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authorAl Viro <viro@zeniv.linux.org.uk>2015-11-17 09:07:57 +0300
committerAl Viro <viro@zeniv.linux.org.uk>2015-12-09 06:41:36 +0300
commit21fc61c73c3903c4c312d0802da01ec2b323d174 (patch)
treea26c29e3fbb766f00b023724e9e5b8b9bba9b879 /Documentation/filesystems
parentaa80deab33a8fb180e718f5e45514db19aade165 (diff)
downloadlinux-21fc61c73c3903c4c312d0802da01ec2b323d174.tar.xz
don't put symlink bodies in pagecache into highmem
kmap() in page_follow_link_light() needed to go - allowing to hold an arbitrary number of kmaps for long is a great way to deadlocking the system. new helper (inode_nohighmem(inode)) needs to be used for pagecache symlinks inodes; done for all in-tree cases. page_follow_link_light() instrumented to yell about anything missed. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Diffstat (limited to 'Documentation/filesystems')
-rw-r--r--Documentation/filesystems/porting5
1 files changed, 5 insertions, 0 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index f24d1b833957..3eb7c35c9698 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -504,3 +504,8 @@ in your dentry operations instead.
[mandatory]
__fd_install() & fd_install() can now sleep. Callers should not
hold a spinlock or other resources that do not allow a schedule.
+--
+[mandatory]
+ any symlink that might use page_follow_link_light/page_put_link() must
+ have inode_nohighmem(inode) called before anything might start playing with
+ its pagecache.