On 10/07/2011 10:47 AM, Darrick J. Wong wrote:
On Fri, Oct 07, 2011 at 12:11:00AM -0700, Allison Henderson wrote: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@xxxxxxxxxxxxxxxxxx> --- :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.boundary+ */ +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; + }Do you need a put_bh here somewhere? --D
I think you're right, I will add that in somewhere, thx!
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