On Tue, 8 Jul 2014, Namjae Jeon wrote:
> Date: Tue, 08 Jul 2014 21:00:02 +0900
> From: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
> To: Dave Chinner <david@xxxxxxxxxxxxx>, Theodore Ts'o <tytso@xxxxxxx>
> Cc: linux-ext4 <linux-ext4@xxxxxxxxxxxxxxx>, linux-fsdevel@xxxxxxxxxxxxxxx,
> linux-kernel@xxxxxxxxxxxxxxx, Lukáš Czerner <lczerner@xxxxxxxxxx>,
> Brian Foster <bfoster@xxxxxxxxxx>, Christoph Hellwig <hch@xxxxxxxxxxxxx>,
> Ashish Sangwan <a.sangwan@xxxxxxxxxxx>, xfs@xxxxxxxxxxx
> Subject: [PATCH 3/3] ext4: Add support IOC_MOV_DATA ioctl
>
> This patch implements fs ioctl's IOC_MOV_DATA for Ext4.
Hmm isn't this basically what ext4_move_extents() does ? eg.
EXT4_IOC_MOVE_EXT ?
I guess that the intention here is to do the move, without actually
moving the data right ? But nevertheless maybe some code can be
shared with ext4_move_extents() ?
-Lukas
>
> The semantics of this ioctl are:
> 1) Like collapse range, offsets and length should be file system block size
> aligned.
> 2) In the receiver file, atleast length size hole should be present at
> receiver_offset
> 3) It does not change file size of any of donor or receiver file.
> 4) It leaves a hole at the place from where blocks are moved out in donor file.
> 5) Both (donor_offset + length) and (receiver_offset + length) should be within
> size of donor file and receiver file respectively.
> Only unwritten extents resides beyond file size and it does not make sense
> to transfer unwritten extents, leave apart the security issues it may raise.
> 6) If the range to be transfered from donor file contain any holes, they are
> replicated as it is in receiver file. It mean holes are preserved and
> the length of hole will be added to moved_len signifying that the hole range
> is succesfully transfered.
>
> Signed-off-by: Namjae Jeon <namjae.jeon@xxxxxxxxxxx>
> Signed-off-by: Ashish Sangwan <a.sangwan@xxxxxxxxxxx>
> ---
> fs/ext4/ext4.h | 2 +
> fs/ext4/extents.c | 375 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
> fs/ext4/file.c | 1 +
> 3 files changed, 378 insertions(+)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 6386c5f..26478eb 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -2725,6 +2725,8 @@ extern int ext4_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo,
> extern int ext4_ext_precache(struct inode *inode);
> extern int ext4_collapse_range(struct inode *inode, loff_t offset, loff_t len);
> extern int ext4_insert_range(struct file *file, loff_t offset, loff_t len);
> +extern int ext4_mov_data(struct inode *, struct inode *, loff_t, loff_t, loff_t,
> + loff_t *);
>
> /* move_extent.c */
> extern void ext4_double_down_write_data_sem(struct inode *first,
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index 0c2432e..511db03 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -5811,3 +5811,378 @@ out_mutex:
> mutex_unlock(&inode->i_mutex);
> return ret;
> }
> +
> +/*
> + * If offset_lblk does not lie on the extent start boundary, split extent
> + */
> +int ext4_find_and_split_extent_at(struct inode *inode, ext4_lblk_t offset_lblk)
> +{
> + struct ext4_ext_path *path;
> + handle_t *handle;
> + int credits, err = 0, split_flag, ex_len;
> + struct ext4_extent *ex;
> + int depth = ext_depth(inode);
> + ext4_lblk_t ex_start;
> +
> + path = ext4_ext_find_extent(inode, offset_lblk, NULL, 0);
> + if (IS_ERR(path))
> + return PTR_ERR(path);
> +
> + ex = path[depth].p_ext;
> + if (!ex)
> + goto free_path;
> + ex_start = le32_to_cpu(ex->ee_block);
> + ex_len = ext4_ext_get_actual_len(ex);
> +
> + if (offset_lblk > ex_start && offset_lblk < (ex_start + ex_len)) {
> + credits = ext4_writepage_trans_blocks(inode);
> + handle = ext4_journal_start(inode, EXT4_HT_TRUNCATE, credits);
> + if (IS_ERR(handle)) {
> + err = PTR_ERR(handle);
> + goto free_path;
> + }
> + if (ext4_ext_is_unwritten(ex))
> + split_flag = EXT4_EXT_MARK_UNWRIT1 |
> + EXT4_EXT_MARK_UNWRIT2;
> + else
> + split_flag = 0;
> +
> + err = ext4_split_extent_at(handle, inode, path, offset_lblk,
> + split_flag, EXT4_EX_NOCACHE |
> + EXT4_GET_BLOCKS_PRE_IO);
> + ext4_journal_stop(handle);
> + }
> +
> +free_path:
> + ext4_ext_drop_refs(path);
> + kfree(path);
> + return err;
> +}
> +
> +/*
> + * Compute the size of hole in terms of filesystem blocks present at offset_lblk
> + * until the next extent is found OR till we reach the last block within isize.
> + * Store the computed value in hole_blkcnt.
> + * offset_lblk should be within isize of inode.
> + */
> +int ext4_compute_hole_size(struct inode *inode, ext4_lblk_t offset_lblk,
> + ext4_lblk_t *hole_blkcnt)
> +{
> + struct ext4_ext_path *path;
> + struct ext4_extent *ex;
> + ext4_lblk_t ex_start, isize_lblk;
> + int ret = 0, depth, ex_len;
> +
> + isize_lblk = (inode->i_size + EXT4_BLOCK_SIZE(inode->i_sb) - 1) >>
> + EXT4_BLOCK_SIZE_BITS(inode->i_sb);
> +
> + if (offset_lblk > isize_lblk)
> + return -EINVAL;
> +
> + *hole_blkcnt = 0;
> + path = ext4_ext_find_extent(inode, offset_lblk, NULL, 0);
> + if (IS_ERR(path))
> + return PTR_ERR(path);
> +
> + depth = ext_depth(inode);
> + ex = path[depth].p_ext;
> + if (!ex) {
> + /* No blocks allocated in this file */
> + *hole_blkcnt = isize_lblk - offset_lblk;
> + goto out;
> + }
> + ex_start = le32_to_cpu(ex->ee_block);
> + ex_len = ext4_ext_get_actual_len(ex);
> +
> + /* if offset_lblk lies within extent? */
> + if (offset_lblk >= ex_start && offset_lblk < (ex_start + ex_len))
> + goto out;
> +
> + if (ex_start < offset_lblk) {
> + ret = mext_next_extent(inode, path, &ex);
> + if (!ret) {
> + ex_start = le32_to_cpu(ex->ee_block);
> + } else {
> + if (ret == 1) {
> + *hole_blkcnt = isize_lblk - offset_lblk;
> + ret = 0;
> + }
> + goto out;
> + }
> + }
> + *hole_blkcnt = (ex_start < isize_lblk) ? (ex_start - offset_lblk) :
> + (isize_lblk - offset_lblk);
> +out:
> + ext4_ext_drop_refs(path);
> + kfree(path);
> +
> + return ret;
> +}
> +
> +/*
> + * Remove a complete extent from in memory and on-disk extent tree
> + * without freeing any data blocks covered by the extent. Caller must call
> + * ext4_mark_inode_dirty() to sync the changes to disk.
> + */
> +int ext4_ext_rm_extent(handle_t *handle, struct inode *inode,
> + struct ext4_ext_path *path, struct ext4_extent *ex)
> +{
> + struct ext4_extent_header *eh;
> + int depth = ext_depth(inode);
> + int credits, err, correct_index = 0;
> + int ex_ee_len = ext4_ext_get_actual_len(ex);
> +
> + if (!path[depth].p_hdr)
> + path[depth].p_hdr = ext_block_hdr(path[depth].p_bh);
> + eh = path[depth].p_hdr;
> +
> + credits = 7 + 2*(ex_ee_len/EXT4_BLOCKS_PER_GROUP(inode->i_sb));
> + if (ex == EXT_FIRST_EXTENT(eh)) {
> + correct_index = 1;
> + credits += (ext_depth(inode)) + 1;
> + }
> + credits += EXT4_MAXQUOTAS_TRANS_BLOCKS(inode->i_sb);
> + err = ext4_ext_truncate_extend_restart(handle, inode, credits);
> + if (err)
> + return err;
> +
> + err = ext4_ext_get_access(handle, inode, path + depth);
> + if (err)
> + return err;
> +
> + ext4_ext_store_pblock(ex, 0);
> + memmove(ex, ex+1,
> + (EXT_LAST_EXTENT(eh) - ex) * sizeof(struct ext4_extent));
> + memset(EXT_LAST_EXTENT(eh), 0, sizeof(struct ext4_extent));
> + le16_add_cpu(&eh->eh_entries, -1);
> +
> + err = ext4_ext_dirty(handle, inode, path + depth);
> + if (err)
> + return err;
> +
> + if (correct_index && eh->eh_entries)
> + err = ext4_ext_correct_indexes(handle, inode, path);
> +
> + if (err == 0 && eh->eh_entries == 0 && path[depth].p_bh != NULL)
> + err = ext4_ext_rm_idx(handle, inode, path, depth);
> +
> + return err;
> +}
> +
> +/*
> + * Move len_lblk amount of blocks from donor inode to receiver inode.
> + * Blocks are to be moved from doffset_lblk and moved to roffset_lblk.
> + * Caller of this function must make sure there is atleast len_lblk size
> + * hole at roffset_lblk. Also doffset_lblk and doffset_lblk + len_lblk
> + * should fall on extent boundary.
> + */
> +int ext4_ext_mov_data(struct inode *donor, struct inode *receiver,
> + ext4_lblk_t doffset_lblk, ext4_lblk_t roffset_lblk,
> + ext4_lblk_t len_lblk, loff_t *bytes_moved)
> +{
> + int error = 0, depth = ext_depth(donor);
> + struct ext4_ext_path *path;
> + struct ext4_extent *ex;
> + loff_t blocks_moved = 0;
> + handle_t *handle;
> + int credits = ext4_writepage_trans_blocks(donor) +
> + ext4_writepage_trans_blocks(receiver);
> +
> + while (blocks_moved < len_lblk && !error) {
> + struct ext4_ext_path *rpath = NULL;
> + ext4_lblk_t ex_start;
> + int ex_len;
> +
> + path = ext4_ext_find_extent(donor, doffset_lblk, NULL, 0);
> + if (IS_ERR(path)) {
> + error = PTR_ERR(path);
> + break;
> + }
> + ex = path[depth].p_ext;
> + /*
> + * No allocated blocks? This could only happen during
> + * 1st iteration. Otherwise it is en error.
> + */
> + if (!ex) {
> + if (blocks_moved)
> + error = -EIO;
> + else
> + blocks_moved = len_lblk;
> + goto out;
> + }
> + ex_start = le32_to_cpu(ex->ee_block);
> + ex_len = ext4_ext_get_actual_len(ex);
> +
> + if (doffset_lblk != ex_start) {
> + /* Hole within range, move to the next extent */
> + if (ex_start < doffset_lblk)
> + error = mext_next_extent(donor, path, &ex);
> + /* Below if will also handle ex_start > doffset_lblk */
> + if (error == 0) {
> + ex_start = le32_to_cpu(ex->ee_block);
> + blocks_moved += ex_start - doffset_lblk;
> + roffset_lblk += ex_start - doffset_lblk;
> + doffset_lblk = ex_start;
> + }
> + if (error == 1) {
> + /* doffset_lblk till EOF is hole. Success!! */
> + blocks_moved = len_lblk;
> + error = 0;
> + }
> + goto out;
> + }
> +
> + /* Add this extent to receiver */
> + handle = ext4_journal_start(donor, EXT4_HT_TRUNCATE, credits);
> + if (IS_ERR(handle)) {
> + error = PTR_ERR(handle);
> + goto out;
> + }
> +
> + rpath = ext4_ext_find_extent(receiver, roffset_lblk, NULL, 0);
> + if (IS_ERR(rpath)) {
> + error = PTR_ERR(rpath);
> + ext4_journal_stop(handle);
> + goto out;
> + }
> + ex->ee_block = cpu_to_le32(roffset_lblk);
> + error = ext4_ext_insert_extent(handle, receiver, rpath, ex, 0);
> + if (error)
> + goto hout;
> +
> + /* Remove this extent from donor */
> + error = ext4_ext_rm_extent(handle, donor, path, ex);
> + if (error)
> + goto hout;
> +
> + /* Extent moved successfully */
> + roffset_lblk += ex_len;
> + doffset_lblk += ex_len;
> + blocks_moved += ex_len;
> +
> + donor->i_blocks -= (ex_len << (donor->i_blkbits - 9));
> + receiver->i_blocks += (ex_len << (receiver->i_blkbits - 9));
> + donor->i_mtime = donor->i_ctime = ext4_current_time(donor);
> + receiver->i_mtime = receiver->i_ctime =
> + ext4_current_time(receiver);
> + ext4_mark_inode_dirty(handle, donor);
> + ext4_mark_inode_dirty(handle, receiver);
> +hout:
> + ext4_journal_stop(handle);
> + ext4_ext_drop_refs(rpath);
> + kfree(rpath);
> +out:
> + ext4_ext_drop_refs(path);
> + kfree(path);
> + }
> +
> + /* This can happen when (doffset_lblk + len_lblk) is in a hole */
> + if (blocks_moved > len_lblk)
> + blocks_moved = len_lblk;
> +
> + *bytes_moved = blocks_moved << EXT4_BLOCK_SIZE_BITS(donor->i_sb);
> + return error;
> +}
> +
> +int ext4_mov_data(struct inode *donor, struct inode *receiver, loff_t doffset,
> + loff_t roffset, loff_t len, loff_t *moved_len)
> +{
> + struct super_block *sb = donor->i_sb;
> + loff_t d_pg_off, r_pg_off, pg_len;
> + ext4_lblk_t doffset_lblk, roffset_lblk, len_lblk, hole_size;
> + int error;
> +
> + if (doffset & (EXT4_BLOCK_SIZE(sb) - 1) ||
> + roffset & (EXT4_BLOCK_SIZE(sb) - 1) ||
> + len & (EXT4_BLOCK_SIZE(sb) - 1))
> + return -EINVAL;
> +
> + if (EXT4_SB(sb)->s_cluster_ratio > 1)
> + return -EOPNOTSUPP;
> +
> + if (!ext4_test_inode_flag(donor, EXT4_INODE_EXTENTS) ||
> + !ext4_test_inode_flag(receiver, EXT4_INODE_EXTENTS))
> + return -EOPNOTSUPP;
> +
> + doffset_lblk = doffset >> EXT4_BLOCK_SIZE_BITS(sb);
> + roffset_lblk = roffset >> EXT4_BLOCK_SIZE_BITS(sb);
> + len_lblk = len >> EXT4_BLOCK_SIZE_BITS(sb);
> +
> + d_pg_off = round_down(doffset, PAGE_SIZE);
> + r_pg_off = round_down(roffset, PAGE_SIZE);
> + pg_len = round_up(len, PAGE_SIZE);
> +
> + if (ext4_should_journal_data(donor)) {
> + error = ext4_force_commit(donor->i_sb);
> + if (error)
> + return error;
> + error = ext4_force_commit(receiver->i_sb);
> + if (error)
> + return error;
> + }
> +
> + error = filemap_write_and_wait_range(donor->i_mapping,
> + d_pg_off, d_pg_off + pg_len);
> + if (error)
> + return error;
> + error = filemap_write_and_wait_range(receiver->i_mapping,
> + r_pg_off, r_pg_off + pg_len);
> + if (error)
> + return error;
> +
> + lock_two_nondirectories(donor, receiver);
> +
> + /* Check for isize limits for both files */
> + if (doffset + len > donor->i_size ||
> + roffset + len > receiver->i_size) {
> + error = -EINVAL;
> + goto out_mutex;
> + }
> +
> + truncate_pagecache_range(donor, d_pg_off, d_pg_off + pg_len - 1);
> + truncate_pagecache_range(receiver, r_pg_off, r_pg_off + pg_len - 1);
> +
> + ext4_inode_block_unlocked_dio(donor);
> + inode_dio_wait(donor);
> + ext4_inode_block_unlocked_dio(receiver);
> + inode_dio_wait(receiver);
> +
> + ext4_discard_preallocations(donor);
> + ext4_discard_preallocations(receiver);
> +
> + error = ext4_es_remove_extent(donor, doffset_lblk, len_lblk);
> + if (error)
> + goto out_sem;
> + error = ext4_es_remove_extent(receiver, roffset_lblk, len_lblk);
> + if (error)
> + goto out_sem;
> +
> + error = ext4_compute_hole_size(receiver, roffset_lblk, &hole_size);
> + if (error)
> + goto out_sem;
> + if (len_lblk > hole_size) {
> + error = -EINVAL;
> + goto out_sem;
> + }
> +
> + error = ext4_find_and_split_extent_at(donor, doffset_lblk);
> + if (error)
> + goto out_sem;
> +
> + error = ext4_find_and_split_extent_at(donor, doffset_lblk + len_lblk);
> + if (error)
> + goto out_sem;
> +
> + error = ext4_ext_mov_data(donor, receiver, doffset_lblk,
> + roffset_lblk, len_lblk, moved_len);
> +
> + ext4_discard_preallocations(donor);
> + ext4_discard_preallocations(receiver);
> +out_sem:
> + ext4_inode_resume_unlocked_dio(donor);
> + ext4_inode_resume_unlocked_dio(receiver);
> +
> +out_mutex:
> + unlock_two_nondirectories(donor, receiver);
> + return error;
> +}
> diff --git a/fs/ext4/file.c b/fs/ext4/file.c
> index 8695f70..d2feaba 100644
> --- a/fs/ext4/file.c
> +++ b/fs/ext4/file.c
> @@ -614,5 +614,6 @@ const struct inode_operations ext4_file_inode_operations = {
> .get_acl = ext4_get_acl,
> .set_acl = ext4_set_acl,
> .fiemap = ext4_fiemap,
> + .mov_data = ext4_mov_data,
> };
>
>
