[PATCH v3 06/12] ext4: Provide ext4_do_writepages()

Jan Kara
2022-12-05T12:29:53Z

Provide ext4_do_writepages() function that takes mpage_da_data as an
argument and make ext4_writepages() just a simple wrapper around it. No
functional changes.

Reviewed-by: Ritesh Harjani (IBM) <ritesh.list@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
---
fs/ext4/inode.c | 96 +++++++++++++++++++++++++++----------------------
1 file changed, 54 insertions(+), 42 deletions(-)

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 9ba843b7a92c..99c66c768cd0 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -1543,9 +1543,12 @@ void ext4_da_release_space(struct inode *inode, int to_free)
*/

struct mpage_da_data {
+ /* These are input fields for ext4_do_writepages() */
struct inode *inode;
struct writeback_control *wbc;
+ unsigned int can_map:1; /* Can writepages call map blocks? */

+ /* These are internal state of ext4_do_writepages() */
pgoff_t first_page; /* The first page to write */
pgoff_t next_page; /* Current page to examine */
pgoff_t last_page; /* Last page to examine */
@@ -1557,7 +1560,6 @@ struct mpage_da_data {
struct ext4_map_blocks map;
struct ext4_io_submit io_submit; /* IO submission data */
unsigned int do_map:1;
- unsigned int can_map:1; /* Can writepages call map blocks? */
unsigned int scanned_until_end:1;
};

@@ -2703,16 +2705,16 @@ static int mpage_prepare_extent_to_map(struct mpage_da_data *mpd)
return err;
}

-static int ext4_writepages(struct address_space *mapping,
- struct writeback_control *wbc)
+static int ext4_do_writepages(struct mpage_da_data *mpd)
{
+ struct writeback_control *wbc = mpd->wbc;
pgoff_t writeback_index = 0;
long nr_to_write = wbc->nr_to_write;
int range_whole = 0;
int cycled = 1;
handle_t *handle = NULL;
- struct mpage_da_data mpd;
- struct inode *inode = mapping->host;
+ struct inode *inode = mpd->inode;
+ struct address_space *mapping = inode->i_mapping;
int needed_blocks, rsv_blocks = 0, ret = 0;
struct ext4_sb_info *sbi = EXT4_SB(mapping->host->i_sb);
struct blk_plug plug;
@@ -2787,19 +2789,18 @@ static int ext4_writepages(struct address_space *mapping,
writeback_index = mapping->writeback_index;
if (writeback_index)
cycled = 0;
- mpd.first_page = writeback_index;
- mpd.last_page = -1;
+ mpd->first_page = writeback_index;
+ mpd->last_page = -1;
} else {
- mpd.first_page = wbc->range_start >> PAGE_SHIFT;
- mpd.last_page = wbc->range_end >> PAGE_SHIFT;
+ mpd->first_page = wbc->range_start >> PAGE_SHIFT;
+ mpd->last_page = wbc->range_end >> PAGE_SHIFT;
}

- mpd.inode = inode;
- mpd.wbc = wbc;
- ext4_io_submit_init(&mpd.io_submit, wbc);
+ ext4_io_submit_init(&mpd->io_submit, wbc);
retry:
if (wbc->sync_mode == WB_SYNC_ALL || wbc->tagged_writepages)
- tag_pages_for_writeback(mapping, mpd.first_page, mpd.last_page);
+ tag_pages_for_writeback(mapping, mpd->first_page,
+ mpd->last_page);
blk_start_plug(&plug);

/*
@@ -2808,28 +2809,27 @@ static int ext4_writepages(struct address_space *mapping,
* in the block layer on device congestion while having transaction
* started.
*/
- mpd.do_map = 0;
- mpd.scanned_until_end = 0;
- mpd.can_map = 1;
- mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
- if (!mpd.io_submit.io_end) {
+ mpd->do_map = 0;
+ mpd->scanned_until_end = 0;
+ mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
+ if (!mpd->io_submit.io_end) {
ret = -ENOMEM;
goto unplug;
}
- ret = mpage_prepare_extent_to_map(&mpd);
+ ret = mpage_prepare_extent_to_map(mpd);
/* Unlock pages we didn't use */
- mpage_release_unused_pages(&mpd, false);
+ mpage_release_unused_pages(mpd, false);
/* Submit prepared bio */
- ext4_io_submit(&mpd.io_submit);
- ext4_put_io_end_defer(mpd.io_submit.io_end);
- mpd.io_submit.io_end = NULL;
+ ext4_io_submit(&mpd->io_submit);
+ ext4_put_io_end_defer(mpd->io_submit.io_end);
+ mpd->io_submit.io_end = NULL;
if (ret < 0)
goto unplug;

- while (!mpd.scanned_until_end && wbc->nr_to_write > 0) {
+ while (!mpd->scanned_until_end && wbc->nr_to_write > 0) {
/* For each extent of pages we use new io_end */
- mpd.io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
- if (!mpd.io_submit.io_end) {
+ mpd->io_submit.io_end = ext4_init_io_end(inode, GFP_KERNEL);
+ if (!mpd->io_submit.io_end) {
ret = -ENOMEM;
break;
}
@@ -2854,16 +2854,16 @@ static int ext4_writepages(struct address_space *mapping,
"%ld pages, ino %lu; err %d", __func__,
wbc->nr_to_write, inode->i_ino, ret);
/* Release allocated io_end */
- ext4_put_io_end(mpd.io_submit.io_end);
- mpd.io_submit.io_end = NULL;
+ ext4_put_io_end(mpd->io_submit.io_end);
+ mpd->io_submit.io_end = NULL;
break;
}
- mpd.do_map = 1;
+ mpd->do_map = 1;

- trace_ext4_da_write_pages(inode, mpd.first_page, mpd.wbc);
- ret = mpage_prepare_extent_to_map(&mpd);
- if (!ret && mpd.map.m_len)
- ret = mpage_map_and_submit_extent(handle, &mpd,
+ trace_ext4_da_write_pages(inode, mpd->first_page, wbc);
+ ret = mpage_prepare_extent_to_map(mpd);
+ if (!ret && mpd->map.m_len)
+ ret = mpage_map_and_submit_extent(handle, mpd,
&give_up_on_write);
/*
* Caution: If the handle is synchronous,
@@ -2878,12 +2878,12 @@ static int ext4_writepages(struct address_space *mapping,
if (!ext4_handle_valid(handle) || handle->h_sync == 0) {
ext4_journal_stop(handle);
handle = NULL;
- mpd.do_map = 0;
+ mpd->do_map = 0;
}
/* Unlock pages we didn't use */
- mpage_release_unused_pages(&mpd, give_up_on_write);
+ mpage_release_unused_pages(mpd, give_up_on_write);
/* Submit prepared bio */
- ext4_io_submit(&mpd.io_submit);
+ ext4_io_submit(&mpd->io_submit);

/*
* Drop our io_end reference we got from init. We have
@@ -2893,11 +2893,11 @@ static int ext4_writepages(struct address_space *mapping,
* up doing unwritten extent conversion.
*/
if (handle) {
- ext4_put_io_end_defer(mpd.io_submit.io_end);
+ ext4_put_io_end_defer(mpd->io_submit.io_end);
ext4_journal_stop(handle);
} else
- ext4_put_io_end(mpd.io_submit.io_end);
- mpd.io_submit.io_end = NULL;
+ ext4_put_io_end(mpd->io_submit.io_end);
+ mpd->io_submit.io_end = NULL;

if (ret == -ENOSPC && sbi->s_journal) {
/*
@@ -2917,8 +2917,8 @@ static int ext4_writepages(struct address_space *mapping,
blk_finish_plug(&plug);
if (!ret && !cycled && wbc->nr_to_write > 0) {
cycled = 1;
- mpd.last_page = writeback_index - 1;
- mpd.first_page = 0;
+ mpd->last_page = writeback_index - 1;
+ mpd->first_page = 0;
goto retry;
}

@@ -2928,7 +2928,7 @@ static int ext4_writepages(struct address_space *mapping,
* Set the writeback_index so that range_cyclic
* mode will write it back later
*/
- mapping->writeback_index = mpd.first_page;
+ mapping->writeback_index = mpd->first_page;

out_writepages:
trace_ext4_writepages_result(inode, wbc, ret,
@@ -2937,6 +2937,18 @@ static int ext4_writepages(struct address_space *mapping,
return ret;
}

+static int ext4_writepages(struct address_space *mapping,
+ struct writeback_control *wbc)
+{
+ struct mpage_da_data mpd = {
+ .inode = mapping->host,
+ .wbc = wbc,
+ .can_map = 1,
+ };
+
+ return ext4_do_writepages(&mpd);
+}
+
static int ext4_dax_writepages(struct address_space *mapping,
struct writeback_control *wbc)
{
--
2.35.3