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ext4: call mpage_da_submit_io() from mpage_da_map_blocks()

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Eventually we need to completely reorganize the ext4 writepage
callpath, but for now, we simplify things a little by calling
mpage_da_submit_io() from mpage_da_map_blocks(), since all of the
places where we call mpage_da_map_blocks() it is followed up by a call
to mpage_da_submit_io().

We're also a wee bit better with respect to error handling, but there
are still a number of issues where it's not clear what the right thing
is to do with ext4 functions deep in the writeback codepath fails.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
This commit is contained in:
Theodore Ts'o 2010-10-27 21:30:09 -04:00
parent 16828088f9
commit 5a87b7a5da
1 changed files with 33 additions and 33 deletions
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66
fs/ext4/inode.c
View file

@ -60,6 +60,7 @@ static inline int ext4_begin_ordered_truncate(struct inode *inode,
}
static void ext4_invalidatepage(struct page *page, unsigned long offset);
static int ext4_writepage(struct page *page, struct writeback_control *wbc);
/*
* Test whether an inode is a fast symlink.
@ -2033,7 +2034,7 @@ static int mpage_da_submit_io(struct mpage_da_data *mpd)
BUG_ON(PageWriteback(page));
pages_skipped = mpd->wbc->pages_skipped;
err = mapping->a_ops->writepage(page, mpd->wbc);
err = ext4_writepage(page, mpd->wbc);
if (!err && (pages_skipped == mpd->wbc->pages_skipped))
/*
* have successfully written the page
@ -2189,14 +2190,15 @@ static void ext4_print_free_blocks(struct inode *inode)
}
/*
* mpage_da_map_blocks - go through given space
* mpage_da_map_and_submit - go through given space, map them
* if necessary, and then submit them for I/O
*
* @mpd - bh describing space
*
* The function skips space we know is already mapped to disk blocks.
*
*/
static int mpage_da_map_blocks(struct mpage_da_data *mpd)
static void mpage_da_map_and_submit(struct mpage_da_data *mpd)
{
int err, blks, get_blocks_flags;
struct ext4_map_blocks map;
@ -2206,18 +2208,14 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
handle_t *handle = NULL;
/*
* We consider only non-mapped and non-allocated blocks
* If the blocks are mapped already, or we couldn't accumulate
* any blocks, then proceed immediately to the submission stage.
*/
if ((mpd->b_state & (1 << BH_Mapped)) &&
!(mpd->b_state & (1 << BH_Delay)) &&
!(mpd->b_state & (1 << BH_Unwritten)))
return 0;
/*
* If we didn't accumulate anything to write simply return
*/
if (!mpd->b_size)
return 0;
if ((mpd->b_size == 0) ||
((mpd->b_state & (1 << BH_Mapped)) &&
!(mpd->b_state & (1 << BH_Delay)) &&
!(mpd->b_state & (1 << BH_Unwritten))))
goto submit_io;
handle = ext4_journal_current_handle();
BUG_ON(!handle);
@ -2254,17 +2252,18 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
err = blks;
/*
* If get block returns with error we simply
* return. Later writepage will redirty the page and
* writepages will find the dirty page again
* If get block returns EAGAIN or ENOSPC and there
* appears to be free blocks we will call
* ext4_writepage() for all of the pages which will
* just redirty the pages.
*/
if (err == -EAGAIN)
return 0;
goto submit_io;
if (err == -ENOSPC &&
ext4_count_free_blocks(sb)) {
mpd->retval = err;
return 0;
goto submit_io;
}
/*
@ -2289,7 +2288,7 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
/* invalidate all the pages */
ext4_da_block_invalidatepages(mpd, next,
mpd->b_size >> mpd->inode->i_blkbits);
return err;
return;
}
BUG_ON(blks == 0);
@ -2312,7 +2311,8 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
if (ext4_should_order_data(mpd->inode)) {
err = ext4_jbd2_file_inode(handle, mpd->inode);
if (err)
return err;
/* This only happens if the journal is aborted */
return;
}
/*
@ -2323,10 +2323,16 @@ static int mpage_da_map_blocks(struct mpage_da_data *mpd)
disksize = i_size_read(mpd->inode);
if (disksize > EXT4_I(mpd->inode)->i_disksize) {
ext4_update_i_disksize(mpd->inode, disksize);
return ext4_mark_inode_dirty(handle, mpd->inode);
err = ext4_mark_inode_dirty(handle, mpd->inode);
if (err)
ext4_error(mpd->inode->i_sb,
"Failed to mark inode %lu dirty",
mpd->inode->i_ino);
}
return 0;
submit_io:
mpage_da_submit_io(mpd);
mpd->io_done = 1;
}
#define BH_FLAGS ((1 << BH_Uptodate) | (1 << BH_Mapped) | \
@ -2403,9 +2409,7 @@ flush_it:
* We couldn't merge the block to our extent, so we
* need to flush current extent and start new one
*/
if (mpage_da_map_blocks(mpd) == 0)
mpage_da_submit_io(mpd);
mpd->io_done = 1;
mpage_da_map_and_submit(mpd);
return;
}
@ -2437,15 +2441,13 @@ static int __mpage_da_writepage(struct page *page,
if (mpd->next_page != page->index) {
/*
* Nope, we can't. So, we map non-allocated blocks
* and start IO on them using writepage()
* and start IO on them
*/
if (mpd->next_page != mpd->first_page) {
if (mpage_da_map_blocks(mpd) == 0)
mpage_da_submit_io(mpd);
mpage_da_map_and_submit(mpd);
/*
* skip rest of the page in the page_vec
*/
mpd->io_done = 1;
redirty_page_for_writepage(wbc, page);
unlock_page(page);
return MPAGE_DA_EXTENT_TAIL;
@ -3071,9 +3073,7 @@ retry:
* them for I/O.
*/
if (!mpd.io_done && mpd.next_page != mpd.first_page) {
if (mpage_da_map_blocks(&mpd) == 0)
mpage_da_submit_io(&mpd);
mpd.io_done = 1;
mpage_da_map_and_submit(&mpd);
ret = MPAGE_DA_EXTENT_TAIL;
}
trace_ext4_da_write_pages(inode, &mpd);