From 2943fdbc688e7a1b4d9e3bc76a8e5ba624550213 Mon Sep 17 00:00:00 2001 From: Ritesh Harjani Date: Wed, 16 Oct 2019 13:07:09 +0530 Subject: ext4: Refactor mpage_map_and_submit_buffers function This patch refactors mpage_map_and_submit_buffers to take out the page buffers processing, as a separate function. This will be required to add support for blocksize < pagesize for dioread_nolock feature. No functionality change in this patch. Signed-off-by: Ritesh Harjani Link: https://lore.kernel.org/r/20191016073711.4141-4-riteshh@linux.ibm.com Signed-off-by: Theodore Ts'o --- fs/ext4/inode.c | 125 +++++++++++++++++++++++++++++++++++++------------------- 1 file changed, 83 insertions(+), 42 deletions(-) (limited to 'fs/ext4') diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c index 516faa280ced..5081f91cc1c4 100644 --- a/fs/ext4/inode.c +++ b/fs/ext4/inode.c @@ -2340,6 +2340,75 @@ static int mpage_process_page_bufs(struct mpage_da_data *mpd, return lblk < blocks; } +/* + * mpage_process_page - update page buffers corresponding to changed extent and + * may submit fully mapped page for IO + * + * @mpd - description of extent to map, on return next extent to map + * @m_lblk - logical block mapping. + * @m_pblk - corresponding physical mapping. + * @map_bh - determines on return whether this page requires any further + * mapping or not. + * Scan given page buffers corresponding to changed extent and update buffer + * state according to new extent state. + * We map delalloc buffers to their physical location, clear unwritten bits. + * If the given page is not fully mapped, we update @map to the next extent in + * the given page that needs mapping & return @map_bh as true. + */ +static int mpage_process_page(struct mpage_da_data *mpd, struct page *page, + ext4_lblk_t *m_lblk, ext4_fsblk_t *m_pblk, + bool *map_bh) +{ + struct buffer_head *head, *bh; + ext4_io_end_t *io_end = mpd->io_submit.io_end; + ext4_lblk_t lblk = *m_lblk; + ext4_fsblk_t pblock = *m_pblk; + int err = 0; + + bh = head = page_buffers(page); + do { + if (lblk < mpd->map.m_lblk) + continue; + if (lblk >= mpd->map.m_lblk + mpd->map.m_len) { + /* + * Buffer after end of mapped extent. + * Find next buffer in the page to map. + */ + mpd->map.m_len = 0; + mpd->map.m_flags = 0; + + /* + * FIXME: If dioread_nolock supports + * blocksize < pagesize, we need to make + * sure we add size mapped so far to + * io_end->size as the following call + * can submit the page for IO. + */ + err = mpage_process_page_bufs(mpd, head, bh, lblk); + if (err > 0) + err = 0; + *map_bh = true; + goto out; + } + if (buffer_delay(bh)) { + clear_buffer_delay(bh); + bh->b_blocknr = pblock++; + } + clear_buffer_unwritten(bh); + } while (lblk++, (bh = bh->b_this_page) != head); + /* + * FIXME: This is going to break if dioread_nolock + * supports blocksize < pagesize as we will try to + * convert potentially unmapped parts of inode. + */ + io_end->size += PAGE_SIZE; + *map_bh = false; +out: + *m_lblk = lblk; + *m_pblk = pblock; + return err; +} + /* * mpage_map_buffers - update buffers corresponding to changed extent and * submit fully mapped pages for IO @@ -2359,12 +2428,12 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd) struct pagevec pvec; int nr_pages, i; struct inode *inode = mpd->inode; - struct buffer_head *head, *bh; int bpp_bits = PAGE_SHIFT - inode->i_blkbits; pgoff_t start, end; ext4_lblk_t lblk; - sector_t pblock; + ext4_fsblk_t pblock; int err; + bool map_bh = false; start = mpd->map.m_lblk >> bpp_bits; end = (mpd->map.m_lblk + mpd->map.m_len - 1) >> bpp_bits; @@ -2380,50 +2449,19 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd) for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; - bh = head = page_buffers(page); - do { - if (lblk < mpd->map.m_lblk) - continue; - if (lblk >= mpd->map.m_lblk + mpd->map.m_len) { - /* - * Buffer after end of mapped extent. - * Find next buffer in the page to map. - */ - mpd->map.m_len = 0; - mpd->map.m_flags = 0; - /* - * FIXME: If dioread_nolock supports - * blocksize < pagesize, we need to make - * sure we add size mapped so far to - * io_end->size as the following call - * can submit the page for IO. - */ - err = mpage_process_page_bufs(mpd, head, - bh, lblk); - pagevec_release(&pvec); - if (err > 0) - err = 0; - return err; - } - if (buffer_delay(bh)) { - clear_buffer_delay(bh); - bh->b_blocknr = pblock++; - } - clear_buffer_unwritten(bh); - } while (lblk++, (bh = bh->b_this_page) != head); - + err = mpage_process_page(mpd, page, &lblk, &pblock, + &map_bh); /* - * FIXME: This is going to break if dioread_nolock - * supports blocksize < pagesize as we will try to - * convert potentially unmapped parts of inode. + * If map_bh is true, means page may require further bh + * mapping, or maybe the page was submitted for IO. + * So we return to call further extent mapping. */ - mpd->io_submit.io_end->size += PAGE_SIZE; + if (err < 0 || map_bh == true) + goto out; /* Page fully mapped - let IO run! */ err = mpage_submit_page(mpd, page); - if (err < 0) { - pagevec_release(&pvec); - return err; - } + if (err < 0) + goto out; } pagevec_release(&pvec); } @@ -2431,6 +2469,9 @@ static int mpage_map_and_submit_buffers(struct mpage_da_data *mpd) mpd->map.m_len = 0; mpd->map.m_flags = 0; return 0; +out: + pagevec_release(&pvec); + return err; } static int mpage_map_one_extent(handle_t *handle, struct mpage_da_data *mpd) -- cgit