From 66c0d855142835a9fd12478299cc337777d6225e Mon Sep 17 00:00:00 2001 From: Brian Foster Date: Tue, 6 May 2025 09:41:18 -0400 Subject: [PATCH] iomap: rework iomap_write_begin() to return folio offset and length iomap_write_begin() returns a folio based on current pos and remaining length in the iter, and each caller then trims the pos/length to the given folio. Clean this up a bit and let iomap_write_begin() return the trimmed range along with the folio. Signed-off-by: Brian Foster Link: https://lore.kernel.org/20250506134118.911396-7-bfoster@redhat.com Reviewed-by: Christoph Hellwig Signed-off-by: Christian Brauner --- fs/iomap/buffered-io.c | 33 +++++++++++++++++++-------------- 1 file changed, 19 insertions(+), 14 deletions(-) diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 86482b8482599..572446635c9a3 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -679,11 +679,12 @@ static int iomap_read_folio_sync(loff_t block_start, struct folio *folio, return submit_bio_wait(&bio); } -static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos, - size_t len, struct folio *folio) +static int __iomap_write_begin(const struct iomap_iter *iter, size_t len, + struct folio *folio) { const struct iomap *srcmap = iomap_iter_srcmap(iter); struct iomap_folio_state *ifs; + loff_t pos = iter->pos; loff_t block_size = i_blocksize(iter->inode); loff_t block_start = round_down(pos, block_size); loff_t block_end = round_up(pos + len, block_size); @@ -794,15 +795,22 @@ static int iomap_write_begin_inline(const struct iomap_iter *iter, return iomap_read_inline_data(iter, folio); } -static int iomap_write_begin(struct iomap_iter *iter, size_t len, - struct folio **foliop) +/* + * Grab and prepare a folio for write based on iter state. Returns the folio, + * offset, and length. Callers can optionally pass a max length *plen, + * otherwise init to zero. + */ +static int iomap_write_begin(struct iomap_iter *iter, struct folio **foliop, + size_t *poffset, u64 *plen) { const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops; const struct iomap *srcmap = iomap_iter_srcmap(iter); loff_t pos = iter->pos; + u64 len = min_t(u64, SIZE_MAX, iomap_length(iter)); struct folio *folio; int status = 0; + len = min_not_zero(len, *plen); BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length); if (srcmap != &iter->iomap) BUG_ON(pos + len > srcmap->offset + srcmap->length); @@ -834,20 +842,20 @@ static int iomap_write_begin(struct iomap_iter *iter, size_t len, } } - if (pos + len > folio_pos(folio) + folio_size(folio)) - len = folio_pos(folio) + folio_size(folio) - pos; + pos = iomap_trim_folio_range(iter, folio, poffset, &len); if (srcmap->type == IOMAP_INLINE) status = iomap_write_begin_inline(iter, folio); else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) status = __block_write_begin_int(folio, pos, len, NULL, srcmap); else - status = __iomap_write_begin(iter, pos, len, folio); + status = __iomap_write_begin(iter, len, folio); if (unlikely(status)) goto out_unlock; *foliop = folio; + *plen = len; return 0; out_unlock: @@ -968,7 +976,7 @@ retry: break; } - status = iomap_write_begin(iter, bytes, &folio); + status = iomap_write_begin(iter, &folio, &offset, &bytes); if (unlikely(status)) { iomap_write_failed(iter->inode, iter->pos, bytes); break; @@ -976,7 +984,7 @@ retry: if (iter->iomap.flags & IOMAP_F_STALE) break; - pos = iomap_trim_folio_range(iter, folio, &offset, &bytes); + pos = iter->pos; if (mapping_writably_mapped(mapping)) flush_dcache_folio(folio); @@ -1296,14 +1304,12 @@ static int iomap_unshare_iter(struct iomap_iter *iter) bool ret; bytes = min_t(u64, SIZE_MAX, bytes); - status = iomap_write_begin(iter, bytes, &folio); + status = iomap_write_begin(iter, &folio, &offset, &bytes); if (unlikely(status)) return status; if (iomap->flags & IOMAP_F_STALE) break; - iomap_trim_folio_range(iter, folio, &offset, &bytes); - ret = iomap_write_end(iter, bytes, bytes, folio); __iomap_put_folio(iter, bytes, folio); if (WARN_ON_ONCE(!ret)) @@ -1368,7 +1374,7 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) bool ret; bytes = min_t(u64, SIZE_MAX, bytes); - status = iomap_write_begin(iter, bytes, &folio); + status = iomap_write_begin(iter, &folio, &offset, &bytes); if (status) return status; if (iter->iomap.flags & IOMAP_F_STALE) @@ -1377,7 +1383,6 @@ static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) /* warn about zeroing folios beyond eof that won't write back */ WARN_ON_ONCE(folio_pos(folio) > iter->inode->i_size); - iomap_trim_folio_range(iter, folio, &offset, &bytes); folio_zero_range(folio, offset, bytes); folio_mark_accessed(folio); -- 2.47.2