
maps4-move-is_swap_pte.patch
maps4-introduce-a-generic-page-walker.patch
maps4-use-pagewalker-in-clear_refs-and-smaps.patch
maps4-simplify-interdependence-of-maps-and-smaps.patch
maps4-move-clear_refs-code-to-task_mmuc.patch
maps4-regroup-task_mmu-by-interface.patch
maps4-add-proc-pid-pagemap-interface.patch
maps4-add-proc-kpagecount-interface.patch
maps4-add-proc-kpageflags-interface.patch
maps4-make-page-monitoring-proc-file-optional.patch
maps4-make-page-monitoring-proc-file-optional-fix.patch
hugetlb-split-alloc_huge_page-into-private-and-shared-components.patch
hugetlb-split-alloc_huge_page-into-private-and-shared-components-checkpatch-fixes.patch
hugetlb-fix-quota-management-for-private-mappings.patch
hugetlb-debit-quota-in-alloc_huge_page.patch
hugetlb-allow-bulk-updating-in-hugetlb__quota.patch
hugetlb-enforce-quotas-during-reservation-for-shared-mappings.patch
add-remove_memory-for-ppc64-2.patch
enable-hotplug-memory-remove-for-ppc64.patch
add-arch-specific-walk_memory_remove-for-ppc64.patch
do-namei_flags-calculation-inside-open_namei.patch
make-open_namei-return-a-filp.patch
kill-do_filp_open.patch
kill-filp_open.patch
kill-filp_open-checkpatch-fixes.patch
rename-open_namei-to-open_pathname.patch
r-o-bind-mounts-stub-functions.patch
r-o-bind-mounts-do_rmdir-elevate-write-count.patch
r-o-bind-mounts-elevate-mnt-writers-for-callers-of-vfs_mkdir.patch
r-o-bind-mounts-elevate-mnt-writers-for-vfs_unlink-callers.patch
r-o-bind-mounts-elevate-mount-count-for-extended-attributes.patch
r-o-bind-mounts-elevate-write-count-during-entire-ncp_ioctl.patch
r-o-bind-mounts-elevate-write-count-for-do_sys_utime-and-touch_atime.patch
r-o-bind-mounts-elevate-write-count-for-do_utimes.patch
r-o-bind-mounts-elevate-write-count-for-file_update_time.patch
r-o-bind-mounts-elevate-write-count-for-link-and-symlink-calls.patch
r-o-bind-mounts-elevate-write-count-for-some-ioctls.patch
r-o-bind-mounts-elevate-write-count-for-some-ioctls-checkpatch-fixes.patch
r-o-bind-mounts-elevate-write-count-for-some-ioctls-vs-forbid-user-to-change-file-flags-on-quota-files.patch
r-o-bind-mounts-elevate-write-count-opened-files.patch
r-o-bind-mounts-elevate-write-count-over-calls-to-vfs_rename.patch
r-o-bind-mounts-elevate-writer-count-for-chown-and-friends.patch
r-o-bind-mounts-elevate-writer-count-for-do_sys_truncate.patch
r-o-bind-mounts-make-access-use-mnt-check.patch
r-o-bind-mounts-nfs-check-mnt-instead-of-superblock-directly.patch
r-o-bind-mounts-sys_mknodat-elevate-write-count-for-vfs_mknod-create.patch
r-o-bind-mounts-track-number-of-mount-writers.patch
r-o-bind-mounts-track-number-of-mount-writers-make-lockdep-happy-with-r-o-bind-mounts.patch
r-o-bind-mounts-honor-r-w-changes-at-do_remount-time.patch
keep-track-of-mnt_writer-state-of-struct-file.patch
reiser4.patch
page-owner-tracking-leak-detector.patch
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