On Tue, Feb 28, 2012 at 7:21 PM, Alex Elder <el...@dreamhost.com> wrote:
> 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 <el...@dreamhost.com>
> ---
> fs/ceph/super.c | 3 ++
> fs/ceph/super.h | 2 +
> fs/ceph/xattr.c | 56
> ++++++++++++++++++++++++++++++++++++++++++++++++++----
> 3 files changed, 56 insertions(+), 5 deletions(-)
>
> diff --git a/fs/ceph/super.c b/fs/ceph/super.c
> index b48f15f..e6325f0 100644
> --- a/fs/ceph/super.c
> +++ b/fs/ceph/super.c
> @@ -906,6 +906,7 @@ static int __init init_ceph(void)
> if (ret)
> goto out;
>
> + ceph_xattr_init();
> ret = register_filesystem(&ceph_fs_type);
> if (ret)
> goto out_icache;
> @@ -915,6 +916,7 @@ static int __init init_ceph(void)
> return 0;
>
> out_icache:
> + ceph_xattr_exit();
> destroy_caches();
> out:
> return ret;
> @@ -924,6 +926,7 @@ static void __exit exit_ceph(void)
> {
> dout("exit_ceph\n");
> unregister_filesystem(&ceph_fs_type);
> + ceph_xattr_exit();
> destroy_caches();
> }
>
> diff --git a/fs/ceph/super.h b/fs/ceph/super.h
> index 5f00e82..4be2dc4 100644
> --- a/fs/ceph/super.h
> +++ b/fs/ceph/super.h
> @@ -732,6 +732,8 @@ extern ssize_t ceph_listxattr(struct dentry *, char *,
> size_t);
> extern int ceph_removexattr(struct dentry *, const char *);
> extern void __ceph_build_xattrs_blob(struct ceph_inode_info *ci);
> extern void __ceph_destroy_xattrs(struct ceph_inode_info *ci);
> +extern void __init ceph_xattr_init(void);
> +extern void ceph_xattr_exit(void);
>
> /* caps.c */
> extern const char *ceph_cap_string(int c);
> diff --git a/fs/ceph/xattr.c b/fs/ceph/xattr.c
> index 83366f9..984c863 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), \
You should use sizeof(x) instead of sizeof x.
> .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",
here too.
> .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)
> +{sizeof
> + 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)
> {
> @@ -614,11 +659,12 @@ 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;
> --
> 1.7.5.4
>
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