diff options
Diffstat (limited to 'fs/iomap/buffered-io.c')
| -rw-r--r-- | fs/iomap/buffered-io.c | 902 |
1 files changed, 443 insertions, 459 deletions
diff --git a/fs/iomap/buffered-io.c b/fs/iomap/buffered-io.c index 4e8e41c8b3c0..233abf598f65 100644 --- a/fs/iomap/buffered-io.c +++ b/fs/iomap/buffered-io.c @@ -12,18 +12,15 @@ #include <linux/buffer_head.h> #include <linux/dax.h> #include <linux/writeback.h> -#include <linux/list_sort.h> #include <linux/swap.h> #include <linux/bio.h> #include <linux/sched/signal.h> #include <linux/migrate.h> +#include "internal.h" #include "trace.h" #include "../internal.h" -#define IOEND_BATCH_SIZE 4096 - -typedef int (*iomap_punch_t)(struct inode *inode, loff_t offset, loff_t length); /* * Structure allocated for each folio to track per-block uptodate, dirty state * and I/O completions. @@ -41,8 +38,6 @@ struct iomap_folio_state { unsigned long state[]; }; -static struct bio_set iomap_ioend_bioset; - static inline bool ifs_is_fully_uptodate(struct folio *folio, struct iomap_folio_state *ifs) { @@ -241,6 +236,7 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio, unsigned block_size = (1 << block_bits); size_t poff = offset_in_folio(folio, *pos); size_t plen = min_t(loff_t, folio_size(folio) - poff, length); + size_t orig_plen = plen; unsigned first = poff >> block_bits; unsigned last = (poff + plen - 1) >> block_bits; @@ -263,7 +259,7 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio, } /* truncate len if we find any trailing uptodate block(s) */ - for ( ; i <= last; i++) { + while (++i <= last) { if (ifs_block_is_uptodate(ifs, i)) { plen -= (last - i + 1) * block_size; last = i - 1; @@ -277,7 +273,7 @@ static void iomap_adjust_read_range(struct inode *inode, struct folio *folio, * handle both halves separately so that we properly zero data in the * page cache for blocks that are entirely outside of i_size. */ - if (orig_pos <= isize && orig_pos + length > isize) { + if (orig_pos <= isize && orig_pos + orig_plen > isize) { unsigned end = offset_in_folio(folio, isize - 1) >> block_bits; if (first <= end && last > end) @@ -306,8 +302,6 @@ static void iomap_finish_folio_read(struct folio *folio, size_t off, spin_unlock_irqrestore(&ifs->state_lock, flags); } - if (error) - folio_set_error(folio); if (finished) folio_end_read(folio, uptodate); } @@ -368,20 +362,24 @@ static inline bool iomap_block_needs_zeroing(const struct iomap_iter *iter, pos >= i_size_read(iter->inode); } -static loff_t iomap_readpage_iter(const struct iomap_iter *iter, - struct iomap_readpage_ctx *ctx, loff_t offset) +static int iomap_readpage_iter(struct iomap_iter *iter, + struct iomap_readpage_ctx *ctx) { const struct iomap *iomap = &iter->iomap; - loff_t pos = iter->pos + offset; - loff_t length = iomap_length(iter) - offset; + loff_t pos = iter->pos; + loff_t length = iomap_length(iter); struct folio *folio = ctx->cur_folio; struct iomap_folio_state *ifs; - loff_t orig_pos = pos; size_t poff, plen; sector_t sector; + int ret; - if (iomap->type == IOMAP_INLINE) - return iomap_read_inline_data(iter, folio); + if (iomap->type == IOMAP_INLINE) { + ret = iomap_read_inline_data(iter, folio); + if (ret) + return ret; + return iomap_iter_advance(iter, &length); + } /* zero post-eof blocks as the page may be mapped */ ifs = ifs_alloc(iter->inode, folio, iter->flags); @@ -440,7 +438,22 @@ done: * we can skip trailing ones as they will be handled in the next * iteration. */ - return pos - orig_pos + plen; + length = pos - iter->pos + plen; + return iomap_iter_advance(iter, &length); +} + +static int iomap_read_folio_iter(struct iomap_iter *iter, + struct iomap_readpage_ctx *ctx) +{ + int ret; + + while (iomap_length(iter)) { + ret = iomap_readpage_iter(iter, ctx); + if (ret) + return ret; + } + + return 0; } int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) @@ -458,10 +471,7 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) trace_iomap_readpage(iter.inode, 1); while ((ret = iomap_iter(&iter, ops)) > 0) - iter.processed = iomap_readpage_iter(&iter, &ctx, 0); - - if (ret < 0) - folio_set_error(folio); + iter.status = iomap_read_folio_iter(&iter, &ctx); if (ctx.bio) { submit_bio(ctx.bio); @@ -480,15 +490,14 @@ int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) } EXPORT_SYMBOL_GPL(iomap_read_folio); -static loff_t iomap_readahead_iter(const struct iomap_iter *iter, +static int iomap_readahead_iter(struct iomap_iter *iter, struct iomap_readpage_ctx *ctx) { - loff_t length = iomap_length(iter); - loff_t done, ret; + int ret; - for (done = 0; done < length; done += ret) { + while (iomap_length(iter)) { if (ctx->cur_folio && - offset_in_folio(ctx->cur_folio, iter->pos + done) == 0) { + offset_in_folio(ctx->cur_folio, iter->pos) == 0) { if (!ctx->cur_folio_in_bio) folio_unlock(ctx->cur_folio); ctx->cur_folio = NULL; @@ -497,12 +506,12 @@ static loff_t iomap_readahead_iter(const struct iomap_iter *iter, ctx->cur_folio = readahead_folio(ctx->rac); ctx->cur_folio_in_bio = false; } - ret = iomap_readpage_iter(iter, ctx, done); - if (ret <= 0) + ret = iomap_readpage_iter(iter, ctx); + if (ret) return ret; } - return done; + return 0; } /** @@ -534,7 +543,7 @@ void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops) trace_iomap_readahead(rac->mapping->host, readahead_count(rac)); while (iomap_iter(&iter, ops) > 0) - iter.processed = iomap_readahead_iter(&iter, &ctx); + iter.status = iomap_readahead_iter(&iter, &ctx); if (ctx.bio) submit_bio(ctx.bio); @@ -590,6 +599,8 @@ struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) if (iter->flags & IOMAP_NOWAIT) fgp |= FGP_NOWAIT; + if (iter->flags & IOMAP_DONTCACHE) + fgp |= FGP_DONTCACHE; fgp |= fgf_set_order(len); return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, @@ -668,11 +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); @@ -697,7 +709,6 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos, if (folio_test_uptodate(folio)) return 0; - folio_clear_error(folio); do { iomap_adjust_read_range(iter->inode, folio, &block_start, @@ -731,10 +742,13 @@ static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos, return 0; } -static struct folio *__iomap_get_folio(struct iomap_iter *iter, loff_t pos, - size_t len) +static struct folio *__iomap_get_folio(struct iomap_iter *iter, size_t len) { const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops; + loff_t pos = iter->pos; + + if (!mapping_large_folio_support(iter->inode->i_mapping)) + len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos)); if (folio_ops && folio_ops->get_folio) return folio_ops->get_folio(iter, pos, len); @@ -742,10 +756,11 @@ static struct folio *__iomap_get_folio(struct iomap_iter *iter, loff_t pos, return iomap_get_folio(iter, pos, len); } -static void __iomap_put_folio(struct iomap_iter *iter, loff_t pos, size_t ret, +static void __iomap_put_folio(struct iomap_iter *iter, size_t ret, struct folio *folio) { const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops; + loff_t pos = iter->pos; if (folio_ops && folio_ops->put_folio) { folio_ops->put_folio(iter->inode, pos, ret, folio); @@ -755,6 +770,22 @@ static void __iomap_put_folio(struct iomap_iter *iter, loff_t pos, size_t ret, } } +/* trim pos and bytes to within a given folio */ +static loff_t iomap_trim_folio_range(struct iomap_iter *iter, + struct folio *folio, size_t *offset, u64 *bytes) +{ + loff_t pos = iter->pos; + size_t fsize = folio_size(folio); + + WARN_ON_ONCE(pos < folio_pos(folio)); + WARN_ON_ONCE(pos >= folio_pos(folio) + fsize); + + *offset = offset_in_folio(folio, pos); + *bytes = min(*bytes, fsize - *offset); + + return pos; +} + static int iomap_write_begin_inline(const struct iomap_iter *iter, struct folio *folio) { @@ -764,14 +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, loff_t pos, - 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); @@ -779,10 +818,7 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos, if (fatal_signal_pending(current)) return -EINTR; - if (!mapping_large_folio_support(iter->inode->i_mapping)) - len = min_t(size_t, len, PAGE_SIZE - offset_in_page(pos)); - - folio = __iomap_get_folio(iter, pos, len); + folio = __iomap_get_folio(iter, len); if (IS_ERR(folio)) return PTR_ERR(folio); @@ -806,30 +842,29 @@ static int iomap_write_begin(struct iomap_iter *iter, loff_t pos, } } - 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: - __iomap_put_folio(iter, pos, 0, folio); - iomap_write_failed(iter->inode, pos, len); + __iomap_put_folio(iter, 0, folio); return status; } -static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len, +static bool __iomap_write_end(struct inode *inode, loff_t pos, size_t len, size_t copied, struct folio *folio) { flush_dcache_folio(folio); @@ -846,14 +881,14 @@ static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len, * redo the whole thing. */ if (unlikely(copied < len && !folio_test_uptodate(folio))) - return 0; + return false; iomap_set_range_uptodate(folio, offset_in_folio(folio, pos), len); iomap_set_range_dirty(folio, offset_in_folio(folio, pos), copied); filemap_dirty_folio(inode->i_mapping, folio); - return copied; + return true; } -static size_t iomap_write_end_inline(const struct iomap_iter *iter, +static void iomap_write_end_inline(const struct iomap_iter *iter, struct folio *folio, loff_t pos, size_t copied) { const struct iomap *iomap = &iter->iomap; @@ -868,71 +903,63 @@ static size_t iomap_write_end_inline(const struct iomap_iter *iter, kunmap_local(addr); mark_inode_dirty(iter->inode); - return copied; } -/* Returns the number of bytes copied. May be 0. Cannot be an errno. */ -static size_t iomap_write_end(struct iomap_iter *iter, loff_t pos, size_t len, - size_t copied, struct folio *folio) +/* + * Returns true if all copied bytes have been written to the pagecache, + * otherwise return false. + */ +static bool iomap_write_end(struct iomap_iter *iter, size_t len, size_t copied, + struct folio *folio) { const struct iomap *srcmap = iomap_iter_srcmap(iter); - loff_t old_size = iter->inode->i_size; - size_t ret; + loff_t pos = iter->pos; if (srcmap->type == IOMAP_INLINE) { - ret = iomap_write_end_inline(iter, folio, pos, copied); - } else if (srcmap->flags & IOMAP_F_BUFFER_HEAD) { - ret = block_write_end(NULL, iter->inode->i_mapping, pos, len, - copied, &folio->page, NULL); - } else { - ret = __iomap_write_end(iter->inode, pos, len, copied, folio); + iomap_write_end_inline(iter, folio, pos, copied); + return true; } - /* - * Update the in-memory inode size after copying the data into the page - * cache. It's up to the file system to write the updated size to disk, - * preferably after I/O completion so that no stale data is exposed. - */ - if (pos + ret > old_size) { - i_size_write(iter->inode, pos + ret); - iter->iomap.flags |= IOMAP_F_SIZE_CHANGED; + if (srcmap->flags & IOMAP_F_BUFFER_HEAD) { + size_t bh_written; + + bh_written = block_write_end(NULL, iter->inode->i_mapping, pos, + len, copied, folio, NULL); + WARN_ON_ONCE(bh_written != copied && bh_written != 0); + return bh_written == copied; } - __iomap_put_folio(iter, pos, ret, folio); - if (old_size < pos) - pagecache_isize_extended(iter->inode, old_size, pos); - if (ret < len) - iomap_write_failed(iter->inode, pos + ret, len - ret); - return ret; + return __iomap_write_end(iter->inode, pos, len, copied, folio); } -static loff_t iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i) +static int iomap_write_iter(struct iomap_iter *iter, struct iov_iter *i) { - loff_t length = iomap_length(iter); - size_t chunk = PAGE_SIZE << MAX_PAGECACHE_ORDER; - loff_t pos = iter->pos; - ssize_t written = 0; - long status = 0; + ssize_t total_written = 0; + int status = 0; struct address_space *mapping = iter->inode->i_mapping; + size_t chunk = mapping_max_folio_size(mapping); unsigned int bdp_flags = (iter->flags & IOMAP_NOWAIT) ? BDP_ASYNC : 0; do { struct folio *folio; + loff_t old_size; size_t offset; /* Offset into folio */ - size_t bytes; /* Bytes to write to folio */ + u64 bytes; /* Bytes to write to folio */ size_t copied; /* Bytes copied from user */ + u64 written; /* Bytes have been written */ + loff_t pos; bytes = iov_iter_count(i); retry: - offset = pos & (chunk - 1); + offset = iter->pos & (chunk - 1); bytes = min(chunk - offset, bytes); status = balance_dirty_pages_ratelimited_flags(mapping, bdp_flags); if (unlikely(status)) break; - if (bytes > length) - bytes = length; + if (bytes > iomap_length(iter)) + bytes = iomap_length(iter); /* * Bring in the user page that we'll copy from _first_. @@ -949,33 +976,51 @@ retry: break; } - status = iomap_write_begin(iter, pos, bytes, &folio); - if (unlikely(status)) + status = iomap_write_begin(iter, &folio, &offset, &bytes); + if (unlikely(status)) { + iomap_write_failed(iter->inode, iter->pos, bytes); break; + } if (iter->iomap.flags & IOMAP_F_STALE) break; - offset = offset_in_folio(folio, pos); - if (bytes > folio_size(folio) - offset) - bytes = folio_size(folio) - offset; + pos = iter->pos; if (mapping_writably_mapped(mapping)) flush_dcache_folio(folio); copied = copy_folio_from_iter_atomic(folio, offset, bytes, i); - status = iomap_write_end(iter, pos, bytes, copied, folio); + written = iomap_write_end(iter, bytes, copied, folio) ? + copied : 0; + + /* + * Update the in-memory inode size after copying the data into + * the page cache. It's up to the file system to write the + * updated size to disk, preferably after I/O completion so that + * no stale data is exposed. Only once that's done can we + * unlock and release the folio. + */ + old_size = iter->inode->i_size; + if (pos + written > old_size) { + i_size_write(iter->inode, pos + written); + iter->iomap.flags |= IOMAP_F_SIZE_CHANGED; + } + __iomap_put_folio(iter, written, folio); - if (unlikely(copied != status)) - iov_iter_revert(i, copied - status); + if (old_size < pos) + pagecache_isize_extended(iter->inode, old_size, pos); cond_resched(); - if (unlikely(status == 0)) { + if (unlikely(written == 0)) { /* * A short copy made iomap_write_end() reject the * thing entirely. Might be memory poisoning * halfway through, might be a race with munmap, * might be severe memory pressure. */ + iomap_write_failed(iter->inode, pos, bytes); + iov_iter_revert(i, copied); + if (chunk > PAGE_SIZE) chunk /= 2; if (copied) { @@ -983,36 +1028,34 @@ retry: goto retry; } } else { - pos += status; - written += status; - length -= status; + total_written += written; + iomap_iter_advance(iter, &written); } - } while (iov_iter_count(i) && length); + } while (iov_iter_count(i) && iomap_length(iter)); - if (status == -EAGAIN) { - iov_iter_revert(i, written); - return -EAGAIN; - } - return written ? written : status; + return total_written ? 0 : status; } ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, - const struct iomap_ops *ops) + const struct iomap_ops *ops, void *private) { struct iomap_iter iter = { .inode = iocb->ki_filp->f_mapping->host, .pos = iocb->ki_pos, .len = iov_iter_count(i), .flags = IOMAP_WRITE, + .private = private, }; ssize_t ret; if (iocb->ki_flags & IOCB_NOWAIT) iter.flags |= IOMAP_NOWAIT; + if (iocb->ki_flags & IOCB_DONTCACHE) + iter.flags |= IOMAP_DONTCACHE; while ((ret = iomap_iter(&iter, ops)) > 0) - iter.processed = iomap_write_iter(&iter, i); + iter.status = iomap_write_iter(&iter, i); if (unlikely(iter.pos == iocb->ki_pos)) return ret; @@ -1022,15 +1065,14 @@ iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, } EXPORT_SYMBOL_GPL(iomap_file_buffered_write); -static int iomap_write_delalloc_ifs_punch(struct inode *inode, +static void iomap_write_delalloc_ifs_punch(struct inode *inode, struct folio *folio, loff_t start_byte, loff_t end_byte, - iomap_punch_t punch) + struct iomap *iomap, iomap_punch_t punch) { unsigned int first_blk, last_blk, i; loff_t last_byte; u8 blkbits = inode->i_blkbits; struct iomap_folio_state *ifs; - int ret = 0; /* * When we have per-block dirty tracking, there can be @@ -1040,47 +1082,35 @@ static int iomap_write_delalloc_ifs_punch(struct inode *inode, */ ifs = folio->private; if (!ifs) - return ret; + return; last_byte = min_t(loff_t, end_byte - 1, folio_pos(folio) + folio_size(folio) - 1); first_blk = offset_in_folio(folio, start_byte) >> blkbits; last_blk = offset_in_folio(folio, last_byte) >> blkbits; for (i = first_blk; i <= last_blk; i++) { - if (!ifs_block_is_dirty(folio, ifs, i)) { - ret = punch(inode, folio_pos(folio) + (i << blkbits), - 1 << blkbits); - if (ret) - return ret; - } + if (!ifs_block_is_dirty(folio, ifs, i)) + punch(inode, folio_pos(folio) + (i << blkbits), + 1 << blkbits, iomap); } - - return ret; } - -static int iomap_write_delalloc_punch(struct inode *inode, struct folio *folio, +static void iomap_write_delalloc_punch(struct inode *inode, struct folio *folio, loff_t *punch_start_byte, loff_t start_byte, loff_t end_byte, - iomap_punch_t punch) + struct iomap *iomap, iomap_punch_t punch) { - int ret = 0; - if (!folio_test_dirty(folio)) - return ret; + return; /* if dirty, punch up to offset */ if (start_byte > *punch_start_byte) { - ret = punch(inode, *punch_start_byte, - start_byte - *punch_start_byte); - if (ret) - return ret; + punch(inode, *punch_start_byte, start_byte - *punch_start_byte, + iomap); } /* Punch non-dirty blocks within folio */ - ret = iomap_write_delalloc_ifs_punch(inode, folio, start_byte, - end_byte, punch); - if (ret) - return ret; + iomap_write_delalloc_ifs_punch(inode, folio, start_byte, end_byte, + iomap, punch); /* * Make sure the next punch start is correctly bound to @@ -1088,8 +1118,6 @@ static int iomap_write_delalloc_punch(struct inode *inode, struct folio *folio, */ *punch_start_byte = min_t(loff_t, end_byte, folio_pos(folio) + folio_size(folio)); - - return ret; } /* @@ -1109,13 +1137,12 @@ static int iomap_write_delalloc_punch(struct inode *inode, struct folio *folio, * This function uses [start_byte, end_byte) intervals (i.e. open ended) to * simplify range iterations. */ -static int iomap_write_delalloc_scan(struct inode *inode, +static void iomap_write_delalloc_scan(struct inode *inode, loff_t *punch_start_byte, loff_t start_byte, loff_t end_byte, - iomap_punch_t punch) + struct iomap *iomap, iomap_punch_t punch) { while (start_byte < end_byte) { struct folio *folio; - int ret; /* grab locked page */ folio = filemap_lock_folio(inode->i_mapping, @@ -1126,27 +1153,47 @@ static int iomap_write_delalloc_scan(struct inode *inode, continue; } - ret = iomap_write_delalloc_punch(inode, folio, punch_start_byte, - start_byte, end_byte, punch); - if (ret) { - folio_unlock(folio); - folio_put(folio); - return ret; - } + iomap_write_delalloc_punch(inode, folio, punch_start_byte, + start_byte, end_byte, iomap, punch); /* move offset to start of next folio in range */ - start_byte = folio_next_index(folio) << PAGE_SHIFT; + start_byte = folio_pos(folio) + folio_size(folio); folio_unlock(folio); folio_put(folio); } - return 0; } /* + * When a short write occurs, the filesystem might need to use ->iomap_end + * to remove space reservations created in ->iomap_begin. + * + * For filesystems that use delayed allocation, there can be dirty pages over + * the delalloc extent outside the range of a short write but still within the + * delalloc extent allocated for this iomap if the write raced with page + * faults. + * * Punch out all the delalloc blocks in the range given except for those that * have dirty data still pending in the page cache - those are going to be * written and so must still retain the delalloc backing for writeback. * + * The punch() callback *must* only punch delalloc extents in the range passed + * to it. It must skip over all other types of extents in the range and leave + * them completely unchanged. It must do this punch atomically with respect to + * other extent modifications. + * + * The punch() callback may be called with a folio locked to prevent writeback + * extent allocation racing at the edge of the range we are currently punching. + * The locked folio may or may not cover the range being punched, so it is not + * safe for the punch() callback to lock folios itself. + * + * Lock order is: + * + * inode->i_rwsem (shared or exclusive) + * inode->i_mapping->invalidate_lock (exclusive) + * folio_lock() + * ->punch + * internal filesystem allocation lock + * * As we are scanning the page cache for data, we don't need to reimplement the * wheel - mapping_seek_hole_data() does exactly what we need to identify the * start and end of data ranges correctly even for sub-folio block sizes. This @@ -1175,20 +1222,21 @@ static int iomap_write_delalloc_scan(struct inode *inode, * require sprinkling this code with magic "+ 1" and "- 1" arithmetic and expose * the code to subtle off-by-one bugs.... */ -static int iomap_write_delalloc_release(struct inode *inode, - loff_t start_byte, loff_t end_byte, iomap_punch_t punch) +void iomap_write_delalloc_release(struct inode *inode, loff_t start_byte, + loff_t end_byte, unsigned flags, struct iomap *iomap, + iomap_punch_t punch) { loff_t punch_start_byte = start_byte; loff_t scan_end_byte = min(i_size_read(inode), end_byte); - int error = 0; /* - * Lock the mapping to avoid races with page faults re-instantiating - * folios and dirtying them via ->page_mkwrite whilst we walk the - * cache and perform delalloc extent removal. Failing to do this can - * leave dirty pages with no space reservation in the cache. + * The caller must hold invalidate_lock to avoid races with page faults + * re-instantiating folios and dirtying them via ->page_mkwrite whilst + * we walk the cache and perform delalloc extent removal. Failing to do + * this can leave dirty pages with no space reservation in the cache. */ - filemap_invalidate_lock(inode->i_mapping); + lockdep_assert_held_write(&inode->i_mapping->invalidate_lock); + while (start_byte < scan_end_byte) { loff_t data_end; @@ -1197,13 +1245,15 @@ static int iomap_write_delalloc_release(struct inode *inode, /* * If there is no more data to scan, all that is left is to * punch out the remaining range. + * + * Note that mapping_seek_hole_data is only supposed to return + * either an offset or -ENXIO, so WARN on any other error as + * that would be an API change without updating the callers. */ if (start_byte == -ENXIO || start_byte == scan_end_byte) break; - if (start_byte < 0) { - error = start_byte; - goto out_unlock; - } + if (WARN_ON_ONCE(start_byte < 0)) + return; WARN_ON_ONCE(start_byte < punch_start_byte); WARN_ON_ONCE(start_byte > scan_end_byte); @@ -1213,140 +1263,68 @@ static int iomap_write_delalloc_release(struct inode *inode, */ data_end = mapping_seek_hole_data(inode->i_mapping, start_byte, scan_end_byte, SEEK_HOLE); - if (data_end < 0) { - error = data_end; - goto out_unlock; - } - WARN_ON_ONCE(data_end <= start_byte); + if (WARN_ON_ONCE(data_end < 0)) + return; + + /* + * If we race with post-direct I/O invalidation of the page cache, + * there might be no data left at start_byte. + */ + if (data_end == start_byte) + continue; + + WARN_ON_ONCE(data_end < start_byte); WARN_ON_ONCE(data_end > scan_end_byte); - error = iomap_write_delalloc_scan(inode, &punch_start_byte, - start_byte, data_end, punch); - if (error) - goto out_unlock; + iomap_write_delalloc_scan(inode, &punch_start_byte, start_byte, + data_end, iomap, punch); /* The next data search starts at the end of this one. */ start_byte = data_end; } if (punch_start_byte < end_byte) - error = punch(inode, punch_start_byte, - end_byte - punch_start_byte); -out_unlock: - filemap_invalidate_unlock(inode->i_mapping); - return error; -} - -/* - * When a short write occurs, the filesystem may need to remove reserved space - * that was allocated in ->iomap_begin from it's ->iomap_end method. For - * filesystems that use delayed allocation, we need to punch out delalloc - * extents from the range that are not dirty in the page cache. As the write can - * race with page faults, there can be dirty pages over the delalloc extent - * outside the range of a short write but still within the delalloc extent - * allocated for this iomap. - * - * This function uses [start_byte, end_byte) intervals (i.e. open ended) to - * simplify range iterations. - * - * The punch() callback *must* only punch delalloc extents in the range passed - * to it. It must skip over all other types of extents in the range and leave - * them completely unchanged. It must do this punch atomically with respect to - * other extent modifications. - * - * The punch() callback may be called with a folio locked to prevent writeback - * extent allocation racing at the edge of the range we are currently punching. - * The locked folio may or may not cover the range being punched, so it is not - * safe for the punch() callback to lock folios itself. - * - * Lock order is: - * - * inode->i_rwsem (shared or exclusive) - * inode->i_mapping->invalidate_lock (exclusive) - * folio_lock() - * ->punch - * internal filesystem allocation lock - */ -int iomap_file_buffered_write_punch_delalloc(struct inode *inode, - struct iomap *iomap, loff_t pos, loff_t length, - ssize_t written, iomap_punch_t punch) -{ - loff_t start_byte; - loff_t end_byte; - unsigned int blocksize = i_blocksize(inode); - - if (iomap->type != IOMAP_DELALLOC) - return 0; - - /* If we didn't reserve the blocks, we're not allowed to punch them. */ - if (!(iomap->flags & IOMAP_F_NEW)) - return 0; - - /* - * start_byte refers to the first unused block after a short write. If - * nothing was written, round offset down to point at the first block in - * the range. - */ - if (unlikely(!written)) - start_byte = round_down(pos, blocksize); - else - start_byte = round_up(pos + written, blocksize); - end_byte = round_up(pos + length, blocksize); - - /* Nothing to do if we've written the entire delalloc extent */ - if (start_byte >= end_byte) - return 0; - - return iomap_write_delalloc_release(inode, start_byte, end_byte, - punch); + punch(inode, punch_start_byte, end_byte - punch_start_byte, + iomap); } -EXPORT_SYMBOL_GPL(iomap_file_buffered_write_punch_delalloc); +EXPORT_SYMBOL_GPL(iomap_write_delalloc_release); -static loff_t iomap_unshare_iter(struct iomap_iter *iter) +static int iomap_unshare_iter(struct iomap_iter *iter) { struct iomap *iomap = &iter->iomap; - const struct iomap *srcmap = iomap_iter_srcmap(iter); - loff_t pos = iter->pos; - loff_t length = iomap_length(iter); - loff_t written = 0; + u64 bytes = iomap_length(iter); + int status; - /* don't bother with blocks that are not shared to start with */ - if (!(iomap->flags & IOMAP_F_SHARED)) - return length; - /* don't bother with holes or unwritten extents */ - if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) - return length; + if (!iomap_want_unshare_iter(iter)) + return iomap_iter_advance(iter, &bytes); do { struct folio *folio; - int status; size_t offset; - size_t bytes = min_t(u64, SIZE_MAX, length); + bool ret; - status = iomap_write_begin(iter, pos, bytes, &folio); + bytes = min_t(u64, SIZE_MAX, bytes); + status = iomap_write_begin(iter, &folio, &offset, &bytes); if (unlikely(status)) return status; if (iomap->flags & IOMAP_F_STALE) break; - offset = offset_in_folio(folio, pos); - if (bytes > folio_size(folio) - offset) - bytes = folio_size(folio) - offset; - - bytes = iomap_write_end(iter, pos, bytes, bytes, folio); - if (WARN_ON_ONCE(bytes == 0)) + ret = iomap_write_end(iter, bytes, bytes, folio); + __iomap_put_folio(iter, bytes, folio); + if (WARN_ON_ONCE(!ret)) return -EIO; cond_resched(); - pos += bytes; - written += bytes; - length -= bytes; - balance_dirty_pages_ratelimited(iter->inode->i_mapping); - } while (length > 0); - return written; + status = iomap_iter_advance(iter, &bytes); + if (status) + break; + } while (bytes > 0); + + return status; } int @@ -1356,82 +1334,145 @@ iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, struct iomap_iter iter = { .inode = inode, .pos = pos, - .len = len, .flags = IOMAP_WRITE | IOMAP_UNSHARE, }; + loff_t size = i_size_read(inode); int ret; + if (pos < 0 || pos >= size) + return 0; + + iter.len = min(len, size - pos); while ((ret = iomap_iter(&iter, ops)) > 0) - iter.processed = iomap_unshare_iter(&iter); + iter.status = iomap_unshare_iter(&iter); return ret; } EXPORT_SYMBOL_GPL(iomap_file_unshare); -static loff_t iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) +/* + * Flush the remaining range of the iter and mark the current mapping stale. + * This is used when zero range sees an unwritten mapping that may have had + * dirty pagecache over it. + */ +static inline int iomap_zero_iter_flush_and_stale(struct iomap_iter *i) { - const struct iomap *srcmap = iomap_iter_srcmap(iter); - loff_t pos = iter->pos; - loff_t length = iomap_length(iter); - loff_t written = 0; + struct address_space *mapping = i->inode->i_mapping; + loff_t end = i->pos + i->len - 1; - /* already zeroed? we're done. */ - if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) - return length; + i->iomap.flags |= IOMAP_F_STALE; + return filemap_write_and_wait_range(mapping, i->pos, end); +} + +static int iomap_zero_iter(struct iomap_iter *iter, bool *did_zero) +{ + u64 bytes = iomap_length(iter); + int status; do { struct folio *folio; - int status; size_t offset; - size_t bytes = min_t(u64, SIZE_MAX, length); + bool ret; - status = iomap_write_begin(iter, pos, bytes, &folio); + bytes = min_t(u64, SIZE_MAX, bytes); + status = iomap_write_begin(iter, &folio, &offset, &bytes); if (status) return status; if (iter->iomap.flags & IOMAP_F_STALE) break; - offset = offset_in_folio(folio, pos); - if (bytes > folio_size(folio) - offset) - bytes = folio_size(folio) - offset; + /* warn about zeroing folios beyond eof that won't write back */ + WARN_ON_ONCE(folio_pos(folio) > iter->inode->i_size); folio_zero_range(folio, offset, bytes); folio_mark_accessed(folio); - bytes = iomap_write_end(iter, pos, bytes, bytes, folio); - if (WARN_ON_ONCE(bytes == 0)) + ret = iomap_write_end(iter, bytes, bytes, folio); + __iomap_put_folio(iter, bytes, folio); + if (WARN_ON_ONCE(!ret)) return -EIO; - pos += bytes; - length -= bytes; - written += bytes; - } while (length > 0); + status = iomap_iter_advance(iter, &bytes); + if (status) + break; + } while (bytes > 0); if (did_zero) *did_zero = true; - return written; + return status; } int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, - const struct iomap_ops *ops) + const struct iomap_ops *ops, void *private) { struct iomap_iter iter = { .inode = inode, .pos = pos, .len = len, .flags = IOMAP_ZERO, + .private = private, }; + struct address_space *mapping = inode->i_mapping; + unsigned int blocksize = i_blocksize(inode); + unsigned int off = pos & (blocksize - 1); + loff_t plen = min_t(loff_t, len, blocksize - off); int ret; + bool range_dirty; - while ((ret = iomap_iter(&iter, ops)) > 0) - iter.processed = iomap_zero_iter(&iter, did_zero); + /* + * Zero range can skip mappings that are zero on disk so long as + * pagecache is clean. If pagecache was dirty prior to zero range, the + * mapping converts on writeback completion and so must be zeroed. + * + * The simplest way to deal with this across a range is to flush + * pagecache and process the updated mappings. To avoid excessive + * flushing on partial eof zeroing, special case it to zero the + * unaligned start portion if already dirty in pagecache. + */ + if (off && + filemap_range_needs_writeback(mapping, pos, pos + plen - 1)) { + iter.len = plen; + while ((ret = iomap_iter(&iter, ops)) > 0) + iter.status = iomap_zero_iter(&iter, did_zero); + + iter.len = len - (iter.pos - pos); + if (ret || !iter.len) + return ret; + } + + /* + * To avoid an unconditional flush, check pagecache state and only flush + * if dirty and the fs returns a mapping that might convert on + * writeback. + */ + range_dirty = filemap_range_needs_writeback(inode->i_mapping, + iter.pos, iter.pos + iter.len - 1); + while ((ret = iomap_iter(&iter, ops)) > 0) { + const struct iomap *srcmap = iomap_iter_srcmap(&iter); + + if (srcmap->type == IOMAP_HOLE || + srcmap->type == IOMAP_UNWRITTEN) { + s64 status; + + if (range_dirty) { + range_dirty = false; + status = iomap_zero_iter_flush_and_stale(&iter); + } else { + status = iomap_iter_advance_full(&iter); + } + iter.status = status; + continue; + } + + iter.status = iomap_zero_iter(&iter, did_zero); + } return ret; } EXPORT_SYMBOL_GPL(iomap_zero_range); int iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, - const struct iomap_ops *ops) + const struct iomap_ops *ops, void *private) { unsigned int blocksize = i_blocksize(inode); unsigned int off = pos & (blocksize - 1); @@ -1439,11 +1480,12 @@ iomap_truncate_page(struct inode *inode, loff_t pos, bool *did_zero, /* Block boundary? Nothing to do */ if (!off) return 0; - return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops); + return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops, + private); } EXPORT_SYMBOL_GPL(iomap_truncate_page); -static loff_t iomap_folio_mkwrite_iter(struct iomap_iter *iter, +static int iomap_folio_mkwrite_iter(struct iomap_iter *iter, struct folio *folio) { loff_t length = iomap_length(iter); @@ -1454,20 +1496,22 @@ static loff_t iomap_folio_mkwrite_iter(struct iomap_iter *iter, &iter->iomap); if (ret) return ret; - block_commit_write(&folio->page, 0, length); + block_commit_write(folio, 0, length); } else { WARN_ON_ONCE(!folio_test_uptodate(folio)); folio_mark_dirty(folio); } - return length; + return iomap_iter_advance(iter, &length); } -vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) +vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops, + void *private) { struct iomap_iter iter = { .inode = file_inode(vmf->vma->vm_file), .flags = IOMAP_WRITE | IOMAP_FAULT, + .private = private, }; struct folio *folio = page_folio(vmf->page); ssize_t ret; @@ -1479,7 +1523,7 @@ vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) iter.pos = folio_pos(folio); iter.len = ret; while ((ret = iomap_iter(&iter, ops)) > 0) - iter.processed = iomap_folio_mkwrite_iter(&iter, folio); + iter.status = iomap_folio_mkwrite_iter(&iter, folio); if (ret < 0) goto out_unlock; @@ -1508,16 +1552,15 @@ static void iomap_finish_folio_write(struct inode *inode, struct folio *folio, * state, release holds on bios, and finally free up memory. Do not use the * ioend after this. */ -static u32 -iomap_finish_ioend(struct iomap_ioend *ioend, int error) +u32 iomap_finish_ioend_buffered(struct iomap_ioend *ioend) { struct inode *inode = ioend->io_inode; struct bio *bio = &ioend->io_bio; struct folio_iter fi; u32 folio_count = 0; - if (error) { - mapping_set_error(inode->i_mapping, error); + if (ioend->io_error) { + mapping_set_error(inode->i_mapping, ioend->io_error); if (!bio_flagged(bio, BIO_QUIET)) { pr_err_ratelimited( "%s: writeback error on inode %lu, offset %lld, sector %llu", @@ -1528,8 +1571,6 @@ iomap_finish_ioend(struct iomap_ioend *ioend, int error) /* walk all folios in bio, ending page IO on them */ bio_for_each_folio_all(fi, bio) { - if (error) - folio_set_error(fi.folio); iomap_finish_folio_write(inode, fi.folio, fi.length); folio_count++; } @@ -1538,114 +1579,16 @@ iomap_finish_ioend(struct iomap_ioend *ioend, int error) return folio_count; } -/* - * Ioend completion routine for merged bios. This can only be called from task - * contexts as merged ioends can be of unbound length. Hence we have to break up - * the writeback completions into manageable chunks to avoid long scheduler - * holdoffs. We aim to keep scheduler holdoffs down below 10ms so that we get - * good batch processing throughput without creating adverse scheduler latency - * conditions. - */ -void -iomap_finish_ioends(struct iomap_ioend *ioend, int error) -{ - struct list_head tmp; - u32 completions; - - might_sleep(); - - list_replace_init(&ioend->io_list, &tmp); - completions = iomap_finish_ioend(ioend, error); - - while (!list_empty(&tmp)) { - if (completions > IOEND_BATCH_SIZE * 8) { - cond_resched(); - completions = 0; - } - ioend = list_first_entry(&tmp, struct iomap_ioend, io_list); - list_del_init(&ioend->io_list); - completions += iomap_finish_ioend(ioend, error); - } -} -EXPORT_SYMBOL_GPL(iomap_finish_ioends); - -/* - * We can merge two adjacent ioends if they have the same set of work to do. - */ -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) - return false; - if ((ioend->io_flags & IOMAP_F_SHARED) ^ - (next->io_flags & IOMAP_F_SHARED)) - return false; - if ((ioend->io_type == IOMAP_UNWRITTEN) ^ - (next->io_type == IOMAP_UNWRITTEN)) - return false; - if (ioend->io_offset + ioend->io_size != next->io_offset) - return false; - /* - * Do not merge physically discontiguous ioends. The filesystem - * completion functions will have to iterate the physical - * discontiguities even if we merge the ioends at a logical level, so - * we don't gain anything by merging physical discontiguities here. - * - * We cannot use bio->bi_iter.bi_sector here as it is modified during - * submission so does not point to the start sector of the bio at - * completion. - */ - if (ioend->io_sector + (ioend->io_size >> 9) != next->io_sector) - return false; - return true; -} - -void -iomap_ioend_try_merge(struct iomap_ioend *ioend, struct list_head *more_ioends) -{ - struct iomap_ioend *next; - - INIT_LIST_HEAD(&ioend->io_list); - - while ((next = list_first_entry_or_null(more_ioends, struct iomap_ioend, - io_list))) { - if (!iomap_ioend_can_merge(ioend, next)) - break; - list_move_tail(&next->io_list, &ioend->io_list); - ioend->io_size += next->io_size; - } -} -EXPORT_SYMBOL_GPL(iomap_ioend_try_merge); - -static int -iomap_ioend_compare(void *priv, const struct list_head *a, - const struct list_head *b) -{ - struct iomap_ioend *ia = container_of(a, struct iomap_ioend, io_list); - struct iomap_ioend *ib = container_of(b, struct iomap_ioend, io_list); - - if (ia->io_offset < ib->io_offset) - return -1; - if (ia->io_offset > ib->io_offset) - return 1; - return 0; -} - -void -iomap_sort_ioends(struct list_head *ioend_list) -{ - list_sort(NULL, ioend_list, iomap_ioend_compare); -} -EXPORT_SYMBOL_GPL(iomap_sort_ioends); - static void iomap_writepage_end_bio(struct bio *bio) { - iomap_finish_ioend(iomap_ioend_from_bio(bio), - blk_status_to_errno(bio->bi_status)); + struct iomap_ioend *ioend = iomap_ioend_from_bio(bio); + + ioend->io_error = blk_status_to_errno(bio->bi_status); + iomap_finish_ioend_buffered(ioend); } /* - * Submit the final bio for an ioend. + * Submit 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. @@ -1664,14 +1607,18 @@ static int iomap_submit_ioend(struct iomap_writepage_ctx *wpc, int error) * 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(wpc->ioend, error); + if (wpc->ops->submit_ioend) { + error = wpc->ops->submit_ioend(wpc, error); + } else { + if (WARN_ON_ONCE(wpc->iomap.flags & IOMAP_F_ANON_WRITE)) + error = -EIO; + if (!error) + submit_bio(&wpc->ioend->io_bio); + } if (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); } wpc->ioend = NULL; @@ -1679,9 +1626,9 @@ static int iomap_submit_ioend(struct iomap_writepage_ctx *wpc, int error) } static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc, - struct writeback_control *wbc, struct inode *inode, loff_t pos) + struct writeback_control *wbc, struct inode *inode, loff_t pos, + u16 ioend_flags) { - struct iomap_ioend *ioend; struct bio *bio; bio = bio_alloc_bioset(wpc->iomap.bdev, BIO_MAX_VECS, @@ -1689,32 +1636,24 @@ static struct iomap_ioend *iomap_alloc_ioend(struct iomap_writepage_ctx *wpc, 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); bio->bi_write_hint = inode->i_write_hint; - - 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_sector = bio->bi_iter.bi_sector; - + wbc_init_bio(wbc, bio); wpc->nr_folios = 0; - return ioend; + return iomap_init_ioend(inode, bio, pos, ioend_flags); } -static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos) +static bool iomap_can_add_to_ioend(struct iomap_writepage_ctx *wpc, loff_t pos, + u16 ioend_flags) { - if ((wpc->iomap.flags & IOMAP_F_SHARED) != - (wpc->ioend->io_flags & IOMAP_F_SHARED)) + if (ioend_flags & IOMAP_IOEND_BOUNDARY) return false; - if (wpc->iomap.type != wpc->ioend->io_type) + if ((ioend_flags & IOMAP_IOEND_NOMERGE_FLAGS) != + (wpc->ioend->io_flags & IOMAP_IOEND_NOMERGE_FLAGS)) return false; if (pos != wpc->ioend->io_offset + wpc->ioend->io_size) return false; - if (iomap_sector(&wpc->iomap, pos) != + if (!(wpc->iomap.flags & IOMAP_F_ANON_WRITE) && + iomap_sector(&wpc->iomap, pos) != bio_end_sector(&wpc->ioend->io_bio)) return false; /* @@ -1740,18 +1679,28 @@ 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, unsigned len) + struct inode *inode, loff_t pos, loff_t end_pos, + unsigned len) { struct iomap_folio_state *ifs = folio->private; size_t poff = offset_in_folio(folio, pos); + unsigned int ioend_flags = 0; int error; - if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, pos)) { + if (wpc->iomap.type == IOMAP_UNWRITTEN) + ioend_flags |= IOMAP_IOEND_UNWRITTEN; + if (wpc->iomap.flags & IOMAP_F_SHARED) + ioend_flags |= IOMAP_IOEND_SHARED; + if (pos == wpc->iomap.offset && (wpc->iomap.flags & IOMAP_F_BOUNDARY)) + ioend_flags |= IOMAP_IOEND_BOUNDARY; + + if (!wpc->ioend || !iomap_can_add_to_ioend(wpc, pos, ioend_flags)) { new_ioend: error = iomap_submit_ioend(wpc, 0); if (error) return error; - wpc->ioend = iomap_alloc_ioend(wpc, wbc, inode, pos); + wpc->ioend = iomap_alloc_ioend(wpc, wbc, inode, pos, + ioend_flags); } if (!bio_add_folio(&wpc->ioend->io_bio, folio, len, poff)) @@ -1759,15 +1708,60 @@ new_ioend: if (ifs) atomic_add(len, &ifs->write_bytes_pending); + + /* + * Clamp io_offset and io_size to the incore EOF so that ondisk + * file size updates in the ioend completion are byte-accurate. + * This avoids recovering files with zeroed tail regions when + * writeback races with appending writes: + * + * Thread 1: Thread 2: + * ------------ ----------- + * write [A, A+B] + * update inode size to A+B + * submit I/O [A, A+BS] + * write [A+B, A+B+C] + * update inode size to A+B+C + * <I/O completes, updates disk size to min(A+B+C, A+BS)> + * <power failure> + * + * After reboot: + * 1) with A+B+C < A+BS, the file has zero padding in range + * [A+B, A+B+C] + * + * |< Block Size (BS) >| + * |DDDDDDDDDDDD0000000000000| + * ^ ^ ^ + * A A+B A+B+C + * (EOF) + * + * 2) with A+B+C > A+BS, the file has zero padding in range + * [A+B, A+BS] + * + * |< Block Size (BS) >|< Block Size (BS) >| + * |DDDDDDDDDDDD0000000000000|00000000000000000000000000| + * ^ ^ ^ ^ + * A A+B A+BS A+B+C + * (EOF) + * + * D = Valid Data + * 0 = Zero Padding + * + * Note that this defeats the ability to chain the ioends of + * appending writes. + */ wpc->ioend->io_size += len; - wbc_account_cgroup_owner(wbc, &folio->page, len); + if (wpc->ioend->io_offset + wpc->ioend->io_size > end_pos) + wpc->ioend->io_size = end_pos - wpc->ioend->io_offset; + + wbc_account_cgroup_owner(wbc, folio, 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 dirty_len, - unsigned *count) + struct inode *inode, u64 pos, u64 end_pos, + unsigned dirty_len, unsigned *count) { int error; @@ -1792,7 +1786,7 @@ static int iomap_writepage_map_blocks(struct iomap_writepage_ctx *wpc, break; default: error = iomap_add_to_ioend(wpc, wbc, folio, inode, pos, - map_len); + end_pos, map_len); if (!error) (*count)++; break; @@ -1863,11 +1857,11 @@ static bool iomap_writepage_handle_eof(struct folio *folio, struct inode *inode, * 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. + * Also adjust the end_pos to the end of file and skip writeback + * for all blocks entirely beyond i_size. */ folio_zero_segment(folio, poff, folio_size(folio)); - *end_pos = round_up(isize, i_blocksize(inode)); + *end_pos = isize; } return true; @@ -1880,6 +1874,7 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, struct inode *inode = folio->mapping->host; u64 pos = folio_pos(folio); u64 end_pos = pos + folio_size(folio); + u64 end_aligned = 0; unsigned count = 0; int error = 0; u32 rlen; @@ -1921,9 +1916,10 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, /* * Walk through the folio to find dirty areas to write back. */ - while ((rlen = iomap_find_dirty_range(folio, &pos, end_pos))) { + end_aligned = round_up(end_pos, i_blocksize(inode)); + while ((rlen = iomap_find_dirty_range(folio, &pos, end_aligned))) { error = iomap_writepage_map_blocks(wpc, wbc, folio, inode, - pos, rlen, &count); + pos, end_pos, rlen, &count); if (error) break; pos += rlen; @@ -1958,18 +1954,13 @@ static int iomap_writepage_map(struct iomap_writepage_ctx *wpc, return error; } -static int iomap_do_writepage(struct folio *folio, - struct writeback_control *wbc, void *data) -{ - return iomap_writepage_map(data, wbc, folio); -} - int iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, struct iomap_writepage_ctx *wpc, const struct iomap_writeback_ops *ops) { - int ret; + struct folio *folio = NULL; + int error; /* * Writeback from reclaim context should never happen except in the case @@ -1980,15 +1971,8 @@ iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, return -EIO; wpc->ops = ops; - ret = write_cache_pages(mapping, wbc, iomap_do_writepage, wpc); - return iomap_submit_ioend(wpc, ret); + while ((folio = writeback_iter(mapping, wbc, folio, &error))) + error = iomap_writepage_map(wpc, wbc, folio); + return iomap_submit_ioend(wpc, error); } 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_bio), - BIOSET_NEED_BVECS); -} -fs_initcall(iomap_init); |