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authorTheodore Ts'o <tytso@mit.edu>2012-12-11 03:31:49 -0500
committerTheodore Ts'o <tytso@mit.edu>2012-12-11 03:31:49 -0500
commitbd9926e80330d43f15b710c2935fa41b792d56fd (patch)
treeccc30335831784996b7435d10df39ee14e92afad
parent9a4c8019471386c6fb039ae9e30f5216b6b55a9e (diff)
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>
-rw-r--r--fs/ext4/inline.c2
-rw-r--r--fs/ext4/xattr.c22
-rw-r--r--fs/ext4/xattr.h1
3 files changed, 18 insertions, 7 deletions
diff --git a/fs/ext4/inline.c b/fs/ext4/inline.c
index 53b2f65091d..387c47c6cda 100644
--- a/fs/ext4/inline.c
+++ b/fs/ext4/inline.c
@@ -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 = "";
diff --git a/fs/ext4/xattr.c b/fs/ext4/xattr.c
index 2251769a3c5..3a91ebc2b66 100644
--- a/fs/ext4/xattr.c
+++ b/fs/ext4/xattr.c
@@ -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);
- 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 @@ 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);
- 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 7b5513ed3b3..69eda787a96 100644
--- a/fs/ext4/xattr.h
+++ b/fs/ext4/xattr.h
@@ -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;