fs: change d_hash for rcu-walk
Change d_hash so it may be called from lock-free RCU lookups. See similar
patch for d_compare for details.
For in-tree filesystems, this is just a mechanical change.
Signed-off-by: Nick Piggin <npiggin@kernel.dk>
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 9a76f8d..a15ee20 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -10,7 +10,8 @@
--------------------------- dentry_operations --------------------------
prototypes:
int (*d_revalidate)(struct dentry *, int);
- int (*d_hash) (struct dentry *, struct qstr *);
+ int (*d_hash)(const struct dentry *, const struct inode *,
+ struct qstr *);
int (*d_compare)(const struct dentry *, const struct inode *,
const struct dentry *, const struct inode *,
unsigned int, const char *, const struct qstr *);
@@ -22,7 +23,7 @@
locking rules:
dcache_lock rename_lock ->d_lock may block
d_revalidate: no no no yes
-d_hash no no no yes
+d_hash no no no no
d_compare: no yes no no
d_delete: yes no yes no
d_release: no no no yes
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index d44511e..9fd3194 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -333,3 +333,10 @@
.d_compare() calling convention and locking rules are significantly
changed. Read updated documentation in Documentation/filesystems/vfs.txt (and
look at examples of other filesystems) for guidance.
+
+---
+[mandatory]
+
+ .d_hash() calling convention and locking rules are significantly
+changed. Read updated documentation in Documentation/filesystems/vfs.txt (and
+look at examples of other filesystems) for guidance.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 250681b..69b10ff 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -847,7 +847,8 @@
struct dentry_operations {
int (*d_revalidate)(struct dentry *, struct nameidata *);
- int (*d_hash)(struct dentry *, struct qstr *);
+ int (*d_hash)(const struct dentry *, const struct inode *,
+ struct qstr *);
int (*d_compare)(const struct dentry *, const struct inode *,
const struct dentry *, const struct inode *,
unsigned int, const char *, const struct qstr *);
@@ -864,7 +865,10 @@
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.
+ to be hashed into. The inode is the dentry's inode.
+
+ Same locking and synchronisation rules as d_compare regarding
+ what is safe to dereference etc.
d_compare: called to compare a dentry name with a given name. The first
dentry is the parent of the dentry to be compared, the second is