| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* handling of writes to regular files and writing back to the server |
| * |
| * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| */ |
| |
| #include <linux/backing-dev.h> |
| #include <linux/slab.h> |
| #include <linux/fs.h> |
| #include <linux/pagemap.h> |
| #include <linux/writeback.h> |
| #include <linux/pagevec.h> |
| #include "internal.h" |
| |
| /* |
| * mark a page as having been made dirty and thus needing writeback |
| */ |
| int afs_set_page_dirty(struct page *page) |
| { |
| _enter(""); |
| return __set_page_dirty_nobuffers(page); |
| } |
| |
| /* |
| * partly or wholly fill a page that's under preparation for writing |
| */ |
| static int afs_fill_page(struct afs_vnode *vnode, struct key *key, |
| loff_t pos, unsigned int len, struct page *page) |
| { |
| struct afs_read *req; |
| size_t p; |
| void *data; |
| int ret; |
| |
| _enter(",,%llu", (unsigned long long)pos); |
| |
| if (pos >= vnode->vfs_inode.i_size) { |
| p = pos & ~PAGE_MASK; |
| ASSERTCMP(p + len, <=, PAGE_SIZE); |
| data = kmap(page); |
| memset(data + p, 0, len); |
| kunmap(page); |
| return 0; |
| } |
| |
| req = kzalloc(struct_size(req, array, 1), GFP_KERNEL); |
| if (!req) |
| return -ENOMEM; |
| |
| refcount_set(&req->usage, 1); |
| req->pos = pos; |
| req->len = len; |
| req->nr_pages = 1; |
| req->pages = req->array; |
| req->pages[0] = page; |
| get_page(page); |
| |
| ret = afs_fetch_data(vnode, key, req); |
| afs_put_read(req); |
| if (ret < 0) { |
| if (ret == -ENOENT) { |
| _debug("got NOENT from server" |
| " - marking file deleted and stale"); |
| set_bit(AFS_VNODE_DELETED, &vnode->flags); |
| ret = -ESTALE; |
| } |
| } |
| |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * prepare to perform part of a write to a page |
| */ |
| int afs_write_begin(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned flags, |
| struct page **_page, void **fsdata) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
| struct page *page; |
| struct key *key = afs_file_key(file); |
| unsigned long priv; |
| unsigned f, from = pos & (PAGE_SIZE - 1); |
| unsigned t, to = from + len; |
| pgoff_t index = pos >> PAGE_SHIFT; |
| int ret; |
| |
| _enter("{%llx:%llu},{%lx},%u,%u", |
| vnode->fid.vid, vnode->fid.vnode, index, from, to); |
| |
| page = grab_cache_page_write_begin(mapping, index, flags); |
| if (!page) |
| return -ENOMEM; |
| |
| if (!PageUptodate(page) && len != PAGE_SIZE) { |
| ret = afs_fill_page(vnode, key, pos & PAGE_MASK, PAGE_SIZE, page); |
| if (ret < 0) { |
| unlock_page(page); |
| put_page(page); |
| _leave(" = %d [prep]", ret); |
| return ret; |
| } |
| SetPageUptodate(page); |
| } |
| |
| try_again: |
| /* See if this page is already partially written in a way that we can |
| * merge the new write with. |
| */ |
| t = f = 0; |
| if (PagePrivate(page)) { |
| priv = page_private(page); |
| f = afs_page_dirty_from(priv); |
| t = afs_page_dirty_to(priv); |
| ASSERTCMP(f, <=, t); |
| } |
| |
| if (f != t) { |
| if (PageWriteback(page)) { |
| trace_afs_page_dirty(vnode, tracepoint_string("alrdy"), |
| page->index, priv); |
| goto flush_conflicting_write; |
| } |
| /* If the file is being filled locally, allow inter-write |
| * spaces to be merged into writes. If it's not, only write |
| * back what the user gives us. |
| */ |
| if (!test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags) && |
| (to < f || from > t)) |
| goto flush_conflicting_write; |
| } |
| |
| *_page = page; |
| _leave(" = 0"); |
| return 0; |
| |
| /* The previous write and this write aren't adjacent or overlapping, so |
| * flush the page out. |
| */ |
| flush_conflicting_write: |
| _debug("flush conflict"); |
| ret = write_one_page(page); |
| if (ret < 0) |
| goto error; |
| |
| ret = lock_page_killable(page); |
| if (ret < 0) |
| goto error; |
| goto try_again; |
| |
| error: |
| put_page(page); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * finalise part of a write to a page |
| */ |
| int afs_write_end(struct file *file, struct address_space *mapping, |
| loff_t pos, unsigned len, unsigned copied, |
| struct page *page, void *fsdata) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(file_inode(file)); |
| struct key *key = afs_file_key(file); |
| unsigned long priv; |
| unsigned int f, from = pos & (PAGE_SIZE - 1); |
| unsigned int t, to = from + copied; |
| loff_t i_size, maybe_i_size; |
| int ret = 0; |
| |
| _enter("{%llx:%llu},{%lx}", |
| vnode->fid.vid, vnode->fid.vnode, page->index); |
| |
| if (copied == 0) |
| goto out; |
| |
| maybe_i_size = pos + copied; |
| |
| i_size = i_size_read(&vnode->vfs_inode); |
| if (maybe_i_size > i_size) { |
| write_seqlock(&vnode->cb_lock); |
| i_size = i_size_read(&vnode->vfs_inode); |
| if (maybe_i_size > i_size) |
| afs_set_i_size(vnode, maybe_i_size); |
| write_sequnlock(&vnode->cb_lock); |
| } |
| |
| if (!PageUptodate(page)) { |
| if (copied < len) { |
| /* Try and load any missing data from the server. The |
| * unmarshalling routine will take care of clearing any |
| * bits that are beyond the EOF. |
| */ |
| ret = afs_fill_page(vnode, key, pos + copied, |
| len - copied, page); |
| if (ret < 0) |
| goto out; |
| } |
| SetPageUptodate(page); |
| } |
| |
| if (PagePrivate(page)) { |
| priv = page_private(page); |
| f = afs_page_dirty_from(priv); |
| t = afs_page_dirty_to(priv); |
| if (from < f) |
| f = from; |
| if (to > t) |
| t = to; |
| priv = afs_page_dirty(f, t); |
| set_page_private(page, priv); |
| trace_afs_page_dirty(vnode, tracepoint_string("dirty+"), |
| page->index, priv); |
| } else { |
| priv = afs_page_dirty(from, to); |
| attach_page_private(page, (void *)priv); |
| trace_afs_page_dirty(vnode, tracepoint_string("dirty"), |
| page->index, priv); |
| } |
| |
| set_page_dirty(page); |
| if (PageDirty(page)) |
| _debug("dirtied"); |
| ret = copied; |
| |
| out: |
| unlock_page(page); |
| put_page(page); |
| return ret; |
| } |
| |
| /* |
| * kill all the pages in the given range |
| */ |
| static void afs_kill_pages(struct address_space *mapping, |
| pgoff_t first, pgoff_t last) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(mapping->host); |
| struct pagevec pv; |
| unsigned count, loop; |
| |
| _enter("{%llx:%llu},%lx-%lx", |
| vnode->fid.vid, vnode->fid.vnode, first, last); |
| |
| pagevec_init(&pv); |
| |
| do { |
| _debug("kill %lx-%lx", first, last); |
| |
| count = last - first + 1; |
| if (count > PAGEVEC_SIZE) |
| count = PAGEVEC_SIZE; |
| pv.nr = find_get_pages_contig(mapping, first, count, pv.pages); |
| ASSERTCMP(pv.nr, ==, count); |
| |
| for (loop = 0; loop < count; loop++) { |
| struct page *page = pv.pages[loop]; |
| ClearPageUptodate(page); |
| SetPageError(page); |
| end_page_writeback(page); |
| if (page->index >= first) |
| first = page->index + 1; |
| lock_page(page); |
| generic_error_remove_page(mapping, page); |
| unlock_page(page); |
| } |
| |
| __pagevec_release(&pv); |
| } while (first <= last); |
| |
| _leave(""); |
| } |
| |
| /* |
| * Redirty all the pages in a given range. |
| */ |
| static void afs_redirty_pages(struct writeback_control *wbc, |
| struct address_space *mapping, |
| pgoff_t first, pgoff_t last) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(mapping->host); |
| struct pagevec pv; |
| unsigned count, loop; |
| |
| _enter("{%llx:%llu},%lx-%lx", |
| vnode->fid.vid, vnode->fid.vnode, first, last); |
| |
| pagevec_init(&pv); |
| |
| do { |
| _debug("redirty %lx-%lx", first, last); |
| |
| count = last - first + 1; |
| if (count > PAGEVEC_SIZE) |
| count = PAGEVEC_SIZE; |
| pv.nr = find_get_pages_contig(mapping, first, count, pv.pages); |
| ASSERTCMP(pv.nr, ==, count); |
| |
| for (loop = 0; loop < count; loop++) { |
| struct page *page = pv.pages[loop]; |
| |
| redirty_page_for_writepage(wbc, page); |
| end_page_writeback(page); |
| if (page->index >= first) |
| first = page->index + 1; |
| } |
| |
| __pagevec_release(&pv); |
| } while (first <= last); |
| |
| _leave(""); |
| } |
| |
| /* |
| * completion of write to server |
| */ |
| static void afs_pages_written_back(struct afs_vnode *vnode, |
| pgoff_t first, pgoff_t last) |
| { |
| struct pagevec pv; |
| unsigned long priv; |
| unsigned count, loop; |
| |
| _enter("{%llx:%llu},{%lx-%lx}", |
| vnode->fid.vid, vnode->fid.vnode, first, last); |
| |
| pagevec_init(&pv); |
| |
| do { |
| _debug("done %lx-%lx", first, last); |
| |
| count = last - first + 1; |
| if (count > PAGEVEC_SIZE) |
| count = PAGEVEC_SIZE; |
| pv.nr = find_get_pages_contig(vnode->vfs_inode.i_mapping, |
| first, count, pv.pages); |
| ASSERTCMP(pv.nr, ==, count); |
| |
| for (loop = 0; loop < count; loop++) { |
| priv = (unsigned long)detach_page_private(pv.pages[loop]); |
| trace_afs_page_dirty(vnode, tracepoint_string("clear"), |
| pv.pages[loop]->index, priv); |
| end_page_writeback(pv.pages[loop]); |
| } |
| first += count; |
| __pagevec_release(&pv); |
| } while (first <= last); |
| |
| afs_prune_wb_keys(vnode); |
| _leave(""); |
| } |
| |
| /* |
| * Find a key to use for the writeback. We cached the keys used to author the |
| * writes on the vnode. *_wbk will contain the last writeback key used or NULL |
| * and we need to start from there if it's set. |
| */ |
| static int afs_get_writeback_key(struct afs_vnode *vnode, |
| struct afs_wb_key **_wbk) |
| { |
| struct afs_wb_key *wbk = NULL; |
| struct list_head *p; |
| int ret = -ENOKEY, ret2; |
| |
| spin_lock(&vnode->wb_lock); |
| if (*_wbk) |
| p = (*_wbk)->vnode_link.next; |
| else |
| p = vnode->wb_keys.next; |
| |
| while (p != &vnode->wb_keys) { |
| wbk = list_entry(p, struct afs_wb_key, vnode_link); |
| _debug("wbk %u", key_serial(wbk->key)); |
| ret2 = key_validate(wbk->key); |
| if (ret2 == 0) { |
| refcount_inc(&wbk->usage); |
| _debug("USE WB KEY %u", key_serial(wbk->key)); |
| break; |
| } |
| |
| wbk = NULL; |
| if (ret == -ENOKEY) |
| ret = ret2; |
| p = p->next; |
| } |
| |
| spin_unlock(&vnode->wb_lock); |
| if (*_wbk) |
| afs_put_wb_key(*_wbk); |
| *_wbk = wbk; |
| return 0; |
| } |
| |
| static void afs_store_data_success(struct afs_operation *op) |
| { |
| struct afs_vnode *vnode = op->file[0].vnode; |
| |
| op->ctime = op->file[0].scb.status.mtime_client; |
| afs_vnode_commit_status(op, &op->file[0]); |
| if (op->error == 0) { |
| if (!op->store.laundering) |
| afs_pages_written_back(vnode, op->store.first, op->store.last); |
| afs_stat_v(vnode, n_stores); |
| atomic_long_add((op->store.last * PAGE_SIZE + op->store.last_to) - |
| (op->store.first * PAGE_SIZE + op->store.first_offset), |
| &afs_v2net(vnode)->n_store_bytes); |
| } |
| } |
| |
| static const struct afs_operation_ops afs_store_data_operation = { |
| .issue_afs_rpc = afs_fs_store_data, |
| .issue_yfs_rpc = yfs_fs_store_data, |
| .success = afs_store_data_success, |
| }; |
| |
| /* |
| * write to a file |
| */ |
| static int afs_store_data(struct address_space *mapping, |
| pgoff_t first, pgoff_t last, |
| unsigned offset, unsigned to, bool laundering) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(mapping->host); |
| struct afs_operation *op; |
| struct afs_wb_key *wbk = NULL; |
| int ret; |
| |
| _enter("%s{%llx:%llu.%u},%lx,%lx,%x,%x", |
| vnode->volume->name, |
| vnode->fid.vid, |
| vnode->fid.vnode, |
| vnode->fid.unique, |
| first, last, offset, to); |
| |
| ret = afs_get_writeback_key(vnode, &wbk); |
| if (ret) { |
| _leave(" = %d [no keys]", ret); |
| return ret; |
| } |
| |
| op = afs_alloc_operation(wbk->key, vnode->volume); |
| if (IS_ERR(op)) { |
| afs_put_wb_key(wbk); |
| return -ENOMEM; |
| } |
| |
| afs_op_set_vnode(op, 0, vnode); |
| op->file[0].dv_delta = 1; |
| op->store.mapping = mapping; |
| op->file[0].modification = true; |
| op->store.first = first; |
| op->store.last = last; |
| op->store.first_offset = offset; |
| op->store.last_to = to; |
| op->store.laundering = laundering; |
| op->mtime = vnode->vfs_inode.i_mtime; |
| op->flags |= AFS_OPERATION_UNINTR; |
| op->ops = &afs_store_data_operation; |
| |
| try_next_key: |
| afs_begin_vnode_operation(op); |
| afs_wait_for_operation(op); |
| |
| switch (op->error) { |
| case -EACCES: |
| case -EPERM: |
| case -ENOKEY: |
| case -EKEYEXPIRED: |
| case -EKEYREJECTED: |
| case -EKEYREVOKED: |
| _debug("next"); |
| |
| ret = afs_get_writeback_key(vnode, &wbk); |
| if (ret == 0) { |
| key_put(op->key); |
| op->key = key_get(wbk->key); |
| goto try_next_key; |
| } |
| break; |
| } |
| |
| afs_put_wb_key(wbk); |
| _leave(" = %d", op->error); |
| return afs_put_operation(op); |
| } |
| |
| /* |
| * Synchronously write back the locked page and any subsequent non-locked dirty |
| * pages. |
| */ |
| static int afs_write_back_from_locked_page(struct address_space *mapping, |
| struct writeback_control *wbc, |
| struct page *primary_page, |
| pgoff_t final_page) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(mapping->host); |
| struct page *pages[8], *page; |
| unsigned long count, priv; |
| unsigned n, offset, to, f, t; |
| pgoff_t start, first, last; |
| loff_t i_size, end; |
| int loop, ret; |
| |
| _enter(",%lx", primary_page->index); |
| |
| count = 1; |
| if (test_set_page_writeback(primary_page)) |
| BUG(); |
| |
| /* Find all consecutive lockable dirty pages that have contiguous |
| * written regions, stopping when we find a page that is not |
| * immediately lockable, is not dirty or is missing, or we reach the |
| * end of the range. |
| */ |
| start = primary_page->index; |
| priv = page_private(primary_page); |
| offset = afs_page_dirty_from(priv); |
| to = afs_page_dirty_to(priv); |
| trace_afs_page_dirty(vnode, tracepoint_string("store"), |
| primary_page->index, priv); |
| |
| WARN_ON(offset == to); |
| if (offset == to) |
| trace_afs_page_dirty(vnode, tracepoint_string("WARN"), |
| primary_page->index, priv); |
| |
| if (start >= final_page || |
| (to < PAGE_SIZE && !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags))) |
| goto no_more; |
| |
| start++; |
| do { |
| _debug("more %lx [%lx]", start, count); |
| n = final_page - start + 1; |
| if (n > ARRAY_SIZE(pages)) |
| n = ARRAY_SIZE(pages); |
| n = find_get_pages_contig(mapping, start, ARRAY_SIZE(pages), pages); |
| _debug("fgpc %u", n); |
| if (n == 0) |
| goto no_more; |
| if (pages[0]->index != start) { |
| do { |
| put_page(pages[--n]); |
| } while (n > 0); |
| goto no_more; |
| } |
| |
| for (loop = 0; loop < n; loop++) { |
| page = pages[loop]; |
| if (to != PAGE_SIZE && |
| !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) |
| break; |
| if (page->index > final_page) |
| break; |
| if (!trylock_page(page)) |
| break; |
| if (!PageDirty(page) || PageWriteback(page)) { |
| unlock_page(page); |
| break; |
| } |
| |
| priv = page_private(page); |
| f = afs_page_dirty_from(priv); |
| t = afs_page_dirty_to(priv); |
| if (f != 0 && |
| !test_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags)) { |
| unlock_page(page); |
| break; |
| } |
| to = t; |
| |
| trace_afs_page_dirty(vnode, tracepoint_string("store+"), |
| page->index, priv); |
| |
| if (!clear_page_dirty_for_io(page)) |
| BUG(); |
| if (test_set_page_writeback(page)) |
| BUG(); |
| unlock_page(page); |
| put_page(page); |
| } |
| count += loop; |
| if (loop < n) { |
| for (; loop < n; loop++) |
| put_page(pages[loop]); |
| goto no_more; |
| } |
| |
| start += loop; |
| } while (start <= final_page && count < 65536); |
| |
| no_more: |
| /* We now have a contiguous set of dirty pages, each with writeback |
| * set; the first page is still locked at this point, but all the rest |
| * have been unlocked. |
| */ |
| unlock_page(primary_page); |
| |
| first = primary_page->index; |
| last = first + count - 1; |
| |
| end = (loff_t)last * PAGE_SIZE + to; |
| i_size = i_size_read(&vnode->vfs_inode); |
| |
| _debug("write back %lx[%u..] to %lx[..%u]", first, offset, last, to); |
| if (end > i_size) |
| to = i_size & ~PAGE_MASK; |
| |
| ret = afs_store_data(mapping, first, last, offset, to, false); |
| switch (ret) { |
| case 0: |
| ret = count; |
| break; |
| |
| default: |
| pr_notice("kAFS: Unexpected error from FS.StoreData %d\n", ret); |
| fallthrough; |
| case -EACCES: |
| case -EPERM: |
| case -ENOKEY: |
| case -EKEYEXPIRED: |
| case -EKEYREJECTED: |
| case -EKEYREVOKED: |
| afs_redirty_pages(wbc, mapping, first, last); |
| mapping_set_error(mapping, ret); |
| break; |
| |
| case -EDQUOT: |
| case -ENOSPC: |
| afs_redirty_pages(wbc, mapping, first, last); |
| mapping_set_error(mapping, -ENOSPC); |
| break; |
| |
| case -EROFS: |
| case -EIO: |
| case -EREMOTEIO: |
| case -EFBIG: |
| case -ENOENT: |
| case -ENOMEDIUM: |
| case -ENXIO: |
| trace_afs_file_error(vnode, ret, afs_file_error_writeback_fail); |
| afs_kill_pages(mapping, first, last); |
| mapping_set_error(mapping, ret); |
| break; |
| } |
| |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * write a page back to the server |
| * - the caller locked the page for us |
| */ |
| int afs_writepage(struct page *page, struct writeback_control *wbc) |
| { |
| int ret; |
| |
| _enter("{%lx},", page->index); |
| |
| ret = afs_write_back_from_locked_page(page->mapping, wbc, page, |
| wbc->range_end >> PAGE_SHIFT); |
| if (ret < 0) { |
| _leave(" = %d", ret); |
| return 0; |
| } |
| |
| wbc->nr_to_write -= ret; |
| |
| _leave(" = 0"); |
| return 0; |
| } |
| |
| /* |
| * write a region of pages back to the server |
| */ |
| static int afs_writepages_region(struct address_space *mapping, |
| struct writeback_control *wbc, |
| pgoff_t index, pgoff_t end, pgoff_t *_next) |
| { |
| struct page *page; |
| int ret, n; |
| |
| _enter(",,%lx,%lx,", index, end); |
| |
| do { |
| n = find_get_pages_range_tag(mapping, &index, end, |
| PAGECACHE_TAG_DIRTY, 1, &page); |
| if (!n) |
| break; |
| |
| _debug("wback %lx", page->index); |
| |
| /* |
| * at this point we hold neither the i_pages lock nor the |
| * page lock: the page may be truncated or invalidated |
| * (changing page->mapping to NULL), or even swizzled |
| * back from swapper_space to tmpfs file mapping |
| */ |
| ret = lock_page_killable(page); |
| if (ret < 0) { |
| put_page(page); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| if (page->mapping != mapping || !PageDirty(page)) { |
| unlock_page(page); |
| put_page(page); |
| continue; |
| } |
| |
| if (PageWriteback(page)) { |
| unlock_page(page); |
| if (wbc->sync_mode != WB_SYNC_NONE) |
| wait_on_page_writeback(page); |
| put_page(page); |
| continue; |
| } |
| |
| if (!clear_page_dirty_for_io(page)) |
| BUG(); |
| ret = afs_write_back_from_locked_page(mapping, wbc, page, end); |
| put_page(page); |
| if (ret < 0) { |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| wbc->nr_to_write -= ret; |
| |
| cond_resched(); |
| } while (index < end && wbc->nr_to_write > 0); |
| |
| *_next = index; |
| _leave(" = 0 [%lx]", *_next); |
| return 0; |
| } |
| |
| /* |
| * write some of the pending data back to the server |
| */ |
| int afs_writepages(struct address_space *mapping, |
| struct writeback_control *wbc) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(mapping->host); |
| pgoff_t start, end, next; |
| int ret; |
| |
| _enter(""); |
| |
| /* We have to be careful as we can end up racing with setattr() |
| * truncating the pagecache since the caller doesn't take a lock here |
| * to prevent it. |
| */ |
| if (wbc->sync_mode == WB_SYNC_ALL) |
| down_read(&vnode->validate_lock); |
| else if (!down_read_trylock(&vnode->validate_lock)) |
| return 0; |
| |
| if (wbc->range_cyclic) { |
| start = mapping->writeback_index; |
| end = -1; |
| ret = afs_writepages_region(mapping, wbc, start, end, &next); |
| if (start > 0 && wbc->nr_to_write > 0 && ret == 0) |
| ret = afs_writepages_region(mapping, wbc, 0, start, |
| &next); |
| mapping->writeback_index = next; |
| } else if (wbc->range_start == 0 && wbc->range_end == LLONG_MAX) { |
| end = (pgoff_t)(LLONG_MAX >> PAGE_SHIFT); |
| ret = afs_writepages_region(mapping, wbc, 0, end, &next); |
| if (wbc->nr_to_write > 0) |
| mapping->writeback_index = next; |
| } else { |
| start = wbc->range_start >> PAGE_SHIFT; |
| end = wbc->range_end >> PAGE_SHIFT; |
| ret = afs_writepages_region(mapping, wbc, start, end, &next); |
| } |
| |
| up_read(&vnode->validate_lock); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * write to an AFS file |
| */ |
| ssize_t afs_file_write(struct kiocb *iocb, struct iov_iter *from) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(file_inode(iocb->ki_filp)); |
| ssize_t result; |
| size_t count = iov_iter_count(from); |
| |
| _enter("{%llx:%llu},{%zu},", |
| vnode->fid.vid, vnode->fid.vnode, count); |
| |
| if (IS_SWAPFILE(&vnode->vfs_inode)) { |
| printk(KERN_INFO |
| "AFS: Attempt to write to active swap file!\n"); |
| return -EBUSY; |
| } |
| |
| if (!count) |
| return 0; |
| |
| result = generic_file_write_iter(iocb, from); |
| |
| _leave(" = %zd", result); |
| return result; |
| } |
| |
| /* |
| * flush any dirty pages for this process, and check for write errors. |
| * - the return status from this call provides a reliable indication of |
| * whether any write errors occurred for this process. |
| */ |
| int afs_fsync(struct file *file, loff_t start, loff_t end, int datasync) |
| { |
| struct inode *inode = file_inode(file); |
| struct afs_vnode *vnode = AFS_FS_I(inode); |
| |
| _enter("{%llx:%llu},{n=%pD},%d", |
| vnode->fid.vid, vnode->fid.vnode, file, |
| datasync); |
| |
| return file_write_and_wait_range(file, start, end); |
| } |
| |
| /* |
| * notification that a previously read-only page is about to become writable |
| * - if it returns an error, the caller will deliver a bus error signal |
| */ |
| vm_fault_t afs_page_mkwrite(struct vm_fault *vmf) |
| { |
| struct file *file = vmf->vma->vm_file; |
| struct inode *inode = file_inode(file); |
| struct afs_vnode *vnode = AFS_FS_I(inode); |
| unsigned long priv; |
| |
| _enter("{{%llx:%llu}},{%lx}", |
| vnode->fid.vid, vnode->fid.vnode, vmf->page->index); |
| |
| sb_start_pagefault(inode->i_sb); |
| |
| /* Wait for the page to be written to the cache before we allow it to |
| * be modified. We then assume the entire page will need writing back. |
| */ |
| #ifdef CONFIG_AFS_FSCACHE |
| fscache_wait_on_page_write(vnode->cache, vmf->page); |
| #endif |
| |
| if (PageWriteback(vmf->page) && |
| wait_on_page_bit_killable(vmf->page, PG_writeback) < 0) |
| return VM_FAULT_RETRY; |
| |
| if (lock_page_killable(vmf->page) < 0) |
| return VM_FAULT_RETRY; |
| |
| /* We mustn't change page->private until writeback is complete as that |
| * details the portion of the page we need to write back and we might |
| * need to redirty the page if there's a problem. |
| */ |
| wait_on_page_writeback(vmf->page); |
| |
| priv = afs_page_dirty(0, PAGE_SIZE); |
| priv = afs_page_dirty_mmapped(priv); |
| trace_afs_page_dirty(vnode, tracepoint_string("mkwrite"), |
| vmf->page->index, priv); |
| if (PagePrivate(vmf->page)) |
| set_page_private(vmf->page, priv); |
| else |
| attach_page_private(vmf->page, (void *)priv); |
| file_update_time(file); |
| |
| sb_end_pagefault(inode->i_sb); |
| return VM_FAULT_LOCKED; |
| } |
| |
| /* |
| * Prune the keys cached for writeback. The caller must hold vnode->wb_lock. |
| */ |
| void afs_prune_wb_keys(struct afs_vnode *vnode) |
| { |
| LIST_HEAD(graveyard); |
| struct afs_wb_key *wbk, *tmp; |
| |
| /* Discard unused keys */ |
| spin_lock(&vnode->wb_lock); |
| |
| if (!mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_WRITEBACK) && |
| !mapping_tagged(&vnode->vfs_inode.i_data, PAGECACHE_TAG_DIRTY)) { |
| list_for_each_entry_safe(wbk, tmp, &vnode->wb_keys, vnode_link) { |
| if (refcount_read(&wbk->usage) == 1) |
| list_move(&wbk->vnode_link, &graveyard); |
| } |
| } |
| |
| spin_unlock(&vnode->wb_lock); |
| |
| while (!list_empty(&graveyard)) { |
| wbk = list_entry(graveyard.next, struct afs_wb_key, vnode_link); |
| list_del(&wbk->vnode_link); |
| afs_put_wb_key(wbk); |
| } |
| } |
| |
| /* |
| * Clean up a page during invalidation. |
| */ |
| int afs_launder_page(struct page *page) |
| { |
| struct address_space *mapping = page->mapping; |
| struct afs_vnode *vnode = AFS_FS_I(mapping->host); |
| unsigned long priv; |
| unsigned int f, t; |
| int ret = 0; |
| |
| _enter("{%lx}", page->index); |
| |
| priv = page_private(page); |
| if (clear_page_dirty_for_io(page)) { |
| f = 0; |
| t = PAGE_SIZE; |
| if (PagePrivate(page)) { |
| f = afs_page_dirty_from(priv); |
| t = afs_page_dirty_to(priv); |
| } |
| |
| trace_afs_page_dirty(vnode, tracepoint_string("launder"), |
| page->index, priv); |
| ret = afs_store_data(mapping, page->index, page->index, t, f, true); |
| } |
| |
| priv = (unsigned long)detach_page_private(page); |
| trace_afs_page_dirty(vnode, tracepoint_string("laundered"), |
| page->index, priv); |
| |
| #ifdef CONFIG_AFS_FSCACHE |
| if (PageFsCache(page)) { |
| fscache_wait_on_page_write(vnode->cache, page); |
| fscache_uncache_page(vnode->cache, page); |
| } |
| #endif |
| return ret; |
| } |