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Commit bd9926e8 authored by Theodore Ts'o's avatar Theodore Ts'o
Browse files

ext4: zero out inline data using memset() instead of empty_zero_page 



Not all architectures (in particular, sparc64) have empty_zero_page.
So instead of copying from empty_zero_page, use memset to clear the
inline data by signalling to ext4_xattr_set_entry() via a magic
pointer value, EXT4_ZERO_ATTR_VALUE, which is defined by casting -1 to
a pointer.

This fixes a build failure on sparc64, and the memset() should be more
efficient than using memcpy() anyway.

Signed-off-by: default avatarTao Ma <boyu.mt@taobao.com>
Signed-off-by: default avatar"Theodore Ts'o" <tytso@mit.edu>
parent 9a4c8019

fs/ext4/inline.c

+1 −1
Original line number Diff line number Diff line
@@ -268,7 +268,7 @@ static int ext4_create_inline_data(handle_t *handle, 
		goto out;



	if (len > EXT4_MIN_INLINE_DATA_SIZE) {

		value = (void *)empty_zero_page;

		value = EXT4_ZERO_XATTR_VALUE;

		len -= EXT4_MIN_INLINE_DATA_SIZE;

	} else {

		value = "";

fs/ext4/xattr.c

+16 −6
Original line number Diff line number Diff line
@@ -628,9 +628,14 @@ ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 
				   size. Just replace. */

				s->here->e_value_size =

					cpu_to_le32(i->value_len);

				if (i->value == EXT4_ZERO_XATTR_VALUE) {

					memset(val, 0, size);

				} else {

					/* Clear pad bytes first. */

					memset(val + size - EXT4_XATTR_PAD, 0,

				       EXT4_XATTR_PAD); /* Clear pad bytes. */

					       EXT4_XATTR_PAD);

					memcpy(val, i->value, i->value_len);

				}

				return 0;

			}
@@ -669,11 +674,16 @@ ext4_xattr_set_entry(struct ext4_xattr_info *i, struct ext4_xattr_search *s) 
			size_t size = EXT4_XATTR_SIZE(i->value_len);

			void *val = s->base + min_offs - size;

			s->here->e_value_offs = cpu_to_le16(min_offs - size);

			if (i->value == EXT4_ZERO_XATTR_VALUE) {

				memset(val, 0, size);

			} else {

				/* Clear the pad bytes first. */

				memset(val + size - EXT4_XATTR_PAD, 0,

			       EXT4_XATTR_PAD); /* Clear the pad bytes. */

				       EXT4_XATTR_PAD);

				memcpy(val, i->value, i->value_len);

			}

		}

	}

	return 0;

}

fs/ext4/xattr.h

+1 −0
Original line number Diff line number Diff line
@@ -71,6 +71,7 @@ struct ext4_xattr_entry { 
#define BFIRST(bh) ENTRY(BHDR(bh)+1)

#define IS_LAST_ENTRY(entry) (*(__u32 *)(entry) == 0)



#define EXT4_ZERO_XATTR_VALUE ((void *)-1)



struct ext4_xattr_info {

	int name_index;