/* * Copyright (C) 2010 Red Hat, Inc. * Copyright (c) 2016-2018 Christoph Hellwig. * * This program is free software; you can redistribute it and/or modify it * under the terms and conditions of the GNU General Public License, * version 2, as published by the Free Software Foundation. * * This program is distributed in the hope it will be useful, but WITHOUT * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for * more details. */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include "internal.h" /* * Execute a iomap write on a segment of the mapping that spans a * contiguous range of pages that have identical block mapping state. * * This avoids the need to map pages individually, do individual allocations * for each page and most importantly avoid the need for filesystem specific * locking per page. Instead, all the operations are amortised over the entire * range of pages. It is assumed that the filesystems will lock whatever * resources they require in the iomap_begin call, and release them in the * iomap_end call. */ loff_t iomap_apply(struct inode *inode, loff_t pos, loff_t length, unsigned flags, const struct iomap_ops *ops, void *data, iomap_actor_t actor) { struct iomap iomap = { 0 }; loff_t written = 0, ret; /* * Need to map a range from start position for length bytes. This can * span multiple pages - it is only guaranteed to return a range of a * single type of pages (e.g. all into a hole, all mapped or all * unwritten). Failure at this point has nothing to undo. * * If allocation is required for this range, reserve the space now so * that the allocation is guaranteed to succeed later on. Once we copy * the data into the page cache pages, then we cannot fail otherwise we * expose transient stale data. If the reserve fails, we can safely * back out at this point as there is nothing to undo. */ ret = ops->iomap_begin(inode, pos, length, flags, &iomap); if (ret) return ret; if (WARN_ON(iomap.offset > pos)) return -EIO; if (WARN_ON(iomap.length == 0)) return -EIO; /* * Cut down the length to the one actually provided by the filesystem, * as it might not be able to give us the whole size that we requested. */ if (iomap.offset + iomap.length < pos + length) length = iomap.offset + iomap.length - pos; /* * Now that we have guaranteed that the space allocation will succeed. * we can do the copy-in page by page without having to worry about * failures exposing transient data. */ written = actor(inode, pos, length, data, &iomap); /* * Now the data has been copied, commit the range we've copied. This * should not fail unless the filesystem has had a fatal error. */ if (ops->iomap_end) { ret = ops->iomap_end(inode, pos, length, written > 0 ? written : 0, flags, &iomap); } return written ? written : ret; } static sector_t iomap_sector(struct iomap *iomap, loff_t pos) { return (iomap->addr + pos - iomap->offset) >> SECTOR_SHIFT; } static void iomap_read_inline_data(struct inode *inode, struct page *page, struct iomap *iomap) { size_t size = i_size_read(inode); void *addr; if (PageUptodate(page)) return; BUG_ON(page->index); BUG_ON(size > PAGE_SIZE - offset_in_page(iomap->inline_data)); addr = kmap_atomic(page); memcpy(addr, iomap->inline_data, size); memset(addr + size, 0, PAGE_SIZE - size); kunmap_atomic(addr); SetPageUptodate(page); } static void iomap_read_end_io(struct bio *bio) { int error = blk_status_to_errno(bio->bi_status); struct bio_vec *bvec; int i; bio_for_each_segment_all(bvec, bio, i) page_endio(bvec->bv_page, false, error); bio_put(bio); } struct iomap_readpage_ctx { struct page *cur_page; bool cur_page_in_bio; bool is_readahead; struct bio *bio; struct list_head *pages; }; static loff_t iomap_readpage_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct iomap_readpage_ctx *ctx = data; struct page *page = ctx->cur_page; unsigned poff = pos & (PAGE_SIZE - 1); unsigned plen = min_t(loff_t, PAGE_SIZE - poff, length); bool is_contig = false; sector_t sector; if (iomap->type == IOMAP_INLINE) { WARN_ON_ONCE(poff); iomap_read_inline_data(inode, page, iomap); return PAGE_SIZE; } /* we don't support blocksize < PAGE_SIZE quite yet. */ WARN_ON_ONCE(pos != page_offset(page)); WARN_ON_ONCE(plen != PAGE_SIZE); if (iomap->type != IOMAP_MAPPED || pos >= i_size_read(inode)) { zero_user(page, poff, plen); SetPageUptodate(page); goto done; } ctx->cur_page_in_bio = true; /* * Try to merge into a previous segment if we can. */ sector = iomap_sector(iomap, pos); if (ctx->bio && bio_end_sector(ctx->bio) == sector) { if (__bio_try_merge_page(ctx->bio, page, plen, poff)) goto done; is_contig = true; } if (!ctx->bio || !is_contig || bio_full(ctx->bio)) { gfp_t gfp = mapping_gfp_constraint(page->mapping, GFP_KERNEL); int nr_vecs = (length + PAGE_SIZE - 1) >> PAGE_SHIFT; if (ctx->bio) submit_bio(ctx->bio); if (ctx->is_readahead) /* same as readahead_gfp_mask */ gfp |= __GFP_NORETRY | __GFP_NOWARN; ctx->bio = bio_alloc(gfp, min(BIO_MAX_PAGES, nr_vecs)); ctx->bio->bi_opf = REQ_OP_READ; if (ctx->is_readahead) ctx->bio->bi_opf |= REQ_RAHEAD; ctx->bio->bi_iter.bi_sector = sector; bio_set_dev(ctx->bio, iomap->bdev); ctx->bio->bi_end_io = iomap_read_end_io; } __bio_add_page(ctx->bio, page, plen, poff); done: return plen; } int iomap_readpage(struct page *page, const struct iomap_ops *ops) { struct iomap_readpage_ctx ctx = { .cur_page = page }; struct inode *inode = page->mapping->host; unsigned poff; loff_t ret; WARN_ON_ONCE(page_has_buffers(page)); for (poff = 0; poff < PAGE_SIZE; poff += ret) { ret = iomap_apply(inode, page_offset(page) + poff, PAGE_SIZE - poff, 0, ops, &ctx, iomap_readpage_actor); if (ret <= 0) { WARN_ON_ONCE(ret == 0); SetPageError(page); break; } } if (ctx.bio) { submit_bio(ctx.bio); WARN_ON_ONCE(!ctx.cur_page_in_bio); } else { WARN_ON_ONCE(ctx.cur_page_in_bio); unlock_page(page); } /* * Just like mpage_readpages and block_read_full_page we always * return 0 and just mark the page as PageError on errors. This * should be cleaned up all through the stack eventually. */ return 0; } EXPORT_SYMBOL_GPL(iomap_readpage); static struct page * iomap_next_page(struct inode *inode, struct list_head *pages, loff_t pos, loff_t length, loff_t *done) { while (!list_empty(pages)) { struct page *page = lru_to_page(pages); if (page_offset(page) >= (u64)pos + length) break; list_del(&page->lru); if (!add_to_page_cache_lru(page, inode->i_mapping, page->index, GFP_NOFS)) return page; /* * If we already have a page in the page cache at index we are * done. Upper layers don't care if it is uptodate after the * readpages call itself as every page gets checked again once * actually needed. */ *done += PAGE_SIZE; put_page(page); } return NULL; } static loff_t iomap_readpages_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct iomap_readpage_ctx *ctx = data; loff_t done, ret; for (done = 0; done < length; done += ret) { if (ctx->cur_page && ((pos + done) & (PAGE_SIZE - 1)) == 0) { if (!ctx->cur_page_in_bio) unlock_page(ctx->cur_page); put_page(ctx->cur_page); ctx->cur_page = NULL; } if (!ctx->cur_page) { ctx->cur_page = iomap_next_page(inode, ctx->pages, pos, length, &done); if (!ctx->cur_page) break; ctx->cur_page_in_bio = false; } ret = iomap_readpage_actor(inode, pos + done, length - done, ctx, iomap); } return done; } int iomap_readpages(struct address_space *mapping, struct list_head *pages, unsigned nr_pages, const struct iomap_ops *ops) { struct iomap_readpage_ctx ctx = { .pages = pages, .is_readahead = true, }; loff_t pos = page_offset(list_entry(pages->prev, struct page, lru)); loff_t last = page_offset(list_entry(pages->next, struct page, lru)); loff_t length = last - pos + PAGE_SIZE, ret = 0; while (length > 0) { ret = iomap_apply(mapping->host, pos, length, 0, ops, &ctx, iomap_readpages_actor); if (ret <= 0) { WARN_ON_ONCE(ret == 0); goto done; } pos += ret; length -= ret; } ret = 0; done: if (ctx.bio) submit_bio(ctx.bio); if (ctx.cur_page) { if (!ctx.cur_page_in_bio) unlock_page(ctx.cur_page); put_page(ctx.cur_page); } /* * Check that we didn't lose a page due to the arcance calling * conventions.. */ WARN_ON_ONCE(!ret && !list_empty(ctx.pages)); return ret; } EXPORT_SYMBOL_GPL(iomap_readpages); 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); } static int iomap_read_page_sync(struct inode *inode, loff_t block_start, struct page *page, unsigned poff, unsigned plen, unsigned from, unsigned to, struct iomap *iomap) { struct bio_vec bvec; struct bio bio; if (iomap->type != IOMAP_MAPPED || block_start >= i_size_read(inode)) { zero_user_segments(page, poff, from, to, poff + plen); return 0; } bio_init(&bio, &bvec, 1); bio.bi_opf = REQ_OP_READ; bio.bi_iter.bi_sector = iomap_sector(iomap, block_start); bio_set_dev(&bio, iomap->bdev); __bio_add_page(&bio, page, plen, poff); return submit_bio_wait(&bio); } static int __iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, struct page *page, struct iomap *iomap) { loff_t block_size = i_blocksize(inode); loff_t block_start = pos & ~(block_size - 1); loff_t block_end = (pos + len + block_size - 1) & ~(block_size - 1); unsigned poff = block_start & (PAGE_SIZE - 1); unsigned plen = min_t(loff_t, PAGE_SIZE - poff, block_end - block_start); unsigned from = pos & (PAGE_SIZE - 1), to = from + len; WARN_ON_ONCE(i_blocksize(inode) < PAGE_SIZE); if (PageUptodate(page)) return 0; if (from <= poff && to >= poff + plen) return 0; return iomap_read_page_sync(inode, block_start, page, poff, plen, from, to, iomap); } static int iomap_write_begin(struct inode *inode, loff_t pos, unsigned len, unsigned flags, struct page **pagep, struct iomap *iomap) { pgoff_t index = pos >> PAGE_SHIFT; struct page *page; int status = 0; BUG_ON(pos + len > iomap->offset + iomap->length); if (fatal_signal_pending(current)) return -EINTR; page = grab_cache_page_write_begin(inode->i_mapping, index, flags); if (!page) return -ENOMEM; if (iomap->type == IOMAP_INLINE) iomap_read_inline_data(inode, page, iomap); else if (iomap->flags & IOMAP_F_BUFFER_HEAD) status = __block_write_begin_int(page, pos, len, NULL, iomap); else status = __iomap_write_begin(inode, pos, len, page, iomap); if (unlikely(status)) { unlock_page(page); put_page(page); page = NULL; iomap_write_failed(inode, pos, len); } *pagep = page; return status; } int iomap_set_page_dirty(struct page *page) { struct address_space *mapping = page_mapping(page); int newly_dirty; if (unlikely(!mapping)) return !TestSetPageDirty(page); /* * Lock out page->mem_cgroup migration to keep PageDirty * synchronized with per-memcg dirty page counters. */ lock_page_memcg(page); newly_dirty = !TestSetPageDirty(page); if (newly_dirty) __set_page_dirty(page, mapping, 0); unlock_page_memcg(page); if (newly_dirty) __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); return newly_dirty; } EXPORT_SYMBOL_GPL(iomap_set_page_dirty); static int __iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied, struct page *page, struct iomap *iomap) { flush_dcache_page(page); /* * The blocks that were entirely written will now be uptodate, so we * don't have to worry about a readpage reading them and overwriting a * partial write. However if we have encountered a short write and only * partially written into a block, it will not be marked uptodate, so a * readpage 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 && !PageUptodate(page))) { copied = 0; } else { SetPageUptodate(page); iomap_set_page_dirty(page); } return __generic_write_end(inode, pos, copied, page); } static int iomap_write_end_inline(struct inode *inode, struct page *page, struct iomap *iomap, loff_t pos, unsigned copied) { void *addr; WARN_ON_ONCE(!PageUptodate(page)); BUG_ON(pos + copied > PAGE_SIZE - offset_in_page(iomap->inline_data)); addr = kmap_atomic(page); memcpy(iomap->inline_data + pos, addr + pos, copied); kunmap_atomic(addr); mark_inode_dirty(inode); __generic_write_end(inode, pos, copied, page); return copied; } static int iomap_write_end(struct inode *inode, loff_t pos, unsigned len, unsigned copied, struct page *page, struct iomap *iomap) { int ret; if (iomap->type == IOMAP_INLINE) { ret = iomap_write_end_inline(inode, page, iomap, pos, copied); } else if (iomap->flags & IOMAP_F_BUFFER_HEAD) { ret = generic_write_end(NULL, inode->i_mapping, pos, len, copied, page, NULL); } else { ret = __iomap_write_end(inode, pos, len, copied, page, iomap); } if (iomap->page_done) iomap->page_done(inode, pos, copied, page, iomap); if (ret < len) iomap_write_failed(inode, pos, len); return ret; } static loff_t iomap_write_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct iov_iter *i = data; long status = 0; ssize_t written = 0; unsigned int flags = AOP_FLAG_NOFS; do { struct page *page; unsigned long offset; /* Offset into pagecache page */ unsigned long bytes; /* Bytes to write to page */ size_t copied; /* Bytes copied from user */ offset = (pos & (PAGE_SIZE - 1)); bytes = min_t(unsigned long, PAGE_SIZE - offset, iov_iter_count(i)); again: if (bytes > length) bytes = length; /* * Bring in the user page that we will 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. * * Not only is this an optimisation, but it is also required * to check that the address is actually valid, when atomic * usercopies are used, below. */ if (unlikely(iov_iter_fault_in_readable(i, bytes))) { status = -EFAULT; break; } status = iomap_write_begin(inode, pos, bytes, flags, &page, iomap); if (unlikely(status)) break; if (mapping_writably_mapped(inode->i_mapping)) flush_dcache_page(page); copied = iov_iter_copy_from_user_atomic(page, i, offset, bytes); flush_dcache_page(page); status = iomap_write_end(inode, pos, bytes, copied, page, iomap); if (unlikely(status < 0)) break; copied = status; cond_resched(); iov_iter_advance(i, copied); if (unlikely(copied == 0)) { /* * If we were unable to copy any data at all, we must * fall back to a single segment length write. * * If we didn't fallback here, we could livelock * because not all segments in the iov can be copied at * once without a pagefault. */ bytes = min_t(unsigned long, PAGE_SIZE - offset, iov_iter_single_seg_count(i)); goto again; } pos += copied; written += copied; length -= copied; balance_dirty_pages_ratelimited(inode->i_mapping); } while (iov_iter_count(i) && length); return written ? written : status; } ssize_t iomap_file_buffered_write(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops) { struct inode *inode = iocb->ki_filp->f_mapping->host; loff_t pos = iocb->ki_pos, ret = 0, written = 0; while (iov_iter_count(iter)) { ret = iomap_apply(inode, pos, iov_iter_count(iter), IOMAP_WRITE, ops, iter, iomap_write_actor); if (ret <= 0) break; pos += ret; written += ret; } return written ? written : ret; } EXPORT_SYMBOL_GPL(iomap_file_buffered_write); static struct page * __iomap_read_page(struct inode *inode, loff_t offset) { struct address_space *mapping = inode->i_mapping; struct page *page; page = read_mapping_page(mapping, offset >> PAGE_SHIFT, NULL); if (IS_ERR(page)) return page; if (!PageUptodate(page)) { put_page(page); return ERR_PTR(-EIO); } return page; } static loff_t iomap_dirty_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { long status = 0; ssize_t written = 0; do { struct page *page, *rpage; unsigned long offset; /* Offset into pagecache page */ unsigned long bytes; /* Bytes to write to page */ offset = (pos & (PAGE_SIZE - 1)); bytes = min_t(loff_t, PAGE_SIZE - offset, length); rpage = __iomap_read_page(inode, pos); if (IS_ERR(rpage)) return PTR_ERR(rpage); status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_NOFS, &page, iomap); put_page(rpage); if (unlikely(status)) return status; WARN_ON_ONCE(!PageUptodate(page)); status = iomap_write_end(inode, pos, bytes, bytes, page, iomap); if (unlikely(status <= 0)) { if (WARN_ON_ONCE(status == 0)) return -EIO; return status; } cond_resched(); pos += status; written += status; length -= status; balance_dirty_pages_ratelimited(inode->i_mapping); } while (length); return written; } int iomap_file_dirty(struct inode *inode, loff_t pos, loff_t len, const struct iomap_ops *ops) { loff_t ret; while (len) { ret = iomap_apply(inode, pos, len, IOMAP_WRITE, ops, NULL, iomap_dirty_actor); if (ret <= 0) return ret; pos += ret; len -= ret; } return 0; } EXPORT_SYMBOL_GPL(iomap_file_dirty); static int iomap_zero(struct inode *inode, loff_t pos, unsigned offset, unsigned bytes, struct iomap *iomap) { struct page *page; int status; status = iomap_write_begin(inode, pos, bytes, AOP_FLAG_NOFS, &page, iomap); if (status) return status; zero_user(page, offset, bytes); mark_page_accessed(page); return iomap_write_end(inode, pos, bytes, bytes, page, iomap); } static int iomap_dax_zero(loff_t pos, unsigned offset, unsigned bytes, struct iomap *iomap) { return __dax_zero_page_range(iomap->bdev, iomap->dax_dev, iomap_sector(iomap, pos & PAGE_MASK), offset, bytes); } static loff_t iomap_zero_range_actor(struct inode *inode, loff_t pos, loff_t count, void *data, struct iomap *iomap) { bool *did_zero = data; loff_t written = 0; int status; /* already zeroed? we're done. */ if (iomap->type == IOMAP_HOLE || iomap->type == IOMAP_UNWRITTEN) return count; do { unsigned offset, bytes; offset = pos & (PAGE_SIZE - 1); /* Within page */ bytes = min_t(loff_t, PAGE_SIZE - offset, count); if (IS_DAX(inode)) status = iomap_dax_zero(pos, offset, bytes, iomap); else status = iomap_zero(inode, pos, offset, bytes, iomap); if (status < 0) return status; pos += bytes; count -= bytes; written += bytes; if (did_zero) *did_zero = true; } while (count > 0); return written; } int iomap_zero_range(struct inode *inode, loff_t pos, loff_t len, bool *did_zero, const struct iomap_ops *ops) { loff_t ret; while (len > 0) { ret = iomap_apply(inode, pos, len, IOMAP_ZERO, ops, did_zero, iomap_zero_range_actor); if (ret <= 0) return ret; pos += ret; len -= ret; } return 0; } 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_page_mkwrite_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct page *page = data; int ret; if (iomap->flags & IOMAP_F_BUFFER_HEAD) { ret = __block_write_begin_int(page, pos, length, NULL, iomap); if (ret) return ret; block_commit_write(page, 0, length); } else { WARN_ON_ONCE(!PageUptodate(page)); WARN_ON_ONCE(i_blocksize(inode) < PAGE_SIZE); } return length; } int iomap_page_mkwrite(struct vm_fault *vmf, const struct iomap_ops *ops) { struct page *page = vmf->page; struct inode *inode = file_inode(vmf->vma->vm_file); unsigned long length; loff_t offset, size; ssize_t ret; lock_page(page); size = i_size_read(inode); if ((page->mapping != inode->i_mapping) || (page_offset(page) > size)) { /* We overload EFAULT to mean page got truncated */ ret = -EFAULT; goto out_unlock; } /* page is wholly or partially inside EOF */ if (((page->index + 1) << PAGE_SHIFT) > size) length = size & ~PAGE_MASK; else length = PAGE_SIZE; offset = page_offset(page); while (length > 0) { ret = iomap_apply(inode, offset, length, IOMAP_WRITE | IOMAP_FAULT, ops, page, iomap_page_mkwrite_actor); if (unlikely(ret <= 0)) goto out_unlock; offset += ret; length -= ret; } set_page_dirty(page); wait_for_stable_page(page); return VM_FAULT_LOCKED; out_unlock: unlock_page(page); return block_page_mkwrite_return(ret); } EXPORT_SYMBOL_GPL(iomap_page_mkwrite); struct fiemap_ctx { struct fiemap_extent_info *fi; struct iomap prev; }; static int iomap_to_fiemap(struct fiemap_extent_info *fi, struct iomap *iomap, u32 flags) { switch (iomap->type) { case IOMAP_HOLE: /* skip holes */ return 0; case IOMAP_DELALLOC: flags |= FIEMAP_EXTENT_DELALLOC | FIEMAP_EXTENT_UNKNOWN; break; case IOMAP_MAPPED: break; case IOMAP_UNWRITTEN: flags |= FIEMAP_EXTENT_UNWRITTEN; break; case IOMAP_INLINE: flags |= FIEMAP_EXTENT_DATA_INLINE; break; } if (iomap->flags & IOMAP_F_MERGED) flags |= FIEMAP_EXTENT_MERGED; if (iomap->flags & IOMAP_F_SHARED) flags |= FIEMAP_EXTENT_SHARED; return fiemap_fill_next_extent(fi, iomap->offset, iomap->addr != IOMAP_NULL_ADDR ? iomap->addr : 0, iomap->length, flags); } static loff_t iomap_fiemap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct fiemap_ctx *ctx = data; loff_t ret = length; if (iomap->type == IOMAP_HOLE) return length; ret = iomap_to_fiemap(ctx->fi, &ctx->prev, 0); ctx->prev = *iomap; switch (ret) { case 0: /* success */ return length; case 1: /* extent array full */ return 0; default: return ret; } } int iomap_fiemap(struct inode *inode, struct fiemap_extent_info *fi, loff_t start, loff_t len, const struct iomap_ops *ops) { struct fiemap_ctx ctx; loff_t ret; memset(&ctx, 0, sizeof(ctx)); ctx.fi = fi; ctx.prev.type = IOMAP_HOLE; ret = fiemap_check_flags(fi, FIEMAP_FLAG_SYNC); if (ret) return ret; if (fi->fi_flags & FIEMAP_FLAG_SYNC) { ret = filemap_write_and_wait(inode->i_mapping); if (ret) return ret; } while (len > 0) { ret = iomap_apply(inode, start, len, IOMAP_REPORT, ops, &ctx, iomap_fiemap_actor); /* inode with no (attribute) mapping will give ENOENT */ if (ret == -ENOENT) break; if (ret < 0) return ret; if (ret == 0) break; start += ret; len -= ret; } if (ctx.prev.type != IOMAP_HOLE) { ret = iomap_to_fiemap(fi, &ctx.prev, FIEMAP_EXTENT_LAST); if (ret < 0) return ret; } return 0; } EXPORT_SYMBOL_GPL(iomap_fiemap); /* * Seek for SEEK_DATA / SEEK_HOLE within @page, starting at @lastoff. * Returns true if found and updates @lastoff to the offset in file. */ static bool page_seek_hole_data(struct inode *inode, struct page *page, loff_t *lastoff, int whence) { const struct address_space_operations *ops = inode->i_mapping->a_ops; unsigned int bsize = i_blocksize(inode), off; bool seek_data = whence == SEEK_DATA; loff_t poff = page_offset(page); if (WARN_ON_ONCE(*lastoff >= poff + PAGE_SIZE)) return false; if (*lastoff < poff) { /* * Last offset smaller than the start of the page means we found * a hole: */ if (whence == SEEK_HOLE) return true; *lastoff = poff; } /* * Just check the page unless we can and should check block ranges: */ if (bsize == PAGE_SIZE || !ops->is_partially_uptodate) return PageUptodate(page) == seek_data; lock_page(page); if (unlikely(page->mapping != inode->i_mapping)) goto out_unlock_not_found; for (off = 0; off < PAGE_SIZE; off += bsize) { if ((*lastoff & ~PAGE_MASK) >= off + bsize) continue; if (ops->is_partially_uptodate(page, off, bsize) == seek_data) { unlock_page(page); return true; } *lastoff = poff + off + bsize; } out_unlock_not_found: unlock_page(page); return false; } /* * Seek for SEEK_DATA / SEEK_HOLE in the page cache. * * Within unwritten extents, the page cache determines which parts are holes * and which are data: uptodate buffer heads count as data; everything else * counts as a hole. * * Returns the resulting offset on successs, and -ENOENT otherwise. */ static loff_t page_cache_seek_hole_data(struct inode *inode, loff_t offset, loff_t length, int whence) { pgoff_t index = offset >> PAGE_SHIFT; pgoff_t end = DIV_ROUND_UP(offset + length, PAGE_SIZE); loff_t lastoff = offset; struct pagevec pvec; if (length <= 0) return -ENOENT; pagevec_init(&pvec); do { unsigned nr_pages, i; nr_pages = pagevec_lookup_range(&pvec, inode->i_mapping, &index, end - 1); if (nr_pages == 0) break; for (i = 0; i < nr_pages; i++) { struct page *page = pvec.pages[i]; if (page_seek_hole_data(inode, page, &lastoff, whence)) goto check_range; lastoff = page_offset(page) + PAGE_SIZE; } pagevec_release(&pvec); } while (index < end); /* When no page at lastoff and we are not done, we found a hole. */ if (whence != SEEK_HOLE) goto not_found; check_range: if (lastoff < offset + length) goto out; not_found: lastoff = -ENOENT; out: pagevec_release(&pvec); return lastoff; } static loff_t iomap_seek_hole_actor(struct inode *inode, loff_t offset, loff_t length, void *data, struct iomap *iomap) { switch (iomap->type) { case IOMAP_UNWRITTEN: offset = page_cache_seek_hole_data(inode, offset, length, SEEK_HOLE); if (offset < 0) return length; /* fall through */ case IOMAP_HOLE: *(loff_t *)data = offset; return 0; default: return length; } } loff_t iomap_seek_hole(struct inode *inode, loff_t offset, const struct iomap_ops *ops) { loff_t size = i_size_read(inode); loff_t length = size - offset; loff_t ret; /* Nothing to be found before or beyond the end of the file. */ if (offset < 0 || offset >= size) return -ENXIO; while (length > 0) { ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops, &offset, iomap_seek_hole_actor); if (ret < 0) return ret; if (ret == 0) break; offset += ret; length -= ret; } return offset; } EXPORT_SYMBOL_GPL(iomap_seek_hole); static loff_t iomap_seek_data_actor(struct inode *inode, loff_t offset, loff_t length, void *data, struct iomap *iomap) { switch (iomap->type) { case IOMAP_HOLE: return length; case IOMAP_UNWRITTEN: offset = page_cache_seek_hole_data(inode, offset, length, SEEK_DATA); if (offset < 0) return length; /*FALLTHRU*/ default: *(loff_t *)data = offset; return 0; } } loff_t iomap_seek_data(struct inode *inode, loff_t offset, const struct iomap_ops *ops) { loff_t size = i_size_read(inode); loff_t length = size - offset; loff_t ret; /* Nothing to be found before or beyond the end of the file. */ if (offset < 0 || offset >= size) return -ENXIO; while (length > 0) { ret = iomap_apply(inode, offset, length, IOMAP_REPORT, ops, &offset, iomap_seek_data_actor); if (ret < 0) return ret; if (ret == 0) break; offset += ret; length -= ret; } if (length <= 0) return -ENXIO; return offset; } EXPORT_SYMBOL_GPL(iomap_seek_data); /* * Private flags for iomap_dio, must not overlap with the public ones in * iomap.h: */ #define IOMAP_DIO_WRITE_FUA (1 << 28) #define IOMAP_DIO_NEED_SYNC (1 << 29) #define IOMAP_DIO_WRITE (1 << 30) #define IOMAP_DIO_DIRTY (1 << 31) struct iomap_dio { struct kiocb *iocb; iomap_dio_end_io_t *end_io; loff_t i_size; loff_t size; atomic_t ref; unsigned flags; int error; bool wait_for_completion; union { /* used during submission and for synchronous completion: */ struct { struct iov_iter *iter; struct task_struct *waiter; struct request_queue *last_queue; blk_qc_t cookie; } submit; /* used for aio completion: */ struct { struct work_struct work; } aio; }; }; static ssize_t iomap_dio_complete(struct iomap_dio *dio) { struct kiocb *iocb = dio->iocb; struct inode *inode = file_inode(iocb->ki_filp); loff_t offset = iocb->ki_pos; ssize_t ret; if (dio->end_io) { ret = dio->end_io(iocb, dio->error ? dio->error : dio->size, dio->flags); } else { ret = dio->error; } if (likely(!ret)) { ret = dio->size; /* check for short read */ if (offset + ret > dio->i_size && !(dio->flags & IOMAP_DIO_WRITE)) ret = dio->i_size - offset; iocb->ki_pos += ret; } /* * Try again to invalidate clean pages which might have been cached by * non-direct readahead, or faulted in by get_user_pages() if the source * of the write was an mmap'ed region of the file we're writing. Either * one is a pretty crazy thing to do, so we don't support it 100%. If * this invalidation fails, tough, the write still worked... * * And this page cache invalidation has to be after dio->end_io(), as * some filesystems convert unwritten extents to real allocations in * end_io() when necessary, otherwise a racing buffer read would cache * zeros from unwritten extents. */ if (!dio->error && (dio->flags & IOMAP_DIO_WRITE) && inode->i_mapping->nrpages) { int err; err = invalidate_inode_pages2_range(inode->i_mapping, offset >> PAGE_SHIFT, (offset + dio->size - 1) >> PAGE_SHIFT); if (err) dio_warn_stale_pagecache(iocb->ki_filp); } /* * If this is a DSYNC write, make sure we push it to stable storage now * that we've written data. */ if (ret > 0 && (dio->flags & IOMAP_DIO_NEED_SYNC)) ret = generic_write_sync(iocb, ret); inode_dio_end(file_inode(iocb->ki_filp)); kfree(dio); return ret; } static void iomap_dio_complete_work(struct work_struct *work) { struct iomap_dio *dio = container_of(work, struct iomap_dio, aio.work); struct kiocb *iocb = dio->iocb; iocb->ki_complete(iocb, iomap_dio_complete(dio), 0); } /* * Set an error in the dio if none is set yet. We have to use cmpxchg * as the submission context and the completion context(s) can race to * update the error. */ static inline void iomap_dio_set_error(struct iomap_dio *dio, int ret) { cmpxchg(&dio->error, 0, ret); } static void iomap_dio_bio_end_io(struct bio *bio) { struct iomap_dio *dio = bio->bi_private; bool should_dirty = (dio->flags & IOMAP_DIO_DIRTY); if (bio->bi_status) iomap_dio_set_error(dio, blk_status_to_errno(bio->bi_status)); if (atomic_dec_and_test(&dio->ref)) { if (dio->wait_for_completion) { struct task_struct *waiter = dio->submit.waiter; WRITE_ONCE(dio->submit.waiter, NULL); wake_up_process(waiter); } else if (dio->flags & IOMAP_DIO_WRITE) { struct inode *inode = file_inode(dio->iocb->ki_filp); INIT_WORK(&dio->aio.work, iomap_dio_complete_work); queue_work(inode->i_sb->s_dio_done_wq, &dio->aio.work); } else { iomap_dio_complete_work(&dio->aio.work); } } if (should_dirty) { bio_check_pages_dirty(bio); } else { struct bio_vec *bvec; int i; bio_for_each_segment_all(bvec, bio, i) put_page(bvec->bv_page); bio_put(bio); } } static blk_qc_t iomap_dio_zero(struct iomap_dio *dio, struct iomap *iomap, loff_t pos, unsigned len) { struct page *page = ZERO_PAGE(0); struct bio *bio; bio = bio_alloc(GFP_KERNEL, 1); bio_set_dev(bio, iomap->bdev); bio->bi_iter.bi_sector = iomap_sector(iomap, pos); bio->bi_private = dio; bio->bi_end_io = iomap_dio_bio_end_io; get_page(page); __bio_add_page(bio, page, len, 0); bio_set_op_attrs(bio, REQ_OP_WRITE, REQ_SYNC | REQ_IDLE); atomic_inc(&dio->ref); return submit_bio(bio); } static loff_t iomap_dio_bio_actor(struct inode *inode, loff_t pos, loff_t length, struct iomap_dio *dio, struct iomap *iomap) { unsigned int blkbits = blksize_bits(bdev_logical_block_size(iomap->bdev)); unsigned int fs_block_size = i_blocksize(inode), pad; unsigned int align = iov_iter_alignment(dio->submit.iter); struct iov_iter iter; struct bio *bio; bool need_zeroout = false; bool use_fua = false; int nr_pages, ret; size_t copied = 0; if ((pos | length | align) & ((1 << blkbits) - 1)) return -EINVAL; if (iomap->type == IOMAP_UNWRITTEN) { dio->flags |= IOMAP_DIO_UNWRITTEN; need_zeroout = true; } if (iomap->flags & IOMAP_F_SHARED) dio->flags |= IOMAP_DIO_COW; if (iomap->flags & IOMAP_F_NEW) { need_zeroout = true; } else { /* * Use a FUA write if we need datasync semantics, this * is a pure data IO that doesn't require any metadata * updates and the underlying device supports FUA. This * allows us to avoid cache flushes on IO completion. */ if (!(iomap->flags & (IOMAP_F_SHARED|IOMAP_F_DIRTY)) && (dio->flags & IOMAP_DIO_WRITE_FUA) && blk_queue_fua(bdev_get_queue(iomap->bdev))) use_fua = true; } /* * Operate on a partial iter trimmed to the extent we were called for. * We'll update the iter in the dio once we're done with this extent. */ iter = *dio->submit.iter; iov_iter_truncate(&iter, length); nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES); if (nr_pages <= 0) return nr_pages; if (need_zeroout) { /* zero out from the start of the block to the write offset */ pad = pos & (fs_block_size - 1); if (pad) iomap_dio_zero(dio, iomap, pos - pad, pad); } do { size_t n; if (dio->error) { iov_iter_revert(dio->submit.iter, copied); return 0; } bio = bio_alloc(GFP_KERNEL, nr_pages); bio_set_dev(bio, iomap->bdev); bio->bi_iter.bi_sector = iomap_sector(iomap, pos); bio->bi_write_hint = dio->iocb->ki_hint; bio->bi_ioprio = dio->iocb->ki_ioprio; bio->bi_private = dio; bio->bi_end_io = iomap_dio_bio_end_io; ret = bio_iov_iter_get_pages(bio, &iter); if (unlikely(ret)) { bio_put(bio); return copied ? copied : ret; } n = bio->bi_iter.bi_size; if (dio->flags & IOMAP_DIO_WRITE) { bio->bi_opf = REQ_OP_WRITE | REQ_SYNC | REQ_IDLE; if (use_fua) bio->bi_opf |= REQ_FUA; else dio->flags &= ~IOMAP_DIO_WRITE_FUA; task_io_account_write(n); } else { bio->bi_opf = REQ_OP_READ; if (dio->flags & IOMAP_DIO_DIRTY) bio_set_pages_dirty(bio); } iov_iter_advance(dio->submit.iter, n); dio->size += n; pos += n; copied += n; nr_pages = iov_iter_npages(&iter, BIO_MAX_PAGES); atomic_inc(&dio->ref); dio->submit.last_queue = bdev_get_queue(iomap->bdev); dio->submit.cookie = submit_bio(bio); } while (nr_pages); if (need_zeroout) { /* zero out from the end of the write to the end of the block */ pad = pos & (fs_block_size - 1); if (pad) iomap_dio_zero(dio, iomap, pos, fs_block_size - pad); } return copied; } static loff_t iomap_dio_hole_actor(loff_t length, struct iomap_dio *dio) { length = iov_iter_zero(length, dio->submit.iter); dio->size += length; return length; } static loff_t iomap_dio_inline_actor(struct inode *inode, loff_t pos, loff_t length, struct iomap_dio *dio, struct iomap *iomap) { struct iov_iter *iter = dio->submit.iter; size_t copied; BUG_ON(pos + length > PAGE_SIZE - offset_in_page(iomap->inline_data)); if (dio->flags & IOMAP_DIO_WRITE) { loff_t size = inode->i_size; if (pos > size) memset(iomap->inline_data + size, 0, pos - size); copied = copy_from_iter(iomap->inline_data + pos, length, iter); if (copied) { if (pos + copied > size) i_size_write(inode, pos + copied); mark_inode_dirty(inode); } } else { copied = copy_to_iter(iomap->inline_data + pos, length, iter); } dio->size += copied; return copied; } static loff_t iomap_dio_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { struct iomap_dio *dio = data; switch (iomap->type) { case IOMAP_HOLE: if (WARN_ON_ONCE(dio->flags & IOMAP_DIO_WRITE)) return -EIO; return iomap_dio_hole_actor(length, dio); case IOMAP_UNWRITTEN: if (!(dio->flags & IOMAP_DIO_WRITE)) return iomap_dio_hole_actor(length, dio); return iomap_dio_bio_actor(inode, pos, length, dio, iomap); case IOMAP_MAPPED: return iomap_dio_bio_actor(inode, pos, length, dio, iomap); case IOMAP_INLINE: return iomap_dio_inline_actor(inode, pos, length, dio, iomap); default: WARN_ON_ONCE(1); return -EIO; } } /* * iomap_dio_rw() always completes O_[D]SYNC writes regardless of whether the IO * is being issued as AIO or not. This allows us to optimise pure data writes * to use REQ_FUA rather than requiring generic_write_sync() to issue a * REQ_FLUSH post write. This is slightly tricky because a single request here * can be mapped into multiple disjoint IOs and only a subset of the IOs issued * may be pure data writes. In that case, we still need to do a full data sync * completion. */ ssize_t iomap_dio_rw(struct kiocb *iocb, struct iov_iter *iter, const struct iomap_ops *ops, iomap_dio_end_io_t end_io) { struct address_space *mapping = iocb->ki_filp->f_mapping; struct inode *inode = file_inode(iocb->ki_filp); size_t count = iov_iter_count(iter); loff_t pos = iocb->ki_pos, start = pos; loff_t end = iocb->ki_pos + count - 1, ret = 0; unsigned int flags = IOMAP_DIRECT; struct blk_plug plug; struct iomap_dio *dio; lockdep_assert_held(&inode->i_rwsem); if (!count) return 0; dio = kmalloc(sizeof(*dio), GFP_KERNEL); if (!dio) return -ENOMEM; dio->iocb = iocb; atomic_set(&dio->ref, 1); dio->size = 0; dio->i_size = i_size_read(inode); dio->end_io = end_io; dio->error = 0; dio->flags = 0; dio->wait_for_completion = is_sync_kiocb(iocb); dio->submit.iter = iter; dio->submit.waiter = current; dio->submit.cookie = BLK_QC_T_NONE; dio->submit.last_queue = NULL; if (iov_iter_rw(iter) == READ) { if (pos >= dio->i_size) goto out_free_dio; if (iter->type == ITER_IOVEC) dio->flags |= IOMAP_DIO_DIRTY; } else { flags |= IOMAP_WRITE; dio->flags |= IOMAP_DIO_WRITE; /* for data sync or sync, we need sync completion processing */ if (iocb->ki_flags & IOCB_DSYNC) dio->flags |= IOMAP_DIO_NEED_SYNC; /* * For datasync only writes, we optimistically try using FUA for * this IO. Any non-FUA write that occurs will clear this flag, * hence we know before completion whether a cache flush is * necessary. */ if ((iocb->ki_flags & (IOCB_DSYNC | IOCB_SYNC)) == IOCB_DSYNC) dio->flags |= IOMAP_DIO_WRITE_FUA; } if (iocb->ki_flags & IOCB_NOWAIT) { if (filemap_range_has_page(mapping, start, end)) { ret = -EAGAIN; goto out_free_dio; } flags |= IOMAP_NOWAIT; } ret = filemap_write_and_wait_range(mapping, start, end); if (ret) goto out_free_dio; /* * Try to invalidate cache pages for the range we're direct * writing. If this invalidation fails, tough, the write will * still work, but racing two incompatible write paths is a * pretty crazy thing to do, so we don't support it 100%. */ ret = invalidate_inode_pages2_range(mapping, start >> PAGE_SHIFT, end >> PAGE_SHIFT); if (ret) dio_warn_stale_pagecache(iocb->ki_filp); ret = 0; if (iov_iter_rw(iter) == WRITE && !dio->wait_for_completion && !inode->i_sb->s_dio_done_wq) { ret = sb_init_dio_done_wq(inode->i_sb); if (ret < 0) goto out_free_dio; } inode_dio_begin(inode); blk_start_plug(&plug); do { ret = iomap_apply(inode, pos, count, flags, ops, dio, iomap_dio_actor); if (ret <= 0) { /* magic error code to fall back to buffered I/O */ if (ret == -ENOTBLK) { dio->wait_for_completion = true; ret = 0; } break; } pos += ret; if (iov_iter_rw(iter) == READ && pos >= dio->i_size) break; } while ((count = iov_iter_count(iter)) > 0); blk_finish_plug(&plug); if (ret < 0) iomap_dio_set_error(dio, ret); /* * If all the writes we issued were FUA, we don't need to flush the * cache on IO completion. Clear the sync flag for this case. */ if (dio->flags & IOMAP_DIO_WRITE_FUA) dio->flags &= ~IOMAP_DIO_NEED_SYNC; if (!atomic_dec_and_test(&dio->ref)) { if (!dio->wait_for_completion) return -EIOCBQUEUED; for (;;) { set_current_state(TASK_UNINTERRUPTIBLE); if (!READ_ONCE(dio->submit.waiter)) break; if (!(iocb->ki_flags & IOCB_HIPRI) || !dio->submit.last_queue || !blk_poll(dio->submit.last_queue, dio->submit.cookie)) io_schedule(); } __set_current_state(TASK_RUNNING); } ret = iomap_dio_complete(dio); return ret; out_free_dio: kfree(dio); return ret; } EXPORT_SYMBOL_GPL(iomap_dio_rw); /* Swapfile activation */ #ifdef CONFIG_SWAP struct iomap_swapfile_info { struct iomap iomap; /* accumulated iomap */ struct swap_info_struct *sis; uint64_t lowest_ppage; /* lowest physical addr seen (pages) */ uint64_t highest_ppage; /* highest physical addr seen (pages) */ unsigned long nr_pages; /* number of pages collected */ int nr_extents; /* extent count */ }; /* * Collect physical extents for this swap file. Physical extents reported to * the swap code must be trimmed to align to a page boundary. The logical * offset within the file is irrelevant since the swapfile code maps logical * page numbers of the swap device to the physical page-aligned extents. */ static int iomap_swapfile_add_extent(struct iomap_swapfile_info *isi) { struct iomap *iomap = &isi->iomap; unsigned long nr_pages; uint64_t first_ppage; uint64_t first_ppage_reported; uint64_t next_ppage; int error; /* * Round the start up and the end down so that the physical * extent aligns to a page boundary. */ first_ppage = ALIGN(iomap->addr, PAGE_SIZE) >> PAGE_SHIFT; next_ppage = ALIGN_DOWN(iomap->addr + iomap->length, PAGE_SIZE) >> PAGE_SHIFT; /* Skip too-short physical extents. */ if (first_ppage >= next_ppage) return 0; nr_pages = next_ppage - first_ppage; /* * Calculate how much swap space we're adding; the first page contains * the swap header and doesn't count. The mm still wants that first * page fed to add_swap_extent, however. */ first_ppage_reported = first_ppage; if (iomap->offset == 0) first_ppage_reported++; if (isi->lowest_ppage > first_ppage_reported) isi->lowest_ppage = first_ppage_reported; if (isi->highest_ppage < (next_ppage - 1)) isi->highest_ppage = next_ppage - 1; /* Add extent, set up for the next call. */ error = add_swap_extent(isi->sis, isi->nr_pages, nr_pages, first_ppage); if (error < 0) return error; isi->nr_extents += error; isi->nr_pages += nr_pages; return 0; } /* * Accumulate iomaps for this swap file. We have to accumulate iomaps because * swap only cares about contiguous page-aligned physical extents and makes no * distinction between written and unwritten extents. */ static loff_t iomap_swapfile_activate_actor(struct inode *inode, loff_t pos, loff_t count, void *data, struct iomap *iomap) { struct iomap_swapfile_info *isi = data; int error; switch (iomap->type) { case IOMAP_MAPPED: case IOMAP_UNWRITTEN: /* Only real or unwritten extents. */ break; case IOMAP_INLINE: /* No inline data. */ pr_err("swapon: file is inline\n"); return -EINVAL; default: pr_err("swapon: file has unallocated extents\n"); return -EINVAL; } /* No uncommitted metadata or shared blocks. */ if (iomap->flags & IOMAP_F_DIRTY) { pr_err("swapon: file is not committed\n"); return -EINVAL; } if (iomap->flags & IOMAP_F_SHARED) { pr_err("swapon: file has shared extents\n"); return -EINVAL; } /* Only one bdev per swap file. */ if (iomap->bdev != isi->sis->bdev) { pr_err("swapon: file is on multiple devices\n"); return -EINVAL; } if (isi->iomap.length == 0) { /* No accumulated extent, so just store it. */ memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); } else if (isi->iomap.addr + isi->iomap.length == iomap->addr) { /* Append this to the accumulated extent. */ isi->iomap.length += iomap->length; } else { /* Otherwise, add the retained iomap and store this one. */ error = iomap_swapfile_add_extent(isi); if (error) return error; memcpy(&isi->iomap, iomap, sizeof(isi->iomap)); } return count; } /* * Iterate a swap file's iomaps to construct physical extents that can be * passed to the swapfile subsystem. */ int iomap_swapfile_activate(struct swap_info_struct *sis, struct file *swap_file, sector_t *pagespan, const struct iomap_ops *ops) { struct iomap_swapfile_info isi = { .sis = sis, .lowest_ppage = (sector_t)-1ULL, }; struct address_space *mapping = swap_file->f_mapping; struct inode *inode = mapping->host; loff_t pos = 0; loff_t len = ALIGN_DOWN(i_size_read(inode), PAGE_SIZE); loff_t ret; /* * Persist all file mapping metadata so that we won't have any * IOMAP_F_DIRTY iomaps. */ ret = vfs_fsync(swap_file, 1); if (ret) return ret; while (len > 0) { ret = iomap_apply(inode, pos, len, IOMAP_REPORT, ops, &isi, iomap_swapfile_activate_actor); if (ret <= 0) return ret; pos += ret; len -= ret; } if (isi.iomap.length) { ret = iomap_swapfile_add_extent(&isi); if (ret) return ret; } *pagespan = 1 + isi.highest_ppage - isi.lowest_ppage; sis->max = isi.nr_pages; sis->pages = isi.nr_pages - 1; sis->highest_bit = isi.nr_pages - 1; return isi.nr_extents; } EXPORT_SYMBOL_GPL(iomap_swapfile_activate); #endif /* CONFIG_SWAP */ static loff_t iomap_bmap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) { sector_t *bno = data, addr; if (iomap->type == IOMAP_MAPPED) { addr = (pos - iomap->offset + iomap->addr) >> inode->i_blkbits; if (addr > INT_MAX) WARN(1, "would truncate bmap result\n"); else *bno = addr; } return 0; } /* legacy ->bmap interface. 0 is the error return (!) */ sector_t iomap_bmap(struct address_space *mapping, sector_t bno, const struct iomap_ops *ops) { struct inode *inode = mapping->host; loff_t pos = bno >> inode->i_blkbits; unsigned blocksize = i_blocksize(inode); if (filemap_write_and_wait(mapping)) return 0; bno = 0; iomap_apply(inode, pos, blocksize, 0, ops, &bno, iomap_bmap_actor); return bno; } EXPORT_SYMBOL_GPL(iomap_bmap);