From: Allison Henderson Subject: [Ext4 Secure Delete 2/7v4] ext4: Secure Delete: Add ext4_ind_hole_lookup function Date: Fri, 7 Oct 2011 00:11:00 -0700 Message-ID: <1317971465-8517-3-git-send-email-achender@linux.vnet.ibm.com> References: <1317971465-8517-1-git-send-email-achender@linux.vnet.ibm.com> Cc: Allison Henderson To: linux-ext4@vger.kernel.org, linux-fsdevel@vger.kernel.org Return-path: In-Reply-To: <1317971465-8517-1-git-send-email-achender@linux.vnet.ibm.com> Sender: linux-fsdevel-owner@vger.kernel.org List-Id: linux-ext4.vger.kernel.org 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 --- :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