| // SPDX-License-Identifier: GPL-2.0 |
| /* |
| * Copyright (C) 2010 Red Hat, Inc. |
| * Copyright (C) 2016-2019 Christoph Hellwig. |
| */ |
| #include <linux/module.h> |
| #include <linux/compiler.h> |
| #include <linux/fs.h> |
| #include <linux/iomap.h> |
| #include <linux/pagemap.h> |
| #include <linux/uio.h> |
| #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 "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. |
| */ |
| struct iomap_folio_state { |
| atomic_t read_bytes_pending; |
| atomic_t write_bytes_pending; |
| spinlock_t state_lock; |
| |
| /* |
| * Each block has two bits in this bitmap: |
| * Bits [0..blocks_per_folio) has the uptodate status. |
| * Bits [b_p_f...(2*b_p_f)) has the dirty status. |
| */ |
| 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) |
| { |
| struct inode *inode = folio->mapping->host; |
| |
| return bitmap_full(ifs->state, i_blocks_per_folio(inode, folio)); |
| } |
| |
| static inline bool ifs_block_is_uptodate(struct iomap_folio_state *ifs, |
| unsigned int block) |
| { |
| return test_bit(block, ifs->state); |
| } |
| |
| static void ifs_set_range_uptodate(struct folio *folio, |
| struct iomap_folio_state *ifs, size_t off, size_t len) |
| { |
| struct inode *inode = folio->mapping->host; |
| unsigned int first_blk = off >> inode->i_blkbits; |
| unsigned int last_blk = (off + len - 1) >> inode->i_blkbits; |
| unsigned int nr_blks = last_blk - first_blk + 1; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ifs->state_lock, flags); |
| bitmap_set(ifs->state, first_blk, nr_blks); |
| if (ifs_is_fully_uptodate(folio, ifs)) |
| folio_mark_uptodate(folio); |
| spin_unlock_irqrestore(&ifs->state_lock, flags); |
| } |
| |
| static void iomap_set_range_uptodate(struct folio *folio, size_t off, |
| size_t len) |
| { |
| struct iomap_folio_state *ifs = folio->private; |
| |
| if (ifs) |
| ifs_set_range_uptodate(folio, ifs, off, len); |
| else |
| folio_mark_uptodate(folio); |
| } |
| |
| static inline bool ifs_block_is_dirty(struct folio *folio, |
| struct iomap_folio_state *ifs, int block) |
| { |
| struct inode *inode = folio->mapping->host; |
| unsigned int blks_per_folio = i_blocks_per_folio(inode, folio); |
| |
| return test_bit(block + blks_per_folio, ifs->state); |
| } |
| |
| static void ifs_clear_range_dirty(struct folio *folio, |
| struct iomap_folio_state *ifs, size_t off, size_t len) |
| { |
| struct inode *inode = folio->mapping->host; |
| unsigned int blks_per_folio = i_blocks_per_folio(inode, folio); |
| unsigned int first_blk = (off >> inode->i_blkbits); |
| unsigned int last_blk = (off + len - 1) >> inode->i_blkbits; |
| unsigned int nr_blks = last_blk - first_blk + 1; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ifs->state_lock, flags); |
| bitmap_clear(ifs->state, first_blk + blks_per_folio, nr_blks); |
| spin_unlock_irqrestore(&ifs->state_lock, flags); |
| } |
| |
| static void iomap_clear_range_dirty(struct folio *folio, size_t off, size_t len) |
| { |
| struct iomap_folio_state *ifs = folio->private; |
| |
| if (ifs) |
| ifs_clear_range_dirty(folio, ifs, off, len); |
| } |
| |
| static void ifs_set_range_dirty(struct folio *folio, |
| struct iomap_folio_state *ifs, size_t off, size_t len) |
| { |
| struct inode *inode = folio->mapping->host; |
| unsigned int blks_per_folio = i_blocks_per_folio(inode, folio); |
| unsigned int first_blk = (off >> inode->i_blkbits); |
| unsigned int last_blk = (off + len - 1) >> inode->i_blkbits; |
| unsigned int nr_blks = last_blk - first_blk + 1; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ifs->state_lock, flags); |
| bitmap_set(ifs->state, first_blk + blks_per_folio, nr_blks); |
| spin_unlock_irqrestore(&ifs->state_lock, flags); |
| } |
| |
| static void iomap_set_range_dirty(struct folio *folio, size_t off, size_t len) |
| { |
| struct iomap_folio_state *ifs = folio->private; |
| |
| if (ifs) |
| ifs_set_range_dirty(folio, ifs, off, len); |
| } |
| |
| static struct iomap_folio_state *ifs_alloc(struct inode *inode, |
| struct folio *folio, unsigned int flags) |
| { |
| struct iomap_folio_state *ifs = folio->private; |
| unsigned int nr_blocks = i_blocks_per_folio(inode, folio); |
| gfp_t gfp; |
| |
| if (ifs || nr_blocks <= 1) |
| return ifs; |
| |
| if (flags & IOMAP_NOWAIT) |
| gfp = GFP_NOWAIT; |
| else |
| gfp = GFP_NOFS | __GFP_NOFAIL; |
| |
| /* |
| * ifs->state tracks two sets of state flags when the |
| * filesystem block size is smaller than the folio size. |
| * The first state tracks per-block uptodate and the |
| * second tracks per-block dirty state. |
| */ |
| ifs = kzalloc(struct_size(ifs, state, |
| BITS_TO_LONGS(2 * nr_blocks)), gfp); |
| if (!ifs) |
| return ifs; |
| |
| spin_lock_init(&ifs->state_lock); |
| if (folio_test_uptodate(folio)) |
| bitmap_set(ifs->state, 0, nr_blocks); |
| if (folio_test_dirty(folio)) |
| bitmap_set(ifs->state, nr_blocks, nr_blocks); |
| folio_attach_private(folio, ifs); |
| |
| return ifs; |
| } |
| |
| static void ifs_free(struct folio *folio) |
| { |
| struct iomap_folio_state *ifs = folio_detach_private(folio); |
| |
| if (!ifs) |
| return; |
| WARN_ON_ONCE(atomic_read(&ifs->read_bytes_pending)); |
| WARN_ON_ONCE(atomic_read(&ifs->write_bytes_pending)); |
| WARN_ON_ONCE(ifs_is_fully_uptodate(folio, ifs) != |
| folio_test_uptodate(folio)); |
| kfree(ifs); |
| } |
| |
| /* |
| * Calculate the range inside the folio that we actually need to read. |
| */ |
| static void iomap_adjust_read_range(struct inode *inode, struct folio *folio, |
| loff_t *pos, loff_t length, size_t *offp, size_t *lenp) |
| { |
| struct iomap_folio_state *ifs = folio->private; |
| loff_t orig_pos = *pos; |
| loff_t isize = i_size_read(inode); |
| unsigned block_bits = inode->i_blkbits; |
| 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); |
| unsigned first = poff >> block_bits; |
| unsigned last = (poff + plen - 1) >> block_bits; |
| |
| /* |
| * If the block size is smaller than the page size, we need to check the |
| * per-block uptodate status and adjust the offset and length if needed |
| * to avoid reading in already uptodate ranges. |
| */ |
| if (ifs) { |
| unsigned int i; |
| |
| /* move forward for each leading block marked uptodate */ |
| for (i = first; i <= last; i++) { |
| if (!ifs_block_is_uptodate(ifs, i)) |
| break; |
| *pos += block_size; |
| poff += block_size; |
| plen -= block_size; |
| first++; |
| } |
| |
| /* truncate len if we find any trailing uptodate block(s) */ |
| for ( ; i <= last; i++) { |
| if (ifs_block_is_uptodate(ifs, i)) { |
| plen -= (last - i + 1) * block_size; |
| last = i - 1; |
| break; |
| } |
| } |
| } |
| |
| /* |
| * If the extent spans the block that contains the i_size, we need to |
| * 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) { |
| unsigned end = offset_in_folio(folio, isize - 1) >> block_bits; |
| |
| if (first <= end && last > end) |
| plen -= (last - end) * block_size; |
| } |
| |
| *offp = poff; |
| *lenp = plen; |
| } |
| |
| static void iomap_finish_folio_read(struct folio *folio, size_t offset, |
| size_t len, int error) |
| { |
| struct iomap_folio_state *ifs = folio->private; |
| |
| if (unlikely(error)) { |
| folio_clear_uptodate(folio); |
| folio_set_error(folio); |
| } else { |
| iomap_set_range_uptodate(folio, offset, len); |
| } |
| |
| if (!ifs || atomic_sub_and_test(len, &ifs->read_bytes_pending)) |
| folio_unlock(folio); |
| } |
| |
| static void iomap_read_end_io(struct bio *bio) |
| { |
| int error = blk_status_to_errno(bio->bi_status); |
| struct folio_iter fi; |
| |
| bio_for_each_folio_all(fi, bio) |
| iomap_finish_folio_read(fi.folio, fi.offset, fi.length, error); |
| bio_put(bio); |
| } |
| |
| struct iomap_readpage_ctx { |
| struct folio *cur_folio; |
| bool cur_folio_in_bio; |
| struct bio *bio; |
| struct readahead_control *rac; |
| }; |
| |
| /** |
| * iomap_read_inline_data - copy inline data into the page cache |
| * @iter: iteration structure |
| * @folio: folio to copy to |
| * |
| * Copy the inline data in @iter into @folio and zero out the rest of the folio. |
| * Only a single IOMAP_INLINE extent is allowed at the end of each file. |
| * Returns zero for success to complete the read, or the usual negative errno. |
| */ |
| static int iomap_read_inline_data(const struct iomap_iter *iter, |
| struct folio *folio) |
| { |
| const struct iomap *iomap = iomap_iter_srcmap(iter); |
| size_t size = i_size_read(iter->inode) - iomap->offset; |
| size_t poff = offset_in_page(iomap->offset); |
| size_t offset = offset_in_folio(folio, iomap->offset); |
| void *addr; |
| |
| if (folio_test_uptodate(folio)) |
| return 0; |
| |
| if (WARN_ON_ONCE(size > PAGE_SIZE - poff)) |
| return -EIO; |
| if (WARN_ON_ONCE(size > PAGE_SIZE - |
| offset_in_page(iomap->inline_data))) |
| return -EIO; |
| if (WARN_ON_ONCE(size > iomap->length)) |
| return -EIO; |
| if (offset > 0) |
| ifs_alloc(iter->inode, folio, iter->flags); |
| |
| addr = kmap_local_folio(folio, offset); |
| memcpy(addr, iomap->inline_data, size); |
| memset(addr + size, 0, PAGE_SIZE - poff - size); |
| kunmap_local(addr); |
| iomap_set_range_uptodate(folio, offset, PAGE_SIZE - poff); |
| return 0; |
| } |
| |
| static inline bool iomap_block_needs_zeroing(const struct iomap_iter *iter, |
| loff_t pos) |
| { |
| const struct iomap *srcmap = iomap_iter_srcmap(iter); |
| |
| return srcmap->type != IOMAP_MAPPED || |
| (srcmap->flags & IOMAP_F_NEW) || |
| 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) |
| { |
| const struct iomap *iomap = &iter->iomap; |
| loff_t pos = iter->pos + offset; |
| loff_t length = iomap_length(iter) - offset; |
| struct folio *folio = ctx->cur_folio; |
| struct iomap_folio_state *ifs; |
| loff_t orig_pos = pos; |
| size_t poff, plen; |
| sector_t sector; |
| |
| if (iomap->type == IOMAP_INLINE) |
| return iomap_read_inline_data(iter, folio); |
| |
| /* zero post-eof blocks as the page may be mapped */ |
| ifs = ifs_alloc(iter->inode, folio, iter->flags); |
| iomap_adjust_read_range(iter->inode, folio, &pos, length, &poff, &plen); |
| if (plen == 0) |
| goto done; |
| |
| if (iomap_block_needs_zeroing(iter, pos)) { |
| folio_zero_range(folio, poff, plen); |
| iomap_set_range_uptodate(folio, poff, plen); |
| goto done; |
| } |
| |
| ctx->cur_folio_in_bio = true; |
| if (ifs) |
| atomic_add(plen, &ifs->read_bytes_pending); |
| |
| sector = iomap_sector(iomap, pos); |
| if (!ctx->bio || |
| bio_end_sector(ctx->bio) != sector || |
| !bio_add_folio(ctx->bio, folio, plen, poff)) { |
| gfp_t gfp = mapping_gfp_constraint(folio->mapping, GFP_KERNEL); |
| gfp_t orig_gfp = gfp; |
| unsigned int nr_vecs = DIV_ROUND_UP(length, PAGE_SIZE); |
| |
| if (ctx->bio) |
| submit_bio(ctx->bio); |
| |
| if (ctx->rac) /* same as readahead_gfp_mask */ |
| gfp |= __GFP_NORETRY | __GFP_NOWARN; |
| ctx->bio = bio_alloc(iomap->bdev, bio_max_segs(nr_vecs), |
| REQ_OP_READ, gfp); |
| /* |
| * If the bio_alloc fails, try it again for a single page to |
| * avoid having to deal with partial page reads. This emulates |
| * what do_mpage_read_folio does. |
| */ |
| if (!ctx->bio) { |
| ctx->bio = bio_alloc(iomap->bdev, 1, REQ_OP_READ, |
| orig_gfp); |
| } |
| if (ctx->rac) |
| ctx->bio->bi_opf |= REQ_RAHEAD; |
| ctx->bio->bi_iter.bi_sector = sector; |
| ctx->bio->bi_end_io = iomap_read_end_io; |
| bio_add_folio_nofail(ctx->bio, folio, plen, poff); |
| } |
| |
| done: |
| /* |
| * Move the caller beyond our range so that it keeps making progress. |
| * For that, we have to include any leading non-uptodate ranges, but |
| * we can skip trailing ones as they will be handled in the next |
| * iteration. |
| */ |
| return pos - orig_pos + plen; |
| } |
| |
| int iomap_read_folio(struct folio *folio, const struct iomap_ops *ops) |
| { |
| struct iomap_iter iter = { |
| .inode = folio->mapping->host, |
| .pos = folio_pos(folio), |
| .len = folio_size(folio), |
| }; |
| struct iomap_readpage_ctx ctx = { |
| .cur_folio = folio, |
| }; |
| int ret; |
| |
| 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); |
| |
| if (ctx.bio) { |
| submit_bio(ctx.bio); |
| WARN_ON_ONCE(!ctx.cur_folio_in_bio); |
| } else { |
| WARN_ON_ONCE(ctx.cur_folio_in_bio); |
| folio_unlock(folio); |
| } |
| |
| /* |
| * Just like mpage_readahead and block_read_full_folio, we always |
| * return 0 and just set the folio error flag on errors. This |
| * should be cleaned up throughout the stack eventually. |
| */ |
| return 0; |
| } |
| EXPORT_SYMBOL_GPL(iomap_read_folio); |
| |
| static loff_t iomap_readahead_iter(const struct iomap_iter *iter, |
| struct iomap_readpage_ctx *ctx) |
| { |
| loff_t length = iomap_length(iter); |
| loff_t done, ret; |
| |
| for (done = 0; done < length; done += ret) { |
| if (ctx->cur_folio && |
| offset_in_folio(ctx->cur_folio, iter->pos + done) == 0) { |
| if (!ctx->cur_folio_in_bio) |
| folio_unlock(ctx->cur_folio); |
| ctx->cur_folio = NULL; |
| } |
| if (!ctx->cur_folio) { |
| ctx->cur_folio = readahead_folio(ctx->rac); |
| ctx->cur_folio_in_bio = false; |
| } |
| ret = iomap_readpage_iter(iter, ctx, done); |
| if (ret <= 0) |
| return ret; |
| } |
| |
| return done; |
| } |
| |
| /** |
| * iomap_readahead - Attempt to read pages from a file. |
| * @rac: Describes the pages to be read. |
| * @ops: The operations vector for the filesystem. |
| * |
| * This function is for filesystems to call to implement their readahead |
| * address_space operation. |
| * |
| * Context: The @ops callbacks may submit I/O (eg to read the addresses of |
| * blocks from disc), and may wait for it. The caller may be trying to |
| * access a different page, and so sleeping excessively should be avoided. |
| * It may allocate memory, but should avoid costly allocations. This |
| * function is called with memalloc_nofs set, so allocations will not cause |
| * the filesystem to be reentered. |
| */ |
| void iomap_readahead(struct readahead_control *rac, const struct iomap_ops *ops) |
| { |
| struct iomap_iter iter = { |
| .inode = rac->mapping->host, |
| .pos = readahead_pos(rac), |
| .len = readahead_length(rac), |
| }; |
| struct iomap_readpage_ctx ctx = { |
| .rac = rac, |
| }; |
| |
| trace_iomap_readahead(rac->mapping->host, readahead_count(rac)); |
| |
| while (iomap_iter(&iter, ops) > 0) |
| iter.processed = iomap_readahead_iter(&iter, &ctx); |
| |
| if (ctx.bio) |
| submit_bio(ctx.bio); |
| if (ctx.cur_folio) { |
| if (!ctx.cur_folio_in_bio) |
| folio_unlock(ctx.cur_folio); |
| } |
| } |
| EXPORT_SYMBOL_GPL(iomap_readahead); |
| |
| /* |
| * iomap_is_partially_uptodate checks whether blocks within a folio are |
| * uptodate or not. |
| * |
| * Returns true if all blocks which correspond to the specified part |
| * of the folio are uptodate. |
| */ |
| bool iomap_is_partially_uptodate(struct folio *folio, size_t from, size_t count) |
| { |
| struct iomap_folio_state *ifs = folio->private; |
| struct inode *inode = folio->mapping->host; |
| unsigned first, last, i; |
| |
| if (!ifs) |
| return false; |
| |
| /* Caller's range may extend past the end of this folio */ |
| count = min(folio_size(folio) - from, count); |
| |
| /* First and last blocks in range within folio */ |
| first = from >> inode->i_blkbits; |
| last = (from + count - 1) >> inode->i_blkbits; |
| |
| for (i = first; i <= last; i++) |
| if (!ifs_block_is_uptodate(ifs, i)) |
| return false; |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(iomap_is_partially_uptodate); |
| |
| /** |
| * iomap_get_folio - get a folio reference for writing |
| * @iter: iteration structure |
| * @pos: start offset of write |
| * @len: Suggested size of folio to create. |
| * |
| * Returns a locked reference to the folio at @pos, or an error pointer if the |
| * folio could not be obtained. |
| */ |
| struct folio *iomap_get_folio(struct iomap_iter *iter, loff_t pos, size_t len) |
| { |
| fgf_t fgp = FGP_WRITEBEGIN | FGP_NOFS; |
| |
| if (iter->flags & IOMAP_NOWAIT) |
| fgp |= FGP_NOWAIT; |
| fgp |= fgf_set_order(len); |
| |
| return __filemap_get_folio(iter->inode->i_mapping, pos >> PAGE_SHIFT, |
| fgp, mapping_gfp_mask(iter->inode->i_mapping)); |
| } |
| EXPORT_SYMBOL_GPL(iomap_get_folio); |
| |
| bool iomap_release_folio(struct folio *folio, gfp_t gfp_flags) |
| { |
| trace_iomap_release_folio(folio->mapping->host, folio_pos(folio), |
| folio_size(folio)); |
| |
| /* |
| * If the folio is dirty, we refuse to release our metadata because |
| * it may be partially dirty. Once we track per-block dirty state, |
| * we can release the metadata if every block is dirty. |
| */ |
| if (folio_test_dirty(folio)) |
| return false; |
| ifs_free(folio); |
| return true; |
| } |
| EXPORT_SYMBOL_GPL(iomap_release_folio); |
| |
| void iomap_invalidate_folio(struct folio *folio, size_t offset, size_t len) |
| { |
| trace_iomap_invalidate_folio(folio->mapping->host, |
| folio_pos(folio) + offset, len); |
| |
| /* |
| * If we're invalidating the entire folio, clear the dirty state |
| * from it and release it to avoid unnecessary buildup of the LRU. |
| */ |
| if (offset == 0 && len == folio_size(folio)) { |
| WARN_ON_ONCE(folio_test_writeback(folio)); |
| folio_cancel_dirty(folio); |
| ifs_free(folio); |
| } |
| } |
| EXPORT_SYMBOL_GPL(iomap_invalidate_folio); |
| |
| bool iomap_dirty_folio(struct address_space *mapping, struct folio *folio) |
| { |
| struct inode *inode = mapping->host; |
| size_t len = folio_size(folio); |
| |
| ifs_alloc(inode, folio, 0); |
| iomap_set_range_dirty(folio, 0, len); |
| return filemap_dirty_folio(mapping, folio); |
| } |
| EXPORT_SYMBOL_GPL(iomap_dirty_folio); |
| |
| static void |
| iomap_write_failed(struct inode *inode, loff_t pos, unsigned len) |
| { |
| loff_t i_size = i_size_read(inode); |
| |
| /* |
| * Only truncate newly allocated pages beyoned EOF, even if the |
| * write started inside the existing inode size. |
| */ |
| if (pos + len > i_size) |
| truncate_pagecache_range(inode, max(pos, i_size), |
| pos + len - 1); |
| } |
| |
| static int iomap_read_folio_sync(loff_t block_start, struct folio *folio, |
| size_t poff, size_t plen, const struct iomap *iomap) |
| { |
| struct bio_vec bvec; |
| struct bio bio; |
| |
| bio_init(&bio, iomap->bdev, &bvec, 1, REQ_OP_READ); |
| bio.bi_iter.bi_sector = iomap_sector(iomap, block_start); |
| bio_add_folio_nofail(&bio, folio, plen, poff); |
| return submit_bio_wait(&bio); |
| } |
| |
| static int __iomap_write_begin(const struct iomap_iter *iter, loff_t pos, |
| size_t len, struct folio *folio) |
| { |
| const struct iomap *srcmap = iomap_iter_srcmap(iter); |
| struct iomap_folio_state *ifs; |
| 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); |
| unsigned int nr_blocks = i_blocks_per_folio(iter->inode, folio); |
| size_t from = offset_in_folio(folio, pos), to = from + len; |
| size_t poff, plen; |
| |
| /* |
| * If the write or zeroing completely overlaps the current folio, then |
| * entire folio will be dirtied so there is no need for |
| * per-block state tracking structures to be attached to this folio. |
| * For the unshare case, we must read in the ondisk contents because we |
| * are not changing pagecache contents. |
| */ |
| if (!(iter->flags & IOMAP_UNSHARE) && pos <= folio_pos(folio) && |
| pos + len >= folio_pos(folio) + folio_size(folio)) |
| return 0; |
| |
| ifs = ifs_alloc(iter->inode, folio, iter->flags); |
| if ((iter->flags & IOMAP_NOWAIT) && !ifs && nr_blocks > 1) |
| return -EAGAIN; |
| |
| if (folio_test_uptodate(folio)) |
| return 0; |
| folio_clear_error(folio); |
| |
| do { |
| iomap_adjust_read_range(iter->inode, folio, &block_start, |
| block_end - block_start, &poff, &plen); |
| if (plen == 0) |
| break; |
| |
| if (!(iter->flags & IOMAP_UNSHARE) && |
| (from <= poff || from >= poff + plen) && |
| (to <= poff || to >= poff + plen)) |
| continue; |
| |
| if (iomap_block_needs_zeroing(iter, block_start)) { |
| if (WARN_ON_ONCE(iter->flags & IOMAP_UNSHARE)) |
| return -EIO; |
| folio_zero_segments(folio, poff, from, to, poff + plen); |
| } else { |
| int status; |
| |
| if (iter->flags & IOMAP_NOWAIT) |
| return -EAGAIN; |
| |
| status = iomap_read_folio_sync(block_start, folio, |
| poff, plen, srcmap); |
| if (status) |
| return status; |
| } |
| iomap_set_range_uptodate(folio, poff, plen); |
| } while ((block_start += plen) < block_end); |
| |
| return 0; |
| } |
| |
| static struct folio *__iomap_get_folio(struct iomap_iter *iter, loff_t pos, |
| size_t len) |
| { |
| const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops; |
| |
| if (folio_ops && folio_ops->get_folio) |
| return folio_ops->get_folio(iter, pos, len); |
| else |
| return iomap_get_folio(iter, pos, len); |
| } |
| |
| static void __iomap_put_folio(struct iomap_iter *iter, loff_t pos, size_t ret, |
| struct folio *folio) |
| { |
| const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops; |
| |
| if (folio_ops && folio_ops->put_folio) { |
| folio_ops->put_folio(iter->inode, pos, ret, folio); |
| } else { |
| folio_unlock(folio); |
| folio_put(folio); |
| } |
| } |
| |
| static int iomap_write_begin_inline(const struct iomap_iter *iter, |
| struct folio *folio) |
| { |
| /* needs more work for the tailpacking case; disable for now */ |
| if (WARN_ON_ONCE(iomap_iter_srcmap(iter)->offset != 0)) |
| return -EIO; |
| 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) |
| { |
| const struct iomap_folio_ops *folio_ops = iter->iomap.folio_ops; |
| const struct iomap *srcmap = iomap_iter_srcmap(iter); |
| struct folio *folio; |
| int status = 0; |
| |
| BUG_ON(pos + len > iter->iomap.offset + iter->iomap.length); |
| if (srcmap != &iter->iomap) |
| BUG_ON(pos + len > srcmap->offset + srcmap->length); |
| |
| 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); |
| if (IS_ERR(folio)) |
| return PTR_ERR(folio); |
| |
| /* |
| * Now we have a locked folio, before we do anything with it we need to |
| * check that the iomap we have cached is not stale. The inode extent |
| * mapping can change due to concurrent IO in flight (e.g. |
| * IOMAP_UNWRITTEN state can change and memory reclaim could have |
| * reclaimed a previously partially written page at this index after IO |
| * completion before this write reaches this file offset) and hence we |
| * could do the wrong thing here (zero a page range incorrectly or fail |
| * to zero) and corrupt data. |
| */ |
| if (folio_ops && folio_ops->iomap_valid) { |
| bool iomap_valid = folio_ops->iomap_valid(iter->inode, |
| &iter->iomap); |
| if (!iomap_valid) { |
| iter->iomap.flags |= IOMAP_F_STALE; |
| status = 0; |
| goto out_unlock; |
| } |
| } |
| |
| if (pos + len > folio_pos(folio) + folio_size(folio)) |
| len = folio_pos(folio) + folio_size(folio) - pos; |
| |
| 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); |
| |
| if (unlikely(status)) |
| goto out_unlock; |
| |
| *foliop = folio; |
| return 0; |
| |
| out_unlock: |
| __iomap_put_folio(iter, pos, 0, folio); |
| iomap_write_failed(iter->inode, pos, len); |
| |
| return status; |
| } |
| |
| static size_t __iomap_write_end(struct inode *inode, loff_t pos, size_t len, |
| size_t copied, struct folio *folio) |
| { |
| flush_dcache_folio(folio); |
| |
| /* |
| * The blocks that were entirely written will now be uptodate, so we |
| * don't have to worry about a read_folio reading them and overwriting a |
| * partial write. However, if we've encountered a short write and only |
| * partially written into a block, it will not be marked uptodate, so a |
| * read_folio might come in and destroy our partial write. |
| * |
| * Do the simplest thing and just treat any short write to a |
| * non-uptodate page as a zero-length write, and force the caller to |
| * redo the whole thing. |
| */ |
| if (unlikely(copied < len && !folio_test_uptodate(folio))) |
| return 0; |
| 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; |
| } |
| |
| static size_t iomap_write_end_inline(const struct iomap_iter *iter, |
| struct folio *folio, loff_t pos, size_t copied) |
| { |
| const struct iomap *iomap = &iter->iomap; |
| void *addr; |
| |
| WARN_ON_ONCE(!folio_test_uptodate(folio)); |
| BUG_ON(!iomap_inline_data_valid(iomap)); |
| |
| flush_dcache_folio(folio); |
| addr = kmap_local_folio(folio, pos); |
| memcpy(iomap_inline_data(iomap, pos), addr, copied); |
| 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) |
| { |
| const struct iomap *srcmap = iomap_iter_srcmap(iter); |
| loff_t old_size = iter->inode->i_size; |
| size_t ret; |
| |
| 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); |
| } |
| |
| /* |
| * 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; |
| } |
| __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; |
| } |
| |
| static loff_t 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; |
| struct address_space *mapping = iter->inode->i_mapping; |
| unsigned int bdp_flags = (iter->flags & IOMAP_NOWAIT) ? BDP_ASYNC : 0; |
| |
| do { |
| struct folio *folio; |
| size_t offset; /* Offset into folio */ |
| size_t bytes; /* Bytes to write to folio */ |
| size_t copied; /* Bytes copied from user */ |
| |
| bytes = iov_iter_count(i); |
| retry: |
| offset = 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; |
| |
| /* |
| * Bring in the user page that we'll copy from _first_. |
| * Otherwise there's a nasty deadlock on copying from the |
| * same page as we're writing to, without it being marked |
| * up-to-date. |
| * |
| * For async buffered writes the assumption is that the user |
| * page has already been faulted in. This can be optimized by |
| * faulting the user page. |
| */ |
| if (unlikely(fault_in_iov_iter_readable(i, bytes) == bytes)) { |
| status = -EFAULT; |
| break; |
| } |
| |
| status = iomap_write_begin(iter, pos, bytes, &folio); |
| if (unlikely(status)) |
| 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; |
| |
| 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); |
| |
| if (unlikely(copied != status)) |
| iov_iter_revert(i, copied - status); |
| |
| cond_resched(); |
| if (unlikely(status == 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. |
| */ |
| if (chunk > PAGE_SIZE) |
| chunk /= 2; |
| if (copied) { |
| bytes = copied; |
| goto retry; |
| } |
| } else { |
| pos += status; |
| written += status; |
| length -= status; |
| } |
| } while (iov_iter_count(i) && length); |
| |
| if (status == -EAGAIN) { |
| iov_iter_revert(i, written); |
| return -EAGAIN; |
| } |
| return written ? written : status; |
| } |
| |
| ssize_t |
| iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *i, |
| const struct iomap_ops *ops) |
| { |
| struct iomap_iter iter = { |
| .inode = iocb->ki_filp->f_mapping->host, |
| .pos = iocb->ki_pos, |
| .len = iov_iter_count(i), |
| .flags = IOMAP_WRITE, |
| }; |
| ssize_t ret; |
| |
| if (iocb->ki_flags & IOCB_NOWAIT) |
| iter.flags |= IOMAP_NOWAIT; |
| |
| while ((ret = iomap_iter(&iter, ops)) > 0) |
| iter.processed = iomap_write_iter(&iter, i); |
| |
| if (unlikely(iter.pos == iocb->ki_pos)) |
| return ret; |
| ret = iter.pos - iocb->ki_pos; |
| iocb->ki_pos = iter.pos; |
| return ret; |
| } |
| EXPORT_SYMBOL_GPL(iomap_file_buffered_write); |
| |
| static int iomap_write_delalloc_ifs_punch(struct inode *inode, |
| struct folio *folio, loff_t start_byte, loff_t end_byte, |
| 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 |
| * blocks within a folio which are marked uptodate |
| * but not dirty. In that case it is necessary to punch |
| * out such blocks to avoid leaking any delalloc blocks. |
| */ |
| ifs = folio->private; |
| if (!ifs) |
| return ret; |
| |
| 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; |
| } |
| } |
| |
| return ret; |
| } |
| |
| |
| static int 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) |
| { |
| int ret = 0; |
| |
| if (!folio_test_dirty(folio)) |
| return ret; |
| |
| /* 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 non-dirty blocks within folio */ |
| ret = iomap_write_delalloc_ifs_punch(inode, folio, start_byte, |
| end_byte, punch); |
| if (ret) |
| return ret; |
| |
| /* |
| * Make sure the next punch start is correctly bound to |
| * the end of this data range, not the end of the folio. |
| */ |
| *punch_start_byte = min_t(loff_t, end_byte, |
| folio_pos(folio) + folio_size(folio)); |
| |
| return ret; |
| } |
| |
| /* |
| * Scan the data range passed to us for dirty page cache folios. If we find a |
| * dirty folio, punch out the preceding range and update the offset from which |
| * the next punch will start from. |
| * |
| * We can punch out storage reservations under clean pages because they either |
| * contain data that has been written back - in which case the delalloc punch |
| * over that range is a no-op - or they have been read faults in which case they |
| * contain zeroes and we can remove the delalloc backing range and any new |
| * writes to those pages will do the normal hole filling operation... |
| * |
| * This makes the logic simple: we only need to keep the delalloc extents only |
| * over the dirty ranges of the page cache. |
| * |
| * 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, |
| loff_t *punch_start_byte, loff_t start_byte, loff_t end_byte, |
| iomap_punch_t punch) |
| { |
| while (start_byte < end_byte) { |
| struct folio *folio; |
| int ret; |
| |
| /* grab locked page */ |
| folio = filemap_lock_folio(inode->i_mapping, |
| start_byte >> PAGE_SHIFT); |
| if (IS_ERR(folio)) { |
| start_byte = ALIGN_DOWN(start_byte, PAGE_SIZE) + |
| PAGE_SIZE; |
| 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; |
| } |
| |
| /* move offset to start of next folio in range */ |
| start_byte = folio_next_index(folio) << PAGE_SHIFT; |
| folio_unlock(folio); |
| folio_put(folio); |
| } |
| return 0; |
| } |
| |
| /* |
| * 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. |
| * |
| * 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 |
| * byte range based iteration is especially convenient because it means we |
| * don't have to care about variable size folios, nor where the start or end of |
| * the data range lies within a folio, if they lie within the same folio or even |
| * if there are multiple discontiguous data ranges within the folio. |
| * |
| * It should be noted that mapping_seek_hole_data() is not aware of EOF, and so |
| * can return data ranges that exist in the cache beyond EOF. e.g. a page fault |
| * spanning EOF will initialise the post-EOF data to zeroes and mark it up to |
| * date. A write page fault can then mark it dirty. If we then fail a write() |
| * beyond EOF into that up to date cached range, we allocate a delalloc block |
| * beyond EOF and then have to punch it out. Because the range is up to date, |
| * mapping_seek_hole_data() will return it, and we will skip the punch because |
| * the folio is dirty. THis is incorrect - we always need to punch out delalloc |
| * beyond EOF in this case as writeback will never write back and covert that |
| * delalloc block beyond EOF. Hence we limit the cached data scan range to EOF, |
| * resulting in always punching out the range from the EOF to the end of the |
| * range the iomap spans. |
| * |
| * Intervals are of the form [start_byte, end_byte) (i.e. open ended) because it |
| * matches the intervals returned by mapping_seek_hole_data(). i.e. SEEK_DATA |
| * returns the start of a data range (start_byte), and SEEK_HOLE(start_byte) |
| * returns the end of the data range (data_end). Using closed intervals would |
| * 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) |
| { |
| 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. |
| */ |
| filemap_invalidate_lock(inode->i_mapping); |
| while (start_byte < scan_end_byte) { |
| loff_t data_end; |
| |
| start_byte = mapping_seek_hole_data(inode->i_mapping, |
| start_byte, scan_end_byte, SEEK_DATA); |
| /* |
| * If there is no more data to scan, all that is left is to |
| * punch out the remaining range. |
| */ |
| if (start_byte == -ENXIO || start_byte == scan_end_byte) |
| break; |
| if (start_byte < 0) { |
| error = start_byte; |
| goto out_unlock; |
| } |
| WARN_ON_ONCE(start_byte < punch_start_byte); |
| WARN_ON_ONCE(start_byte > scan_end_byte); |
| |
| /* |
| * We find the end of this contiguous cached data range by |
| * seeking from start_byte to the beginning of the next hole. |
| */ |
| 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); |
| 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; |
| |
| /* 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); |
| } |
| EXPORT_SYMBOL_GPL(iomap_file_buffered_write_punch_delalloc); |
| |
| static loff_t 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; |
| |
| /* 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; |
| |
| do { |
| struct folio *folio; |
| int status; |
| size_t offset; |
| size_t bytes = min_t(u64, SIZE_MAX, length); |
| |
| status = iomap_write_begin(iter, pos, bytes, &folio); |
| 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)) |
| return -EIO; |
| |
| cond_resched(); |
| |
| pos += bytes; |
| written += bytes; |
| length -= bytes; |
| |
| balance_dirty_pages_ratelimited(iter->inode->i_mapping); |
| } while (length > 0); |
| |
| return written; |
| } |
| |
| int |
| iomap_file_unshare(struct inode *inode, loff_t pos, loff_t len, |
| const struct iomap_ops *ops) |
| { |
| struct iomap_iter iter = { |
| .inode = inode, |
| .pos = pos, |
| .len = len, |
| .flags = IOMAP_WRITE | IOMAP_UNSHARE, |
| }; |
| int ret; |
| |
| while ((ret = iomap_iter(&iter, ops)) > 0) |
| iter.processed = 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) |
| { |
| const struct iomap *srcmap = iomap_iter_srcmap(iter); |
| loff_t pos = iter->pos; |
| loff_t length = iomap_length(iter); |
| loff_t written = 0; |
| |
| /* already zeroed? we're done. */ |
| if (srcmap->type == IOMAP_HOLE || srcmap->type == IOMAP_UNWRITTEN) |
| return length; |
| |
| do { |
| struct folio *folio; |
| int status; |
| size_t offset; |
| size_t bytes = min_t(u64, SIZE_MAX, length); |
| |
| status = iomap_write_begin(iter, pos, bytes, &folio); |
| 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; |
| |
| 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)) |
| return -EIO; |
| |
| pos += bytes; |
| length -= bytes; |
| written += bytes; |
| } while (length > 0); |
| |
| if (did_zero) |
| *did_zero = true; |
| return written; |
| } |
| |
| int |
| iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, |
| const struct iomap_ops *ops) |
| { |
| struct iomap_iter iter = { |
| .inode = inode, |
| .pos = pos, |
| .len = len, |
| .flags = IOMAP_ZERO, |
| }; |
| int ret; |
| |
| while ((ret = iomap_iter(&iter, ops)) > 0) |
| iter.processed = 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) |
| { |
| unsigned int blocksize = i_blocksize(inode); |
| unsigned int off = pos & (blocksize - 1); |
| |
| /* Block boundary? Nothing to do */ |
| if (!off) |
| return 0; |
| return iomap_zero_range(inode, pos, blocksize - off, did_zero, ops); |
| } |
| EXPORT_SYMBOL_GPL(iomap_truncate_page); |
| |
| static loff_t iomap_folio_mkwrite_iter(struct iomap_iter *iter, |
| struct folio *folio) |
| { |
| loff_t length = iomap_length(iter); |
| int ret; |
| |
| if (iter->iomap.flags & IOMAP_F_BUFFER_HEAD) { |
| ret = __block_write_begin_int(folio, iter->pos, length, NULL, |
| &iter->iomap); |
| if (ret) |
| return ret; |
| block_commit_write(&folio->page, 0, length); |
| } else { |
| WARN_ON_ONCE(!folio_test_uptodate(folio)); |
| folio_mark_dirty(folio); |
| } |
| |
| return length; |
| } |
| |
| vm_fault_t iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) |
| { |
| struct iomap_iter iter = { |
| .inode = file_inode(vmf->vma->vm_file), |
| .flags = IOMAP_WRITE | IOMAP_FAULT, |
| }; |
| struct folio *folio = page_folio(vmf->page); |
| ssize_t ret; |
| |
| folio_lock(folio); |
| ret = folio_mkwrite_check_truncate(folio, iter.inode); |
| if (ret < 0) |
| goto out_unlock; |
| iter.pos = folio_pos(folio); |
| iter.len = ret; |
| while ((ret = iomap_iter(&iter, ops)) > 0) |
| iter.processed = iomap_folio_mkwrite_iter(&iter, folio); |
| |
| if (ret < 0) |
| goto out_unlock; |
| folio_wait_stable(folio); |
| return VM_FAULT_LOCKED; |
| out_unlock: |
| folio_unlock(folio); |
| return vmf_fs_error(ret); |
| } |
| EXPORT_SYMBOL_GPL(iomap_page_mkwrite); |
| |
| static void iomap_finish_folio_write(struct inode *inode, struct folio *folio, |
| size_t len, int error) |
| { |
| 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); |
| |
| if (!ifs || atomic_sub_and_test(len, &ifs->write_bytes_pending)) |
| folio_end_writeback(folio); |
| } |
| |
| /* |
| * We're now finished for good with this ioend structure. Update the page |
| * 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) |
| { |
| 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); |
| 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); |
| } |
| /* The ioend has been freed by bio_put() */ |
| |
| if (unlikely(error && !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); |
| } |
| 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) |
| { |
| struct iomap_ioend *ioend = bio->bi_private; |
| |
| iomap_finish_ioend(ioend, blk_status_to_errno(bio->bi_status)); |
| } |
| |
| /* |
| * 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. |
| */ |
| 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) { |
| /* |
| * 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; |
| } |
| |
| submit_bio(ioend->io_bio); |
| 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) |
| { |
| struct iomap_ioend *ioend; |
| struct bio *bio; |
| |
| 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; |
| wbc_init_bio(wbc, bio); |
| |
| ioend = container_of(bio, struct iomap_ioend, io_inline_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_folios = 0; |
| ioend->io_offset = offset; |
| ioend->io_bio = bio; |
| ioend->io_sector = sector; |
| 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 offset, |
| sector_t sector) |
| { |
| 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) |
| return false; |
| if (sector != bio_end_sector(wpc->ioend->io_bio)) |
| return false; |
| /* |
| * Limit ioend bio chain lengths to minimise IO completion latency. This |
| * also prevents long tight loops ending page writeback on all the |
| * folios in the ioend. |
| */ |
| if (wpc->ioend->io_folios >= IOEND_BATCH_SIZE) |
| return false; |
| return true; |
| } |
| |
| /* |
| * 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) |
| { |
| 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) |
| list_add(&wpc->ioend->io_list, iolist); |
| wpc->ioend = iomap_alloc_ioend(inode, wpc, pos, sector, wbc); |
| } |
| |
| 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 (ifs) |
| atomic_add(len, &ifs->write_bytes_pending); |
| wpc->ioend->io_size += len; |
| wbc_account_cgroup_owner(wbc, &folio->page, len); |
| } |
| |
| /* |
| * 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 inode *inode, |
| struct folio *folio, u64 end_pos) |
| { |
| struct iomap_folio_state *ifs = folio->private; |
| struct iomap_ioend *ioend, *next; |
| unsigned len = i_blocksize(inode); |
| unsigned nblocks = i_blocks_per_folio(inode, folio); |
| u64 pos = folio_pos(folio); |
| int error = 0, count = 0, i; |
| LIST_HEAD(submit_list); |
| |
| 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); |
| } |
| |
| WARN_ON_ONCE(ifs && atomic_read(&ifs->write_bytes_pending) != 0); |
| |
| /* |
| * 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. |
| */ |
| 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); |
| if (error) |
| break; |
| trace_iomap_writepage_map(inode, &wpc->iomap); |
| if (WARN_ON_ONCE(wpc->iomap.type == IOMAP_INLINE)) |
| continue; |
| if (wpc->iomap.type == IOMAP_HOLE) |
| continue; |
| iomap_add_to_ioend(inode, pos, folio, ifs, wpc, wbc, |
| &submit_list); |
| count++; |
| } |
| if (count) |
| wpc->ioend->io_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 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 |
| * all the dirty bits in the folio here. |
| */ |
| 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. |
| */ |
| 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; |
| } |
| |
| /* |
| * 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; |
| } |
| |
| /* |
| * 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, isize; |
| |
| 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? |
| * |
| * The folio index is less than the end_index, adjust the end_pos |
| * to the highest offset that this folio should represent. |
| * ----------------------------------------------------- |
| * | file mapping | <EOF> | |
| * ----------------------------------------------------- |
| * | 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 | <EOF> | |
| * ------------------------------------------------------- |
| * | 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; |
| } |
| |
| return iomap_writepage_map(wpc, wbc, inode, folio, end_pos); |
| |
| redirty: |
| folio_redirty_for_writepage(wbc, folio); |
| unlock: |
| folio_unlock(folio); |
| return 0; |
| } |
| |
| int |
| iomap_writepages(struct address_space *mapping, struct writeback_control *wbc, |
| struct iomap_writepage_ctx *wpc, |
| const struct iomap_writeback_ops *ops) |
| { |
| int ret; |
| |
| 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); |
| } |
| 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), |
| BIOSET_NEED_BVECS); |
| } |
| fs_initcall(iomap_init); |