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authorNick Piggin <npiggin@kernel.dk>2011-01-07 17:49:57 +1100
committerNick Piggin <npiggin@kernel.dk>2011-01-07 17:50:29 +1100
commit34286d6662308d82aed891852d04c7c3a2649b16 (patch)
treec4b7311404d302e7cb94df7a4690298e1059910a /Documentation/filesystems/vfs.txt
parent44a7d7a878c9cbb74f236ea755b25b6b2e26a9a9 (diff)
fs: rcu-walk aware d_revalidate method
Require filesystems be aware of .d_revalidate being called in rcu-walk mode (nd->flags & LOOKUP_RCU). For now do a simple push down, returning -ECHILD from all implementations. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
Diffstat (limited to 'Documentation/filesystems/vfs.txt')
-rw-r--r--Documentation/filesystems/vfs.txt9
1 files changed, 9 insertions, 0 deletions
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 69b10ff5ec8..c936b491238 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -863,6 +863,15 @@ struct dentry_operations {
dcache. Most filesystems leave this as NULL, because all their
dentries in the dcache are valid
+ d_revalidate may be called in rcu-walk mode (nd->flags & LOOKUP_RCU).
+ If in rcu-walk mode, the filesystem must revalidate the dentry without
+ blocking or storing to the dentry, d_parent and d_inode should not be
+ used without care (because they can go NULL), instead nd->inode should
+ be used.
+
+ If a situation is encountered that rcu-walk cannot handle, return
+ -ECHILD and it will be called again in ref-walk mode.
+
d_hash: called when the VFS adds a dentry to the hash table. The first
dentry passed to d_hash is the parent directory that the name is
to be hashed into. The inode is the dentry's inode.