On Tue, Feb 25, 2014 at 2:14 PM, Lukas Czerner <lczerner@xxxxxxxxxx> wrote:
> Introduce new FALLOC_FL_ZERO_RANGE flag for fallocate. This has the same
> functionality as xfs ioctl XFS_IOC_ZERO_RANGE.
>
> It can be used to convert a range of file to zeros preferably without
> issuing data IO. Blocks should be preallocated for the regions that span
> holes in the file, and the entire range is preferable converted to
> unwritten extents
>
> This can be also used to preallocate blocks past EOF in the same way as
> with fallocate. Flag FALLOC_FL_KEEP_SIZE which should cause the inode
> size to remain the same.
>
> Also add appropriate tracepoints.
>
> Signed-off-by: Lukas Czerner <lczerner@xxxxxxxxxx>
> ---
> fs/ext4/ext4.h | 2 +
> fs/ext4/extents.c | 270 +++++++++++++++++++++++++++++++++++++++++---
> fs/ext4/inode.c | 17 ++-
> include/trace/events/ext4.h | 64 +++++------
> 4 files changed, 300 insertions(+), 53 deletions(-)
>
> diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
> index 3b9601c..a649abe 100644
> --- a/fs/ext4/ext4.h
> +++ b/fs/ext4/ext4.h
> @@ -568,6 +568,8 @@ enum {
> #define EXT4_GET_BLOCKS_NO_LOCK 0x0100
> /* Do not put hole in extent cache */
> #define EXT4_GET_BLOCKS_NO_PUT_HOLE 0x0200
> + /* Convert written extents to unwritten */
> +#define EXT4_GET_BLOCKS_CONVERT_UNWRITTEN 0x0400
>
> /*
> * The bit position of these flags must not overlap with any of the
> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
> index e5485eb..017b4fb 100644
> --- a/fs/ext4/extents.c
> +++ b/fs/ext4/extents.c
> @@ -3568,6 +3568,8 @@ out:
> * b> Splits in two extents: Write is happening at either end of the extent
> * c> Splits in three extents: Somone is writing in middle of the extent
> *
> + * This works the same way in the case of initialized -> unwritten conversion.
> + *
> * One of more index blocks maybe needed if the extent tree grow after
> * the uninitialized extent split. To prevent ENOSPC occur at the IO
> * complete, we need to split the uninitialized extent before DIO submit
> @@ -3578,7 +3580,7 @@ out:
> *
> * Returns the size of uninitialized extent to be written on success.
> */
> -static int ext4_split_unwritten_extents(handle_t *handle,
> +static int ext4_split_convert_extents(handle_t *handle,
> struct inode *inode,
> struct ext4_map_blocks *map,
> struct ext4_ext_path *path,
> @@ -3590,9 +3592,9 @@ static int ext4_split_unwritten_extents(handle_t *handle,
> unsigned int ee_len;
> int split_flag = 0, depth;
>
> - ext_debug("ext4_split_unwritten_extents: inode %lu, logical"
> - "block %llu, max_blocks %u\n", inode->i_ino,
> - (unsigned long long)map->m_lblk, map->m_len);
> + ext_debug("%s: inode %lu, logical block %llu, max_blocks %u\n",
> + __func__, inode->i_ino,
> + (unsigned long long)map->m_lblk, map->m_len);
>
> eof_block = (inode->i_size + inode->i_sb->s_blocksize - 1) >>
> inode->i_sb->s_blocksize_bits;
> @@ -3607,14 +3609,73 @@ static int ext4_split_unwritten_extents(handle_t *handle,
> ee_block = le32_to_cpu(ex->ee_block);
> ee_len = ext4_ext_get_actual_len(ex);
>
> - split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
> - split_flag |= EXT4_EXT_MARK_UNINIT2;
> - if (flags & EXT4_GET_BLOCKS_CONVERT)
> - split_flag |= EXT4_EXT_DATA_VALID2;
> + /* Convert to unwritten */
> + if (flags | EXT4_GET_BLOCKS_CONVERT_UNWRITTEN) {
> + split_flag |= EXT4_EXT_DATA_VALID1;
> + /* Convert to initialized */
> + } else if (flags | EXT4_GET_BLOCKS_CONVERT) {
> + split_flag |= ee_block + ee_len <= eof_block ?
> + EXT4_EXT_MAY_ZEROOUT : 0;
> + split_flag |= (EXT4_EXT_MARK_UNINIT2 & EXT4_EXT_DATA_VALID2);
> + }
> flags |= EXT4_GET_BLOCKS_PRE_IO;
> return ext4_split_extent(handle, inode, path, map, split_flag, flags);
> }
>
> +static int ext4_convert_initialized_extents(handle_t *handle,
> + struct inode *inode,
> + struct ext4_map_blocks *map,
> + struct ext4_ext_path *path)
> +{
> + struct ext4_extent *ex;
> + ext4_lblk_t ee_block;
> + unsigned int ee_len;
> + int depth;
> + int err = 0;
> +
> + depth = ext_depth(inode);
> + ex = path[depth].p_ext;
> + ee_block = le32_to_cpu(ex->ee_block);
> + ee_len = ext4_ext_get_actual_len(ex);
> +
> + ext_debug("%s: inode %lu, logical"
> + "block %llu, max_blocks %u\n", __func__, inode->i_ino,
> + (unsigned long long)ee_block, ee_len);
> +
> + if (ee_block != map->m_lblk || ee_len > map->m_len) {
> + err = ext4_split_convert_extents(handle, inode, map, path,
> + EXT4_GET_BLOCKS_CONVERT_UNWRITTEN);
> + if (err < 0)
> + goto out;
> + ext4_ext_drop_refs(path);
> + path = ext4_ext_find_extent(inode, map->m_lblk, path, 0);
> + if (IS_ERR(path)) {
> + err = PTR_ERR(path);
> + goto out;
> + }
> + depth = ext_depth(inode);
> + ex = path[depth].p_ext;
> + }
> +
> + err = ext4_ext_get_access(handle, inode, path + depth);
> + if (err)
> + goto out;
> + /* first mark the extent as uninitialized */
> + ext4_ext_mark_uninitialized(ex);
> +
> + /* note: ext4_ext_correct_indexes() isn't needed here because
> + * borders are not changed
> + */
> + ext4_ext_try_to_merge(handle, inode, path, ex);
> +
> + /* Mark modified extent as dirty */
> + err = ext4_ext_dirty(handle, inode, path + path->p_depth);
> +out:
> + ext4_ext_show_leaf(inode, path);
> + return err;
> +}
> +
> +
> static int ext4_convert_unwritten_extents_endio(handle_t *handle,
> struct inode *inode,
> struct ext4_map_blocks *map,
> @@ -3648,8 +3709,8 @@ static int ext4_convert_unwritten_extents_endio(handle_t *handle,
> inode->i_ino, (unsigned long long)ee_block, ee_len,
> (unsigned long long)map->m_lblk, map->m_len);
> #endif
> - err = ext4_split_unwritten_extents(handle, inode, map, path,
> - EXT4_GET_BLOCKS_CONVERT);
> + err = ext4_split_convert_extents(handle, inode, map, path,
> + EXT4_GET_BLOCKS_CONVERT);
> if (err < 0)
> goto out;
> ext4_ext_drop_refs(path);
> @@ -3850,6 +3911,42 @@ get_reserved_cluster_alloc(struct inode *inode, ext4_lblk_t lblk_start,
> }
>
> static int
> +ext4_ext_convert_initialized_extent(handle_t *handle, struct inode *inode,
> + struct ext4_map_blocks *map,
> + struct ext4_ext_path *path, int flags,
> + unsigned int allocated, ext4_fsblk_t newblock)
> +{
> + int ret = 0;
> + int err = 0;
> +
> + /*
> + * Make sure that the extent is no bigger than we support with
> + * uninitialized extent
> + */
> + if (map->m_len > EXT_UNINIT_MAX_LEN)
> + map->m_len = EXT_UNINIT_MAX_LEN / 2;
Pardon my possible dumb question. Why do you use "EXT_UNINIT_MAX_LEN
/ 2;" here instead of "EXT_UNINIT_MAX_LEN"
I don't see the reason why we can't use EXT_UNINIT_MAX_LEN here.
Thanks!
Jon
> +
> + ret = ext4_convert_initialized_extents(handle, inode, map,
> + path);
> + if (ret >= 0) {
> + ext4_update_inode_fsync_trans(handle, inode, 1);
> + err = check_eofblocks_fl(handle, inode, map->m_lblk,
> + path, map->m_len);
> + } else
> + err = ret;
> + map->m_flags |= EXT4_MAP_UNWRITTEN;
> + if (allocated > map->m_len)
> + allocated = map->m_len;
> + map->m_len = allocated;
> +
> + if (path) {
> + ext4_ext_drop_refs(path);
> + kfree(path);
> + }
> + return err ? err : allocated;
> +}
> +
> +static int
> ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
> struct ext4_map_blocks *map,
> struct ext4_ext_path *path, int flags,
> @@ -3876,8 +3973,8 @@ ext4_ext_handle_uninitialized_extents(handle_t *handle, struct inode *inode,
>
> /* get_block() before submit the IO, split the extent */
> if ((flags & EXT4_GET_BLOCKS_PRE_IO)) {
> - ret = ext4_split_unwritten_extents(handle, inode, map,
> - path, flags);
> + ret = ext4_split_convert_extents(handle, inode, map,
> + path, flags | EXT4_GET_BLOCKS_CONVERT);
> if (ret <= 0)
> goto out;
> /*
> @@ -4168,6 +4265,7 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
> ext4_fsblk_t ee_start = ext4_ext_pblock(ex);
> unsigned short ee_len;
>
> +
> /*
> * Uninitialized extents are treated as holes, except that
> * we split out initialized portions during a write.
> @@ -4184,7 +4282,17 @@ int ext4_ext_map_blocks(handle_t *handle, struct inode *inode,
> ext_debug("%u fit into %u:%d -> %llu\n", map->m_lblk,
> ee_block, ee_len, newblock);
>
> - if (!ext4_ext_is_uninitialized(ex))
> + /*
> + * If the extent is initialized check whether the
> + * caller wants to convert it to unwritten.
> + */
> + if ((!ext4_ext_is_uninitialized(ex)) &&
> + (flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN)) {
> + allocated = ext4_ext_convert_initialized_extent(
> + handle, inode, map, path, flags,
> + allocated, newblock);
> + goto out3;
> + } else if (!ext4_ext_is_uninitialized(ex))
> goto out;
>
> allocated = ext4_ext_handle_uninitialized_extents(
> @@ -4570,6 +4678,136 @@ retry:
> return ret > 0 ? ret2 : ret;
> }
>
> +static long ext4_zero_range(struct file *file, loff_t offset,
> + loff_t len, int mode)
> +{
> + struct inode *inode = file_inode(file);
> + handle_t *handle = NULL;
> + unsigned int max_blocks;
> + loff_t new_size = 0;
> + int ret = 0;
> + int flags;
> + int partial;
> + loff_t start, end;
> + ext4_lblk_t lblk;
> + struct address_space *mapping = inode->i_mapping;
> + unsigned int blkbits = inode->i_blkbits;
> +
> + trace_ext4_zero_range(inode, offset, len, mode);
> +
> + /*
> + * Write out all dirty pages to avoid race conditions
> + * Then release them.
> + */
> + if (mapping->nrpages && mapping_tagged(mapping, PAGECACHE_TAG_DIRTY)) {
> + ret = filemap_write_and_wait_range(mapping, offset,
> + offset + len - 1);
> + if (ret)
> + return ret;
> + }
> +
> + /*
> + * Round up offset. This is not fallocate, we neet to zero out
> + * blocks, so convert interior block aligned part of the range to
> + * unwritten and possibly manually zero out unaligned parts of the
> + * range.
> + */
> + start = round_up(offset, 1 << blkbits);
> + end = round_down((offset + len), 1 << blkbits);
> +
> + if (start < offset || end > offset + len)
> + return -EINVAL;
> + partial = (offset + len) & ((1 << blkbits) - 1);
> +
> + lblk = start >> blkbits;
> + max_blocks = (end >> blkbits);
> + if (max_blocks < lblk)
> + max_blocks = 0;
> + else
> + max_blocks -= lblk;
> +
> + flags = EXT4_GET_BLOCKS_CREATE_UNINIT_EXT |
> + EXT4_GET_BLOCKS_CONVERT_UNWRITTEN;
> + if (mode & FALLOC_FL_KEEP_SIZE)
> + flags |= EXT4_GET_BLOCKS_KEEP_SIZE;
> +
> + mutex_lock(&inode->i_mutex);
> +
> + /*
> + * Indirect files do not support unwritten extnets
> + */
> + if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
> + ret = -EOPNOTSUPP;
> + goto out_mutex;
> + }
> +
> + if (!(mode & FALLOC_FL_KEEP_SIZE) &&
> + offset + len > i_size_read(inode)) {
> + new_size = offset + len;
> + ret = inode_newsize_ok(inode, new_size);
> + if (ret)
> + goto out_mutex;
> + /*
> + * If we have a partial block after EOF we have to allocate
> + * the entire block.
> + */
> + if (partial)
> + max_blocks += 1;
> + }
> +
> + if (max_blocks > 0) {
> +
> + /* Now release the pages and zero block aligned part of pages*/
> + truncate_pagecache_range(inode, start, end - 1);
> +
> + /* Wait all existing dio workers, newcomers will block on i_mutex */
> + ext4_inode_block_unlocked_dio(inode);
> + inode_dio_wait(inode);
> +
> + /*
> + * Remove entire range from the extent status tree.
> + */
> + ret = ext4_es_remove_extent(inode, lblk, max_blocks);
> + if (ret)
> + goto out_dio;
> +
> + ret = ext4_alloc_file_blocks(file, lblk, max_blocks, flags,
> + mode);
> + if (ret)
> + goto out_dio;
> + }
> +
> + handle = ext4_journal_start(inode, EXT4_HT_MISC, 4);
> + if (IS_ERR(handle)) {
> + ret = PTR_ERR(handle);
> + ext4_std_error(inode->i_sb, ret);
> + goto out_dio;
> + }
> +
> + inode->i_mtime = inode->i_ctime = ext4_current_time(inode);
> +
> + if (!ret && new_size) {
> + if (new_size > i_size_read(inode))
> + i_size_write(inode, new_size);
> + if (new_size > EXT4_I(inode)->i_disksize)
> + ext4_update_i_disksize(inode, new_size);
> + }
> + ext4_mark_inode_dirty(handle, inode);
> +
> + /* Zero out partial block at the edges of the range */
> + ret = ext4_zero_partial_blocks(handle, inode, offset, len);
> +
> + if (file->f_flags & O_SYNC)
> + ext4_handle_sync(handle);
> +
> + ext4_journal_stop(handle);
> +out_dio:
> + ext4_inode_resume_unlocked_dio(inode);
> +out_mutex:
> + mutex_unlock(&inode->i_mutex);
> + return ret;
> +}
> +
> /*
> * preallocate space for a file. This implements ext4's fallocate file
> * operation, which gets called from sys_fallocate system call.
> @@ -4590,7 +4828,8 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
> unsigned int blkbits = inode->i_blkbits;
>
> /* Return error if mode is not supported */
> - if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE))
> + if (mode & ~(FALLOC_FL_KEEP_SIZE | FALLOC_FL_PUNCH_HOLE |
> + FALLOC_FL_ZERO_RANGE))
> return -EOPNOTSUPP;
>
> if (mode & FALLOC_FL_PUNCH_HOLE)
> @@ -4607,6 +4846,9 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
> if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
> return -EOPNOTSUPP;
>
> + if (mode & FALLOC_FL_ZERO_RANGE)
> + return ext4_zero_range(file, offset, len, mode);
> +
> trace_ext4_fallocate_enter(inode, offset, len, mode);
> lblk = offset >> blkbits;
> /*
> diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
> index 6e39895..e64807f 100644
> --- a/fs/ext4/inode.c
> +++ b/fs/ext4/inode.c
> @@ -503,6 +503,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
> {
> struct extent_status es;
> int retval;
> + int ret = 0;
> #ifdef ES_AGGRESSIVE_TEST
> struct ext4_map_blocks orig_map;
>
> @@ -552,7 +553,6 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
> EXT4_GET_BLOCKS_KEEP_SIZE);
> }
> if (retval > 0) {
> - int ret;
> unsigned int status;
>
> if (unlikely(retval != map->m_len)) {
> @@ -579,7 +579,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
>
> found:
> if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
> - int ret = check_block_validity(inode, map);
> + ret = check_block_validity(inode, map);
> if (ret != 0)
> return ret;
> }
> @@ -596,7 +596,13 @@ found:
> * with buffer head unmapped.
> */
> if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED)
> - return retval;
> + /*
> + * If we need to convert extent to unwritten
> + * we continue and do the actual work in
> + * ext4_ext_map_blocks()
> + */
> + if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
> + return retval;
>
> /*
> * Here we clear m_flags because after allocating an new extent,
> @@ -652,7 +658,6 @@ found:
> ext4_clear_inode_state(inode, EXT4_STATE_DELALLOC_RESERVED);
>
> if (retval > 0) {
> - int ret;
> unsigned int status;
>
> if (unlikely(retval != map->m_len)) {
> @@ -687,7 +692,7 @@ found:
> has_zeroout:
> up_write((&EXT4_I(inode)->i_data_sem));
> if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
> - int ret = check_block_validity(inode, map);
> + ret = check_block_validity(inode, map);
> if (ret != 0)
> return ret;
> }
> @@ -3501,7 +3506,7 @@ int ext4_punch_hole(struct inode *inode, loff_t offset, loff_t length)
> if (!S_ISREG(inode->i_mode))
> return -EOPNOTSUPP;
>
> - trace_ext4_punch_hole(inode, offset, length);
> + trace_ext4_punch_hole(inode, offset, length, 0);
>
> /*
> * Write out all dirty pages to avoid race conditions
> diff --git a/include/trace/events/ext4.h b/include/trace/events/ext4.h
> index 451e020..7bb26aa 100644
> --- a/include/trace/events/ext4.h
> +++ b/include/trace/events/ext4.h
> @@ -71,7 +71,8 @@ struct extent_status;
> #define show_falloc_mode(mode) __print_flags(mode, "|", \
> { FALLOC_FL_KEEP_SIZE, "KEEP_SIZE"}, \
> { FALLOC_FL_PUNCH_HOLE, "PUNCH_HOLE"}, \
> - { FALLOC_FL_NO_HIDE_STALE, "NO_HIDE_STALE"})
> + { FALLOC_FL_NO_HIDE_STALE, "NO_HIDE_STALE"}, \
> + { FALLOC_FL_ZERO_RANGE, "ZERO_RANGE"})
>
>
> TRACE_EVENT(ext4_free_inode,
> @@ -1333,7 +1334,7 @@ TRACE_EVENT(ext4_direct_IO_exit,
> __entry->rw, __entry->ret)
> );
>
> -TRACE_EVENT(ext4_fallocate_enter,
> +DECLARE_EVENT_CLASS(ext4__fallocate_mode,
> TP_PROTO(struct inode *inode, loff_t offset, loff_t len, int mode),
>
> TP_ARGS(inode, offset, len, mode),
> @@ -1341,23 +1342,45 @@ TRACE_EVENT(ext4_fallocate_enter,
> TP_STRUCT__entry(
> __field( dev_t, dev )
> __field( ino_t, ino )
> - __field( loff_t, pos )
> - __field( loff_t, len )
> + __field( loff_t, offset )
> + __field( loff_t, len )
> __field( int, mode )
> ),
>
> TP_fast_assign(
> __entry->dev = inode->i_sb->s_dev;
> __entry->ino = inode->i_ino;
> - __entry->pos = offset;
> + __entry->offset = offset;
> __entry->len = len;
> __entry->mode = mode;
> ),
>
> - TP_printk("dev %d,%d ino %lu pos %lld len %lld mode %s",
> + TP_printk("dev %d,%d ino %lu offset %lld len %lld mode %s",
> MAJOR(__entry->dev), MINOR(__entry->dev),
> - (unsigned long) __entry->ino, __entry->pos,
> - __entry->len, show_falloc_mode(__entry->mode))
> + (unsigned long) __entry->ino,
> + __entry->offset, __entry->len,
> + show_falloc_mode(__entry->mode))
> +);
> +
> +DEFINE_EVENT(ext4__fallocate_mode, ext4_fallocate_enter,
> +
> + TP_PROTO(struct inode *inode, loff_t offset, loff_t len, int mode),
> +
> + TP_ARGS(inode, offset, len, mode)
> +);
> +
> +DEFINE_EVENT(ext4__fallocate_mode, ext4_punch_hole,
> +
> + TP_PROTO(struct inode *inode, loff_t offset, loff_t len, int mode),
> +
> + TP_ARGS(inode, offset, len, mode)
> +);
> +
> +DEFINE_EVENT(ext4__fallocate_mode, ext4_zero_range,
> +
> + TP_PROTO(struct inode *inode, loff_t offset, loff_t len, int mode),
> +
> + TP_ARGS(inode, offset, len, mode)
> );
>
> TRACE_EVENT(ext4_fallocate_exit,
> @@ -1389,31 +1412,6 @@ TRACE_EVENT(ext4_fallocate_exit,
> __entry->ret)
> );
>
> -TRACE_EVENT(ext4_punch_hole,
> - TP_PROTO(struct inode *inode, loff_t offset, loff_t len),
> -
> - TP_ARGS(inode, offset, len),
> -
> - TP_STRUCT__entry(
> - __field( dev_t, dev )
> - __field( ino_t, ino )
> - __field( loff_t, offset )
> - __field( loff_t, len )
> - ),
> -
> - TP_fast_assign(
> - __entry->dev = inode->i_sb->s_dev;
> - __entry->ino = inode->i_ino;
> - __entry->offset = offset;
> - __entry->len = len;
> - ),
> -
> - TP_printk("dev %d,%d ino %lu offset %lld len %lld",
> - MAJOR(__entry->dev), MINOR(__entry->dev),
> - (unsigned long) __entry->ino,
> - __entry->offset, __entry->len)
> -);
> -
> TRACE_EVENT(ext4_unlink_enter,
> TP_PROTO(struct inode *parent, struct dentry *dentry),
>
> --
> 1.8.3.1
>
> --
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