vfs: new d_init method
Allow filesystem to initialize dentry at allocation time.
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index a38da93..794adbe 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -15,6 +15,7 @@
int (*d_compare)(const struct dentry *, const struct dentry *,
unsigned int, const char *, const struct qstr *);
int (*d_delete)(struct dentry *);
+ int (*d_init)(struct dentry *);
void (*d_release)(struct dentry *);
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)((struct dentry *dentry, char *buffer, int buflen);
@@ -30,6 +31,7 @@
d_hash no no no maybe
d_compare: yes no no maybe
d_delete: no yes no no
+d_init: no no yes no
d_release: no no yes no
d_prune: no yes no no
d_iput: no no yes no
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 70a056f..15c3fa7 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -923,6 +923,7 @@
int (*d_compare)(const struct dentry *, const struct dentry *,
unsigned int, const char *, const struct qstr *);
int (*d_delete)(const struct dentry *);
+ int (*d_init)(struct dentry *);
void (*d_release)(struct dentry *);
void (*d_iput)(struct dentry *, struct inode *);
char *(*d_dname)(struct dentry *, char *, int);
@@ -995,6 +996,8 @@
always cache a reachable dentry. d_delete must be constant and
idempotent.
+ d_init: called when a dentry is allocated
+
d_release: called when a dentry is really deallocated
d_iput: called when a dentry loses its inode (just prior to its
diff --git a/fs/dcache.c b/fs/dcache.c
index d5beef0..6d60a76 100644
--- a/fs/dcache.c
+++ b/fs/dcache.c
@@ -1569,6 +1569,7 @@
{
struct dentry *dentry;
char *dname;
+ int err;
dentry = kmem_cache_alloc(dentry_cache, GFP_KERNEL);
if (!dentry)
@@ -1627,6 +1628,16 @@
INIT_LIST_HEAD(&dentry->d_child);
d_set_d_op(dentry, dentry->d_sb->s_d_op);
+ if (dentry->d_op && dentry->d_op->d_init) {
+ err = dentry->d_op->d_init(dentry);
+ if (err) {
+ if (dname_external(dentry))
+ kfree(external_name(dentry));
+ kmem_cache_free(dentry_cache, dentry);
+ return NULL;
+ }
+ }
+
this_cpu_inc(nr_dentry);
return dentry;
diff --git a/include/linux/dcache.h b/include/linux/dcache.h
index 14df836..98044a8 100644
--- a/include/linux/dcache.h
+++ b/include/linux/dcache.h
@@ -133,6 +133,7 @@
int (*d_compare)(const struct dentry *, const struct dentry *,
unsigned int, const char *, const struct qstr *);
int (*d_delete)(const struct dentry *);
+ int (*d_init)(struct dentry *);
void (*d_release)(struct dentry *);
void (*d_prune)(struct dentry *);
void (*d_iput)(struct dentry *, struct inode *);