void linvfs_unwritten_done( struct buffer_head *bh, int uptodate) { xfs_buf_t *pb = (xfs_buf_t *)bh->b_private; ASSERT(buffer_unwritten(bh)); bh->b_end_io = NULL; clear_buffer_unwritten(bh); if (!uptodate) pagebuf_ioerror(pb, EIO); if (atomic_dec_and_test(&pb->pb_io_remaining) == 1) { pagebuf_iodone(pb, 1, 1); } end_buffer_async_write(bh, uptodate); }
struct page *read_dax_sector(struct block_device *bdev, sector_t n) { struct page *page = alloc_pages(GFP_KERNEL, 0); struct blk_dax_ctl dax = { .size = PAGE_SIZE, .sector = n & ~((((int) PAGE_SIZE) / 512) - 1), }; long rc; if (!page) return ERR_PTR(-ENOMEM); rc = dax_map_atomic(bdev, &dax); if (rc < 0) return ERR_PTR(rc); memcpy_from_pmem(page_address(page), dax.addr, PAGE_SIZE); dax_unmap_atomic(bdev, &dax); return page; } static bool buffer_written(struct buffer_head *bh) { return buffer_mapped(bh) && !buffer_unwritten(bh); } /* * When ext4 encounters a hole, it returns without modifying the buffer_head * which means that we can't trust b_size. To cope with this, we set b_state * to 0 before calling get_block and, if any bit is set, we know we can trust * b_size. Unfortunate, really, since ext4 knows precisely how long a hole is * and would save us time calling get_block repeatedly. */ static bool buffer_size_valid(struct buffer_head *bh) { return bh->b_state != 0; } static sector_t to_sector(const struct buffer_head *bh, const struct inode *inode) { sector_t sector = bh->b_blocknr << (inode->i_blkbits - 9); return sector; }
void xfs_count_page_state( struct page *page, int *delalloc, int *unwritten) { struct buffer_head *bh, *head; *delalloc = *unwritten = 0; bh = head = page_buffers(page); do { if (buffer_unwritten(bh)) (*unwritten) = 1; else if (buffer_delay(bh)) (*delalloc) = 1; } while ((bh = bh->b_this_page) != head); }
/* * Lookup the desired type of offset from the given page. * * On success, return true and the offset argument will point to the * start of the region that was found. Otherwise this function will * return false and keep the offset argument unchanged. */ STATIC bool xfs_lookup_buffer_offset( struct page *page, loff_t *offset, unsigned int type) { loff_t lastoff = page_offset(page); bool found = false; struct buffer_head *bh, *head; bh = head = page_buffers(page); do { /* * Unwritten extents that have data in the page * cache covering them can be identified by the * BH_Unwritten state flag. Pages with multiple * buffers might have a mix of holes, data and * unwritten extents - any buffer with valid * data in it should have BH_Uptodate flag set * on it. */ if (buffer_unwritten(bh) || buffer_uptodate(bh)) { if (type == DATA_OFF) found = true; } else { if (type == HOLE_OFF) found = true; } if (found) { *offset = lastoff; break; } lastoff += bh->b_size; } while ((bh = bh->b_this_page) != head); return found; }
int __dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, pmd_t *pmd, unsigned int flags, get_block_t get_block, dax_iodone_t complete_unwritten) { struct file *file = vma->vm_file; struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; struct buffer_head bh; unsigned blkbits = inode->i_blkbits; unsigned long pmd_addr = address & PMD_MASK; bool write = flags & FAULT_FLAG_WRITE; struct block_device *bdev; pgoff_t size, pgoff; sector_t block; int error, result = 0; bool alloc = false; /* dax pmd mappings require pfn_t_devmap() */ if (!IS_ENABLED(CONFIG_FS_DAX_PMD)) return VM_FAULT_FALLBACK; /* Fall back to PTEs if we're going to COW */ if (write && !(vma->vm_flags & VM_SHARED)) { split_huge_pmd(vma, pmd, address); dax_pmd_dbg(NULL, address, "cow write"); return VM_FAULT_FALLBACK; } /* If the PMD would extend outside the VMA */ if (pmd_addr < vma->vm_start) { dax_pmd_dbg(NULL, address, "vma start unaligned"); return VM_FAULT_FALLBACK; } if ((pmd_addr + PMD_SIZE) > vma->vm_end) { dax_pmd_dbg(NULL, address, "vma end unaligned"); return VM_FAULT_FALLBACK; } pgoff = linear_page_index(vma, pmd_addr); size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; if (pgoff >= size) return VM_FAULT_SIGBUS; /* If the PMD would cover blocks out of the file */ if ((pgoff | PG_PMD_COLOUR) >= size) { dax_pmd_dbg(NULL, address, "offset + huge page size > file size"); return VM_FAULT_FALLBACK; } memset(&bh, 0, sizeof(bh)); bh.b_bdev = inode->i_sb->s_bdev; block = (sector_t)pgoff << (PAGE_SHIFT - blkbits); bh.b_size = PMD_SIZE; if (get_block(inode, block, &bh, 0) != 0) return VM_FAULT_SIGBUS; if (!buffer_mapped(&bh) && write) { if (get_block(inode, block, &bh, 1) != 0) return VM_FAULT_SIGBUS; alloc = true; } bdev = bh.b_bdev; /* * If the filesystem isn't willing to tell us the length of a hole, * just fall back to PTEs. Calling get_block 512 times in a loop * would be silly. */ if (!buffer_size_valid(&bh) || bh.b_size < PMD_SIZE) { dax_pmd_dbg(&bh, address, "allocated block too small"); return VM_FAULT_FALLBACK; } /* * If we allocated new storage, make sure no process has any * zero pages covering this hole */ if (alloc) { loff_t lstart = pgoff << PAGE_SHIFT; loff_t lend = lstart + PMD_SIZE - 1; /* inclusive */ truncate_pagecache_range(inode, lstart, lend); } i_mmap_lock_read(mapping); /* * If a truncate happened while we were allocating blocks, we may * leave blocks allocated to the file that are beyond EOF. We can't * take i_mutex here, so just leave them hanging; they'll be freed * when the file is deleted. */ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; if (pgoff >= size) { result = VM_FAULT_SIGBUS; goto out; } if ((pgoff | PG_PMD_COLOUR) >= size) { dax_pmd_dbg(&bh, address, "offset + huge page size > file size"); goto fallback; } if (!write && !buffer_mapped(&bh) && buffer_uptodate(&bh)) { spinlock_t *ptl; pmd_t entry; struct page *zero_page = get_huge_zero_page(); if (unlikely(!zero_page)) { dax_pmd_dbg(&bh, address, "no zero page"); goto fallback; } ptl = pmd_lock(vma->vm_mm, pmd); if (!pmd_none(*pmd)) { spin_unlock(ptl); dax_pmd_dbg(&bh, address, "pmd already present"); goto fallback; } dev_dbg(part_to_dev(bdev->bd_part), "%s: %s addr: %lx pfn: <zero> sect: %llx\n", __func__, current->comm, address, (unsigned long long) to_sector(&bh, inode)); entry = mk_pmd(zero_page, vma->vm_page_prot); entry = pmd_mkhuge(entry); set_pmd_at(vma->vm_mm, pmd_addr, pmd, entry); result = VM_FAULT_NOPAGE; spin_unlock(ptl); } else { struct blk_dax_ctl dax = { .sector = to_sector(&bh, inode), .size = PMD_SIZE, }; long length = dax_map_atomic(bdev, &dax); if (length < 0) { result = VM_FAULT_SIGBUS; goto out; } if (length < PMD_SIZE) { dax_pmd_dbg(&bh, address, "dax-length too small"); dax_unmap_atomic(bdev, &dax); goto fallback; } if (pfn_t_to_pfn(dax.pfn) & PG_PMD_COLOUR) { dax_pmd_dbg(&bh, address, "pfn unaligned"); dax_unmap_atomic(bdev, &dax); goto fallback; } if (!pfn_t_devmap(dax.pfn)) { dax_unmap_atomic(bdev, &dax); dax_pmd_dbg(&bh, address, "pfn not in memmap"); goto fallback; } if (buffer_unwritten(&bh) || buffer_new(&bh)) { clear_pmem(dax.addr, PMD_SIZE); wmb_pmem(); count_vm_event(PGMAJFAULT); mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); result |= VM_FAULT_MAJOR; } dax_unmap_atomic(bdev, &dax); /* * For PTE faults we insert a radix tree entry for reads, and * leave it clean. Then on the first write we dirty the radix * tree entry via the dax_pfn_mkwrite() path. This sequence * allows the dax_pfn_mkwrite() call to be simpler and avoid a * call into get_block() to translate the pgoff to a sector in * order to be able to create a new radix tree entry. * * The PMD path doesn't have an equivalent to * dax_pfn_mkwrite(), though, so for a read followed by a * write we traverse all the way through __dax_pmd_fault() * twice. This means we can just skip inserting a radix tree * entry completely on the initial read and just wait until * the write to insert a dirty entry. */ if (write) { error = dax_radix_entry(mapping, pgoff, dax.sector, true, true); if (error) { dax_pmd_dbg(&bh, address, "PMD radix insertion failed"); goto fallback; } } dev_dbg(part_to_dev(bdev->bd_part), "%s: %s addr: %lx pfn: %lx sect: %llx\n", __func__, current->comm, address, pfn_t_to_pfn(dax.pfn), (unsigned long long) dax.sector); result |= vmf_insert_pfn_pmd(vma, address, pmd, dax.pfn, write); } out: i_mmap_unlock_read(mapping); if (buffer_unwritten(&bh)) complete_unwritten(&bh, !(result & VM_FAULT_ERROR)); return result; fallback: count_vm_event(THP_FAULT_FALLBACK); result = VM_FAULT_FALLBACK; goto out; } EXPORT_SYMBOL_GPL(__dax_pmd_fault); /** * dax_pmd_fault - handle a PMD fault on a DAX file * @vma: The virtual memory area where the fault occurred * @vmf: The description of the fault * @get_block: The filesystem method used to translate file offsets to blocks * * When a page fault occurs, filesystems may call this helper in their * pmd_fault handler for DAX files. */ int dax_pmd_fault(struct vm_area_struct *vma, unsigned long address, pmd_t *pmd, unsigned int flags, get_block_t get_block, dax_iodone_t complete_unwritten) { int result; struct super_block *sb = file_inode(vma->vm_file)->i_sb; if (flags & FAULT_FLAG_WRITE) { sb_start_pagefault(sb); file_update_time(vma->vm_file); } result = __dax_pmd_fault(vma, address, pmd, flags, get_block, complete_unwritten); if (flags & FAULT_FLAG_WRITE) sb_end_pagefault(sb); return result; }
static int copy_user_bh(struct page *to, struct inode *inode, struct buffer_head *bh, unsigned long vaddr) { struct blk_dax_ctl dax = { .sector = to_sector(bh, inode), .size = bh->b_size, }; struct block_device *bdev = bh->b_bdev; void *vto; if (dax_map_atomic(bdev, &dax) < 0) return PTR_ERR(dax.addr); vto = kmap_atomic(to); copy_user_page(vto, (void __force *)dax.addr, vaddr, to); kunmap_atomic(vto); dax_unmap_atomic(bdev, &dax); return 0; } #define NO_SECTOR -1 #define DAX_PMD_INDEX(page_index) (page_index & (PMD_MASK >> PAGE_SHIFT)) static int dax_radix_entry(struct address_space *mapping, pgoff_t index, sector_t sector, bool pmd_entry, bool dirty) { struct radix_tree_root *page_tree = &mapping->page_tree; pgoff_t pmd_index = DAX_PMD_INDEX(index); int type, error = 0; void *entry; WARN_ON_ONCE(pmd_entry && !dirty); if (dirty) __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); spin_lock_irq(&mapping->tree_lock); entry = radix_tree_lookup(page_tree, pmd_index); if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD) { index = pmd_index; goto dirty; } entry = radix_tree_lookup(page_tree, index); if (entry) { type = RADIX_DAX_TYPE(entry); if (WARN_ON_ONCE(type != RADIX_DAX_PTE && type != RADIX_DAX_PMD)) { error = -EIO; goto unlock; } if (!pmd_entry || type == RADIX_DAX_PMD) goto dirty; /* * We only insert dirty PMD entries into the radix tree. This * means we don't need to worry about removing a dirty PTE * entry and inserting a clean PMD entry, thus reducing the * range we would flush with a follow-up fsync/msync call. */ radix_tree_delete(&mapping->page_tree, index); mapping->nrexceptional--; } if (sector == NO_SECTOR) { /* * This can happen during correct operation if our pfn_mkwrite * fault raced against a hole punch operation. If this * happens the pte that was hole punched will have been * unmapped and the radix tree entry will have been removed by * the time we are called, but the call will still happen. We * will return all the way up to wp_pfn_shared(), where the * pte_same() check will fail, eventually causing page fault * to be retried by the CPU. */ goto unlock; } error = radix_tree_insert(page_tree, index, RADIX_DAX_ENTRY(sector, pmd_entry)); if (error) goto unlock; mapping->nrexceptional++; dirty: if (dirty) radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY); unlock: spin_unlock_irq(&mapping->tree_lock); return error; } static int dax_writeback_one(struct block_device *bdev, struct address_space *mapping, pgoff_t index, void *entry) { struct radix_tree_root *page_tree = &mapping->page_tree; int type = RADIX_DAX_TYPE(entry); struct radix_tree_node *node; struct blk_dax_ctl dax; void **slot; int ret = 0; spin_lock_irq(&mapping->tree_lock); /* * Regular page slots are stabilized by the page lock even * without the tree itself locked. These unlocked entries * need verification under the tree lock. */ if (!__radix_tree_lookup(page_tree, index, &node, &slot)) goto unlock; if (*slot != entry) goto unlock; /* another fsync thread may have already written back this entry */ if (!radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)) goto unlock; if (WARN_ON_ONCE(type != RADIX_DAX_PTE && type != RADIX_DAX_PMD)) { ret = -EIO; goto unlock; } dax.sector = RADIX_DAX_SECTOR(entry); dax.size = (type == RADIX_DAX_PMD ? PMD_SIZE : PAGE_SIZE); spin_unlock_irq(&mapping->tree_lock); /* * We cannot hold tree_lock while calling dax_map_atomic() because it * eventually calls cond_resched(). */ ret = dax_map_atomic(bdev, &dax); if (ret < 0) return ret; if (WARN_ON_ONCE(ret < dax.size)) { ret = -EIO; goto unmap; } wb_cache_pmem(dax.addr, dax.size); spin_lock_irq(&mapping->tree_lock); radix_tree_tag_clear(page_tree, index, PAGECACHE_TAG_TOWRITE); spin_unlock_irq(&mapping->tree_lock); unmap: dax_unmap_atomic(bdev, &dax); return ret; unlock: spin_unlock_irq(&mapping->tree_lock); return ret; } /* * Flush the mapping to the persistent domain within the byte range of [start, * end]. This is required by data integrity operations to ensure file data is * on persistent storage prior to completion of the operation. */ int dax_writeback_mapping_range(struct address_space *mapping, struct block_device *bdev, struct writeback_control *wbc) { struct inode *inode = mapping->host; pgoff_t start_index, end_index, pmd_index; pgoff_t indices[PAGEVEC_SIZE]; struct pagevec pvec; bool done = false; int i, ret = 0; void *entry; if (WARN_ON_ONCE(inode->i_blkbits != PAGE_SHIFT)) return -EIO; if (!mapping->nrexceptional || wbc->sync_mode != WB_SYNC_ALL) return 0; start_index = wbc->range_start >> PAGE_SHIFT; end_index = wbc->range_end >> PAGE_SHIFT; pmd_index = DAX_PMD_INDEX(start_index); rcu_read_lock(); entry = radix_tree_lookup(&mapping->page_tree, pmd_index); rcu_read_unlock(); /* see if the start of our range is covered by a PMD entry */ if (entry && RADIX_DAX_TYPE(entry) == RADIX_DAX_PMD) start_index = pmd_index; tag_pages_for_writeback(mapping, start_index, end_index); pagevec_init(&pvec, 0); while (!done) { pvec.nr = find_get_entries_tag(mapping, start_index, PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE, pvec.pages, indices); if (pvec.nr == 0) break; for (i = 0; i < pvec.nr; i++) { if (indices[i] > end_index) { done = true; break; } ret = dax_writeback_one(bdev, mapping, indices[i], pvec.pages[i]); if (ret < 0) return ret; } } wmb_pmem(); return 0; } EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); static int dax_insert_mapping(struct inode *inode, struct buffer_head *bh, struct vm_area_struct *vma, struct vm_fault *vmf) { unsigned long vaddr = (unsigned long)vmf->virtual_address; struct address_space *mapping = inode->i_mapping; struct block_device *bdev = bh->b_bdev; struct blk_dax_ctl dax = { .sector = to_sector(bh, inode), .size = bh->b_size, }; pgoff_t size; int error; i_mmap_lock_read(mapping); /* * Check truncate didn't happen while we were allocating a block. * If it did, this block may or may not be still allocated to the * file. We can't tell the filesystem to free it because we can't * take i_mutex here. In the worst case, the file still has blocks * allocated past the end of the file. */ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; if (unlikely(vmf->pgoff >= size)) { error = -EIO; goto out; } if (dax_map_atomic(bdev, &dax) < 0) { error = PTR_ERR(dax.addr); goto out; } if (buffer_unwritten(bh) || buffer_new(bh)) { clear_pmem(dax.addr, PAGE_SIZE); wmb_pmem(); } dax_unmap_atomic(bdev, &dax); error = dax_radix_entry(mapping, vmf->pgoff, dax.sector, false, vmf->flags & FAULT_FLAG_WRITE); if (error) goto out; error = vm_insert_mixed(vma, vaddr, dax.pfn); out: i_mmap_unlock_read(mapping); return error; } /** * __dax_fault - handle a page fault on a DAX file * @vma: The virtual memory area where the fault occurred * @vmf: The description of the fault * @get_block: The filesystem method used to translate file offsets to blocks * @complete_unwritten: The filesystem method used to convert unwritten blocks * to written so the data written to them is exposed. This is required for * required by write faults for filesystems that will return unwritten * extent mappings from @get_block, but it is optional for reads as * dax_insert_mapping() will always zero unwritten blocks. If the fs does * not support unwritten extents, the it should pass NULL. * * When a page fault occurs, filesystems may call this helper in their * fault handler for DAX files. __dax_fault() assumes the caller has done all * the necessary locking for the page fault to proceed successfully. */ int __dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf, get_block_t get_block, dax_iodone_t complete_unwritten) { struct file *file = vma->vm_file; struct address_space *mapping = file->f_mapping; struct inode *inode = mapping->host; struct page *page; struct buffer_head bh; unsigned long vaddr = (unsigned long)vmf->virtual_address; unsigned blkbits = inode->i_blkbits; sector_t block; pgoff_t size; int error; int major = 0; size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; if (vmf->pgoff >= size) return VM_FAULT_SIGBUS; memset(&bh, 0, sizeof(bh)); block = (sector_t)vmf->pgoff << (PAGE_SHIFT - blkbits); bh.b_bdev = inode->i_sb->s_bdev; bh.b_size = PAGE_SIZE; repeat: page = find_get_page(mapping, vmf->pgoff); if (page) { if (!lock_page_or_retry(page, vma->vm_mm, vmf->flags)) { put_page(page); return VM_FAULT_RETRY; } if (unlikely(page->mapping != mapping)) { unlock_page(page); put_page(page); goto repeat; } size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; if (unlikely(vmf->pgoff >= size)) { /* * We have a struct page covering a hole in the file * from a read fault and we've raced with a truncate */ error = -EIO; goto unlock_page; } } error = get_block(inode, block, &bh, 0); if (!error && (bh.b_size < PAGE_SIZE)) error = -EIO; /* fs corruption? */ if (error) goto unlock_page; if (!buffer_mapped(&bh) && !buffer_unwritten(&bh) && !vmf->cow_page) { if (vmf->flags & FAULT_FLAG_WRITE) { error = get_block(inode, block, &bh, 1); count_vm_event(PGMAJFAULT); mem_cgroup_count_vm_event(vma->vm_mm, PGMAJFAULT); major = VM_FAULT_MAJOR; if (!error && (bh.b_size < PAGE_SIZE)) error = -EIO; if (error) goto unlock_page; } else { return dax_load_hole(mapping, page, vmf); } } if (vmf->cow_page) { struct page *new_page = vmf->cow_page; if (buffer_written(&bh)) error = copy_user_bh(new_page, inode, &bh, vaddr); else clear_user_highpage(new_page, vaddr); if (error) goto unlock_page; vmf->page = page; if (!page) { i_mmap_lock_read(mapping); /* Check we didn't race with truncate */ size = (i_size_read(inode) + PAGE_SIZE - 1) >> PAGE_SHIFT; if (vmf->pgoff >= size) { i_mmap_unlock_read(mapping); error = -EIO; goto out; } } return VM_FAULT_LOCKED; } /* Check we didn't race with a read fault installing a new page */ if (!page && major) page = find_lock_page(mapping, vmf->pgoff); if (page) { unmap_mapping_range(mapping, vmf->pgoff << PAGE_SHIFT, PAGE_SIZE, 0); delete_from_page_cache(page); unlock_page(page); put_page(page); page = NULL; } /* * If we successfully insert the new mapping over an unwritten extent, * we need to ensure we convert the unwritten extent. If there is an * error inserting the mapping, the filesystem needs to leave it as * unwritten to prevent exposure of the stale underlying data to * userspace, but we still need to call the completion function so * the private resources on the mapping buffer can be released. We * indicate what the callback should do via the uptodate variable, same * as for normal BH based IO completions. */ error = dax_insert_mapping(inode, &bh, vma, vmf); if (buffer_unwritten(&bh)) { if (complete_unwritten) complete_unwritten(&bh, !error); else WARN_ON_ONCE(!(vmf->flags & FAULT_FLAG_WRITE)); } out: if (error == -ENOMEM) return VM_FAULT_OOM | major; /* -EBUSY is fine, somebody else faulted on the same PTE */ if ((error < 0) && (error != -EBUSY)) return VM_FAULT_SIGBUS | major; return VM_FAULT_NOPAGE | major; unlock_page: if (page) { unlock_page(page); put_page(page); } goto out; }
static ssize_t dax_io(struct inode *inode, struct iov_iter *iter, loff_t start, loff_t end, get_block_t get_block, struct buffer_head *bh) { loff_t pos = start, max = start, bh_max = start; bool hole = false, need_wmb = false; struct block_device *bdev = NULL; int rw = iov_iter_rw(iter), rc; long map_len = 0; struct blk_dax_ctl dax = { .addr = (void __pmem *) ERR_PTR(-EIO), }; if (rw == READ) end = min(end, i_size_read(inode)); while (pos < end) { size_t len; if (pos == max) { unsigned blkbits = inode->i_blkbits; long page = pos >> PAGE_SHIFT; sector_t block = page << (PAGE_SHIFT - blkbits); unsigned first = pos - (block << blkbits); long size; if (pos == bh_max) { bh->b_size = PAGE_ALIGN(end - pos); bh->b_state = 0; rc = get_block(inode, block, bh, rw == WRITE); if (rc) break; if (!buffer_size_valid(bh)) bh->b_size = 1 << blkbits; bh_max = pos - first + bh->b_size; bdev = bh->b_bdev; } else { unsigned done = bh->b_size - (bh_max - (pos - first)); bh->b_blocknr += done >> blkbits; bh->b_size -= done; } hole = rw == READ && !buffer_written(bh); if (hole) { size = bh->b_size - first; } else { dax_unmap_atomic(bdev, &dax); dax.sector = to_sector(bh, inode); dax.size = bh->b_size; map_len = dax_map_atomic(bdev, &dax); if (map_len < 0) { rc = map_len; break; } if (buffer_unwritten(bh) || buffer_new(bh)) { dax_new_buf(dax.addr, map_len, first, pos, end); need_wmb = true; } dax.addr += first; size = map_len - first; } max = min(pos + size, end); } if (iov_iter_rw(iter) == WRITE) { len = copy_from_iter_pmem(dax.addr, max - pos, iter); need_wmb = true; } else if (!hole) len = copy_to_iter((void __force *) dax.addr, max - pos, iter); else len = iov_iter_zero(max - pos, iter); if (!len) { rc = -EFAULT; break; } pos += len; if (!IS_ERR(dax.addr)) dax.addr += len; } if (need_wmb) wmb_pmem(); dax_unmap_atomic(bdev, &dax); return (pos == start) ? rc : pos - start; }
static bool buffer_written(struct buffer_head *bh) { return buffer_mapped(bh) && !buffer_unwritten(bh); }
int f2fs_fiemap(struct inode *inode, struct fiemap_extent_info *fieinfo, u64 start, u64 len) { struct buffer_head map_bh; sector_t start_blk, last_blk; loff_t isize = i_size_read(inode); u64 logical = 0, phys = 0, size = 0; u32 flags = 0; bool past_eof = false, whole_file = false; int ret = 0; ret = fiemap_check_flags(fieinfo, FIEMAP_FLAG_SYNC); if (ret) return ret; mutex_lock(&inode->i_mutex); if (len >= isize) { whole_file = true; len = isize; } if (logical_to_blk(inode, len) == 0) len = blk_to_logical(inode, 1); start_blk = logical_to_blk(inode, start); last_blk = logical_to_blk(inode, start + len - 1); next: memset(&map_bh, 0, sizeof(struct buffer_head)); map_bh.b_size = len; ret = get_data_block(inode, start_blk, &map_bh, 0, F2FS_GET_BLOCK_FIEMAP); if (ret) goto out; /* HOLE */ if (!buffer_mapped(&map_bh)) { start_blk++; if (!past_eof && blk_to_logical(inode, start_blk) >= isize) past_eof = 1; if (past_eof && size) { flags |= FIEMAP_EXTENT_LAST; ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); } else if (size) { ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); size = 0; } /* if we have holes up to/past EOF then we're done */ if (start_blk > last_blk || past_eof || ret) goto out; } else { if (start_blk > last_blk && !whole_file) { ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); goto out; } /* * if size != 0 then we know we already have an extent * to add, so add it. */ if (size) { ret = fiemap_fill_next_extent(fieinfo, logical, phys, size, flags); if (ret) goto out; } logical = blk_to_logical(inode, start_blk); phys = blk_to_logical(inode, map_bh.b_blocknr); size = map_bh.b_size; flags = 0; if (buffer_unwritten(&map_bh)) flags = FIEMAP_EXTENT_UNWRITTEN; start_blk += logical_to_blk(inode, size); /* * If we are past the EOF, then we need to make sure as * soon as we find a hole that the last extent we found * is marked with FIEMAP_EXTENT_LAST */ if (!past_eof && logical + size >= isize) past_eof = true; } cond_resched(); if (fatal_signal_pending(current)) ret = -EINTR; else goto next; out: if (ret == 1) ret = 0; mutex_unlock(&inode->i_mutex); return ret; }
static ssize_t dax_io(struct inode *inode, struct iov_iter *iter, loff_t start, loff_t end, get_block_t get_block, struct buffer_head *bh) { loff_t pos = start, max = start, bh_max = start; bool hole = false, need_wmb = false; struct block_device *bdev = NULL; int rw = iov_iter_rw(iter), rc; long map_len = 0; struct blk_dax_ctl dax = { .addr = (void __pmem *) ERR_PTR(-EIO), }; unsigned blkbits = inode->i_blkbits; sector_t file_blks = (i_size_read(inode) + (1 << blkbits) - 1) >> blkbits; if (rw == READ) end = min(end, i_size_read(inode)); while (pos < end) { size_t len; if (pos == max) { long page = pos >> PAGE_SHIFT; sector_t block = page << (PAGE_SHIFT - blkbits); unsigned first = pos - (block << blkbits); long size; if (pos == bh_max) { bh->b_size = PAGE_ALIGN(end - pos); bh->b_state = 0; rc = get_block(inode, block, bh, rw == WRITE); if (rc) break; if (!buffer_size_valid(bh)) bh->b_size = 1 << blkbits; bh_max = pos - first + bh->b_size; bdev = bh->b_bdev; /* * We allow uninitialized buffers for writes * beyond EOF as those cannot race with faults */ WARN_ON_ONCE( (buffer_new(bh) && block < file_blks) || (rw == WRITE && buffer_unwritten(bh))); } else { unsigned done = bh->b_size - (bh_max - (pos - first)); bh->b_blocknr += done >> blkbits; bh->b_size -= done; } hole = rw == READ && !buffer_written(bh); if (hole) { size = bh->b_size - first; } else { dax_unmap_atomic(bdev, &dax); dax.sector = to_sector(bh, inode); dax.size = bh->b_size; map_len = dax_map_atomic(bdev, &dax); if (map_len < 0) { rc = map_len; break; } dax.addr += first; size = map_len - first; } /* * pos + size is one past the last offset for IO, * so pos + size can overflow loff_t at extreme offsets. * Cast to u64 to catch this and get the true minimum. */ max = min_t(u64, pos + size, end); } if (iov_iter_rw(iter) == WRITE) { len = copy_from_iter_pmem(dax.addr, max - pos, iter); need_wmb = true; } else if (!hole) len = copy_to_iter((void __force *) dax.addr, max - pos, iter); else len = iov_iter_zero(max - pos, iter); if (!len) { rc = -EFAULT; break; } pos += len; if (!IS_ERR(dax.addr)) dax.addr += len; } if (need_wmb) wmb_pmem(); dax_unmap_atomic(bdev, &dax); return (pos == start) ? rc : pos - start; }