From e7fd96492c8d70ff0e3187a7d7f2492c2afca1cd Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:26:58 +0100 Subject: [PATCH 01/14] iomap: treat inline data in iomap_writepage_map as an I/O error ANBZ: #20084 commit 80d012e98894ac9112cbcddf2fbf276c2e4be0ec upstream. iomap_writepage_map aready warns about inline data, but then just ignores it. Treat it as an error and return -EIO. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-3-hch@lst.de Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index a05ee2cbb779..1ee8fbd2210e 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1813,8 +1813,10 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, if (error) break; trace_iomap_writepage_map(inode, &wpc->iomap); - if (WARN_ON_ONCE(wpc->iomap.type == IOMAP_INLINE)) - continue; + if (WARN_ON_ONCE(wpc->iomap.type == IOMAP_INLINE)) { + error = -EIO; + break; + } if (wpc->iomap.type == IOMAP_HOLE) continue; iomap_add_to_ioend(inode, pos, folio, ifs, wpc, wbc, -- Gitee From d8189264e44ab52eb63b8338111453c011d4cf41 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:26:59 +0100 Subject: [PATCH 02/14] iomap: move the io_folios field out of struct iomap_ioend ANBZ: #20084 commit 432acd550e3607d5fea23e27f6ab4e4567deccfd upstream. The io_folios member in struct iomap_ioend counts the number of folios added to an ioend. It is only used at submission time and can thus be moved to iomap_writepage_ctx instead. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-4-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 7 ++++--- include/linux/iomap.h | 2 +- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 1ee8fbd2210e..e8402ccb5396 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1680,10 +1680,11 @@ iomap_alloc_ioend(struct inode *inode, struct iomap_writepage_ctx *wpc, ioend->io_flags = wpc->iomap.flags; ioend->io_inode = inode; ioend->io_size = 0; - ioend->io_folios = 0; ioend->io_offset = offset; ioend->io_bio = bio; ioend->io_sector = sector; + + wpc->nr_folios = 0; return ioend; } @@ -1727,7 +1728,7 @@ iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t offset, * also prevents long tight loops ending page writeback on all the * folios in the ioend. */ - if (wpc->ioend->io_folios >= IOEND_BATCH_SIZE) + if (wpc->nr_folios >= IOEND_BATCH_SIZE) return false; return true; } @@ -1824,7 +1825,7 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, count++; } if (count) - wpc->ioend->io_folios++; + wpc->nr_folios++; WARN_ON_ONCE(!wpc->ioend && !list_empty(&submit_list)); WARN_ON_ONCE(!folio_test_locked(folio)); diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 47b81ebf6e59..4230c3d924f9 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -312,7 +312,6 @@ struct iomap_ioend { struct list_head io_list; /* next ioend in chain */ u16 io_type; u16 io_flags; /* IOMAP_F_* */ - u32 io_folios; /* folios added to ioend */ struct inode *io_inode; /* file being written to */ size_t io_size; /* size of the extent */ loff_t io_offset; /* offset in the file */ @@ -348,6 +347,7 @@ struct iomap_writepage_ctx { struct iomap iomap; struct iomap_ioend *ioend; const struct iomap_writeback_ops *ops; + u32 nr_folios; /* folios added to the ioend */ }; void iomap_finish_ioends(struct iomap_ioend *ioend, int error); -- Gitee From 21ac78eca56d35048094c8b438826db18a0d17ea Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:00 +0100 Subject: [PATCH 03/14] iomap: move the PF_MEMALLOC check to iomap_writepages ANBZ: #20084 commit c2dc7e5589a19cff8147f27d4beef7fc0aec2f86 upstream. The iomap writepage implementation has been removed in commit 478af190cb6c ("iomap: remove iomap_writepage") and this code is now only called through ->writepages which never happens from memory reclaim. Nove the check from iomap_do_writepage to iomap_writepages so that is only called once per ->writepage invocation. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-5-hch@lst.de Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 24 ++++++++---------------- 1 file changed, 8 insertions(+), 16 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index e8402ccb5396..6f7ba57aab49 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1907,20 +1907,6 @@ static int iomap_do_writepage(struct folio *folio, trace_iomap_writepage(inode, folio_pos(folio), folio_size(folio)); - /* - * Refuse to write the folio out if we're called from reclaim context. - * - * This avoids stack overflows when called from deeply used stacks in - * random callers for direct reclaim or memcg reclaim. We explicitly - * allow reclaim from kswapd as the stack usage there is relatively low. - * - * This should never happen except in the case of a VM regression so - * warn about it. - */ - if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC|PF_KSWAPD)) == - PF_MEMALLOC)) - goto redirty; - /* * Is this folio beyond the end of the file? * @@ -1986,8 +1972,6 @@ static int iomap_do_writepage(struct folio *folio, return iomap_writepage_map(wpc, wbc, inode, folio, end_pos); -redirty: - folio_redirty_for_writepage(wbc, folio); unlock: folio_unlock(folio); return 0; @@ -2000,6 +1984,14 @@ iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, { int ret; + /* + * Writeback from reclaim context should never happen except in the case + * of a VM regression so warn about it and refuse to write the data. + */ + if (WARN_ON_ONCE((current->flags & (PF_MEMALLOC | PF_KSWAPD)) == + PF_MEMALLOC)) + return -EIO; + wpc->ops = ops; ret = write_cache_pages(mapping, wbc, iomap_do_writepage, wpc); if (!wpc->ioend) -- Gitee From b70f4abf929ee0ca178bced5f8c4062f39cc49b9 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:01 +0100 Subject: [PATCH 04/14] iomap: factor out a iomap_writepage_handle_eof helper ANBZ: #20084 commit e3a491a26b62466ad14a423e8c81a04d5969bfe5 upstream. Most of iomap_do_writepage is dedidcated to handling a folio crossing or beyond i_size. Split this is into a separate helper and update the commens to deal with folios instead of pages and make them more readable. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-6-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 128 ++++++++++++++++++++--------------------- 1 file changed, 62 insertions(+), 66 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 6f7ba57aab49..ba68cffc8fab 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1763,6 +1763,64 @@ iomap_add_to_ioend(struct inode *inode, loff_t pos, struct folio *folio, wbc_account_cgroup_owner(wbc, &folio->page, len); } +/* + * Check interaction of the folio with the file end. + * + * If the folio is entirely beyond i_size, return false. If it straddles + * i_size, adjust end_pos and zero all data beyond i_size. + */ +static bool iomap_writepage_handle_eof(struct folio *folio, struct inode *inode, + u64 *end_pos) +{ + u64 isize = i_size_read(inode); + + if (*end_pos > isize) { + size_t poff = offset_in_folio(folio, isize); + pgoff_t end_index = isize >> PAGE_SHIFT; + + /* + * If the folio is entirely ouside of i_size, skip it. + * + * This can happen due to a truncate operation that is in + * progress and in that case truncate will finish it off once + * we've dropped the folio lock. + * + * Note that the pgoff_t used for end_index is an unsigned long. + * If the given offset is greater than 16TB on a 32-bit system, + * then if we checked if the folio is fully outside i_size with + * "if (folio->index >= end_index + 1)", "end_index + 1" would + * overflow and evaluate to 0. Hence this folio would be + * redirtied and written out repeatedly, which would result in + * an infinite loop; the user program performing this operation + * would hang. Instead, we can detect this situation by + * checking if the folio is totally beyond i_size or if its + * offset is just equal to the EOF. + */ + if (folio->index > end_index || + (folio->index == end_index && poff == 0)) + return false; + + /* + * The folio straddles i_size. + * + * It must be zeroed out on each and every writepage invocation + * because it may be mmapped: + * + * A file is mapped in multiples of the page size. For a + * file that is not a multiple of the page size, the + * remaining memory is zeroed when mapped, and writes to that + * region are not written out to the file. + * + * Also adjust the writeback range to skip all blocks entirely + * beyond i_size. + */ + folio_zero_segment(folio, poff, folio_size(folio)); + *end_pos = isize; + } + + return true; +} + /* * We implement an immediate ioend submission policy here to avoid needing to * chain multiple ioends and hence nest mempool allocations which can violate @@ -1903,78 +1961,16 @@ static int iomap_do_writepage(struct folio *folio, { struct iomap_writepage_ctx *wpc = data; struct inode *inode = folio->mapping->host; - u64 end_pos, isize; + u64 end_pos = folio_pos(folio) + folio_size(folio); trace_iomap_writepage(inode, folio_pos(folio), folio_size(folio)); - /* - * Is this folio beyond the end of the file? - * - * The folio index is less than the end_index, adjust the end_pos - * to the highest offset that this folio should represent. - * ----------------------------------------------------- - * | file mapping | | - * ----------------------------------------------------- - * | Page ... | Page N-2 | Page N-1 | Page N | | - * ^--------------------------------^----------|-------- - * | desired writeback range | see else | - * ---------------------------------^------------------| - */ - isize = i_size_read(inode); - end_pos = folio_pos(folio) + folio_size(folio); - if (end_pos > isize) { - /* - * Check whether the page to write out is beyond or straddles - * i_size or not. - * ------------------------------------------------------- - * | file mapping | | - * ------------------------------------------------------- - * | Page ... | Page N-2 | Page N-1 | Page N | Beyond | - * ^--------------------------------^-----------|--------- - * | | Straddles | - * ---------------------------------^-----------|--------| - */ - size_t poff = offset_in_folio(folio, isize); - pgoff_t end_index = isize >> PAGE_SHIFT; - - /* - * Skip the page if it's fully outside i_size, e.g. - * due to a truncate operation that's in progress. We've - * cleaned this page and truncate will finish things off for - * us. - * - * Note that the end_index is unsigned long. If the given - * offset is greater than 16TB on a 32-bit system then if we - * checked if the page is fully outside i_size with - * "if (page->index >= end_index + 1)", "end_index + 1" would - * overflow and evaluate to 0. Hence this page would be - * redirtied and written out repeatedly, which would result in - * an infinite loop; the user program performing this operation - * would hang. Instead, we can detect this situation by - * checking if the page is totally beyond i_size or if its - * offset is just equal to the EOF. - */ - if (folio->index > end_index || - (folio->index == end_index && poff == 0)) - goto unlock; - - /* - * The page straddles i_size. It must be zeroed out on each - * and every writepage invocation because it may be mmapped. - * "A file is mapped in multiples of the page size. For a file - * that is not a multiple of the page size, the remaining - * memory is zeroed when mapped, and writes to that region are - * not written out to the file." - */ - folio_zero_segment(folio, poff, folio_size(folio)); - end_pos = isize; + if (!iomap_writepage_handle_eof(folio, inode, &end_pos)) { + folio_unlock(folio); + return 0; } return iomap_writepage_map(wpc, wbc, inode, folio, end_pos); - -unlock: - folio_unlock(folio); - return 0; } int -- Gitee From c68da5b61819113f7f9bbf35e98027de131a3d74 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:02 +0100 Subject: [PATCH 05/14] iomap: move all remaining per-folio logic into iomap_writepage_map ANBZ: #20084 commit cc9542534bf09f33b4da32025b31335588fcefb9 upstream. Move the tracepoint and the iomap check from iomap_do_writepage into iomap_writepage_map. This keeps all logic in one places, and leaves iomap_do_writepage just as the wrapper for the callback conventions of write_cache_pages, which will go away when that is converted to an iterator. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-7-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 34 +++++++++++----------------------- 1 file changed, 11 insertions(+), 23 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index ba68cffc8fab..e9eedb3b40fa 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1837,19 +1837,25 @@ static bool iomap_writepage_handle_eof(struct folio *folio, struct inode *inode, * At the end of a writeback pass, there will be a cached ioend remaining on the * writepage context that the caller will need to submit. */ -static int -iomap_writepage_map(struct iomap_writepage_ctx *wpc, - struct writeback_control *wbc, struct inode *inode, - struct folio *folio, u64 end_pos) +static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, + struct writeback_control *wbc, struct folio *folio) { struct iomap_folio_state *ifs = folio->private; + struct inode *inode = folio->mapping->host; struct iomap_ioend *ioend, *next; unsigned len = i_blocksize(inode); unsigned nblocks = i_blocks_per_folio(inode, folio); u64 pos = folio_pos(folio); + u64 end_pos = pos + folio_size(folio); int error = 0, count = 0, i; LIST_HEAD(submit_list); + trace_iomap_writepage(inode, pos, folio_size(folio)); + + if (!iomap_writepage_handle_eof(folio, inode, &end_pos)) { + folio_unlock(folio); + return 0; + } WARN_ON_ONCE(end_pos <= pos); if (!ifs && nblocks > 1) { @@ -1949,28 +1955,10 @@ iomap_writepage_map(struct iomap_writepage_ctx *wpc, return error; } -/* - * Write out a dirty page. - * - * For delalloc space on the page, we need to allocate space and flush it. - * For unwritten space on the page, we need to start the conversion to - * regular allocated space. - */ static int iomap_do_writepage(struct folio *folio, struct writeback_control *wbc, void *data) { - struct iomap_writepage_ctx *wpc = data; - struct inode *inode = folio->mapping->host; - u64 end_pos = folio_pos(folio) + folio_size(folio); - - trace_iomap_writepage(inode, folio_pos(folio), folio_size(folio)); - - if (!iomap_writepage_handle_eof(folio, inode, &end_pos)) { - folio_unlock(folio); - return 0; - } - - return iomap_writepage_map(wpc, wbc, inode, folio, end_pos); + return iomap_writepage_map(data, wbc, folio); } int -- Gitee From 00d83fc8f85341a271ccc7636561a070c002770b Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:03 +0100 Subject: [PATCH 06/14] iomap: clean up the iomap_alloc_ioend calling convention ANBZ: #20084 commit 7edfc610ec315de96963e66889511212ad87e3de upstream. Switch to the same argument order as iomap_writepage_map and remove the ifs argument that can be trivially recalculated. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-8-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index e9eedb3b40fa..53680c0419c9 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1737,11 +1737,11 @@ iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t offset, * Test to see if we have an existing ioend structure that we could append to * first; otherwise finish off the current ioend and start another. */ -static void -iomap_add_to_ioend(struct inode *inode, loff_t pos, struct folio *folio, - struct iomap_folio_state *ifs, struct iomap_writepage_ctx *wpc, - struct writeback_control *wbc, struct list_head *iolist) +static void iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, + struct writeback_control *wbc, struct folio *folio, + struct inode *inode, loff_t pos, struct list_head *iolist) { + struct iomap_folio_state *ifs = folio->private; sector_t sector = iomap_sector(&wpc->iomap, pos); unsigned len = i_blocksize(inode); size_t poff = offset_in_folio(folio, pos); @@ -1884,8 +1884,7 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, } if (wpc->iomap.type == IOMAP_HOLE) continue; - iomap_add_to_ioend(inode, pos, folio, ifs, wpc, wbc, - &submit_list); + iomap_add_to_ioend(wpc, wbc, folio, inode, pos, &submit_list); count++; } if (count) -- Gitee From f3de9d7869cb75e55a9b963b37f0385d91960f43 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:04 +0100 Subject: [PATCH 07/14] iomap: move the iomap_sector sector calculation out of iomap_add_to_ioend ANBZ: #20084 commit dec3a7b3aa45802e70c350d73e11564cd444e448 upstream. The calculation in iomap_sector is pretty trivial and most of the time iomap_add_to_ioend only callers either iomap_can_add_to_ioend or iomap_alloc_ioend from a single invocation. Calculate the sector in the two lower level functions and stop passing it from iomap_add_to_ioend and update the iomap_alloc_ioend argument passing order to match that of iomap_add_to_ioend. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-9-hch@lst.de Reviewed-by: Ritesh Harjani (IBM) Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 25 +++++++++++-------------- 1 file changed, 11 insertions(+), 14 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 53680c0419c9..80ce80e75553 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1661,9 +1661,8 @@ iomap_submit_ioend(struct iomap_writepage_ctx *wpc, struct iomap_ioend *ioend, return 0; } -static struct iomap_ioend * -iomap_alloc_ioend(struct inode *inode, struct iomap_writepage_ctx *wpc, - loff_t offset, sector_t sector, struct writeback_control *wbc) +static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc, + struct writeback_control *wbc, struct inode *inode, loff_t pos) { struct iomap_ioend *ioend; struct bio *bio; @@ -1671,7 +1670,7 @@ iomap_alloc_ioend(struct inode *inode, struct iomap_writepage_ctx *wpc, bio = bio_alloc_bioset(wpc->iomap.bdev, BIO_MAX_VECS, REQ_OP_WRITE | wbc_to_write_flags(wbc), GFP_NOFS, &iomap_ioend_bioset); - bio->bi_iter.bi_sector = sector; + bio->bi_iter.bi_sector = iomap_sector(&wpc->iomap, pos); wbc_init_bio(wbc, bio); ioend = container_of(bio, struct iomap_ioend, io_inline_bio); @@ -1680,9 +1679,9 @@ iomap_alloc_ioend(struct inode *inode, struct iomap_writepage_ctx *wpc, ioend->io_flags = wpc->iomap.flags; ioend->io_inode = inode; ioend->io_size = 0; - ioend->io_offset = offset; + ioend->io_offset = pos; ioend->io_bio = bio; - ioend->io_sector = sector; + ioend->io_sector = bio->bi_iter.bi_sector; wpc->nr_folios = 0; return ioend; @@ -1710,18 +1709,17 @@ iomap_chain_bio(struct bio *prev) return new; } -static bool -iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t offset, - sector_t sector) +static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos) { if ((wpc->iomap.flags & IOMAP_F_SHARED) != (wpc->ioend->io_flags & IOMAP_F_SHARED)) return false; if (wpc->iomap.type != wpc->ioend->io_type) return false; - if (offset != wpc->ioend->io_offset + wpc->ioend->io_size) + if (pos != wpc->ioend->io_offset + wpc->ioend->io_size) return false; - if (sector != bio_end_sector(wpc->ioend->io_bio)) + if (iomap_sector(&wpc->iomap, pos) != + bio_end_sector(wpc->ioend->io_bio)) return false; /* * Limit ioend bio chain lengths to minimise IO completion latency. This @@ -1742,14 +1740,13 @@ static void iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct inode *inode, loff_t pos, struct list_head *iolist) { struct iomap_folio_state *ifs = folio->private; - sector_t sector = iomap_sector(&wpc->iomap, pos); unsigned len = i_blocksize(inode); size_t poff = offset_in_folio(folio, pos); - if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, pos, sector)) { + if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, pos)) { if (wpc->ioend) list_add(&wpc->ioend->io_list, iolist); - wpc->ioend = iomap_alloc_ioend(inode, wpc, pos, sector, wbc); + wpc->ioend = iomap_alloc_ioend(wpc, wbc, inode, pos); } if (!bio_add_folio(wpc->ioend->io_bio, folio, len, poff)) { -- Gitee From 9aa5ca95de28b2299c69c4dbefc4201eee5c11f2 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:05 +0100 Subject: [PATCH 08/14] iomap: don't chain bios ANBZ: #20084 commit ae5535efd8c445ad6033ac0d5da0197897b148ea upstream. Back in the days when a single bio could only be filled to the hardware limits, and we scheduled a work item for each bio completion, chaining multiple bios for a single ioend made a lot of sense to reduce the number of completions. But these days bios can be filled until we reach the number of vectors or total size limit, which means we can always fit at least 1 megabyte worth of data in the worst case, but usually a lot more due to large folios. The only thing bio chaining is buying us now is to reduce the size of the allocation from an ioend with an embedded bio into a plain bio, which is a 52 bytes differences on 64-bit systems. This is not worth the added complexity, so remove the bio chaining and only use the bio embedded into the ioend. This will help to simplify further changes to the iomap writeback code. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-10-hch@lst.de Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 90 +++++++++++------------------------------- fs/xfs/xfs_aops.c | 6 +-- include/linux/iomap.h | 8 +++- 3 files changed, 32 insertions(+), 72 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 80ce80e75553..5f2b251a8fac 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1484,40 +1484,23 @@ static u32 iomap_finish_ioend(struct iomap_ioend *ioend, int error) { struct inode *inode = ioend->io_inode; - struct bio *bio = &ioend->io_inline_bio; - struct bio *last = ioend->io_bio, *next; - u64 start = bio->bi_iter.bi_sector; - loff_t offset = ioend->io_offset; - bool quiet = bio_flagged(bio, BIO_QUIET); + struct bio *bio = &ioend->io_bio; + struct folio_iter fi; u32 folio_count = 0; - for (bio = &ioend->io_inline_bio; bio; bio = next) { - struct folio_iter fi; - - /* - * For the last bio, bi_private points to the ioend, so we - * need to explicitly end the iteration here. - */ - if (bio == last) - next = NULL; - else - next = bio->bi_private; - - /* walk all folios in bio, ending page IO on them */ - bio_for_each_folio_all(fi, bio) { - iomap_finish_folio_write(inode, fi.folio, fi.length, - error); - folio_count++; - } - bio_put(bio); + /* walk all folios in bio, ending page IO on them */ + bio_for_each_folio_all(fi, bio) { + iomap_finish_folio_write(inode, fi.folio, fi.length, error); + folio_count++; } - /* The ioend has been freed by bio_put() */ - if (unlikely(error && !quiet)) { + if (unlikely(error && !bio_flagged(bio, BIO_QUIET))) { printk_ratelimited(KERN_ERR "%s: writeback error on inode %lu, offset %lld, sector %llu", - inode->i_sb->s_id, inode->i_ino, offset, start); + inode->i_sb->s_id, inode->i_ino, + ioend->io_offset, ioend->io_sector); } + bio_put(bio); /* frees the ioend */ return folio_count; } @@ -1558,7 +1541,7 @@ EXPORT_SYMBOL_GPL(iomap_finish_ioends); static bool iomap_ioend_can_merge(struct iomap_ioend *ioend, struct iomap_ioend *next) { - if (ioend->io_bio->bi_status != next->io_bio->bi_status) + if (ioend->io_bio.bi_status != next->io_bio.bi_status) return false; if ((ioend->io_flags & IOMAP_F_SHARED) ^ (next->io_flags & IOMAP_F_SHARED)) @@ -1623,9 +1606,8 @@ EXPORT_SYMBOL_GPL(iomap_sort_ioends); static void iomap_writepage_end_bio(struct bio *bio) { - struct iomap_ioend *ioend = bio->bi_private; - - iomap_finish_ioend(ioend, blk_status_to_errno(bio->bi_status)); + iomap_finish_ioend(iomap_ioend_from_bio(bio), + blk_status_to_errno(bio->bi_status)); } /* @@ -1640,9 +1622,6 @@ static int iomap_submit_ioend(struct iomap_writepage_ctx *wpc, struct iomap_ioend *ioend, int error) { - ioend->io_bio->bi_private = ioend; - ioend->io_bio->bi_end_io = iomap_writepage_end_bio; - if (wpc->ops->prepare_ioend) error = wpc->ops->prepare_ioend(ioend, error); if (error) { @@ -1652,12 +1631,12 @@ iomap_submit_ioend(struct iomap_writepage_ctx *wpc, struct iomap_ioend *ioend, * as there is only one reference to the ioend at this point in * time. */ - ioend->io_bio->bi_status = errno_to_blk_status(error); - bio_endio(ioend->io_bio); + ioend->io_bio.bi_status = errno_to_blk_status(error); + bio_endio(&ioend->io_bio); return error; } - submit_bio(ioend->io_bio); + submit_bio(&ioend->io_bio); return 0; } @@ -1671,44 +1650,22 @@ static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc, REQ_OP_WRITE | wbc_to_write_flags(wbc), GFP_NOFS, &iomap_ioend_bioset); bio->bi_iter.bi_sector = iomap_sector(&wpc->iomap, pos); + bio->bi_end_io = iomap_writepage_end_bio; wbc_init_bio(wbc, bio); - ioend = container_of(bio, struct iomap_ioend, io_inline_bio); + ioend = iomap_ioend_from_bio(bio); INIT_LIST_HEAD(&ioend->io_list); ioend->io_type = wpc->iomap.type; ioend->io_flags = wpc->iomap.flags; ioend->io_inode = inode; ioend->io_size = 0; ioend->io_offset = pos; - ioend->io_bio = bio; ioend->io_sector = bio->bi_iter.bi_sector; wpc->nr_folios = 0; return ioend; } -/* - * Allocate a new bio, and chain the old bio to the new one. - * - * Note that we have to perform the chaining in this unintuitive order - * so that the bi_private linkage is set up in the right direction for the - * traversal in iomap_finish_ioend(). - */ -static struct bio * -iomap_chain_bio(struct bio *prev) -{ - struct bio *new; - - new = bio_alloc(prev->bi_bdev, BIO_MAX_VECS, prev->bi_opf, GFP_NOFS); - bio_clone_blkg_association(new, prev); - new->bi_iter.bi_sector = bio_end_sector(prev); - - bio_chain(prev, new); - bio_get(prev); /* for iomap_finish_ioend */ - submit_bio(prev); - return new; -} - static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos) { if ((wpc->iomap.flags & IOMAP_F_SHARED) != @@ -1719,7 +1676,7 @@ static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos) if (pos != wpc->ioend->io_offset + wpc->ioend->io_size) return false; if (iomap_sector(&wpc->iomap, pos) != - bio_end_sector(wpc->ioend->io_bio)) + bio_end_sector(&wpc->ioend->io_bio)) return false; /* * Limit ioend bio chain lengths to minimise IO completion latency. This @@ -1744,15 +1701,14 @@ static void iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, size_t poff = offset_in_folio(folio, pos); if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, pos)) { +new_ioend: if (wpc->ioend) list_add(&wpc->ioend->io_list, iolist); wpc->ioend = iomap_alloc_ioend(wpc, wbc, inode, pos); } - if (!bio_add_folio(wpc->ioend->io_bio, folio, len, poff)) { - wpc->ioend->io_bio = iomap_chain_bio(wpc->ioend->io_bio); - bio_add_folio_nofail(wpc->ioend->io_bio, folio, len, poff); - } + if (!bio_add_folio(&wpc->ioend->io_bio, folio, len, poff)) + goto new_ioend; if (ifs) atomic_add(len, &ifs->write_bytes_pending); @@ -1983,7 +1939,7 @@ EXPORT_SYMBOL_GPL(iomap_writepages); static int __init iomap_init(void) { return bioset_init(&iomap_ioend_bioset, 4 * (PAGE_SIZE / SECTOR_SIZE), - offsetof(struct iomap_ioend, io_inline_bio), + offsetof(struct iomap_ioend, io_bio), BIOSET_NEED_BVECS); } fs_initcall(iomap_init); diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index 688ac031d3a1..ce83587aa52d 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -112,7 +112,7 @@ xfs_end_ioend( * longer dirty. If we don't remove delalloc blocks here, they become * stale and can corrupt free space accounting on unmount. */ - error = blk_status_to_errno(ioend->io_bio->bi_status); + error = blk_status_to_errno(ioend->io_bio.bi_status); if (unlikely(error)) { if (ioend->io_flags & IOMAP_F_SHARED) { xfs_reflink_cancel_cow_range(ip, offset, size, true); @@ -179,7 +179,7 @@ STATIC void xfs_end_bio( struct bio *bio) { - struct iomap_ioend *ioend = bio->bi_private; + struct iomap_ioend *ioend = iomap_ioend_from_bio(bio); struct xfs_inode *ip = XFS_I(ioend->io_inode); unsigned long flags; @@ -418,7 +418,7 @@ xfs_prepare_ioend( /* send ioends that might require a transaction to the completion wq */ if (xfs_ioend_is_append(ioend) || ioend->io_type == IOMAP_UNWRITTEN || (ioend->io_flags & IOMAP_F_SHARED)) - ioend->io_bio->bi_end_io = xfs_end_bio; + ioend->io_bio.bi_end_io = xfs_end_bio; return status; } diff --git a/include/linux/iomap.h b/include/linux/iomap.h index 4230c3d924f9..b4cc3de2fcb1 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -316,10 +316,14 @@ struct iomap_ioend { size_t io_size; /* size of the extent */ loff_t io_offset; /* offset in the file */ sector_t io_sector; /* start sector of ioend */ - struct bio *io_bio; /* bio being built */ - struct bio io_inline_bio; /* MUST BE LAST! */ + struct bio io_bio; /* MUST BE LAST! */ }; +static inline struct iomap_ioend *iomap_ioend_from_bio(struct bio *bio) +{ + return container_of(bio, struct iomap_ioend, io_bio); +} + struct iomap_writeback_ops { /* * Required, maps the blocks so that writeback can be performed on -- Gitee From ccd5d9a28567731dd3ce43ba2c1efacb3559a10c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:06 +0100 Subject: [PATCH 09/14] iomap: only call mapping_set_error once for each failed bio ANBZ: #20084 commit 6b865d6530230b0c446efd93e0207b8eed7eadb2 upstream. Instead of clling mapping_set_error once per folio, only do that once per bio, and consolidate all the writeback error handling code in iomap_finish_ioend. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-11-hch@lst.de Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 27 ++++++++++++++------------- 1 file changed, 14 insertions(+), 13 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 5f2b251a8fac..ac0515f6e408 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1459,15 +1459,10 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) EXPORT_SYMBOL_GPL(iomap_page_mkwrite); static void iomap_finish_folio_write(struct inode *inode, struct folio *folio, - size_t len, int error) + size_t len) { struct iomap_folio_state *ifs = folio->private; - if (error) { - folio_set_error(folio); - mapping_set_error(inode->i_mapping, error); - } - WARN_ON_ONCE(i_blocks_per_folio(inode, folio) > 1 && !ifs); WARN_ON_ONCE(ifs && atomic_read(&ifs->write_bytes_pending) <= 0); @@ -1488,18 +1483,24 @@ iomap_finish_ioend(struct iomap_ioend *ioend, int error) struct folio_iter fi; u32 folio_count = 0; + if (error) { + mapping_set_error(inode->i_mapping, error); + if (!bio_flagged(bio, BIO_QUIET)) { + pr_err_ratelimited( +"%s: writeback error on inode %lu, offset %lld, sector %llu", + inode->i_sb->s_id, inode->i_ino, + ioend->io_offset, ioend->io_sector); + } + } + /* walk all folios in bio, ending page IO on them */ bio_for_each_folio_all(fi, bio) { - iomap_finish_folio_write(inode, fi.folio, fi.length, error); + if (error) + folio_set_error(fi.folio); + iomap_finish_folio_write(inode, fi.folio, fi.length); folio_count++; } - if (unlikely(error && !bio_flagged(bio, BIO_QUIET))) { - printk_ratelimited(KERN_ERR -"%s: writeback error on inode %lu, offset %lld, sector %llu", - inode->i_sb->s_id, inode->i_ino, - ioend->io_offset, ioend->io_sector); - } bio_put(bio); /* frees the ioend */ return folio_count; } -- Gitee From d4537ba7c22c84ead3261564bd2df4f9154f5772 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:07 +0100 Subject: [PATCH 10/14] iomap: factor out a iomap_writepage_map_block helper ANBZ: #20084 commit f525152a0f0ff34eb92b322703d76ba37095f556 upstream. Split the loop body that calls into the file system to map a block and add it to the ioend into a separate helper to prefer for refactoring of the surrounding code. Note that this was the only place in iomap_writepage_map that could return an error, so include the call to ->discard_folio into the new helper as that will help to avoid code duplication in the future. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-12-hch@lst.de Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 70 ++++++++++++++++++++++++++---------------- 1 file changed, 43 insertions(+), 27 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index ac0515f6e408..8bd15fe332b8 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1717,6 +1717,45 @@ static void iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, wbc_account_cgroup_owner(wbc, &folio->page, len); } +static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc, + struct writeback_control *wbc, struct folio *folio, + struct inode *inode, u64 pos, unsigned *count, + struct list_head *submit_list) +{ + int error; + + error = wpc->ops->map_blocks(wpc, inode, pos); + if (error) + goto fail; + trace_iomap_writepage_map(inode, &wpc->iomap); + + switch (wpc->iomap.type) { + case IOMAP_INLINE: + WARN_ON_ONCE(1); + error = -EIO; + break; + case IOMAP_HOLE: + break; + default: + iomap_add_to_ioend(wpc, wbc, folio, inode, pos, submit_list); + (*count)++; + } + +fail: + /* + * We cannot cancel the ioend directly here on error. We may have + * already set other pages under writeback and hence we have to run I/O + * completion to mark the error state of the pages under writeback + * appropriately. + * + * Just let the file system know what portion of the folio failed to + * map. + */ + if (error && wpc->ops->discard_folio) + wpc->ops->discard_folio(folio, pos); + return error; +} + /* * Check interaction of the folio with the file end. * @@ -1801,7 +1840,8 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, unsigned nblocks = i_blocks_per_folio(inode, folio); u64 pos = folio_pos(folio); u64 end_pos = pos + folio_size(folio); - int error = 0, count = 0, i; + unsigned count = 0; + int error = 0, i; LIST_HEAD(submit_list); trace_iomap_writepage(inode, pos, folio_size(folio)); @@ -1827,19 +1867,10 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, for (i = 0; i < nblocks && pos < end_pos; i++, pos += len) { if (ifs && !ifs_block_is_dirty(folio, ifs, i)) continue; - - error = wpc->ops->map_blocks(wpc, inode, pos); + error = iomap_writepage_map_blocks(wpc, wbc, folio, inode, pos, + &count, &submit_list); if (error) break; - trace_iomap_writepage_map(inode, &wpc->iomap); - if (WARN_ON_ONCE(wpc->iomap.type == IOMAP_INLINE)) { - error = -EIO; - break; - } - if (wpc->iomap.type == IOMAP_HOLE) - continue; - iomap_add_to_ioend(wpc, wbc, folio, inode, pos, &submit_list); - count++; } if (count) wpc->nr_folios++; @@ -1849,21 +1880,6 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, WARN_ON_ONCE(folio_test_writeback(folio)); WARN_ON_ONCE(folio_test_dirty(folio)); - /* - * We cannot cancel the ioend directly here on error. We may have - * already set other pages under writeback and hence we have to run I/O - * completion to mark the error state of the pages under writeback - * appropriately. - */ - if (unlikely(error)) { - /* - * Let the filesystem know what portion of the current page - * failed to map. - */ - if (wpc->ops->discard_folio) - wpc->ops->discard_folio(folio, pos); - } - /* * We can have dirty bits set past end of file in page_mkwrite path * while mapping the last partial folio. Hence it's better to clear -- Gitee From 72f8247b59e1c315838ce0cb51769cdaafa50321 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:08 +0100 Subject: [PATCH 11/14] iomap: submit ioends immediately ANBZ: #20084 commit 410bb2ce611133a11d4d11f0aef4c83f095c3200 upstream. Currently the writeback code delays submitting fill ioends until we reach the end of the folio. The reason for that is that otherwise the end I/O handler could clear the writeback bit before we've even finished submitting all I/O for the folio. Add a bias to ifs->write_bytes_pending while we are submitting I/O for a folio so that it never reaches zero until all I/O is completed to prevent the early writeback bit clearing, and remove the now superfluous submit_list. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-13-hch@lst.de Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 162 +++++++++++++++++++---------------------- 1 file changed, 76 insertions(+), 86 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 8bd15fe332b8..a2a0558a7361 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1615,30 +1615,34 @@ static void iomap_writepage_end_bio(struct bio *bio) * Submit the final bio for an ioend. * * If @error is non-zero, it means that we have a situation where some part of - * the submission process has failed after we've marked pages for writeback - * and unlocked them. In this situation, we need to fail the bio instead of - * submitting it. This typically only happens on a filesystem shutdown. + * the submission process has failed after we've marked pages for writeback. + * We cannot cancel ioend directly in that case, so call the bio end I/O handler + * with the error status here to run the normal I/O completion handler to clear + * the writeback bit and let the file system proess the errors. */ -static int -iomap_submit_ioend(struct iomap_writepage_ctx *wpc, struct iomap_ioend *ioend, - int error) +static int iomap_submit_ioend(struct iomap_writepage_ctx *wpc, int error) { + if (!wpc->ioend) + return error; + + /* + * Let the file systems prepare the I/O submission and hook in an I/O + * comletion handler. This also needs to happen in case after a + * failure happened so that the file system end I/O handler gets called + * to clean up. + */ if (wpc->ops->prepare_ioend) - error = wpc->ops->prepare_ioend(ioend, error); + error = wpc->ops->prepare_ioend(wpc->ioend, error); + if (error) { - /* - * If we're failing the IO now, just mark the ioend with an - * error and finish it. This will run IO completion immediately - * as there is only one reference to the ioend at this point in - * time. - */ - ioend->io_bio.bi_status = errno_to_blk_status(error); - bio_endio(&ioend->io_bio); - return error; + wpc->ioend->io_bio.bi_status = errno_to_blk_status(error); + bio_endio(&wpc->ioend->io_bio); + } else { + submit_bio(&wpc->ioend->io_bio); } - submit_bio(&ioend->io_bio); - return 0; + wpc->ioend = NULL; + return error; } static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc, @@ -1692,19 +1696,28 @@ static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos) /* * Test to see if we have an existing ioend structure that we could append to * first; otherwise finish off the current ioend and start another. + * + * If a new ioend is created and cached, the old ioend is submitted to the block + * layer instantly. Batching optimisations are provided by higher level block + * plugging. + * + * At the end of a writeback pass, there will be a cached ioend remaining on the + * writepage context that the caller will need to submit. */ -static void iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, +static int iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct writeback_control *wbc, struct folio *folio, - struct inode *inode, loff_t pos, struct list_head *iolist) + struct inode *inode, loff_t pos) { struct iomap_folio_state *ifs = folio->private; unsigned len = i_blocksize(inode); size_t poff = offset_in_folio(folio, pos); + int error; if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, pos)) { new_ioend: - if (wpc->ioend) - list_add(&wpc->ioend->io_list, iolist); + error = iomap_submit_ioend(wpc, 0); + if (error) + return error; wpc->ioend = iomap_alloc_ioend(wpc, wbc, inode, pos); } @@ -1715,12 +1728,12 @@ static void iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, atomic_add(len, &ifs->write_bytes_pending); wpc->ioend->io_size += len; wbc_account_cgroup_owner(wbc, &folio->page, len); + return 0; } static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc, struct writeback_control *wbc, struct folio *folio, - struct inode *inode, u64 pos, unsigned *count, - struct list_head *submit_list) + struct inode *inode, u64 pos, unsigned *count) { int error; @@ -1737,8 +1750,9 @@ static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc, case IOMAP_HOLE: break; default: - iomap_add_to_ioend(wpc, wbc, folio, inode, pos, submit_list); - (*count)++; + error = iomap_add_to_ioend(wpc, wbc, folio, inode, pos); + if (!error) + (*count)++; } fail: @@ -1814,35 +1828,21 @@ static bool iomap_writepage_handle_eof(struct folio *folio, struct inode *inode, return true; } -/* - * We implement an immediate ioend submission policy here to avoid needing to - * chain multiple ioends and hence nest mempool allocations which can violate - * the forward progress guarantees we need to provide. The current ioend we're - * adding blocks to is cached in the writepage context, and if the new block - * doesn't append to the cached ioend, it will create a new ioend and cache that - * instead. - * - * If a new ioend is created and cached, the old ioend is returned and queued - * locally for submission once the entire page is processed or an error has been - * detected. While ioends are submitted immediately after they are completed, - * batching optimisations are provided by higher level block plugging. - * - * At the end of a writeback pass, there will be a cached ioend remaining on the - * writepage context that the caller will need to submit. - */ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, struct writeback_control *wbc, struct folio *folio) { struct iomap_folio_state *ifs = folio->private; struct inode *inode = folio->mapping->host; - struct iomap_ioend *ioend, *next; unsigned len = i_blocksize(inode); unsigned nblocks = i_blocks_per_folio(inode, folio); u64 pos = folio_pos(folio); u64 end_pos = pos + folio_size(folio); unsigned count = 0; int error = 0, i; - LIST_HEAD(submit_list); + + WARN_ON_ONCE(!folio_test_locked(folio)); + WARN_ON_ONCE(folio_test_dirty(folio)); + WARN_ON_ONCE(folio_test_writeback(folio)); trace_iomap_writepage(inode, pos, folio_size(folio)); @@ -1852,12 +1852,27 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, } WARN_ON_ONCE(end_pos <= pos); - if (!ifs && nblocks > 1) { - ifs = ifs_alloc(inode, folio, 0); - iomap_set_range_dirty(folio, 0, end_pos - pos); + if (nblocks > 1) { + if (!ifs) { + ifs = ifs_alloc(inode, folio, 0); + iomap_set_range_dirty(folio, 0, end_pos - pos); + } + + /* + * Keep the I/O completion handler from clearing the writeback + * bit until we have submitted all blocks by adding a bias to + * ifs->write_bytes_pending, which is dropped after submitting + * all blocks. + */ + WARN_ON_ONCE(atomic_read(&ifs->write_bytes_pending) != 0); + atomic_inc(&ifs->write_bytes_pending); } - WARN_ON_ONCE(ifs && atomic_read(&ifs->write_bytes_pending) != 0); + /* + * Set the writeback bit ASAP, as the I/O completion for the single + * block per folio case happen hit as soon as we're submitting the bio. + */ + folio_start_writeback(folio); /* * Walk through the folio to find areas to write back. If we @@ -1868,18 +1883,13 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, if (ifs && !ifs_block_is_dirty(folio, ifs, i)) continue; error = iomap_writepage_map_blocks(wpc, wbc, folio, inode, pos, - &count, &submit_list); + &count); if (error) break; } if (count) wpc->nr_folios++; - WARN_ON_ONCE(!wpc->ioend && !list_empty(&submit_list)); - WARN_ON_ONCE(!folio_test_locked(folio)); - WARN_ON_ONCE(folio_test_writeback(folio)); - WARN_ON_ONCE(folio_test_dirty(folio)); - /* * We can have dirty bits set past end of file in page_mkwrite path * while mapping the last partial folio. Hence it's better to clear @@ -1888,38 +1898,20 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, iomap_clear_range_dirty(folio, 0, folio_size(folio)); /* - * If the page hasn't been added to the ioend, it won't be affected by - * I/O completion and we must unlock it now. + * Usually the writeback bit is cleared by the I/O completion handler. + * But we may end up either not actually writing any blocks, or (when + * there are multiple blocks in a folio) all I/O might have finished + * already at this point. In that case we need to clear the writeback + * bit ourselves right after unlocking the page. */ - if (error && !count) { - folio_unlock(folio); - goto done; - } - - folio_start_writeback(folio); folio_unlock(folio); - - /* - * Preserve the original error if there was one; catch - * submission errors here and propagate into subsequent ioend - * submissions. - */ - list_for_each_entry_safe(ioend, next, &submit_list, io_list) { - int error2; - - list_del_init(&ioend->io_list); - error2 = iomap_submit_ioend(wpc, ioend, error); - if (error2 && !error) - error = error2; + if (ifs) { + if (atomic_dec_and_test(&ifs->write_bytes_pending)) + folio_end_writeback(folio); + } else { + if (!count) + folio_end_writeback(folio); } - - /* - * We can end up here with no error and nothing to write only if we race - * with a partial page truncate on a sub-page block sized filesystem. - */ - if (!count) - folio_end_writeback(folio); -done: mapping_set_error(inode->i_mapping, error); return error; } @@ -1947,9 +1939,7 @@ iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, wpc->ops = ops; ret = write_cache_pages(mapping, wbc, iomap_do_writepage, wpc); - if (!wpc->ioend) - return ret; - return iomap_submit_ioend(wpc, wpc->ioend, ret); + return iomap_submit_ioend(wpc, ret); } EXPORT_SYMBOL_GPL(iomap_writepages); -- Gitee From 454c6fe0f4aadcabd0ff77214112d8e351ded242 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:09 +0100 Subject: [PATCH 12/14] iomap: map multiple blocks at a time ANBZ: #20084 commit 30deff8531f469453ccc0981f14eceb0a2ea68d6 upstream. The ->map_blocks interface returns a valid range for writeback, but we still call back into it for every block, which is a bit inefficient. Change iomap_writepage_map to use the valid range in the map until the end of the folio or the dirty range inside the folio instead of calling back into every block. Note that the range is not used over folio boundaries as we need to be able to check the mapping sequence count under the folio lock. Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-14-hch@lst.de Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 116 ++++++++++++++++++++++++++++------------- include/linux/iomap.h | 7 +++ 2 files changed, 88 insertions(+), 35 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index a2a0558a7361..b22660008ebf 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1,7 +1,7 @@ // SPDX-License-Identifier: GPL-2.0 /* * Copyright (C) 2010 Red Hat, Inc. - * Copyright (C) 2016-2019 Christoph Hellwig. + * Copyright (C) 2016-2023 Christoph Hellwig. */ #include #include @@ -93,6 +93,44 @@ static inline bool ifs_block_is_dirty(struct folio *folio, return test_bit(block + blks_per_folio, ifs->state); } +static unsigned ifs_find_dirty_range(struct folio *folio, + struct iomap_folio_state *ifs, u64 *range_start, u64 range_end) +{ + struct inode *inode = folio->mapping->host; + unsigned start_blk = + offset_in_folio(folio, *range_start) >> inode->i_blkbits; + unsigned end_blk = min_not_zero( + offset_in_folio(folio, range_end) >> inode->i_blkbits, + i_blocks_per_folio(inode, folio)); + unsigned nblks = 1; + + while (!ifs_block_is_dirty(folio, ifs, start_blk)) + if (++start_blk == end_blk) + return 0; + + while (start_blk + nblks < end_blk) { + if (!ifs_block_is_dirty(folio, ifs, start_blk + nblks)) + break; + nblks++; + } + + *range_start = folio_pos(folio) + (start_blk << inode->i_blkbits); + return nblks << inode->i_blkbits; +} + +static unsigned iomap_find_dirty_range(struct folio *folio, u64 *range_start, + u64 range_end) +{ + struct iomap_folio_state *ifs = folio->private; + + if (*range_start >= range_end) + return 0; + + if (ifs) + return ifs_find_dirty_range(folio, ifs, range_start, range_end); + return range_end - *range_start; +} + static void ifs_clear_range_dirty(struct folio *folio, struct iomap_folio_state *ifs, size_t off, size_t len) { @@ -1706,10 +1744,9 @@ static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos) */ static int iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, struct writeback_control *wbc, struct folio *folio, - struct inode *inode, loff_t pos) + struct inode *inode, loff_t pos, unsigned len) { struct iomap_folio_state *ifs = folio->private; - unsigned len = i_blocksize(inode); size_t poff = offset_in_folio(folio, pos); int error; @@ -1733,29 +1770,41 @@ static int iomap_add_to_ioend(struct iomap_writepage_ctx *wpc, static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc, struct writeback_control *wbc, struct folio *folio, - struct inode *inode, u64 pos, unsigned *count) + struct inode *inode, u64 pos, unsigned dirty_len, + unsigned *count) { int error; - error = wpc->ops->map_blocks(wpc, inode, pos); - if (error) - goto fail; - trace_iomap_writepage_map(inode, &wpc->iomap); - - switch (wpc->iomap.type) { - case IOMAP_INLINE: - WARN_ON_ONCE(1); - error = -EIO; - break; - case IOMAP_HOLE: - break; - default: - error = iomap_add_to_ioend(wpc, wbc, folio, inode, pos); - if (!error) - (*count)++; - } + do { + unsigned map_len; + + error = wpc->ops->map_blocks(wpc, inode, pos); + if (error) + break; + trace_iomap_writepage_map(inode, &wpc->iomap); + + map_len = min_t(u64, dirty_len, + wpc->iomap.offset + wpc->iomap.length - pos); + WARN_ON_ONCE(!folio->private && map_len < dirty_len); + + switch (wpc->iomap.type) { + case IOMAP_INLINE: + WARN_ON_ONCE(1); + error = -EIO; + break; + case IOMAP_HOLE: + break; + default: + error = iomap_add_to_ioend(wpc, wbc, folio, inode, pos, + map_len); + if (!error) + (*count)++; + break; + } + dirty_len -= map_len; + pos += map_len; + } while (dirty_len && !error); -fail: /* * We cannot cancel the ioend directly here on error. We may have * already set other pages under writeback and hence we have to run I/O @@ -1822,7 +1871,7 @@ static bool iomap_writepage_handle_eof(struct folio *folio, struct inode *inode, * beyond i_size. */ folio_zero_segment(folio, poff, folio_size(folio)); - *end_pos = isize; + *end_pos = round_up(isize, i_blocksize(inode)); } return true; @@ -1833,12 +1882,11 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, { struct iomap_folio_state *ifs = folio->private; struct inode *inode = folio->mapping->host; - unsigned len = i_blocksize(inode); - unsigned nblocks = i_blocks_per_folio(inode, folio); u64 pos = folio_pos(folio); u64 end_pos = pos + folio_size(folio); unsigned count = 0; - int error = 0, i; + int error = 0; + u32 rlen; WARN_ON_ONCE(!folio_test_locked(folio)); WARN_ON_ONCE(folio_test_dirty(folio)); @@ -1852,7 +1900,7 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, } WARN_ON_ONCE(end_pos <= pos); - if (nblocks > 1) { + if (i_blocks_per_folio(inode, folio) > 1) { if (!ifs) { ifs = ifs_alloc(inode, folio, 0); iomap_set_range_dirty(folio, 0, end_pos - pos); @@ -1875,18 +1923,16 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, folio_start_writeback(folio); /* - * Walk through the folio to find areas to write back. If we - * run off the end of the current map or find the current map - * invalid, grab a new one. + * Walk through the folio to find dirty areas to write back. */ - for (i = 0; i < nblocks && pos < end_pos; i++, pos += len) { - if (ifs && !ifs_block_is_dirty(folio, ifs, i)) - continue; - error = iomap_writepage_map_blocks(wpc, wbc, folio, inode, pos, - &count); + while ((rlen = iomap_find_dirty_range(folio, &pos, end_pos))) { + error = iomap_writepage_map_blocks(wpc, wbc, folio, inode, + pos, rlen, &count); if (error) break; + pos += rlen; } + if (count) wpc->nr_folios++; diff --git a/include/linux/iomap.h b/include/linux/iomap.h index b4cc3de2fcb1..a97c8649d53d 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -328,6 +328,13 @@ struct iomap_writeback_ops { /* * Required, maps the blocks so that writeback can be performed on * the range starting at offset. + * + * Can return arbitrarily large regions, but we need to call into it at + * least once per folio to allow the file systems to synchronize with + * the write path that could be invalidating mappings. + * + * An existing mapping from a previous call to this method can be reused + * by the file system if it is still valid. */ int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode, loff_t offset); -- Gitee From f13dfe590cc710c038c4e2e5dbfff2f9623de367 Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 7 Dec 2023 08:27:10 +0100 Subject: [PATCH 13/14] iomap: pass the length of the dirty region to ->map_blocks ANBZ: #20084 commit 19871b5c7a003946d3cd4209a348ab7c0df5dbad upstream. Let the file system know how much dirty data exists at the passed in offset. This allows file systems to allocate the right amount of space that actually is written back if they can't eagerly convert (e.g. because they don't support unwritten extents). Signed-off-by: Christoph Hellwig Link: https://lore.kernel.org/r/20231207072710.176093-15-hch@lst.de Signed-off-by: Christian Brauner Signed-off-by: Jia He --- block/fops.c | 2 +- fs/gfs2/bmap.c | 2 +- fs/iomap/buffered-io.c | 2 +- fs/xfs/xfs_aops.c | 3 ++- fs/zonefs/file.c | 3 ++- include/linux/iomap.h | 2 +- 6 files changed, 8 insertions(+), 6 deletions(-) diff --git a/block/fops.c b/block/fops.c index 1df187b30679..f2d9b5a2f296 100644 --- a/block/fops.c +++ b/block/fops.c @@ -467,7 +467,7 @@ static void blkdev_readahead(struct readahead_control *rac) } static int blkdev_map_blocks(struct iomap_writepage_ctx *wpc, - struct inode *inode, loff_t offset) + struct inode *inode, loff_t offset, unsigned int len) { loff_t isize = i_size_read(inode); diff --git a/fs/gfs2/bmap.c b/fs/gfs2/bmap.c index 7ed276a8f599..73d3d4c5d583 100644 --- a/fs/gfs2/bmap.c +++ b/fs/gfs2/bmap.c @@ -2463,7 +2463,7 @@ int __gfs2_punch_hole(struct file *file, loff_t offset, loff_t length) } static int gfs2_map_blocks(struct iomap_writepage_ctx *wpc, struct inode *inode, - loff_t offset) + loff_t offset, unsigned int len) { int ret; diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index b22660008ebf..ad3aab6e26ed 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1778,7 +1778,7 @@ static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc, do { unsigned map_len; - error = wpc->ops->map_blocks(wpc, inode, pos); + error = wpc->ops->map_blocks(wpc, inode, pos, dirty_len); if (error) break; trace_iomap_writepage_map(inode, &wpc->iomap); diff --git a/fs/xfs/xfs_aops.c b/fs/xfs/xfs_aops.c index ce83587aa52d..82f18f28c1c1 100644 --- a/fs/xfs/xfs_aops.c +++ b/fs/xfs/xfs_aops.c @@ -237,7 +237,8 @@ static int xfs_map_blocks( struct iomap_writepage_ctx *wpc, struct inode *inode, - loff_t offset) + loff_t offset, + unsigned int len) { struct xfs_inode *ip = XFS_I(inode); struct xfs_mount *mp = ip->i_mount; diff --git a/fs/zonefs/file.c b/fs/zonefs/file.c index 897b12ec61e2..e66de2191245 100644 --- a/fs/zonefs/file.c +++ b/fs/zonefs/file.c @@ -125,7 +125,8 @@ static void zonefs_readahead(struct readahead_control *rac) * which implies that the page range can only be within the fixed inode size. */ static int zonefs_write_map_blocks(struct iomap_writepage_ctx *wpc, - struct inode *inode, loff_t offset) + struct inode *inode, loff_t offset, + unsigned int len) { struct zonefs_zone *z = zonefs_inode_zone(inode); diff --git a/include/linux/iomap.h b/include/linux/iomap.h index a97c8649d53d..034399030609 100644 --- a/include/linux/iomap.h +++ b/include/linux/iomap.h @@ -337,7 +337,7 @@ struct iomap_writeback_ops { * by the file system if it is still valid. */ int (*map_blocks)(struct iomap_writepage_ctx *wpc, struct inode *inode, - loff_t offset); + loff_t offset, unsigned len); /* * Optional, allows the file systems to perform actions just before -- Gitee From 3c5a0c0359a18e8e018f01f80748f32db6ea80d9 Mon Sep 17 00:00:00 2001 From: Zhang Yi Date: Tue, 20 Feb 2024 19:57:59 +0800 Subject: [PATCH 14/14] iomap: add pos and dirty_len into trace_iomap_writepage_map ANBZ: #20084 commit 54943abce0927156ba9909f1a533b25410bfe2ca upstream. Since commit fd07e0aa23c4 ("iomap: map multiple blocks at a time"), we could map multi-blocks once a time, and the dirty_len indicates the expected map length, map_len won't large than it. The pos and dirty_len means the dirty range that should be mapped to write, add them into trace_iomap_writepage_map() could be more useful for debug. Signed-off-by: Zhang Yi Link: https://lore.kernel.org/r/20240220115759.3445025-1-yi.zhang@huaweicloud.com Reviewed-by: Christoph Hellwig Reviewed-by: Darrick J. Wong Signed-off-by: Christian Brauner Signed-off-by: Jia He --- fs/iomap/buffered-io.c | 2 +- fs/iomap/trace.h | 43 +++++++++++++++++++++++++++++++++++++++++- 2 files changed, 43 insertions(+), 2 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index ad3aab6e26ed..c7325156d1fc 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -1781,7 +1781,7 @@ static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc, error = wpc->ops->map_blocks(wpc, inode, pos, dirty_len); if (error) break; - trace_iomap_writepage_map(inode, &wpc->iomap); + trace_iomap_writepage_map(inode, pos, dirty_len, &wpc->iomap); map_len = min_t(u64, dirty_len, wpc->iomap.offset + wpc->iomap.length - pos); diff --git a/fs/iomap/trace.h b/fs/iomap/trace.h index c16fd55f5595..3ef694f9489f 100644 --- a/fs/iomap/trace.h +++ b/fs/iomap/trace.h @@ -154,7 +154,48 @@ DEFINE_EVENT(iomap_class, name, \ TP_ARGS(inode, iomap)) DEFINE_IOMAP_EVENT(iomap_iter_dstmap); DEFINE_IOMAP_EVENT(iomap_iter_srcmap); -DEFINE_IOMAP_EVENT(iomap_writepage_map); + +TRACE_EVENT(iomap_writepage_map, + TP_PROTO(struct inode *inode, u64 pos, unsigned int dirty_len, + struct iomap *iomap), + TP_ARGS(inode, pos, dirty_len, iomap), + TP_STRUCT__entry( + __field(dev_t, dev) + __field(u64, ino) + __field(u64, pos) + __field(u64, dirty_len) + __field(u64, addr) + __field(loff_t, offset) + __field(u64, length) + __field(u16, type) + __field(u16, flags) + __field(dev_t, bdev) + ), + TP_fast_assign( + __entry->dev = inode->i_sb->s_dev; + __entry->ino = inode->i_ino; + __entry->pos = pos; + __entry->dirty_len = dirty_len; + __entry->addr = iomap->addr; + __entry->offset = iomap->offset; + __entry->length = iomap->length; + __entry->type = iomap->type; + __entry->flags = iomap->flags; + __entry->bdev = iomap->bdev ? iomap->bdev->bd_dev : 0; + ), + TP_printk("dev %d:%d ino 0x%llx bdev %d:%d pos 0x%llx dirty len 0x%llx " + "addr 0x%llx offset 0x%llx length 0x%llx type %s flags %s", + MAJOR(__entry->dev), MINOR(__entry->dev), + __entry->ino, + MAJOR(__entry->bdev), MINOR(__entry->bdev), + __entry->pos, + __entry->dirty_len, + __entry->addr, + __entry->offset, + __entry->length, + __print_symbolic(__entry->type, IOMAP_TYPE_STRINGS), + __print_flags(__entry->flags, "|", IOMAP_F_FLAGS_STRINGS)) +); TRACE_EVENT(iomap_iter, TP_PROTO(struct iomap_iter *iter, const void *ops, -- Gitee