[RFC PATCH v4 10/34] ext4: factor out ext4_map_create_blocks() to allocate new blocks

Zhang Yi
2024-04-10T14:38:35Z

Factor out a common helper ext4_map_create_blocks() from
ext4_map_blocks(), it allocate new blocks and create a new extent, no
logic changes.

Signed-off-by: Zhang Yi <yi.zhang@huawei.com>
---
fs/ext4/inode.c | 157 +++++++++++++++++++++++++-----------------------
1 file changed, 81 insertions(+), 76 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 1731c1d24362..10a256cfcaa1 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -482,6 +482,86 @@ static int ext4_map_query_blocks(handle_t *handle, struct inode *inode,
return retval;
}

+static int ext4_map_create_blocks(handle_t *handle, struct inode *inode,
+ struct ext4_map_blocks *map, int flags)
+{
+ struct extent_status es;
+ unsigned int status;
+ int err, retval = 0;
+
+ /*
+ * Here we clear m_flags because after allocating an new extent,
+ * it will be set again.
+ */
+ map->m_flags &= ~EXT4_MAP_FLAGS;
+
+ /*
+ * We need to check for EXT4 here because migrate could have
+ * changed the inode type in between.
+ */
+ if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
+ retval = ext4_ext_map_blocks(handle, inode, map, flags);
+ } else {
+ retval = ext4_ind_map_blocks(handle, inode, map, flags);
+
+ /*
+ * We allocated new blocks which will result in i_data's
+ * format changing. Force the migrate to fail by clearing
+ * migrate flags.
+ */
+ if (retval > 0 && map->m_flags & EXT4_MAP_NEW)
+ ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
+ }
+ if (retval <= 0)
+ return retval;
+
+ if (unlikely(retval != map->m_len)) {
+ ext4_warning(inode->i_sb,
+ "ES len assertion failed for inode %lu: "
+ "retval %d != map->m_len %d",
+ inode->i_ino, retval, map->m_len);
+ WARN_ON(1);
+ }
+
+ /*
+ * We have to zeroout blocks before inserting them into extent
+ * status tree. Otherwise someone could look them up there and
+ * use them before they are really zeroed. We also have to
+ * unmap metadata before zeroing as otherwise writeback can
+ * overwrite zeros with stale data from block device.
+ */
+ if (flags & EXT4_GET_BLOCKS_ZERO &&
+ map->m_flags & EXT4_MAP_MAPPED && map->m_flags & EXT4_MAP_NEW) {
+ err = ext4_issue_zeroout(inode, map->m_lblk, map->m_pblk,
+ map->m_len);
+ if (err)
+ return err;
+ }
+
+ /*
+ * If the extent has been zeroed out, we don't need to update
+ * extent status tree.
+ */
+ if (flags & EXT4_GET_BLOCKS_PRE_IO &&
+ ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
+ if (ext4_es_is_written(&es))
+ return retval;
+ }
+
+ status = map->m_flags & EXT4_MAP_UNWRITTEN ?
+ EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
+ if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
+ !(status & EXTENT_STATUS_WRITTEN) &&
+ ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
+ map->m_lblk + map->m_len - 1))
+ status |= EXTENT_STATUS_DELAYED;
+
+ ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
+ map->m_pblk, status);
+
+ return retval;
+}
+
/*
* The ext4_map_blocks() function tries to look up the requested blocks,
* and returns if the blocks are already mapped.
@@ -630,12 +710,6 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
if (!(flags & EXT4_GET_BLOCKS_CONVERT_UNWRITTEN))
return retval;

- /*
- * Here we clear m_flags because after allocating an new extent,
- * it will be set again.
- */
- map->m_flags &= ~EXT4_MAP_FLAGS;
-
/*
* New blocks allocate and/or writing to unwritten extent
* will possibly result in updating i_data, so we take
@@ -643,76 +717,7 @@ int ext4_map_blocks(handle_t *handle, struct inode *inode,
* with create == 1 flag.
*/
down_write(&EXT4_I(inode)->i_data_sem);
-
- /*
- * We need to check for EXT4 here because migrate
- * could have changed the inode type in between
- */
- if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)) {
- retval = ext4_ext_map_blocks(handle, inode, map, flags);
- } else {
- retval = ext4_ind_map_blocks(handle, inode, map, flags);
-
- if (retval > 0 && map->m_flags & EXT4_MAP_NEW) {
- /*
- * We allocated new blocks which will result in
- * i_data's format changing. Force the migrate
- * to fail by clearing migrate flags
- */
- ext4_clear_inode_state(inode, EXT4_STATE_EXT_MIGRATE);
- }
- }
-
- if (retval > 0) {
- unsigned int status;
-
- if (unlikely(retval != map->m_len)) {
- ext4_warning(inode->i_sb,
- "ES len assertion failed for inode "
- "%lu: retval %d != map->m_len %d",
- inode->i_ino, retval, map->m_len);
- WARN_ON(1);
- }
-
- /*
- * We have to zeroout blocks before inserting them into extent
- * status tree. Otherwise someone could look them up there and
- * use them before they are really zeroed. We also have to
- * unmap metadata before zeroing as otherwise writeback can
- * overwrite zeros with stale data from block device.
- */
- if (flags & EXT4_GET_BLOCKS_ZERO &&
- map->m_flags & EXT4_MAP_MAPPED &&
- map->m_flags & EXT4_MAP_NEW) {
- ret = ext4_issue_zeroout(inode, map->m_lblk,
- map->m_pblk, map->m_len);
- if (ret) {
- retval = ret;
- goto out_sem;
- }
- }
-
- /*
- * If the extent has been zeroed out, we don't need to update
- * extent status tree.
- */
- if ((flags & EXT4_GET_BLOCKS_PRE_IO) &&
- ext4_es_lookup_extent(inode, map->m_lblk, NULL, &es)) {
- if (ext4_es_is_written(&es))
- goto out_sem;
- }
- status = map->m_flags & EXT4_MAP_UNWRITTEN ?
- EXTENT_STATUS_UNWRITTEN : EXTENT_STATUS_WRITTEN;
- if (!(flags & EXT4_GET_BLOCKS_DELALLOC_RESERVE) &&
- !(status & EXTENT_STATUS_WRITTEN) &&
- ext4_es_scan_range(inode, &ext4_es_is_delayed, map->m_lblk,
- map->m_lblk + map->m_len - 1))
- status |= EXTENT_STATUS_DELAYED;
- ext4_es_insert_extent(inode, map->m_lblk, map->m_len,
- map->m_pblk, status);
- }
-
-out_sem:
+ retval = ext4_map_create_blocks(handle, inode, map, flags);
up_write((&EXT4_I(inode)->i_data_sem));
if (retval > 0 && map->m_flags & EXT4_MAP_MAPPED) {
ret = check_block_validity(inode, map);
--
2.39.2