diff options
| -rw-r--r-- | fs/dax.c | 243 | ||||
| -rw-r--r-- | fs/ext2/inode.c | 3 | ||||
| -rw-r--r-- | fs/ext4/file.c | 48 | ||||
| -rw-r--r-- | include/linux/dax.h | 3 | ||||
| -rw-r--r-- | mm/truncate.c | 75 |
5 files changed, 229 insertions, 143 deletions
@@ -451,16 +451,37 @@ void dax_wake_mapping_entry_waiter(struct address_space *mapping, __wake_up(wq, TASK_NORMAL, wake_all ? 0 : 1, &key); } +static int __dax_invalidate_mapping_entry(struct address_space *mapping, + pgoff_t index, bool trunc) +{ + int ret = 0; + void *entry; + struct radix_tree_root *page_tree = &mapping->page_tree; + + spin_lock_irq(&mapping->tree_lock); + entry = get_unlocked_mapping_entry(mapping, index, NULL); + if (!entry || !radix_tree_exceptional_entry(entry)) + goto out; + if (!trunc && + (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) || + radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE))) + goto out; + radix_tree_delete(page_tree, index); + mapping->nrexceptional--; + ret = 1; +out: + put_unlocked_mapping_entry(mapping, index, entry); + spin_unlock_irq(&mapping->tree_lock); + return ret; +} /* * Delete exceptional DAX entry at @index from @mapping. Wait for radix tree * entry to get unlocked before deleting it. */ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) { - void *entry; + int ret = __dax_invalidate_mapping_entry(mapping, index, true); - spin_lock_irq(&mapping->tree_lock); - entry = get_unlocked_mapping_entry(mapping, index, NULL); /* * This gets called from truncate / punch_hole path. As such, the caller * must hold locks protecting against concurrent modifications of the @@ -468,16 +489,46 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) * caller has seen exceptional entry for this index, we better find it * at that index as well... */ - if (WARN_ON_ONCE(!entry || !radix_tree_exceptional_entry(entry))) { - spin_unlock_irq(&mapping->tree_lock); - return 0; - } - radix_tree_delete(&mapping->page_tree, index); + WARN_ON_ONCE(!ret); + return ret; +} + +/* + * Invalidate exceptional DAX entry if easily possible. This handles DAX + * entries for invalidate_inode_pages() so we evict the entry only if we can + * do so without blocking. + */ +int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index) +{ + int ret = 0; + void *entry, **slot; + struct radix_tree_root *page_tree = &mapping->page_tree; + + spin_lock_irq(&mapping->tree_lock); + entry = __radix_tree_lookup(page_tree, index, NULL, &slot); + if (!entry || !radix_tree_exceptional_entry(entry) || + slot_locked(mapping, slot)) + goto out; + if (radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_DIRTY) || + radix_tree_tag_get(page_tree, index, PAGECACHE_TAG_TOWRITE)) + goto out; + radix_tree_delete(page_tree, index); mapping->nrexceptional--; + ret = 1; +out: spin_unlock_irq(&mapping->tree_lock); - dax_wake_mapping_entry_waiter(mapping, index, entry, true); + if (ret) + dax_wake_mapping_entry_waiter(mapping, index, entry, true); + return ret; +} - return 1; +/* + * Invalidate exceptional DAX entry if it is clean. + */ +int dax_invalidate_mapping_entry_sync(struct address_space *mapping, + pgoff_t index) +{ + return __dax_invalidate_mapping_entry(mapping, index, false); } /* @@ -488,15 +539,16 @@ int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index) * otherwise it will simply fall out of the page cache under memory * pressure without ever having been dirtied. */ -static int dax_load_hole(struct address_space *mapping, void *entry, +static int dax_load_hole(struct address_space *mapping, void **entry, struct vm_fault *vmf) { struct page *page; + int ret; /* Hole page already exists? Return it... */ - if (!radix_tree_exceptional_entry(entry)) { - vmf->page = entry; - return VM_FAULT_LOCKED; + if (!radix_tree_exceptional_entry(*entry)) { + page = *entry; + goto out; } /* This will replace locked radix tree entry with a hole page */ @@ -504,8 +556,17 @@ static int dax_load_hole(struct address_space *mapping, void *entry, vmf->gfp_mask | __GFP_ZERO); if (!page) return VM_FAULT_OOM; + out: vmf->page = page; - return VM_FAULT_LOCKED; + ret = finish_fault(vmf); + vmf->page = NULL; + *entry = page; + if (!ret) { + /* Grab reference for PTE that is now referencing the page */ + get_page(page); + return VM_FAULT_NOPAGE; + } + return ret; } static int copy_user_dax(struct block_device *bdev, sector_t sector, size_t size, @@ -934,6 +995,17 @@ dax_iomap_actor(struct inode *inode, loff_t pos, loff_t length, void *data, if (WARN_ON_ONCE(iomap->type != IOMAP_MAPPED)) return -EIO; + /* + * Write can allocate block for an area which has a hole page mapped + * into page tables. We have to tear down these mappings so that data + * written by write(2) is visible in mmap. + */ + if ((iomap->flags & IOMAP_F_NEW) && inode->i_mapping->nrpages) { + invalidate_inode_pages2_range(inode->i_mapping, + pos >> PAGE_SHIFT, + (end - 1) >> PAGE_SHIFT); + } + while (pos < end) { unsigned offset = pos & (PAGE_SIZE - 1); struct blk_dax_ctl dax = { 0 }; @@ -992,23 +1064,6 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, if (iov_iter_rw(iter) == WRITE) flags |= IOMAP_WRITE; - /* - * Yes, even DAX files can have page cache attached to them: A zeroed - * page is inserted into the pagecache when we have to serve a write - * fault on a hole. It should never be dirtied and can simply be - * dropped from the pagecache once we get real data for the page. - * - * XXX: This is racy against mmap, and there's nothing we can do about - * it. We'll eventually need to shift this down even further so that - * we can check if we allocated blocks over a hole first. - */ - if (mapping->nrpages) { - ret = invalidate_inode_pages2_range(mapping, - pos >> PAGE_SHIFT, - (pos + iov_iter_count(iter) - 1) >> PAGE_SHIFT); - WARN_ON_ONCE(ret); - } - while (iov_iter_count(iter)) { ret = iomap_apply(inode, pos, iov_iter_count(iter), flags, ops, iter, dax_iomap_actor); @@ -1023,6 +1078,15 @@ dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, } EXPORT_SYMBOL_GPL(dax_iomap_rw); +static int dax_fault_return(int error) +{ + if (error == 0) + return VM_FAULT_NOPAGE; + if (error == -ENOMEM) + return VM_FAULT_OOM; + return VM_FAULT_SIGBUS; +} + /** * dax_iomap_fault - handle a page fault on a DAX file * @vma: The virtual memory area where the fault occurred @@ -1055,12 +1119,6 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, if (pos >= i_size_read(inode)) return VM_FAULT_SIGBUS; - entry = grab_mapping_entry(mapping, vmf->pgoff, 0); - if (IS_ERR(entry)) { - error = PTR_ERR(entry); - goto out; - } - if ((vmf->flags & FAULT_FLAG_WRITE) && !vmf->cow_page) flags |= IOMAP_WRITE; @@ -1071,9 +1129,15 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, */ error = ops->iomap_begin(inode, pos, PAGE_SIZE, flags, &iomap); if (error) - goto unlock_entry; + return dax_fault_return(error); if (WARN_ON_ONCE(iomap.offset + iomap.length < pos + PAGE_SIZE)) { - error = -EIO; /* fs corruption? */ + vmf_ret = dax_fault_return(-EIO); /* fs corruption? */ + goto finish_iomap; + } + + entry = grab_mapping_entry(mapping, vmf->pgoff, 0); + if (IS_ERR(entry)) { + vmf_ret = dax_fault_return(PTR_ERR(entry)); goto finish_iomap; } @@ -1096,13 +1160,13 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } if (error) - goto finish_iomap; + goto error_unlock_entry; __SetPageUptodate(vmf->cow_page); vmf_ret = finish_fault(vmf); if (!vmf_ret) vmf_ret = VM_FAULT_DONE_COW; - goto finish_iomap; + goto unlock_entry; } switch (iomap.type) { @@ -1114,12 +1178,15 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, } error = dax_insert_mapping(mapping, iomap.bdev, sector, PAGE_SIZE, &entry, vma, vmf); + /* -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)) { - vmf_ret = dax_load_hole(mapping, entry, vmf); - break; + vmf_ret = dax_load_hole(mapping, &entry, vmf); + goto unlock_entry; } /*FALLTHRU*/ default: @@ -1128,31 +1195,25 @@ int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, break; } + error_unlock_entry: + vmf_ret = dax_fault_return(error) | major; + unlock_entry: + put_locked_mapping_entry(mapping, vmf->pgoff, entry); finish_iomap: if (ops->iomap_end) { - if (error || (vmf_ret & VM_FAULT_ERROR)) { - /* keep previous error */ - ops->iomap_end(inode, pos, PAGE_SIZE, 0, flags, - &iomap); - } else { - error = ops->iomap_end(inode, pos, PAGE_SIZE, - PAGE_SIZE, flags, &iomap); - } - } - unlock_entry: - if (vmf_ret != VM_FAULT_LOCKED || error) - put_locked_mapping_entry(mapping, vmf->pgoff, entry); - 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; - if (vmf_ret) { - WARN_ON_ONCE(error); /* -EBUSY from ops->iomap_end? */ - return vmf_ret; + int copied = PAGE_SIZE; + + if (vmf_ret & VM_FAULT_ERROR) + copied = 0; + /* + * The fault is done by now and there's no way back (other + * thread may be already happily using PTE we have installed). + * Just ignore error from ->iomap_end since we cannot do much + * with it. + */ + ops->iomap_end(inode, pos, PAGE_SIZE, copied, flags, &iomap); } - return VM_FAULT_NOPAGE | major; + return vmf_ret; } EXPORT_SYMBOL_GPL(dax_iomap_fault); @@ -1277,16 +1338,6 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, goto fallback; /* - * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX - * PMD or a HZP entry. If it can't (because a 4k page is already in - * the tree, for instance), it will return -EEXIST and we just fall - * back to 4k entries. - */ - entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); - if (IS_ERR(entry)) - goto fallback; - - /* * Note that we don't use iomap_apply here. We aren't doing I/O, only * setting up a mapping, so really we're using iomap_begin() as a way * to look up our filesystem block. @@ -1294,10 +1345,21 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, pos = (loff_t)pgoff << PAGE_SHIFT; error = ops->iomap_begin(inode, pos, PMD_SIZE, iomap_flags, &iomap); if (error) - goto unlock_entry; + goto fallback; + if (iomap.offset + iomap.length < pos + PMD_SIZE) goto finish_iomap; + /* + * grab_mapping_entry() will make sure we get a 2M empty entry, a DAX + * PMD or a HZP entry. If it can't (because a 4k page is already in + * the tree, for instance), it will return -EEXIST and we just fall + * back to 4k entries. + */ + entry = grab_mapping_entry(mapping, pgoff, RADIX_DAX_PMD); + if (IS_ERR(entry)) + goto finish_iomap; + vmf.pgoff = pgoff; vmf.flags = flags; vmf.gfp_mask = mapping_gfp_mask(mapping) | __GFP_IO; @@ -1310,7 +1372,7 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, case IOMAP_UNWRITTEN: case IOMAP_HOLE: if (WARN_ON_ONCE(write)) - goto finish_iomap; + goto unlock_entry; result = dax_pmd_load_hole(vma, pmd, &vmf, address, &iomap, &entry); break; @@ -1319,20 +1381,23 @@ int dax_iomap_pmd_fault(struct vm_area_struct *vma, unsigned long address, break; } + unlock_entry: + put_locked_mapping_entry(mapping, pgoff, entry); finish_iomap: if (ops->iomap_end) { - if (result == VM_FAULT_FALLBACK) { - ops->iomap_end(inode, pos, PMD_SIZE, 0, iomap_flags, - &iomap); - } else { - error = ops->iomap_end(inode, pos, PMD_SIZE, PMD_SIZE, - iomap_flags, &iomap); - if (error) - result = VM_FAULT_FALLBACK; - } + int copied = PMD_SIZE; + + if (result == VM_FAULT_FALLBACK) + copied = 0; + /* + * The fault is done by now and there's no way back (other + * thread may be already happily using PMD we have installed). + * Just ignore error from ->iomap_end since we cannot do much + * with it. + */ + ops->iomap_end(inode, pos, PMD_SIZE, copied, iomap_flags, + &iomap); } - unlock_entry: - put_locked_mapping_entry(mapping, pgoff, entry); fallback: if (result == VM_FAULT_FALLBACK) { split_huge_pmd(vma, pmd, address); diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c index 0093ea2..f073bfc 100644 --- a/fs/ext2/inode.c +++ b/fs/ext2/inode.c @@ -751,9 +751,8 @@ static int ext2_get_blocks(struct inode *inode, mutex_unlock(&ei->truncate_mutex); goto cleanup; } - } else { - *new = true; } + *new = true; ext2_splice_branch(inode, iblock, partial, indirect_blks, count); mutex_unlock(&ei->truncate_mutex); diff --git a/fs/ext4/file.c b/fs/ext4/file.c index b5f1844..d663d3d 100644 --- a/fs/ext4/file.c +++ b/fs/ext4/file.c @@ -258,7 +258,6 @@ out: static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) { int result; - handle_t *handle = NULL; struct inode *inode = file_inode(vma->vm_file); struct super_block *sb = inode->i_sb; bool write = vmf->flags & FAULT_FLAG_WRITE; @@ -266,24 +265,12 @@ static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) if (write) { sb_start_pagefault(sb); file_update_time(vma->vm_file); - down_read(&EXT4_I(inode)->i_mmap_sem); - handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, - EXT4_DATA_TRANS_BLOCKS(sb)); - } else - down_read(&EXT4_I(inode)->i_mmap_sem); - - if (IS_ERR(handle)) - result = VM_FAULT_SIGBUS; - else - result = dax_iomap_fault(vma, vmf, &ext4_iomap_ops); - - if (write) { - if (!IS_ERR(handle)) - ext4_journal_stop(handle); - up_read(&EXT4_I(inode)->i_mmap_sem); + } + down_read(&EXT4_I(inode)->i_mmap_sem); + result = dax_iomap_fault(vma, vmf, &ext4_iomap_ops); + up_read(&EXT4_I(inode)->i_mmap_sem); + if (write) sb_end_pagefault(sb); - } else - up_read(&EXT4_I(inode)->i_mmap_sem); return result; } @@ -292,7 +279,6 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, pmd_t *pmd, unsigned int flags) { int result; - handle_t *handle = NULL; struct inode *inode = file_inode(vma->vm_file); struct super_block *sb = inode->i_sb; bool write = flags & FAULT_FLAG_WRITE; @@ -300,27 +286,13 @@ static int ext4_dax_pmd_fault(struct vm_area_struct *vma, unsigned long addr, if (write) { sb_start_pagefault(sb); file_update_time(vma->vm_file); - down_read(&EXT4_I(inode)->i_mmap_sem); - handle = ext4_journal_start_sb(sb, EXT4_HT_WRITE_PAGE, - ext4_chunk_trans_blocks(inode, - PMD_SIZE / PAGE_SIZE)); - } else - down_read(&EXT4_I(inode)->i_mmap_sem); - - if (IS_ERR(handle)) - result = VM_FAULT_SIGBUS; - else { - result = dax_iomap_pmd_fault(vma, addr, pmd, flags, - &ext4_iomap_ops); } - - if (write) { - if (!IS_ERR(handle)) - ext4_journal_stop(handle); - up_read(&EXT4_I(inode)->i_mmap_sem); + down_read(&EXT4_I(inode)->i_mmap_sem); + result = dax_iomap_pmd_fault(vma, addr, pmd, flags, + &ext4_iomap_ops); + up_read(&EXT4_I(inode)->i_mmap_sem); + if (write) sb_end_pagefault(sb); - } else - up_read(&EXT4_I(inode)->i_mmap_sem); return result; } diff --git a/include/linux/dax.h b/include/linux/dax.h index f97bcfe..24ad711 100644 --- a/include/linux/dax.h +++ b/include/linux/dax.h @@ -41,6 +41,9 @@ ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter, int dax_iomap_fault(struct vm_area_struct *vma, struct vm_fault *vmf, struct iomap_ops *ops); int dax_delete_mapping_entry(struct address_space *mapping, pgoff_t index); +int dax_invalidate_mapping_entry(struct address_space *mapping, pgoff_t index); +int dax_invalidate_mapping_entry_sync(struct address_space *mapping, + pgoff_t index); void dax_wake_mapping_entry_waiter(struct address_space *mapping, pgoff_t index, void *entry, bool wake_all); diff --git a/mm/truncate.c b/mm/truncate.c index fd97f1d..dd7b24e 100644 --- a/mm/truncate.c +++ b/mm/truncate.c @@ -24,20 +24,12 @@ #include <linux/rmap.h> #include "internal.h" -static void clear_exceptional_entry(struct address_space *mapping, - pgoff_t index, void *entry) +static void clear_shadow_entry(struct address_space *mapping, pgoff_t index, + void *entry) { struct radix_tree_node *node; void **slot; - /* Handled by shmem itself */ - if (shmem_mapping(mapping)) - return; - - if (dax_mapping(mapping)) { - dax_delete_mapping_entry(mapping, index); - return; - } spin_lock_irq(&mapping->tree_lock); /* * Regular page slots are stabilized by the page lock even @@ -55,6 +47,56 @@ unlock: spin_unlock_irq(&mapping->tree_lock); } +/* + * Unconditionally remove exceptional entry. Usually called from truncate path. + */ +static void truncate_exceptional_entry(struct address_space *mapping, + pgoff_t index, void *entry) +{ + /* Handled by shmem itself */ + if (shmem_mapping(mapping)) + return; + + if (dax_mapping(mapping)) { + dax_delete_mapping_entry(mapping, index); + return; + } + clear_shadow_entry(mapping, index, entry); +} + +/* + * Invalidate exceptional entry if easily possible. This handles exceptional + * entries for invalidate_inode_pages() so for DAX it evicts only unlocked and + * clean entries. + */ +static int invalidate_exceptional_entry(struct address_space *mapping, + pgoff_t index, void *entry) +{ + /* Handled by shmem itself */ + if (shmem_mapping(mapping)) + return 1; + if (dax_mapping(mapping)) + return dax_invalidate_mapping_entry(mapping, index); + clear_shadow_entry(mapping, index, entry); + return 1; +} + +/* + * Invalidate exceptional entry if clean. This handles exceptional entries for + * invalidate_inode_pages2() so for DAX it evicts only clean entries. + */ +static int invalidate_exceptional_entry2(struct address_space *mapping, + pgoff_t index, void *entry) +{ + /* Handled by shmem itself */ + if (shmem_mapping(mapping)) + return 1; + if (dax_mapping(mapping)) + return dax_invalidate_mapping_entry_sync(mapping, index); + clear_shadow_entry(mapping, index, entry); + return 1; +} + /** * do_invalidatepage - invalidate part or all of a page * @page: the page which is affected @@ -262,7 +304,8 @@ void truncate_inode_pages_range(struct address_space *mapping, break; if (radix_tree_exceptional_entry(page)) { - clear_exceptional_entry(mapping, index, page); + truncate_exceptional_entry(mapping, index, + page); continue; } @@ -351,7 +394,8 @@ void truncate_inode_pages_range(struct address_space *mapping, } if (radix_tree_exceptional_entry(page)) { - clear_exceptional_entry(mapping, index, page); + truncate_exceptional_entry(mapping, index, + page); continue; } @@ -470,7 +514,8 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping, break; if (radix_tree_exceptional_entry(page)) { - clear_exceptional_entry(mapping, index, page); + invalidate_exceptional_entry(mapping, index, + page); continue; } @@ -592,7 +637,9 @@ int invalidate_inode_pages2_range(struct address_space *mapping, break; if (radix_tree_exceptional_entry(page)) { - clear_exceptional_entry(mapping, index, page); + if (!invalidate_exceptional_entry2(mapping, + index, page)) + ret = -EBUSY; continue; } |
