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authorAlex Elder <elder@dreamhost.com>2012-01-24 01:49:28 +0400
committerAlex Elder <elder@dreamhost.com>2012-03-22 19:47:46 +0400
commit3ce6cd1233046eb97d6d2bd5d80c1cd40528ea2f (patch)
tree43025c030db1741222b96156931b6aa2c8b85e51 /fs/ceph/xattr.c
parentaa4066ed7ba60421423c35f66b789bb3dd21d89e (diff)
downloadlinux-3ce6cd1233046eb97d6d2bd5d80c1cd40528ea2f.tar.xz
ceph: avoid repeatedly computing the size of constant vxattr names
All names defined in the directory and file virtual extended attribute tables are constant, and the size of each is known at compile time. So there's no need to compute their length every time any file's attribute is listed. Record the length of each string and use it when needed to determine the space need to represent them. In addition, compute the aggregate size of strings in each table just once at initialization time. Signed-off-by: Alex Elder <elder@dreamhost.com> Signed-off-by: Sage Weil <sage@newdream.net>
Diffstat (limited to 'fs/ceph/xattr.c')
-rw-r--r--fs/ceph/xattr.c56
1 files changed, 51 insertions, 5 deletions
diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
index 46be30d6d127..88eaedf78fa9 100644
--- a/fs/ceph/xattr.c
+++ b/fs/ceph/xattr.c
@@ -26,6 +26,7 @@ static bool ceph_is_valid_xattr(const char *name)
*/
struct ceph_vxattr {
char *name;
+ size_t name_size; /* strlen(name) + 1 (for '\0') */
size_t (*getxattr_cb)(struct ceph_inode_info *ci, char *val,
size_t size);
bool readonly;
@@ -87,6 +88,7 @@ static size_t ceph_vxattrcb_dir_rctime(struct ceph_inode_info *ci, char *val,
#define XATTR_NAME_CEPH(_type, _name) \
{ \
.name = CEPH_XATTR_NAME(_type, _name), \
+ .name_size = sizeof (CEPH_XATTR_NAME(_type, _name)), \
.getxattr_cb = ceph_vxattrcb_ ## _type ## _ ## _name, \
.readonly = true, \
}
@@ -102,6 +104,7 @@ static struct ceph_vxattr ceph_dir_vxattrs[] = {
XATTR_NAME_CEPH(dir, rctime),
{ 0 } /* Required table terminator */
};
+static size_t ceph_dir_vxattrs_name_size; /* total size of all names */
/* files */
@@ -127,11 +130,13 @@ static struct ceph_vxattr ceph_file_vxattrs[] = {
/* The following extended attribute name is deprecated */
{
.name = XATTR_CEPH_PREFIX "layout",
+ .name_size = sizeof (XATTR_CEPH_PREFIX "layout"),
.getxattr_cb = ceph_vxattrcb_file_layout,
.readonly = true,
},
{ 0 } /* Required table terminator */
};
+static size_t ceph_file_vxattrs_name_size; /* total size of all names */
static struct ceph_vxattr *ceph_inode_vxattrs(struct inode *inode)
{
@@ -142,6 +147,46 @@ static struct ceph_vxattr *ceph_inode_vxattrs(struct inode *inode)
return NULL;
}
+static size_t ceph_vxattrs_name_size(struct ceph_vxattr *vxattrs)
+{
+ if (vxattrs == ceph_dir_vxattrs)
+ return ceph_dir_vxattrs_name_size;
+ if (vxattrs == ceph_file_vxattrs)
+ return ceph_file_vxattrs_name_size;
+ BUG();
+
+ return 0;
+}
+
+/*
+ * Compute the aggregate size (including terminating '\0') of all
+ * virtual extended attribute names in the given vxattr table.
+ */
+static size_t __init vxattrs_name_size(struct ceph_vxattr *vxattrs)
+{
+ struct ceph_vxattr *vxattr;
+ size_t size = 0;
+
+ for (vxattr = vxattrs; vxattr->name; vxattr++)
+ size += vxattr->name_size;
+
+ return size;
+}
+
+/* Routines called at initialization and exit time */
+
+void __init ceph_xattr_init(void)
+{
+ ceph_dir_vxattrs_name_size = vxattrs_name_size(ceph_dir_vxattrs);
+ ceph_file_vxattrs_name_size = vxattrs_name_size(ceph_file_vxattrs);
+}
+
+void ceph_xattr_exit(void)
+{
+ ceph_dir_vxattrs_name_size = 0;
+ ceph_file_vxattrs_name_size = 0;
+}
+
static struct ceph_vxattr *ceph_match_vxattr(struct inode *inode,
const char *name)
{
@@ -615,11 +660,12 @@ ssize_t ceph_listxattr(struct dentry *dentry, char *names, size_t size)
goto out;
list_xattr:
- vir_namelen = 0;
- /* include virtual dir xattrs */
- if (vxattrs)
- for (i = 0; vxattrs[i].name; i++)
- vir_namelen += strlen(vxattrs[i].name) + 1;
+ /*
+ * Start with virtual dir xattr names (if any) (including
+ * terminating '\0' characters for each).
+ */
+ vir_namelen = ceph_vxattrs_name_size(vxattrs);
+
/* adding 1 byte per each variable due to the null termination */
namelen = vir_namelen + ci->i_xattrs.names_size + ci->i_xattrs.count;
err = -ERANGE;