ceph: add dir_layout to inode
Add a ceph_dir_layout to the inode, and calculate dentry hash values based
on the parent directory's specified dir_hash function. This is needed
because the old default Linux dcache hash function is extremely week and
leads to a poor distribution of files among dir fragments.
Signed-off-by: Sage Weil <sage@newdream.net>
diff --git a/fs/ceph/dir.c b/fs/ceph/dir.c
index d902948..562f988 100644
--- a/fs/ceph/dir.c
+++ b/fs/ceph/dir.c
@@ -1216,6 +1216,26 @@
}
}
+/*
+ * Return name hash for a given dentry. This is dependent on
+ * the parent directory's hash function.
+ */
+unsigned ceph_dentry_hash(struct dentry *dn)
+{
+ struct inode *dir = dn->d_parent->d_inode;
+ struct ceph_inode_info *dci = ceph_inode(dir);
+
+ switch (dci->i_dir_layout.dl_dir_hash) {
+ case 0: /* for backward compat */
+ case CEPH_STR_HASH_LINUX:
+ return dn->d_name.hash;
+
+ default:
+ return ceph_str_hash(dci->i_dir_layout.dl_dir_hash,
+ dn->d_name.name, dn->d_name.len);
+ }
+}
+
const struct file_operations ceph_dir_fops = {
.read = ceph_read_dir,
.readdir = ceph_readdir,
diff --git a/fs/ceph/export.c b/fs/ceph/export.c
index 2297d94..e410561 100644
--- a/fs/ceph/export.c
+++ b/fs/ceph/export.c
@@ -59,7 +59,7 @@
dout("encode_fh %p connectable\n", dentry);
cfh->ino = ceph_ino(dentry->d_inode);
cfh->parent_ino = ceph_ino(parent->d_inode);
- cfh->parent_name_hash = parent->d_name.hash;
+ cfh->parent_name_hash = ceph_dentry_hash(parent);
*max_len = connected_handle_length;
type = 2;
} else if (*max_len >= handle_length) {
diff --git a/fs/ceph/inode.c b/fs/ceph/inode.c
index bf12865..045283c 100644
--- a/fs/ceph/inode.c
+++ b/fs/ceph/inode.c
@@ -297,6 +297,8 @@
ci->i_release_count = 0;
ci->i_symlink = NULL;
+ memset(&ci->i_dir_layout, 0, sizeof(ci->i_dir_layout));
+
ci->i_fragtree = RB_ROOT;
mutex_init(&ci->i_fragtree_mutex);
diff --git a/fs/ceph/super.h b/fs/ceph/super.h
index 7f01728..6e08266 100644
--- a/fs/ceph/super.h
+++ b/fs/ceph/super.h
@@ -239,6 +239,7 @@
unsigned i_ceph_flags;
unsigned long i_release_count;
+ struct ceph_dir_layout i_dir_layout;
struct ceph_file_layout i_layout;
char *i_symlink;
@@ -768,6 +769,7 @@
extern void ceph_dentry_lru_touch(struct dentry *dn);
extern void ceph_dentry_lru_del(struct dentry *dn);
extern void ceph_invalidate_dentry_lease(struct dentry *dentry);
+extern unsigned ceph_dentry_hash(struct dentry *dn);
/*
* our d_ops vary depending on whether the inode is live,
diff --git a/include/linux/ceph/ceph_fs.h b/include/linux/ceph/ceph_fs.h
index c3c74ae..09dcc0c 100644
--- a/include/linux/ceph/ceph_fs.h
+++ b/include/linux/ceph/ceph_fs.h
@@ -43,6 +43,10 @@
#define CEPH_FEATURE_NOSRCADDR (1<<1)
#define CEPH_FEATURE_MONCLOCKCHECK (1<<2)
#define CEPH_FEATURE_FLOCK (1<<3)
+#define CEPH_FEATURE_SUBSCRIBE2 (1<<4)
+#define CEPH_FEATURE_MONNAMES (1<<5)
+#define CEPH_FEATURE_RECONNECT_SEQ (1<<6)
+#define CEPH_FEATURE_DIRLAYOUTHASH (1<<7)
/*
@@ -55,10 +59,10 @@
__le32 fl_stripe_count; /* over this many objects */
__le32 fl_object_size; /* until objects are this big, then move to
new objects */
- __le32 fl_cas_hash; /* 0 = none; 1 = sha256 */
+ __le32 fl_cas_hash; /* UNUSED. 0 = none; 1 = sha256 */
/* pg -> disk layout */
- __le32 fl_object_stripe_unit; /* for per-object parity, if any */
+ __le32 fl_object_stripe_unit; /* UNUSED. for per-object parity, if any */
/* object -> pg layout */
__le32 fl_pg_preferred; /* preferred primary for pg (-1 for none) */
@@ -69,6 +73,12 @@
int ceph_file_layout_is_valid(const struct ceph_file_layout *layout);
+struct ceph_dir_layout {
+ __u8 dl_dir_hash; /* see ceph_hash.h for ids */
+ __u8 dl_unused1;
+ __u16 dl_unused2;
+ __u32 dl_unused3;
+} __attribute__ ((packed));
/* crypto algorithms */
#define CEPH_CRYPTO_NONE 0x0
@@ -457,7 +467,7 @@
struct ceph_timespec rctime;
struct ceph_frag_tree_head fragtree; /* (must be at end of struct) */
} __attribute__ ((packed));
-/* followed by frag array, then symlink string, then xattr blob */
+/* followed by frag array, symlink string, dir layout, xattr blob */
/* reply_lease follows dname, and reply_inode */
struct ceph_mds_reply_lease {
diff --git a/net/ceph/ceph_hash.c b/net/ceph/ceph_hash.c
index 815ef88..0a1b53b 100644
--- a/net/ceph/ceph_hash.c
+++ b/net/ceph/ceph_hash.c
@@ -1,5 +1,6 @@
#include <linux/ceph/types.h>
+#include <linux/module.h>
/*
* Robert Jenkin's hash function.
@@ -104,6 +105,7 @@
return -1;
}
}
+EXPORT_SYMBOL(ceph_str_hash);
const char *ceph_str_hash_name(int type)
{
@@ -116,3 +118,4 @@
return "unknown";
}
}
+EXPORT_SYMBOL(ceph_str_hash_name);