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Message-ID: <BANLkTinA-6tuZVoc6qrS-LVmgE5HKbhnog@mail.gmail.com>
Date: Fri, 13 May 2011 10:31:44 +0800
From: Yongqiang Yang <xiaoqiangnk@...il.com>
To: Mingming Cao <cmm@...ibm.com>
Cc: achender@...ux.vnet.ibm.com, linux-ext4@...r.kernel.org,
tytso@....edu
Subject: Re: [PATCH v2 3/3] ext4:Reimplement convert and split_unwritten.
On Fri, May 13, 2011 at 10:18 AM, Mingming Cao <cmm@...ibm.com> wrote:
> On Fri, 2011-05-13 at 10:06 +0800, Yongqiang Yang wrote:
>> On Fri, May 13, 2011 at 5:26 AM, Mingming Cao <cmm@...ibm.com> wrote:
>> > On Mon, 2011-05-02 at 19:05 -0700, Yongqiang Yang wrote:
>> >> v0->v1:
>> >> -- ext4_ext_convert_initialized() zeroout whole extent when the extent's
>> >> length is less than 14.
>> >>
>> >> convert and split unwritten are reimplemented based on ext4_split_extent()
>> >> added in last patch.
>> >>
>> >> Signed-off-by: Yongqiang Yang <xiaoqiangnk@...il.com>
>> >> Tested-by: Allison Henderson <achender@...ux.vnet.ibm.com>
>> >> ---
>> >> fs/ext4/extents.c | 480 ++++++++---------------------------------------------
>> >> 1 files changed, 72 insertions(+), 408 deletions(-)
>> >>
>> >> diff --git a/fs/ext4/extents.c b/fs/ext4/extents.c
>> >> index db1d67c..9e7c7b3 100644
>> >> --- a/fs/ext4/extents.c
>> >> +++ b/fs/ext4/extents.c
>> >> @@ -2757,17 +2757,13 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
>> >> struct ext4_map_blocks *map,
>> >> struct ext4_ext_path *path)
>> >> {
>> >> - struct ext4_extent *ex, newex, orig_ex;
>> >> - struct ext4_extent *ex1 = NULL;
>> >> - struct ext4_extent *ex2 = NULL;
>> >> - struct ext4_extent *ex3 = NULL;
>> >> - struct ext4_extent_header *eh;
>> >> + struct ext4_map_blocks split_map;
>> >> + struct ext4_extent zero_ex;
>> >> + struct ext4_extent *ex;
>> >> ext4_lblk_t ee_block, eof_block;
>> >> unsigned int allocated, ee_len, depth;
>> >> - ext4_fsblk_t newblock;
>> >> int err = 0;
>> >> - int ret = 0;
>> >> - int may_zeroout;
>> >> + int split_flag = 0;
>> >>
>> >> ext_debug("ext4_ext_convert_to_initialized: inode %lu, logical"
>> >> "block %llu, max_blocks %u\n", inode->i_ino,
>> >> @@ -2779,280 +2775,87 @@ static int ext4_ext_convert_to_initialized(handle_t *handle,
>> >> eof_block = map->m_lblk + map->m_len;
>> >>
>> >> depth = ext_depth(inode);
>> >> - eh = path[depth].p_hdr;
>> >> ex = path[depth].p_ext;
>> >> ee_block = le32_to_cpu(ex->ee_block);
>> >> ee_len = ext4_ext_get_actual_len(ex);
>> >> allocated = ee_len - (map->m_lblk - ee_block);
>> >> - newblock = map->m_lblk - ee_block + ext4_ext_pblock(ex);
>> >> -
>> >> - ex2 = ex;
>> >> - orig_ex.ee_block = ex->ee_block;
>> >> - orig_ex.ee_len = cpu_to_le16(ee_len);
>> >> - ext4_ext_store_pblock(&orig_ex, ext4_ext_pblock(ex));
>> >>
>> >> + WARN_ON(map->m_lblk < ee_block);
>> >> /*
>> >> * It is safe to convert extent to initialized via explicit
>> >> * zeroout only if extent is fully insde i_size or new_size.
>> >> */
>> >> - may_zeroout = ee_block + ee_len <= eof_block;
>> >> + split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
>> >>
>> >> - err = ext4_ext_get_access(handle, inode, path + depth);
>> >> - if (err)
>> >> - goto out;
>> >> /* If extent has less than 2*EXT4_EXT_ZERO_LEN zerout directly */
>> >> - if (ee_len <= 2*EXT4_EXT_ZERO_LEN && may_zeroout) {
>> >> - err = ext4_ext_zeroout(inode, &orig_ex);
>> >> + if (ee_len <= 2*EXT4_EXT_ZERO_LEN &&
>> >> + (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
>> >> + err = ext4_ext_zeroout(inode, ex);
>> >> if (err)
>> >> - goto fix_extent_len;
>> >> - /* update the extent length and mark as initialized */
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - /* zeroed the full extent */
>> >> - return allocated;
>> >> - }
>> >> -
>> >> - /* ex1: ee_block to map->m_lblk - 1 : uninitialized */
>> >> - if (map->m_lblk > ee_block) {
>> >> - ex1 = ex;
>> >> - ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
>> >> - ext4_ext_mark_uninitialized(ex1);
>> >> - ex2 = &newex;
>> >> - }
>> >> - /*
>> >> - * for sanity, update the length of the ex2 extent before
>> >> - * we insert ex3, if ex1 is NULL. This is to avoid temporary
>> >> - * overlap of blocks.
>> >> - */
>> >> - if (!ex1 && allocated > map->m_len)
>> >> - ex2->ee_len = cpu_to_le16(map->m_len);
>> >> - /* ex3: to ee_block + ee_len : uninitialised */
>> >> - if (allocated > map->m_len) {
>> >> - unsigned int newdepth;
>> >> - /* If extent has less than EXT4_EXT_ZERO_LEN zerout directly */
>> >> - if (allocated <= EXT4_EXT_ZERO_LEN && may_zeroout) {
>> >> - /*
>> >> - * map->m_lblk == ee_block is handled by the zerouout
>> >> - * at the beginning.
>> >> - * Mark first half uninitialized.
>> >> - * Mark second half initialized and zero out the
>> >> - * initialized extent
>> >> - */
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = cpu_to_le16(ee_len - allocated);
>> >> - ext4_ext_mark_uninitialized(ex);
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> -
>> >> - ex3 = &newex;
>> >> - ex3->ee_block = cpu_to_le32(map->m_lblk);
>> >> - ext4_ext_store_pblock(ex3, newblock);
>> >> - ex3->ee_len = cpu_to_le16(allocated);
>> >> - err = ext4_ext_insert_extent(handle, inode, path,
>> >> - ex3, 0);
>> >> - if (err == -ENOSPC) {
>> >> - err = ext4_ext_zeroout(inode, &orig_ex);
>> >> - if (err)
>> >> - goto fix_extent_len;
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex,
>> >> - ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - /* blocks available from map->m_lblk */
>> >> - return allocated;
>> >> -
>> >> - } else if (err)
>> >> - goto fix_extent_len;
>> >> -
>> >> - /*
>> >> - * We need to zero out the second half because
>> >> - * an fallocate request can update file size and
>> >> - * converting the second half to initialized extent
>> >> - * implies that we can leak some junk data to user
>> >> - * space.
>> >> - */
>> >> - err = ext4_ext_zeroout(inode, ex3);
>> >> - if (err) {
>> >> - /*
>> >> - * We should actually mark the
>> >> - * second half as uninit and return error
>> >> - * Insert would have changed the extent
>> >> - */
>> >> - depth = ext_depth(inode);
>> >> - ext4_ext_drop_refs(path);
>> >> - path = ext4_ext_find_extent(inode, map->m_lblk,
>> >> - path);
>> >> - if (IS_ERR(path)) {
>> >> - err = PTR_ERR(path);
>> >> - return err;
>> >> - }
>> >> - /* get the second half extent details */
>> >> - ex = path[depth].p_ext;
>> >> - err = ext4_ext_get_access(handle, inode,
>> >> - path + depth);
>> >> - if (err)
>> >> - return err;
>> >> - ext4_ext_mark_uninitialized(ex);
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - return err;
>> >> - }
>> >> -
>> >> - /* zeroed the second half */
>> >> - return allocated;
>> >> - }
>> >> - ex3 = &newex;
>> >> - ex3->ee_block = cpu_to_le32(map->m_lblk + map->m_len);
>> >> - ext4_ext_store_pblock(ex3, newblock + map->m_len);
>> >> - ex3->ee_len = cpu_to_le16(allocated - map->m_len);
>> >> - ext4_ext_mark_uninitialized(ex3);
>> >> - err = ext4_ext_insert_extent(handle, inode, path, ex3, 0);
>> >> - if (err == -ENOSPC && may_zeroout) {
>> >> - err = ext4_ext_zeroout(inode, &orig_ex);
>> >> - if (err)
>> >> - goto fix_extent_len;
>> >> - /* update the extent length and mark as initialized */
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - /* zeroed the full extent */
>> >> - /* blocks available from map->m_lblk */
>> >> - return allocated;
>> >> -
>> >> - } else if (err)
>> >> - goto fix_extent_len;
>> >> - /*
>> >> - * The depth, and hence eh & ex might change
>> >> - * as part of the insert above.
>> >> - */
>> >> - newdepth = ext_depth(inode);
>> >> - /*
>> >> - * update the extent length after successful insert of the
>> >> - * split extent
>> >> - */
>> >> - ee_len -= ext4_ext_get_actual_len(ex3);
>> >> - orig_ex.ee_len = cpu_to_le16(ee_len);
>> >> - may_zeroout = ee_block + ee_len <= eof_block;
>> >> -
>> >> - depth = newdepth;
>> >> - ext4_ext_drop_refs(path);
>> >> - path = ext4_ext_find_extent(inode, map->m_lblk, path);
>> >> - if (IS_ERR(path)) {
>> >> - err = PTR_ERR(path);
>> >> goto out;
>> >> - }
>> >> - eh = path[depth].p_hdr;
>> >> - ex = path[depth].p_ext;
>> >> - if (ex2 != &newex)
>> >> - ex2 = ex;
>> >>
>> >> err = ext4_ext_get_access(handle, inode, path + depth);
>> >> if (err)
>> >> goto out;
>> >> -
>> >> - allocated = map->m_len;
>> >> -
>> >> - /* If extent has less than EXT4_EXT_ZERO_LEN and we are trying
>> >> - * to insert a extent in the middle zerout directly
>> >> - * otherwise give the extent a chance to merge to left
>> >> - */
>> >> - if (le16_to_cpu(orig_ex.ee_len) <= EXT4_EXT_ZERO_LEN &&
>> >> - map->m_lblk != ee_block && may_zeroout) {
>> >> - err = ext4_ext_zeroout(inode, &orig_ex);
>> >> - if (err)
>> >> - goto fix_extent_len;
>> >> - /* update the extent length and mark as initialized */
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - /* zero out the first half */
>> >> - /* blocks available from map->m_lblk */
>> >> - return allocated;
>> >> - }
>> >> - }
>> >> - /*
>> >> - * If there was a change of depth as part of the
>> >> - * insertion of ex3 above, we need to update the length
>> >> - * of the ex1 extent again here
>> >> - */
>> >> - if (ex1 && ex1 != ex) {
>> >> - ex1 = ex;
>> >> - ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
>> >> - ext4_ext_mark_uninitialized(ex1);
>> >> - ex2 = &newex;
>> >> - }
>> >> - /* ex2: map->m_lblk to map->m_lblk + maxblocks-1 : initialised */
>> >> - ex2->ee_block = cpu_to_le32(map->m_lblk);
>> >> - ext4_ext_store_pblock(ex2, newblock);
>> >> - ex2->ee_len = cpu_to_le16(allocated);
>> >> - if (ex2 != ex)
>> >> - goto insert;
>> >> - /*
>> >> - * New (initialized) extent starts from the first block
>> >> - * in the current extent. i.e., ex2 == ex
>> >> - * We have to see if it can be merged with the extent
>> >> - * on the left.
>> >> - */
>> >> - if (ex2 > EXT_FIRST_EXTENT(eh)) {
>> >> - /*
>> >> - * To merge left, pass "ex2 - 1" to try_to_merge(),
>> >> - * since it merges towards right _only_.
>> >> - */
>> >> - ret = ext4_ext_try_to_merge(inode, path, ex2 - 1);
>> >> - if (ret) {
>> >> - err = ext4_ext_correct_indexes(handle, inode, path);
>> >> - if (err)
>> >> - goto out;
>> >> - depth = ext_depth(inode);
>> >> - ex2--;
>> >> - }
>> >> + ext4_ext_mark_initialized(ex);
>> >> + ext4_ext_try_to_merge(inode, path, ex);
>> >> + err = ext4_ext_dirty(handle, inode, path + depth);
>> >> + goto out;
>> >> }
>> >> +
>> >> /*
>> >> - * Try to Merge towards right. This might be required
>> >> - * only when the whole extent is being written to.
>> >> - * i.e. ex2 == ex and ex3 == NULL.
>> >> + * four cases:
>> >> + * 1. split the extent into three extents.
>> >> + * 2. split the extent into two extents, zeroout the first half.
>> >> + * 3. split the extent into two extents, zeroout the second half.
>> >> + * 4. split the extent into two extents with out zeroout.
>> >> */
>> >> - if (!ex3) {
>> >> - ret = ext4_ext_try_to_merge(inode, path, ex2);
>> >> - if (ret) {
>> >> - err = ext4_ext_correct_indexes(handle, inode, path);
>> >> + split_map.m_lblk = map->m_lblk;
>> >> + split_map.m_len = map->m_len;
>> >> +
>> >> + if (allocated > map->m_len) {
>> >> + if (allocated <= EXT4_EXT_ZERO_LEN &&
>> >> + (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
>> >> + /* case 3 */
>> >> + zero_ex.ee_block =
>> >> + cpu_to_le32(map->m_lblk + map->m_len);
>> >> + zero_ex.ee_len = cpu_to_le16(allocated - map->m_len);
>> > Hmm, the original code zero out the entire [map->m_lblk, allocated],
>> > where here we only zero out a portion of it. it doesnt match the split
>> > len below also.
>> Yeah, I just zero out a portion of it which is not the requested. I
>> think the requested part will have non-zero data.
>
> The requested part is going to be written with data, but since the
> entire [map->m_lblk, allocated] is a relatively small range(<7 blocks),
> the cost of zero out this small range is pretty much the same as zero
> out a portion of it. The saving is, we dont have to the split and
> convert the request part from uninitialized to initialized when the
> overwritten data reach to disk.
Yeah, this patch just zeros a portion of it and [map->m_lblk,
allocated] are converted to initialized.
BTW: I think zeroout can be optimized by zeroing data in pagecache
instead zeroout in disk directly. What's your opinion? It is worth
to do or not?
>
> Mingming
>
>> >
>> >
>> >> + ext4_ext_store_pblock(&zero_ex,
>> >> + ext4_ext_pblock(ex) + map->m_lblk - ee_block);
>> >> + err = ext4_ext_zeroout(inode, &zero_ex);
>> >> if (err)
>> >> goto out;
>> >> + split_map.m_lblk = map->m_lblk;
>> >> + split_map.m_len = allocated;
>> >> + } else if ((map->m_lblk - ee_block + map->m_len <
>> >> + EXT4_EXT_ZERO_LEN) &&
>> >> + (EXT4_EXT_MAY_ZEROOUT & split_flag)) {
>> >> + /* case 2 */
>> >> + if (map->m_lblk != ee_block) {
>> >> + zero_ex.ee_block = ex->ee_block;
>> >> + zero_ex.ee_len = cpu_to_le16(map->m_lblk -
>> >> + ee_block);
>> > similar to above, the original code zero out the entire [ex->ee_block,
>> > map->m_lblk - ee_block + map->m_len], where here we only zero out a
>> > portion of it. same to the mismatch of the split len also.
>> Similar to above. Just a optimization.
>> >
>> >
>> >> + ext4_ext_store_pblock(&zero_ex,
>> >> + ext4_ext_pblock(ex));
>> >> + err = ext4_ext_zeroout(inode, &zero_ex);
>> >> + if (err)
>> >> + goto out;
>> >> + }
>> >> +
>> >> - allocated = map->m_lblk - ee_block + map->m_len;
>> >> +
>> >> + split_map.m_lblk = ee_block;
>> >> + split_map.m_len = map->m_lblk - ee_block + map->m_len;
>> + allocated = map->m_len;
>> >
>> > I am also puzzled whether the zeroed-out extent get marked as
>> > initialized, as done in original patch. The whole point of zero out is
>> > to avoid frequent split of the unitizlized extent if the extent is
>> > short. I will take a closer look at the previous patch.
>> >
>> > Another issue, upon success, "allocated" will return from this function.
>> > But here allocated is the zero out length that start from ee_block, not
>> > the length from map->m_lblk. this is wrong, the caller
>> > ext4_ext_map_blocks expecting the length of mapped blocks from
>> > map->m_lblk. We now return more mapped blocks than what really done. I
>> > suspect the fsx error come from this bug.
>> Yeah. it is a bug.
>>
>> Hi Allison,
>>
>> Could you test with modification above? Here is a bug. I will also test it.
>>
>> Thank you.
>> >
>> >> }
>> >
>> >
>> >> }
>> >> - /* Mark modified extent as dirty */
>> >> - err = ext4_ext_dirty(handle, inode, path + depth);
>> >> - goto out;
>> >> -insert:
>> >> - err = ext4_ext_insert_extent(handle, inode, path, &newex, 0);
>> >> - if (err == -ENOSPC && may_zeroout) {
>> >> - err = ext4_ext_zeroout(inode, &orig_ex);
>> >> - if (err)
>> >> - goto fix_extent_len;
>> >> - /* update the extent length and mark as initialized */
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - /* zero out the first half */
>> >> - return allocated;
>> >> - } else if (err)
>> >> - goto fix_extent_len;
>> >> +
>> >> + allocated = ext4_split_extent(handle, inode, path,
>> >> + &split_map, split_flag, 0);
>> >> + if (allocated < 0)
>> >> + err = allocated;
>> >> +
>> >> out:
>> >> - ext4_ext_show_leaf(inode, path);
>> >> return err ? err : allocated;
>> >> -
>> >> -fix_extent_len:
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_mark_uninitialized(ex);
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - return err;
>> >> }
>> >>
>> >> /*
>> >> @@ -3083,15 +2886,11 @@ static int ext4_split_unwritten_extents(handle_t *handle,
>> >> struct ext4_ext_path *path,
>> >> int flags)
>> >> {
>> >> - struct ext4_extent *ex, newex, orig_ex;
>> >> - struct ext4_extent *ex1 = NULL;
>> >> - struct ext4_extent *ex2 = NULL;
>> >> - struct ext4_extent *ex3 = NULL;
>> >> - ext4_lblk_t ee_block, eof_block;
>> >> - unsigned int allocated, ee_len, depth;
>> >> - ext4_fsblk_t newblock;
>> >> - int err = 0;
>> >> - int may_zeroout;
>> >> + ext4_lblk_t eof_block;
>> >> + ext4_lblk_t ee_block;
>> >> + struct ext4_extent *ex;
>> >> + 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,
>> >> @@ -3101,155 +2900,20 @@ static int ext4_split_unwritten_extents(handle_t *handle,
>> >> inode->i_sb->s_blocksize_bits;
>> >> if (eof_block < map->m_lblk + map->m_len)
>> >> eof_block = map->m_lblk + map->m_len;
>> >> -
>> >> - 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);
>> >> - allocated = ee_len - (map->m_lblk - ee_block);
>> >> - newblock = map->m_lblk - ee_block + ext4_ext_pblock(ex);
>> >> -
>> >> - ex2 = ex;
>> >> - orig_ex.ee_block = ex->ee_block;
>> >> - orig_ex.ee_len = cpu_to_le16(ee_len);
>> >> - ext4_ext_store_pblock(&orig_ex, ext4_ext_pblock(ex));
>> >> -
>> >> /*
>> >> * It is safe to convert extent to initialized via explicit
>> >> * zeroout only if extent is fully insde i_size or new_size.
>> >> */
>> >> - may_zeroout = ee_block + ee_len <= eof_block;
>> >> -
>> >> - /*
>> >> - * If the uninitialized extent begins at the same logical
>> >> - * block where the write begins, and the write completely
>> >> - * covers the extent, then we don't need to split it.
>> >> - */
>> >> - if ((map->m_lblk == ee_block) && (allocated <= map->m_len))
>> >> - return allocated;
>> >> -
>> >> - err = ext4_ext_get_access(handle, inode, path + depth);
>> >> - if (err)
>> >> - goto out;
>> >> - /* ex1: ee_block to map->m_lblk - 1 : uninitialized */
>> >> - if (map->m_lblk > ee_block) {
>> >> - ex1 = ex;
>> >> - ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
>> >> - ext4_ext_mark_uninitialized(ex1);
>> >> - ex2 = &newex;
>> >> - }
>> >> - /*
>> >> - * for sanity, update the length of the ex2 extent before
>> >> - * we insert ex3, if ex1 is NULL. This is to avoid temporary
>> >> - * overlap of blocks.
>> >> - */
>> >> - if (!ex1 && allocated > map->m_len)
>> >> - ex2->ee_len = cpu_to_le16(map->m_len);
>> >> - /* ex3: to ee_block + ee_len : uninitialised */
>> >> - if (allocated > map->m_len) {
>> >> - unsigned int newdepth;
>> >> - ex3 = &newex;
>> >> - ex3->ee_block = cpu_to_le32(map->m_lblk + map->m_len);
>> >> - ext4_ext_store_pblock(ex3, newblock + map->m_len);
>> >> - ex3->ee_len = cpu_to_le16(allocated - map->m_len);
>> >> - ext4_ext_mark_uninitialized(ex3);
>> >> - err = ext4_ext_insert_extent(handle, inode, path, ex3, flags);
>> >> - if (err == -ENOSPC && may_zeroout) {
>> >> - err = ext4_ext_zeroout(inode, &orig_ex);
>> >> - if (err)
>> >> - goto fix_extent_len;
>> >> - /* update the extent length and mark as initialized */
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - /* zeroed the full extent */
>> >> - /* blocks available from map->m_lblk */
>> >> - return allocated;
>> >> -
>> >> - } else if (err)
>> >> - goto fix_extent_len;
>> >> - /*
>> >> - * The depth, and hence eh & ex might change
>> >> - * as part of the insert above.
>> >> - */
>> >> - newdepth = ext_depth(inode);
>> >> - /*
>> >> - * update the extent length after successful insert of the
>> >> - * split extent
>> >> - */
>> >> - ee_len -= ext4_ext_get_actual_len(ex3);
>> >> - orig_ex.ee_len = cpu_to_le16(ee_len);
>> >> - may_zeroout = ee_block + ee_len <= eof_block;
>> >> -
>> >> - depth = newdepth;
>> >> - ext4_ext_drop_refs(path);
>> >> - path = ext4_ext_find_extent(inode, map->m_lblk, path);
>> >> - if (IS_ERR(path)) {
>> >> - err = PTR_ERR(path);
>> >> - goto out;
>> >> - }
>> >> - ex = path[depth].p_ext;
>> >> - if (ex2 != &newex)
>> >> - ex2 = ex;
>> >> + 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);
>> >>
>> >> - err = ext4_ext_get_access(handle, inode, path + depth);
>> >> - if (err)
>> >> - goto out;
>> >> + split_flag |= ee_block + ee_len <= eof_block ? EXT4_EXT_MAY_ZEROOUT : 0;
>> >> + split_flag |= EXT4_EXT_MARK_UNINIT2;
>> >>
>> >> - allocated = map->m_len;
>> >> - }
>> >> - /*
>> >> - * If there was a change of depth as part of the
>> >> - * insertion of ex3 above, we need to update the length
>> >> - * of the ex1 extent again here
>> >> - */
>> >> - if (ex1 && ex1 != ex) {
>> >> - ex1 = ex;
>> >> - ex1->ee_len = cpu_to_le16(map->m_lblk - ee_block);
>> >> - ext4_ext_mark_uninitialized(ex1);
>> >> - ex2 = &newex;
>> >> - }
>> >> - /*
>> >> - * ex2: map->m_lblk to map->m_lblk + map->m_len-1 : to be written
>> >> - * using direct I/O, uninitialised still.
>> >> - */
>> >> - ex2->ee_block = cpu_to_le32(map->m_lblk);
>> >> - ext4_ext_store_pblock(ex2, newblock);
>> >> - ex2->ee_len = cpu_to_le16(allocated);
>> >> - ext4_ext_mark_uninitialized(ex2);
>> >> - if (ex2 != ex)
>> >> - goto insert;
>> >> - /* Mark modified extent as dirty */
>> >> - err = ext4_ext_dirty(handle, inode, path + depth);
>> >> - ext_debug("out here\n");
>> >> - goto out;
>> >> -insert:
>> >> - err = ext4_ext_insert_extent(handle, inode, path, &newex, flags);
>> >> - if (err == -ENOSPC && may_zeroout) {
>> >> - err = ext4_ext_zeroout(inode, &orig_ex);
>> >> - if (err)
>> >> - goto fix_extent_len;
>> >> - /* update the extent length and mark as initialized */
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - /* zero out the first half */
>> >> - return allocated;
>> >> - } else if (err)
>> >> - goto fix_extent_len;
>> >> -out:
>> >> - ext4_ext_show_leaf(inode, path);
>> >> - return err ? err : allocated;
>> >> -
>> >> -fix_extent_len:
>> >> - ex->ee_block = orig_ex.ee_block;
>> >> - ex->ee_len = orig_ex.ee_len;
>> >> - ext4_ext_store_pblock(ex, ext4_ext_pblock(&orig_ex));
>> >> - ext4_ext_mark_uninitialized(ex);
>> >> - ext4_ext_dirty(handle, inode, path + depth);
>> >> - return err;
>> >> + flags |= EXT4_GET_BLOCKS_PRE_IO;
>> >> + return ext4_split_extent(handle, inode, path, map, split_flag, flags);
>> >> }
>> >>
>> >> static int ext4_convert_unwritten_extents_endio(handle_t *handle,
>> >
>> >
>> >
>>
>>
>>
>
>
>
--
Best Wishes
Yongqiang Yang
--
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