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Date: Fri, 7 Oct 2011 00:11:00 -0700
From: Allison Henderson <achender@...ux.vnet.ibm.com>
To: linux-ext4@...r.kernel.org, linux-fsdevel@...r.kernel.org
Cc: Allison Henderson <achender@...ux.vnet.ibm.com>
Subject: [Ext4 Secure Delete 2/7v4] ext4: Secure Delete: Add ext4_ind_hole_lookup function
This patch adds a new ext4_ind_hole_lookup function that
will be used to identify and skip over holes during a
secure delete operation
Signed-off-by: Allison Henderson <achender@...ux.vnet.ibm.com>
---
:100644 100644 db54ce4... 5c9f88c... M fs/ext4/ext4.h
:100644 100644 0962642... 2fe9dfd... M fs/ext4/indirect.c
:100644 100644 c4da98a... 9dc8c14... M fs/ext4/inode.c
fs/ext4/ext4.h | 5 +++
fs/ext4/indirect.c | 2 +-
fs/ext4/inode.c | 73 ++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 79 insertions(+), 1 deletions(-)
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index db54ce4..5c9f88c 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -2241,6 +2241,11 @@ extern int ext4_bio_write_page(struct ext4_io_submit *io,
/* mmp.c */
extern int ext4_multi_mount_protect(struct super_block *, ext4_fsblk_t);
+/* indirects.c */
+extern int ext4_block_to_path(struct inode *inode,
+ ext4_lblk_t i_block,
+ ext4_lblk_t offsets[4], int *boundary);
+
/* BH_Uninit flag: blocks are allocated but uninitialized on disk */
enum ext4_state_bits {
BH_Uninit /* blocks are allocated but uninitialized on disk */
diff --git a/fs/ext4/indirect.c b/fs/ext4/indirect.c
index 0962642..2fe9dfd 100644
--- a/fs/ext4/indirect.c
+++ b/fs/ext4/indirect.c
@@ -69,7 +69,7 @@ static inline void add_chain(Indirect *p, struct buffer_head *bh, __le32 *v)
* get there at all.
*/
-static int ext4_block_to_path(struct inode *inode,
+int ext4_block_to_path(struct inode *inode,
ext4_lblk_t i_block,
ext4_lblk_t offsets[4], int *boundary)
{
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index c4da98a..9dc8c14 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -640,6 +640,79 @@ struct buffer_head *ext4_getblk(handle_t *handle, struct inode *inode,
return bh;
}
+/*
+ * ext4_in_hole_lookup
+ *
+ * Returns the size of the hole located at the given block up to
+ * the first boundry, or 0 if there is no hole. Returns negative on err.
+ */
+static int ext4_ind_hole_lookup(struct inode *inode, ext4_lblk_t block)
+{
+ struct super_block *sb = inode->i_sb;
+ struct buffer_head *bh;
+ ext4_lblk_t offsets[4];
+ ext4_lblk_t offset;
+ __le32 *children;
+ __le32 blk;
+ int blocks_to_boundary = 0;
+ int depth = 0;
+ int hole_size = 0;
+ unsigned int i, j;
+
+ depth = ext4_block_to_path(inode, block, offsets, &blocks_to_boundary);
+
+ if (depth == 0)
+ return 0;
+
+ offset = offsets[0];
+ blk = EXT4_I(inode)->i_data[offset];
+ if (blk == 0) {
+ for (i = *offsets; i < EXT4_NDIR_BLOCKS; i++) {
+ if (EXT4_I(inode)->i_data[i] == 0)
+ hole_size++;
+ else
+ break;
+ }
+ return hole_size;
+ }
+
+
+ for (j = 1; j < depth; j++) {
+ offset = offsets[j];
+ bh = sb_getblk(sb, le32_to_cpu(blk));
+ if (unlikely(!bh))
+ return -EIO;
+
+ if (!bh_uptodate_or_lock(bh)) {
+ if (bh_submit_read(bh) < 0) {
+ put_bh(bh);
+ return -EIO;
+ }
+ /* validate block references */
+ if (ext4_check_indirect_blockref(inode, bh)) {
+ put_bh(bh);
+ return -EIO;
+ }
+ }
+
+ blk = ((__le32 *)bh->b_data)[offset];
+ /* Reader: end */
+ if (blk == 0) {
+ children = (__le32 *)(bh->b_data);
+ for (i = offset; i < offset +
+ blocks_to_boundary; i++) {
+ if (children[i] == 0)
+ hole_size++;
+ else
+ break;
+ }
+ return hole_size;
+ }
+ }
+
+ return 0;
+}
+
struct buffer_head *ext4_bread(handle_t *handle, struct inode *inode,
ext4_lblk_t block, int create, int *err)
{
--
1.7.1
--
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