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: Tao Ma <boyu.mt@taobao.com>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 53b2f65..387c47c 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -268,7 +268,7 @@
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 = "";
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 2251769..3a91ebc 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -628,9 +628,14 @@
size. Just replace. */
s->here->e_value_size =
cpu_to_le32(i->value_len);
- memset(val + size - EXT4_XATTR_PAD, 0,
- EXT4_XATTR_PAD); /* Clear pad bytes. */
- memcpy(val, i->value, 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);
+ memcpy(val, i->value, i->value_len);
+ }
return 0;
}
@@ -669,9 +674,14 @@
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);
- memset(val + size - EXT4_XATTR_PAD, 0,
- EXT4_XATTR_PAD); /* Clear the pad bytes. */
- memcpy(val, i->value, i->value_len);
+ 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);
+ memcpy(val, i->value, i->value_len);
+ }
}
}
return 0;
diff --git a/fs/ext4/xattr.h b/fs/ext4/xattr.h
index 7b5513e..69eda78 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -71,6 +71,7 @@
#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;