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btrfs: optmize listxattr

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The ->list handler is really not useful at all, because we always call
btrfs_xattr_generic_list anyway.  After this is done
find_btrfs_xattr_handler becomes unused, and it becomes obvious that the
temporary name buffer allocation isn't needed but we can directly copy
into the supplied buffer.

Tested with various getfattr -d calls on varying xattr lists.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
This commit is contained in:
Christoph Hellwig 2008-08-28 06:21:16 -04:00 committed by Chris Mason
parent eab922ec89
commit eaa47d8612
3 changed files with 11 additions and 81 deletions
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2
fs/btrfs/acl.c
View File

@ -320,14 +320,12 @@ int btrfs_acl_chmod(struct inode *inode)
struct xattr_handler btrfs_xattr_acl_default_handler = {
.prefix = POSIX_ACL_XATTR_DEFAULT,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_acl_default_get,
.set = btrfs_xattr_acl_default_set,
};
struct xattr_handler btrfs_xattr_acl_access_handler = {
.prefix = POSIX_ACL_XATTR_ACCESS,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_acl_access_get,
.set = btrfs_xattr_acl_access_set,
};

82
fs/btrfs/xattr.c
View File

@ -50,35 +50,6 @@ struct xattr_handler *btrfs_xattr_handlers[] = {
NULL,
};
/*
* @param name - the xattr name
* @return - the xattr_handler for the xattr, NULL if its not found
*
* use this with listxattr where we don't already know the type of xattr we
* have
*/
static struct xattr_handler *find_btrfs_xattr_handler(struct extent_buffer *l,
unsigned long name_ptr,
u16 name_len)
{
struct xattr_handler *handler = NULL;
int i = 0;
for (handler = btrfs_xattr_handlers[i]; handler != NULL; i++,
handler = btrfs_xattr_handlers[i]) {
u16 prefix_len = strlen(handler->prefix);
if (name_len < prefix_len)
continue;
if (memcmp_extent_buffer(l, handler->prefix, name_ptr,
prefix_len) == 0)
break;
}
return handler;
}
/*
* @param name_index - the index for the xattr handler
* @return the xattr_handler if we found it, NULL otherwise
@ -118,19 +89,6 @@ static inline char *get_name(const char *name, int name_index)
return ret;
}
size_t btrfs_xattr_generic_list(struct inode *inode, char *list,
size_t list_size, const char *name,
size_t name_len)
{
if (list && (name_len+1) <= list_size) {
memcpy(list, name, name_len);
list[name_len] = '\0';
} else
return -ERANGE;
return name_len+1;
}
ssize_t btrfs_xattr_get(struct inode *inode, int name_index,
const char *attr_name, void *buffer, size_t size)
{
@ -278,11 +236,10 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
struct btrfs_item *item;
struct extent_buffer *leaf;
struct btrfs_dir_item *di;
struct xattr_handler *handler;
int ret = 0, slot, advance;
size_t total_size = 0, size_left = size, written;
size_t total_size = 0, size_left = size;
unsigned long name_ptr;
char *name;
size_t name_len;
u32 nritems;
/*
@ -344,37 +301,24 @@ ssize_t btrfs_listxattr(struct dentry *dentry, char *buffer, size_t size)
di = btrfs_item_ptr(leaf, slot, struct btrfs_dir_item);
total_size += btrfs_dir_name_len(leaf, di)+1;
name_len = btrfs_dir_name_len(leaf, di);
total_size += name_len + 1;
/* we are just looking for how big our buffer needs to be */
if (!size)
continue;
/* find our handler for this xattr */
name_ptr = (unsigned long)(di + 1);
handler = find_btrfs_xattr_handler(leaf, name_ptr,
btrfs_dir_name_len(leaf, di));
if (!handler) {
printk(KERN_ERR "btrfs: unsupported xattr found\n");
continue;
}
name = kmalloc(btrfs_dir_name_len(leaf, di), GFP_KERNEL);
read_extent_buffer(leaf, name, name_ptr,
btrfs_dir_name_len(leaf, di));
/* call the list function associated with this xattr */
written = handler->list(inode, buffer, size_left, name,
btrfs_dir_name_len(leaf, di));
kfree(name);
if (written < 0) {
if (!buffer || (name_len + 1) > size_left) {
ret = -ERANGE;
break;
}
size_left -= written;
buffer += written;
name_ptr = (unsigned long)(di + 1);
read_extent_buffer(leaf, buffer, name_ptr, name_len);
buffer[name_len] = '\0';
size_left -= name_len + 1;
buffer += name_len + 1;
}
ret = total_size;
@ -412,28 +356,24 @@ BTRFS_XATTR_SETGET_FUNCS(trusted, BTRFS_XATTR_INDEX_TRUSTED);
struct xattr_handler btrfs_xattr_security_handler = {
.prefix = XATTR_SECURITY_PREFIX,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_security_get,
.set = btrfs_xattr_security_set,
};
struct xattr_handler btrfs_xattr_system_handler = {
.prefix = XATTR_SYSTEM_PREFIX,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_system_get,
.set = btrfs_xattr_system_set,
};
struct xattr_handler btrfs_xattr_user_handler = {
.prefix = XATTR_USER_PREFIX,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_user_get,
.set = btrfs_xattr_user_set,
};
struct xattr_handler btrfs_xattr_trusted_handler = {
.prefix = XATTR_TRUSTED_PREFIX,
.list = btrfs_xattr_generic_list,
.get = btrfs_xattr_trusted_get,
.set = btrfs_xattr_trusted_set,
};

8
fs/btrfs/xattr.h
View File

@ -47,12 +47,4 @@ ssize_t btrfs_xattr_get(struct inode *inode, int name_index, const char *name,
int btrfs_xattr_set(struct inode *inode, int name_index, const char *name,
const void *value, size_t size, int flags);
/*
* the only reason this is public is for acl.c. There may be a point where
* acl.c doesn't need it, and if thats the case we need to remove it and make
* it static in xattr.c
*/
size_t btrfs_xattr_generic_list(struct inode *inode, char *list,
size_t list_size, const char *name,
size_t name_len);
#endif /* __XATTR__ */