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-rw-r--r--Documentation/filesystems/porting21
1 files changed, 21 insertions, 0 deletions
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index f24d1b833957..f1b87d8aa2da 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -504,3 +504,24 @@ 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. No highmem pages should end up in the pagecache of such
+ symlinks. That includes any preseeding that might be done during symlink
+ creation. __page_symlink() will honour the mapping gfp flags, so once
+ you've done inode_nohighmem() it's safe to use, but if you allocate and
+ insert the page manually, make sure to use the right gfp flags.
+--
+[mandatory]
+ ->follow_link() is replaced with ->get_link(); same API, except that
+ * ->get_link() gets inode as a separate argument
+ * ->get_link() may be called in RCU mode - in that case NULL
+ dentry is passed
+--
+[mandatory]
+ ->get_link() gets struct delayed_call *done now, and should do
+ set_delayed_call() where it used to set *cookie.
+ ->put_link() is gone - just give the destructor to set_delayed_call()
+ in ->get_link().