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Commit eaa47d86 authored by Christoph Hellwig's avatar Christoph Hellwig Committed by Chris Mason
Browse files

btrfs: optmize listxattr 



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: default avatarChristoph Hellwig <hch@lst.de>
Signed-off-by: default avatarChris Mason <chris.mason@oracle.com>
parent eab922ec

fs/btrfs/acl.c

+0 −2
Original line number Diff line number Diff line
@@ -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,

};

fs/btrfs/xattr.c

+11 −71
Original line number Diff line number Diff line
@@ -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,

};

fs/btrfs/xattr.h

+0 −8
Original line number Diff line number Diff line
@@ -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__ */