diff options
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 298 |
1 files changed, 210 insertions, 88 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index c5af80c43d36..d0cf700bf201 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* * linux/mm/filemap.c * @@ -280,11 +281,11 @@ EXPORT_SYMBOL(delete_from_page_cache); * @pvec: pagevec with pages to delete * * The function walks over mapping->i_pages and removes pages passed in @pvec - * from the mapping. The function expects @pvec to be sorted by page index - * and is optimised for it to be dense. + * from the mapping. The function expects @pvec to be sorted by page index. * It tolerates holes in @pvec (mapping entries at those indices are not * modified). The function expects only THP head pages to be present in the - * @pvec. + * @pvec and takes care to delete all corresponding tail pages from the + * mapping as well. * * The function expects the i_pages lock to be held. */ @@ -293,44 +294,40 @@ static void page_cache_delete_batch(struct address_space *mapping, { XA_STATE(xas, &mapping->i_pages, pvec->pages[0]->index); int total_pages = 0; - int i = 0; + int i = 0, tail_pages = 0; struct page *page; mapping_set_update(&xas, mapping); xas_for_each(&xas, page, ULONG_MAX) { - if (i >= pagevec_count(pvec)) + if (i >= pagevec_count(pvec) && !tail_pages) break; - - /* A swap/dax/shadow entry got inserted? Skip it. */ if (xa_is_value(page)) continue; - /* - * A page got inserted in our range? Skip it. We have our - * pages locked so they are protected from being removed. - * If we see a page whose index is higher than ours, it - * means our page has been removed, which shouldn't be - * possible because we're holding the PageLock. - */ - if (page != pvec->pages[i]) { - VM_BUG_ON_PAGE(page->index > pvec->pages[i]->index, - page); - continue; - } - - WARN_ON_ONCE(!PageLocked(page)); - - if (page->index == xas.xa_index) + if (!tail_pages) { + /* + * Some page got inserted in our range? Skip it. We + * have our pages locked so they are protected from + * being removed. + */ + if (page != pvec->pages[i]) { + VM_BUG_ON_PAGE(page->index > + pvec->pages[i]->index, page); + continue; + } + WARN_ON_ONCE(!PageLocked(page)); + if (PageTransHuge(page) && !PageHuge(page)) + tail_pages = HPAGE_PMD_NR - 1; page->mapping = NULL; - /* Leave page->index set: truncation lookup relies on it */ - - /* - * Move to the next page in the vector if this is a regular - * page or the index is of the last sub-page of this compound - * page. - */ - if (page->index + (1UL << compound_order(page)) - 1 == - xas.xa_index) + /* + * Leave page->index set: truncation lookup relies + * upon it + */ i++; + } else { + VM_BUG_ON_PAGE(page->index + HPAGE_PMD_NR - tail_pages + != pvec->pages[i]->index, page); + tail_pages--; + } xas_store(&xas, NULL); total_pages++; } @@ -553,6 +550,28 @@ int filemap_fdatawait_range(struct address_space *mapping, loff_t start_byte, EXPORT_SYMBOL(filemap_fdatawait_range); /** + * filemap_fdatawait_range_keep_errors - wait for writeback to complete + * @mapping: address space structure to wait for + * @start_byte: offset in bytes where the range starts + * @end_byte: offset in bytes where the range ends (inclusive) + * + * Walk the list of under-writeback pages of the given address space in the + * given range and wait for all of them. Unlike filemap_fdatawait_range(), + * this function does not clear error status of the address space. + * + * Use this function if callers don't handle errors themselves. Expected + * call sites are system-wide / filesystem-wide data flushers: e.g. sync(2), + * fsfreeze(8) + */ +int filemap_fdatawait_range_keep_errors(struct address_space *mapping, + loff_t start_byte, loff_t end_byte) +{ + __filemap_fdatawait_range(mapping, start_byte, end_byte); + return filemap_check_and_keep_errors(mapping); +} +EXPORT_SYMBOL(filemap_fdatawait_range_keep_errors); + +/** * file_fdatawait_range - wait for writeback to complete * @file: file pointing to address space structure to wait for * @start_byte: offset in bytes where the range starts @@ -1497,7 +1516,7 @@ EXPORT_SYMBOL(page_cache_prev_miss); struct page *find_get_entry(struct address_space *mapping, pgoff_t offset) { XA_STATE(xas, &mapping->i_pages, offset); - struct page *page; + struct page *head, *page; rcu_read_lock(); repeat: @@ -1512,19 +1531,25 @@ repeat: if (!page || xa_is_value(page)) goto out; - if (!page_cache_get_speculative(page)) + head = compound_head(page); + if (!page_cache_get_speculative(head)) + goto repeat; + + /* The page was split under us? */ + if (compound_head(page) != head) { + put_page(head); goto repeat; + } /* - * Has the page moved or been split? + * Has the page moved? * This is part of the lockless pagecache protocol. See * include/linux/pagemap.h for details. */ if (unlikely(page != xas_reload(&xas))) { - put_page(page); + put_page(head); goto repeat; } - page = find_subpage(page, offset); out: rcu_read_unlock(); @@ -1706,6 +1731,7 @@ unsigned find_get_entries(struct address_space *mapping, rcu_read_lock(); xas_for_each(&xas, page, ULONG_MAX) { + struct page *head; if (xas_retry(&xas, page)) continue; /* @@ -1716,13 +1742,17 @@ unsigned find_get_entries(struct address_space *mapping, if (xa_is_value(page)) goto export; - if (!page_cache_get_speculative(page)) + head = compound_head(page); + if (!page_cache_get_speculative(head)) goto retry; - /* Has the page moved or been split? */ + /* The page was split under us? */ + if (compound_head(page) != head) + goto put_page; + + /* Has the page moved? */ if (unlikely(page != xas_reload(&xas))) goto put_page; - page = find_subpage(page, xas.xa_index); export: indices[ret] = xas.xa_index; @@ -1731,7 +1761,7 @@ export: break; continue; put_page: - put_page(page); + put_page(head); retry: xas_reset(&xas); } @@ -1773,27 +1803,33 @@ unsigned find_get_pages_range(struct address_space *mapping, pgoff_t *start, rcu_read_lock(); xas_for_each(&xas, page, end) { + struct page *head; if (xas_retry(&xas, page)) continue; /* Skip over shadow, swap and DAX entries */ if (xa_is_value(page)) continue; - if (!page_cache_get_speculative(page)) + head = compound_head(page); + if (!page_cache_get_speculative(head)) goto retry; - /* Has the page moved or been split? */ + /* The page was split under us? */ + if (compound_head(page) != head) + goto put_page; + + /* Has the page moved? */ if (unlikely(page != xas_reload(&xas))) goto put_page; - pages[ret] = find_subpage(page, xas.xa_index); + pages[ret] = page; if (++ret == nr_pages) { *start = xas.xa_index + 1; goto out; } continue; put_page: - put_page(page); + put_page(head); retry: xas_reset(&xas); } @@ -1838,6 +1874,7 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, rcu_read_lock(); for (page = xas_load(&xas); page; page = xas_next(&xas)) { + struct page *head; if (xas_retry(&xas, page)) continue; /* @@ -1847,19 +1884,24 @@ unsigned find_get_pages_contig(struct address_space *mapping, pgoff_t index, if (xa_is_value(page)) break; - if (!page_cache_get_speculative(page)) + head = compound_head(page); + if (!page_cache_get_speculative(head)) goto retry; - /* Has the page moved or been split? */ + /* The page was split under us? */ + if (compound_head(page) != head) + goto put_page; + + /* Has the page moved? */ if (unlikely(page != xas_reload(&xas))) goto put_page; - pages[ret] = find_subpage(page, xas.xa_index); + pages[ret] = page; if (++ret == nr_pages) break; continue; put_page: - put_page(page); + put_page(head); retry: xas_reset(&xas); } @@ -1895,6 +1937,7 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, rcu_read_lock(); xas_for_each_marked(&xas, page, end, tag) { + struct page *head; if (xas_retry(&xas, page)) continue; /* @@ -1905,21 +1948,26 @@ unsigned find_get_pages_range_tag(struct address_space *mapping, pgoff_t *index, if (xa_is_value(page)) continue; - if (!page_cache_get_speculative(page)) + head = compound_head(page); + if (!page_cache_get_speculative(head)) goto retry; - /* Has the page moved or been split? */ + /* The page was split under us? */ + if (compound_head(page) != head) + goto put_page; + + /* Has the page moved? */ if (unlikely(page != xas_reload(&xas))) goto put_page; - pages[ret] = find_subpage(page, xas.xa_index); + pages[ret] = page; if (++ret == nr_pages) { *index = xas.xa_index + 1; goto out; } continue; put_page: - put_page(page); + put_page(head); retry: xas_reset(&xas); } @@ -2456,10 +2504,8 @@ static struct file *do_async_mmap_readahead(struct vm_fault *vmf, * * vma->vm_mm->mmap_sem must be held on entry. * - * If our return value has VM_FAULT_RETRY set, it's because - * lock_page_or_retry() returned 0. - * The mmap_sem has usually been released in this case. - * See __lock_page_or_retry() for the exception. + * If our return value has VM_FAULT_RETRY set, it's because the mmap_sem + * may be dropped before doing I/O or by lock_page_maybe_drop_mmap(). * * If our return value does not have VM_FAULT_RETRY set, the mmap_sem * has not been released. @@ -2602,7 +2648,7 @@ void filemap_map_pages(struct vm_fault *vmf, pgoff_t last_pgoff = start_pgoff; unsigned long max_idx; XA_STATE(xas, &mapping->i_pages, start_pgoff); - struct page *page; + struct page *head, *page; rcu_read_lock(); xas_for_each(&xas, page, end_pgoff) { @@ -2611,19 +2657,24 @@ void filemap_map_pages(struct vm_fault *vmf, if (xa_is_value(page)) goto next; + head = compound_head(page); + /* * Check for a locked page first, as a speculative * reference may adversely influence page migration. */ - if (PageLocked(page)) + if (PageLocked(head)) goto next; - if (!page_cache_get_speculative(page)) + if (!page_cache_get_speculative(head)) goto next; - /* Has the page moved or been split? */ + /* The page was split under us? */ + if (compound_head(page) != head) + goto skip; + + /* Has the page moved? */ if (unlikely(page != xas_reload(&xas))) goto skip; - page = find_subpage(page, xas.xa_index); if (!PageUptodate(page) || PageReadahead(page) || @@ -2772,7 +2823,11 @@ repeat: } filler: - err = filler(data, page); + if (filler) + err = filler(data, page); + else + err = mapping->a_ops->readpage(data, page); + if (err < 0) { put_page(page); return ERR_PTR(err); @@ -2862,7 +2917,8 @@ struct page *read_cache_page(struct address_space *mapping, int (*filler)(void *, struct page *), void *data) { - return do_read_cache_page(mapping, index, filler, data, mapping_gfp_mask(mapping)); + return do_read_cache_page(mapping, index, filler, data, + mapping_gfp_mask(mapping)); } EXPORT_SYMBOL(read_cache_page); @@ -2883,9 +2939,7 @@ struct page *read_cache_page_gfp(struct address_space *mapping, pgoff_t index, gfp_t gfp) { - filler_t *filler = (filler_t *)mapping->a_ops->readpage; - - return do_read_cache_page(mapping, index, filler, NULL, gfp); + return do_read_cache_page(mapping, index, NULL, NULL, gfp); } EXPORT_SYMBOL(read_cache_page_gfp); @@ -2894,24 +2948,11 @@ EXPORT_SYMBOL(read_cache_page_gfp); * LFS limits. If pos is under the limit it becomes a short access. If it * exceeds the limit we return -EFBIG. */ -static int generic_access_check_limits(struct file *file, loff_t pos, - loff_t *count) -{ - struct inode *inode = file->f_mapping->host; - loff_t max_size = inode->i_sb->s_maxbytes; - - if (!(file->f_flags & O_LARGEFILE)) - max_size = MAX_NON_LFS; - - if (unlikely(pos >= max_size)) - return -EFBIG; - *count = min(*count, max_size - pos); - return 0; -} - static int generic_write_check_limits(struct file *file, loff_t pos, loff_t *count) { + struct inode *inode = file->f_mapping->host; + loff_t max_size = inode->i_sb->s_maxbytes; loff_t limit = rlimit(RLIMIT_FSIZE); if (limit != RLIM_INFINITY) { @@ -2922,7 +2963,15 @@ static int generic_write_check_limits(struct file *file, loff_t pos, *count = min(*count, limit - pos); } - return generic_access_check_limits(file, pos, count); + if (!(file->f_flags & O_LARGEFILE)) + max_size = MAX_NON_LFS; + + if (unlikely(pos >= max_size)) + return -EFBIG; + + *count = min(*count, max_size - pos); + + return 0; } /* @@ -2962,7 +3011,7 @@ EXPORT_SYMBOL(generic_write_checks); /* * Performs necessary checks before doing a clone. * - * Can adjust amount of bytes to clone. + * Can adjust amount of bytes to clone via @req_count argument. * Returns appropriate error code that caller should return or * zero in case the clone should be allowed. */ @@ -3000,10 +3049,6 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in, return -EINVAL; count = min(count, size_in - (uint64_t)pos_in); - ret = generic_access_check_limits(file_in, pos_in, &count); - if (ret) - return ret; - ret = generic_write_check_limits(file_out, pos_out, &count); if (ret) return ret; @@ -3040,6 +3085,83 @@ int generic_remap_checks(struct file *file_in, loff_t pos_in, return 0; } + +/* + * Performs common checks before doing a file copy/clone + * from @file_in to @file_out. + */ +int generic_file_rw_checks(struct file *file_in, struct file *file_out) +{ + struct inode *inode_in = file_inode(file_in); + struct inode *inode_out = file_inode(file_out); + + /* Don't copy dirs, pipes, sockets... */ + if (S_ISDIR(inode_in->i_mode) || S_ISDIR(inode_out->i_mode)) + return -EISDIR; + if (!S_ISREG(inode_in->i_mode) || !S_ISREG(inode_out->i_mode)) + return -EINVAL; + + if (!(file_in->f_mode & FMODE_READ) || + !(file_out->f_mode & FMODE_WRITE) || + (file_out->f_flags & O_APPEND)) + return -EBADF; + + return 0; +} + +/* + * Performs necessary checks before doing a file copy + * + * Can adjust amount of bytes to copy via @req_count argument. + * Returns appropriate error code that caller should return or + * zero in case the copy should be allowed. + */ +int generic_copy_file_checks(struct file *file_in, loff_t pos_in, + struct file *file_out, loff_t pos_out, + size_t *req_count, unsigned int flags) +{ + struct inode *inode_in = file_inode(file_in); + struct inode *inode_out = file_inode(file_out); + uint64_t count = *req_count; + loff_t size_in; + int ret; + + ret = generic_file_rw_checks(file_in, file_out); + if (ret) + return ret; + + /* Don't touch certain kinds of inodes */ + if (IS_IMMUTABLE(inode_out)) + return -EPERM; + + if (IS_SWAPFILE(inode_in) || IS_SWAPFILE(inode_out)) + return -ETXTBSY; + + /* Ensure offsets don't wrap. */ + if (pos_in + count < pos_in || pos_out + count < pos_out) + return -EOVERFLOW; + + /* Shorten the copy to EOF */ + size_in = i_size_read(inode_in); + if (pos_in >= size_in) + count = 0; + else + count = min(count, size_in - (uint64_t)pos_in); + + ret = generic_write_check_limits(file_out, pos_out, &count); + if (ret) + return ret; + + /* Don't allow overlapped copying within the same file. */ + if (inode_in == inode_out && + pos_out + count > pos_in && + pos_out < pos_in + count) + return -EINVAL; + + *req_count = count; + return 0; +} + int pagecache_write_begin(struct file *file, struct address_space *mapping, loff_t pos, unsigned len, unsigned flags, struct page **pagep, void **fsdata) |