diff options
Diffstat (limited to 'fs/dax.c')
| -rw-r--r-- | fs/dax.c | 332 |
1 files changed, 228 insertions, 104 deletions
diff --git a/fs/dax.c b/fs/dax.c index f001d8c72a06..95981591977a 100644 --- a/fs/dax.c +++ b/fs/dax.c @@ -526,13 +526,13 @@ static int copy_user_dax(struct block_device *bdev, struct dax_device *dax_dev, static void *dax_insert_mapping_entry(struct address_space *mapping, struct vm_fault *vmf, void *entry, sector_t sector, - unsigned long flags) + unsigned long flags, bool dirty) { struct radix_tree_root *page_tree = &mapping->page_tree; void *new_entry; pgoff_t index = vmf->pgoff; - if (vmf->flags & FAULT_FLAG_WRITE) + if (dirty) __mark_inode_dirty(mapping->host, I_DIRTY_PAGES); if (dax_is_zero_entry(entry) && !(flags & RADIX_DAX_ZERO_PAGE)) { @@ -565,11 +565,11 @@ static void *dax_insert_mapping_entry(struct address_space *mapping, ret = __radix_tree_lookup(page_tree, index, &node, &slot); WARN_ON_ONCE(ret != entry); __radix_tree_replace(page_tree, node, slot, - new_entry, NULL, NULL); + new_entry, NULL); entry = new_entry; } - if (vmf->flags & FAULT_FLAG_WRITE) + if (dirty) radix_tree_tag_set(page_tree, index, PAGECACHE_TAG_DIRTY); spin_unlock_irq(&mapping->tree_lock); @@ -614,6 +614,13 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping, if (follow_pte_pmd(vma->vm_mm, address, &start, &end, &ptep, &pmdp, &ptl)) continue; + /* + * No need to call mmu_notifier_invalidate_range() as we are + * downgrading page table protection not changing it to point + * to a new page. + * + * See Documentation/vm/mmu_notifier.txt + */ if (pmdp) { #ifdef CONFIG_FS_DAX_PMD pmd_t pmd; @@ -628,7 +635,6 @@ static void dax_mapping_entry_mkclean(struct address_space *mapping, pmd = pmd_wrprotect(pmd); pmd = pmd_mkclean(pmd); set_pmd_at(vma->vm_mm, address, pmdp, pmd); - mmu_notifier_invalidate_range(vma->vm_mm, start, end); unlock_pmd: spin_unlock(ptl); #endif @@ -643,7 +649,6 @@ unlock_pmd: pte = pte_wrprotect(pte); pte = pte_mkclean(pte); set_pte_at(vma->vm_mm, address, ptep, pte); - mmu_notifier_invalidate_range(vma->vm_mm, start, end); unlock_pte: pte_unmap_unlock(ptep, ptl); } @@ -789,7 +794,7 @@ int dax_writeback_mapping_range(struct address_space *mapping, tag_pages_for_writeback(mapping, start_index, end_index); - pagevec_init(&pvec, 0); + pagevec_init(&pvec); while (!done) { pvec.nr = find_get_entries_tag(mapping, start_index, PAGECACHE_TAG_TOWRITE, PAGEVEC_SIZE, @@ -820,38 +825,42 @@ out: } EXPORT_SYMBOL_GPL(dax_writeback_mapping_range); -static int dax_insert_mapping(struct address_space *mapping, - struct block_device *bdev, struct dax_device *dax_dev, - sector_t sector, size_t size, void *entry, - struct vm_area_struct *vma, struct vm_fault *vmf) +static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) { - unsigned long vaddr = vmf->address; - void *ret, *kaddr; + return (iomap->addr + (pos & PAGE_MASK) - iomap->offset) >> 9; +} + +static int dax_iomap_pfn(struct iomap *iomap, loff_t pos, size_t size, + pfn_t *pfnp) +{ + const sector_t sector = dax_iomap_sector(iomap, pos); pgoff_t pgoff; + void *kaddr; int id, rc; - pfn_t pfn; + long length; - rc = bdev_dax_pgoff(bdev, sector, size, &pgoff); + rc = bdev_dax_pgoff(iomap->bdev, sector, size, &pgoff); if (rc) return rc; - id = dax_read_lock(); - rc = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); - if (rc < 0) { - dax_read_unlock(id); - return rc; + length = dax_direct_access(iomap->dax_dev, pgoff, PHYS_PFN(size), + &kaddr, pfnp); + if (length < 0) { + rc = length; + goto out; } + rc = -EINVAL; + if (PFN_PHYS(length) < size) + goto out; + if (pfn_t_to_pfn(*pfnp) & (PHYS_PFN(size)-1)) + goto out; + /* For larger pages we need devmap */ + if (length > 1 && !pfn_t_devmap(*pfnp)) + goto out; + rc = 0; +out: dax_read_unlock(id); - - ret = dax_insert_mapping_entry(mapping, vmf, entry, sector, 0); - if (IS_ERR(ret)) - return PTR_ERR(ret); - - trace_dax_insert_mapping(mapping->host, vmf, ret); - if (vmf->flags & FAULT_FLAG_WRITE) - return vm_insert_mixed_mkwrite(vma, vaddr, pfn); - else - return vm_insert_mixed(vma, vaddr, pfn); + return rc; } /* @@ -877,7 +886,7 @@ static int dax_load_hole(struct address_space *mapping, void *entry, } entry2 = dax_insert_mapping_entry(mapping, vmf, entry, 0, - RADIX_DAX_ZERO_PAGE); + RADIX_DAX_ZERO_PAGE, false); if (IS_ERR(entry2)) { ret = VM_FAULT_SIGBUS; goto out; @@ -936,11 +945,6 @@ int __dax_zero_page_range(struct block_device *bdev, } EXPORT_SYMBOL_GPL(__dax_zero_page_range); -static sector_t dax_iomap_sector(struct iomap *iomap, loff_t pos) -{ - return iomap->blkno + (((pos & PAGE_MASK) - iomap->offset) >> 9); -} - static loff_t dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, struct iomap *iomap) @@ -1080,19 +1084,33 @@ static int dax_fault_return(int error) return VM_FAULT_SIGBUS; } -static int dax_iomap_pte_fault(struct vm_fault *vmf, +/* + * MAP_SYNC on a dax mapping guarantees dirty metadata is + * flushed on write-faults (non-cow), but not read-faults. + */ +static bool dax_fault_is_synchronous(unsigned long flags, + struct vm_area_struct *vma, struct iomap *iomap) +{ + return (flags & IOMAP_WRITE) && (vma->vm_flags & VM_SYNC) + && (iomap->flags & IOMAP_F_DIRTY); +} + +static int dax_iomap_pte_fault(struct vm_fault *vmf, pfn_t *pfnp, const struct iomap_ops *ops) { - struct address_space *mapping = vmf->vma->vm_file->f_mapping; + struct vm_area_struct *vma = vmf->vma; + struct address_space *mapping = vma->vm_file->f_mapping; struct inode *inode = mapping->host; unsigned long vaddr = vmf->address; loff_t pos = (loff_t)vmf->pgoff << PAGE_SHIFT; - sector_t sector; struct iomap iomap = { 0 }; unsigned flags = IOMAP_FAULT; int error, major = 0; + bool write = vmf->flags & FAULT_FLAG_WRITE; + bool sync; int vmf_ret = 0; void *entry; + pfn_t pfn; trace_dax_pte_fault(inode, vmf, vmf_ret); /* @@ -1105,7 +1123,7 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, goto out; } - if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page) + if (write && !vmf->cow_page) flags |= IOMAP_WRITE; entry = grab_mapping_entry(mapping, vmf->pgoff, 0); @@ -1140,9 +1158,9 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, goto error_finish_iomap; } - sector = dax_iomap_sector(&iomap, pos); - if (vmf->cow_page) { + sector_t sector = dax_iomap_sector(&iomap, pos); + switch (iomap.type) { case IOMAP_HOLE: case IOMAP_UNWRITTEN: @@ -1168,22 +1186,55 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, goto finish_iomap; } + sync = dax_fault_is_synchronous(flags, vma, &iomap); + switch (iomap.type) { case IOMAP_MAPPED: if (iomap.flags & IOMAP_F_NEW) { count_vm_event(PGMAJFAULT); - count_memcg_event_mm(vmf->vma->vm_mm, PGMAJFAULT); + count_memcg_event_mm(vma->vm_mm, PGMAJFAULT); major = VM_FAULT_MAJOR; } - error = dax_insert_mapping(mapping, iomap.bdev, iomap.dax_dev, - sector, PAGE_SIZE, entry, vmf->vma, vmf); + error = dax_iomap_pfn(&iomap, pos, PAGE_SIZE, &pfn); + if (error < 0) + goto error_finish_iomap; + + entry = dax_insert_mapping_entry(mapping, vmf, entry, + dax_iomap_sector(&iomap, pos), + 0, write && !sync); + if (IS_ERR(entry)) { + error = PTR_ERR(entry); + goto error_finish_iomap; + } + + /* + * If we are doing synchronous page fault and inode needs fsync, + * we can insert PTE into page tables only after that happens. + * Skip insertion for now and return the pfn so that caller can + * insert it after fsync is done. + */ + if (sync) { + if (WARN_ON_ONCE(!pfnp)) { + error = -EIO; + goto error_finish_iomap; + } + *pfnp = pfn; + vmf_ret = VM_FAULT_NEEDDSYNC | major; + goto finish_iomap; + } + trace_dax_insert_mapping(inode, vmf, entry); + if (write) + error = vm_insert_mixed_mkwrite(vma, vaddr, pfn); + else + error = vm_insert_mixed(vma, vaddr, pfn); + /* -EBUSY is fine, somebody else faulted on the same PTE */ if (error == -EBUSY) error = 0; break; case IOMAP_UNWRITTEN: case IOMAP_HOLE: - if (!(vmf->flags & FAULT_FLAG_WRITE)) { + if (!write) { vmf_ret = dax_load_hole(mapping, entry, vmf); goto finish_iomap; } @@ -1218,53 +1269,11 @@ static int dax_iomap_pte_fault(struct vm_fault *vmf, } #ifdef CONFIG_FS_DAX_PMD -static int dax_pmd_insert_mapping(struct vm_fault *vmf, struct iomap *iomap, - loff_t pos, void *entry) -{ - struct address_space *mapping = vmf->vma->vm_file->f_mapping; - const sector_t sector = dax_iomap_sector(iomap, pos); - struct dax_device *dax_dev = iomap->dax_dev; - struct block_device *bdev = iomap->bdev; - struct inode *inode = mapping->host; - const size_t size = PMD_SIZE; - void *ret = NULL, *kaddr; - long length = 0; - pgoff_t pgoff; - pfn_t pfn = {}; - int id; - - if (bdev_dax_pgoff(bdev, sector, size, &pgoff) != 0) - goto fallback; - - id = dax_read_lock(); - length = dax_direct_access(dax_dev, pgoff, PHYS_PFN(size), &kaddr, &pfn); - if (length < 0) - goto unlock_fallback; - length = PFN_PHYS(length); - - if (length < size) - goto unlock_fallback; - if (pfn_t_to_pfn(pfn) & PG_PMD_COLOUR) - goto unlock_fallback; - if (!pfn_t_devmap(pfn)) - goto unlock_fallback; - dax_read_unlock(id); - - ret = dax_insert_mapping_entry(mapping, vmf, entry, sector, - RADIX_DAX_PMD); - if (IS_ERR(ret)) - goto fallback; - - trace_dax_pmd_insert_mapping(inode, vmf, length, pfn, ret); - return vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, - pfn, vmf->flags & FAULT_FLAG_WRITE); - -unlock_fallback: - dax_read_unlock(id); -fallback: - trace_dax_pmd_insert_mapping_fallback(inode, vmf, length, pfn, ret); - return VM_FAULT_FALLBACK; -} +/* + * The 'colour' (ie low bits) within a PMD of a page offset. This comes up + * more often than one might expect in the below functions. + */ +#define PG_PMD_COLOUR ((PMD_SIZE >> PAGE_SHIFT) - 1) static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, void *entry) @@ -1283,7 +1292,7 @@ static int dax_pmd_load_hole(struct vm_fault *vmf, struct iomap *iomap, goto fallback; ret = dax_insert_mapping_entry(mapping, vmf, entry, 0, - RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE); + RADIX_DAX_PMD | RADIX_DAX_ZERO_PAGE, false); if (IS_ERR(ret)) goto fallback; @@ -1305,13 +1314,14 @@ fallback: return VM_FAULT_FALLBACK; } -static int dax_iomap_pmd_fault(struct vm_fault *vmf, +static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, const struct iomap_ops *ops) { struct vm_area_struct *vma = vmf->vma; struct address_space *mapping = vma->vm_file->f_mapping; unsigned long pmd_addr = vmf->address & PMD_MASK; bool write = vmf->flags & FAULT_FLAG_WRITE; + bool sync; unsigned int iomap_flags = (write ? IOMAP_WRITE : 0) | IOMAP_FAULT; struct inode *inode = mapping->host; int result = VM_FAULT_FALLBACK; @@ -1320,6 +1330,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, void *entry; loff_t pos; int error; + pfn_t pfn; /* * Check whether offset isn't beyond end of file now. Caller is @@ -1327,7 +1338,7 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, * this is a reliable test. */ pgoff = linear_page_index(vma, pmd_addr); - max_pgoff = (i_size_read(inode) - 1) >> PAGE_SHIFT; + max_pgoff = DIV_ROUND_UP(i_size_read(inode), PAGE_SIZE); trace_dax_pmd_fault(inode, vmf, max_pgoff, 0); @@ -1351,13 +1362,13 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, if ((pmd_addr + PMD_SIZE) > vma->vm_end) goto fallback; - if (pgoff > max_pgoff) { + if (pgoff >= max_pgoff) { result = VM_FAULT_SIGBUS; goto out; } /* If the PMD would extend beyond the file size */ - if ((pgoff | PG_PMD_COLOUR) > max_pgoff) + if ((pgoff | PG_PMD_COLOUR) >= max_pgoff) goto fallback; /* @@ -1395,9 +1406,37 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, if (iomap.offset + iomap.length < pos + PMD_SIZE) goto finish_iomap; + sync = dax_fault_is_synchronous(iomap_flags, vma, &iomap); + switch (iomap.type) { case IOMAP_MAPPED: - result = dax_pmd_insert_mapping(vmf, &iomap, pos, entry); + error = dax_iomap_pfn(&iomap, pos, PMD_SIZE, &pfn); + if (error < 0) + goto finish_iomap; + + entry = dax_insert_mapping_entry(mapping, vmf, entry, + dax_iomap_sector(&iomap, pos), + RADIX_DAX_PMD, write && !sync); + if (IS_ERR(entry)) + goto finish_iomap; + + /* + * If we are doing synchronous page fault and inode needs fsync, + * we can insert PMD into page tables only after that happens. + * Skip insertion for now and return the pfn so that caller can + * insert it after fsync is done. + */ + if (sync) { + if (WARN_ON_ONCE(!pfnp)) + goto finish_iomap; + *pfnp = pfn; + result = VM_FAULT_NEEDDSYNC; + goto finish_iomap; + } + + trace_dax_pmd_insert_mapping(inode, vmf, PMD_SIZE, pfn, entry); + result = vmf_insert_pfn_pmd(vma, vmf->address, vmf->pmd, pfn, + write); break; case IOMAP_UNWRITTEN: case IOMAP_HOLE: @@ -1437,7 +1476,7 @@ out: return result; } #else -static int dax_iomap_pmd_fault(struct vm_fault *vmf, +static int dax_iomap_pmd_fault(struct vm_fault *vmf, pfn_t *pfnp, const struct iomap_ops *ops) { return VM_FAULT_FALLBACK; @@ -1447,7 +1486,9 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, /** * dax_iomap_fault - handle a page fault on a DAX file * @vmf: The description of the fault - * @ops: iomap ops passed from the file system + * @pe_size: Size of the page to fault in + * @pfnp: PFN to insert for synchronous faults if fsync is required + * @ops: Iomap ops passed from the file system * * When a page fault occurs, filesystems may call this helper in * their fault handler for DAX files. dax_iomap_fault() assumes the caller @@ -1455,15 +1496,98 @@ static int dax_iomap_pmd_fault(struct vm_fault *vmf, * successfully. */ int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size, - const struct iomap_ops *ops) + pfn_t *pfnp, const struct iomap_ops *ops) { switch (pe_size) { case PE_SIZE_PTE: - return dax_iomap_pte_fault(vmf, ops); + return dax_iomap_pte_fault(vmf, pfnp, ops); case PE_SIZE_PMD: - return dax_iomap_pmd_fault(vmf, ops); + return dax_iomap_pmd_fault(vmf, pfnp, ops); default: return VM_FAULT_FALLBACK; } } EXPORT_SYMBOL_GPL(dax_iomap_fault); + +/** + * dax_insert_pfn_mkwrite - insert PTE or PMD entry into page tables + * @vmf: The description of the fault + * @pe_size: Size of entry to be inserted + * @pfn: PFN to insert + * + * This function inserts writeable PTE or PMD entry into page tables for mmaped + * DAX file. It takes care of marking corresponding radix tree entry as dirty + * as well. + */ +static int dax_insert_pfn_mkwrite(struct vm_fault *vmf, + enum page_entry_size pe_size, + pfn_t pfn) +{ + struct address_space *mapping = vmf->vma->vm_file->f_mapping; + void *entry, **slot; + pgoff_t index = vmf->pgoff; + int vmf_ret, error; + + spin_lock_irq(&mapping->tree_lock); + entry = get_unlocked_mapping_entry(mapping, index, &slot); + /* Did we race with someone splitting entry or so? */ + if (!entry || + (pe_size == PE_SIZE_PTE && !dax_is_pte_entry(entry)) || + (pe_size == PE_SIZE_PMD && !dax_is_pmd_entry(entry))) { + put_unlocked_mapping_entry(mapping, index, entry); + spin_unlock_irq(&mapping->tree_lock); + trace_dax_insert_pfn_mkwrite_no_entry(mapping->host, vmf, + VM_FAULT_NOPAGE); + return VM_FAULT_NOPAGE; + } + radix_tree_tag_set(&mapping->page_tree, index, PAGECACHE_TAG_DIRTY); + entry = lock_slot(mapping, slot); + spin_unlock_irq(&mapping->tree_lock); + switch (pe_size) { + case PE_SIZE_PTE: + error = vm_insert_mixed_mkwrite(vmf->vma, vmf->address, pfn); + vmf_ret = dax_fault_return(error); + break; +#ifdef CONFIG_FS_DAX_PMD + case PE_SIZE_PMD: + vmf_ret = vmf_insert_pfn_pmd(vmf->vma, vmf->address, vmf->pmd, + pfn, true); + break; +#endif + default: + vmf_ret = VM_FAULT_FALLBACK; + } + put_locked_mapping_entry(mapping, index); + trace_dax_insert_pfn_mkwrite(mapping->host, vmf, vmf_ret); + return vmf_ret; +} + +/** + * dax_finish_sync_fault - finish synchronous page fault + * @vmf: The description of the fault + * @pe_size: Size of entry to be inserted + * @pfn: PFN to insert + * + * This function ensures that the file range touched by the page fault is + * stored persistently on the media and handles inserting of appropriate page + * table entry. + */ +int dax_finish_sync_fault(struct vm_fault *vmf, enum page_entry_size pe_size, + pfn_t pfn) +{ + int err; + loff_t start = ((loff_t)vmf->pgoff) << PAGE_SHIFT; + size_t len = 0; + + if (pe_size == PE_SIZE_PTE) + len = PAGE_SIZE; + else if (pe_size == PE_SIZE_PMD) + len = PMD_SIZE; + else + WARN_ON_ONCE(1); + err = vfs_fsync_range(vmf->vma->vm_file, start, start + len - 1, 1); + if (err) + return VM_FAULT_SIGBUS; + return dax_insert_pfn_mkwrite(vmf, pe_size, pfn); +} +EXPORT_SYMBOL_GPL(dax_finish_sync_fault); |