| // SPDX-License-Identifier: GPL-2.0-or-later |
| /* AFS filesystem file handling |
| * |
| * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved. |
| * Written by David Howells (dhowells@redhat.com) |
| */ |
| |
| #include <linux/kernel.h> |
| #include <linux/module.h> |
| #include <linux/init.h> |
| #include <linux/fs.h> |
| #include <linux/pagemap.h> |
| #include <linux/writeback.h> |
| #include <linux/gfp.h> |
| #include <linux/task_io_accounting_ops.h> |
| #include <linux/mm.h> |
| #include "internal.h" |
| |
| static int afs_file_mmap(struct file *file, struct vm_area_struct *vma); |
| static int afs_readpage(struct file *file, struct page *page); |
| static void afs_invalidatepage(struct page *page, unsigned int offset, |
| unsigned int length); |
| static int afs_releasepage(struct page *page, gfp_t gfp_flags); |
| |
| static int afs_readpages(struct file *filp, struct address_space *mapping, |
| struct list_head *pages, unsigned nr_pages); |
| |
| const struct file_operations afs_file_operations = { |
| .open = afs_open, |
| .release = afs_release, |
| .llseek = generic_file_llseek, |
| .read_iter = generic_file_read_iter, |
| .write_iter = afs_file_write, |
| .mmap = afs_file_mmap, |
| .splice_read = generic_file_splice_read, |
| .splice_write = iter_file_splice_write, |
| .fsync = afs_fsync, |
| .lock = afs_lock, |
| .flock = afs_flock, |
| }; |
| |
| const struct inode_operations afs_file_inode_operations = { |
| .getattr = afs_getattr, |
| .setattr = afs_setattr, |
| .permission = afs_permission, |
| }; |
| |
| const struct address_space_operations afs_fs_aops = { |
| .readpage = afs_readpage, |
| .readpages = afs_readpages, |
| .set_page_dirty = afs_set_page_dirty, |
| .launder_page = afs_launder_page, |
| .releasepage = afs_releasepage, |
| .invalidatepage = afs_invalidatepage, |
| .write_begin = afs_write_begin, |
| .write_end = afs_write_end, |
| .writepage = afs_writepage, |
| .writepages = afs_writepages, |
| }; |
| |
| static const struct vm_operations_struct afs_vm_ops = { |
| .fault = filemap_fault, |
| .map_pages = filemap_map_pages, |
| .page_mkwrite = afs_page_mkwrite, |
| }; |
| |
| /* |
| * Discard a pin on a writeback key. |
| */ |
| void afs_put_wb_key(struct afs_wb_key *wbk) |
| { |
| if (wbk && refcount_dec_and_test(&wbk->usage)) { |
| key_put(wbk->key); |
| kfree(wbk); |
| } |
| } |
| |
| /* |
| * Cache key for writeback. |
| */ |
| int afs_cache_wb_key(struct afs_vnode *vnode, struct afs_file *af) |
| { |
| struct afs_wb_key *wbk, *p; |
| |
| wbk = kzalloc(sizeof(struct afs_wb_key), GFP_KERNEL); |
| if (!wbk) |
| return -ENOMEM; |
| refcount_set(&wbk->usage, 2); |
| wbk->key = af->key; |
| |
| spin_lock(&vnode->wb_lock); |
| list_for_each_entry(p, &vnode->wb_keys, vnode_link) { |
| if (p->key == wbk->key) |
| goto found; |
| } |
| |
| key_get(wbk->key); |
| list_add_tail(&wbk->vnode_link, &vnode->wb_keys); |
| spin_unlock(&vnode->wb_lock); |
| af->wb = wbk; |
| return 0; |
| |
| found: |
| refcount_inc(&p->usage); |
| spin_unlock(&vnode->wb_lock); |
| af->wb = p; |
| kfree(wbk); |
| return 0; |
| } |
| |
| /* |
| * open an AFS file or directory and attach a key to it |
| */ |
| int afs_open(struct inode *inode, struct file *file) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(inode); |
| struct afs_file *af; |
| struct key *key; |
| int ret; |
| |
| _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode); |
| |
| key = afs_request_key(vnode->volume->cell); |
| if (IS_ERR(key)) { |
| ret = PTR_ERR(key); |
| goto error; |
| } |
| |
| af = kzalloc(sizeof(*af), GFP_KERNEL); |
| if (!af) { |
| ret = -ENOMEM; |
| goto error_key; |
| } |
| af->key = key; |
| |
| ret = afs_validate(vnode, key); |
| if (ret < 0) |
| goto error_af; |
| |
| if (file->f_mode & FMODE_WRITE) { |
| ret = afs_cache_wb_key(vnode, af); |
| if (ret < 0) |
| goto error_af; |
| } |
| |
| if (file->f_flags & O_TRUNC) |
| set_bit(AFS_VNODE_NEW_CONTENT, &vnode->flags); |
| |
| file->private_data = af; |
| _leave(" = 0"); |
| return 0; |
| |
| error_af: |
| kfree(af); |
| error_key: |
| key_put(key); |
| error: |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * release an AFS file or directory and discard its key |
| */ |
| int afs_release(struct inode *inode, struct file *file) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(inode); |
| struct afs_file *af = file->private_data; |
| int ret = 0; |
| |
| _enter("{%llx:%llu},", vnode->fid.vid, vnode->fid.vnode); |
| |
| if ((file->f_mode & FMODE_WRITE)) |
| ret = vfs_fsync(file, 0); |
| |
| file->private_data = NULL; |
| if (af->wb) |
| afs_put_wb_key(af->wb); |
| key_put(af->key); |
| kfree(af); |
| afs_prune_wb_keys(vnode); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * Dispose of a ref to a read record. |
| */ |
| void afs_put_read(struct afs_read *req) |
| { |
| int i; |
| |
| if (refcount_dec_and_test(&req->usage)) { |
| if (req->pages) { |
| for (i = 0; i < req->nr_pages; i++) |
| if (req->pages[i]) |
| put_page(req->pages[i]); |
| if (req->pages != req->array) |
| kfree(req->pages); |
| } |
| kfree(req); |
| } |
| } |
| |
| #ifdef CONFIG_AFS_FSCACHE |
| /* |
| * deal with notification that a page was read from the cache |
| */ |
| static void afs_file_readpage_read_complete(struct page *page, |
| void *data, |
| int error) |
| { |
| _enter("%p,%p,%d", page, data, error); |
| |
| /* if the read completes with an error, we just unlock the page and let |
| * the VM reissue the readpage */ |
| if (!error) |
| SetPageUptodate(page); |
| unlock_page(page); |
| } |
| #endif |
| |
| static void afs_fetch_data_success(struct afs_operation *op) |
| { |
| struct afs_vnode *vnode = op->file[0].vnode; |
| |
| _enter("op=%08x", op->debug_id); |
| afs_vnode_commit_status(op, &op->file[0]); |
| afs_stat_v(vnode, n_fetches); |
| atomic_long_add(op->fetch.req->actual_len, &op->net->n_fetch_bytes); |
| } |
| |
| static void afs_fetch_data_put(struct afs_operation *op) |
| { |
| afs_put_read(op->fetch.req); |
| } |
| |
| static const struct afs_operation_ops afs_fetch_data_operation = { |
| .issue_afs_rpc = afs_fs_fetch_data, |
| .issue_yfs_rpc = yfs_fs_fetch_data, |
| .success = afs_fetch_data_success, |
| .aborted = afs_check_for_remote_deletion, |
| .put = afs_fetch_data_put, |
| }; |
| |
| /* |
| * Fetch file data from the volume. |
| */ |
| int afs_fetch_data(struct afs_vnode *vnode, struct key *key, struct afs_read *req) |
| { |
| struct afs_operation *op; |
| |
| _enter("%s{%llx:%llu.%u},%x,,,", |
| vnode->volume->name, |
| vnode->fid.vid, |
| vnode->fid.vnode, |
| vnode->fid.unique, |
| key_serial(key)); |
| |
| op = afs_alloc_operation(key, vnode->volume); |
| if (IS_ERR(op)) |
| return PTR_ERR(op); |
| |
| afs_op_set_vnode(op, 0, vnode); |
| |
| op->fetch.req = afs_get_read(req); |
| op->ops = &afs_fetch_data_operation; |
| return afs_do_sync_operation(op); |
| } |
| |
| /* |
| * read page from file, directory or symlink, given a key to use |
| */ |
| int afs_page_filler(void *data, struct page *page) |
| { |
| struct inode *inode = page->mapping->host; |
| struct afs_vnode *vnode = AFS_FS_I(inode); |
| struct afs_read *req; |
| struct key *key = data; |
| int ret; |
| |
| _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index); |
| |
| BUG_ON(!PageLocked(page)); |
| |
| ret = -ESTALE; |
| if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) |
| goto error; |
| |
| /* is it cached? */ |
| #ifdef CONFIG_AFS_FSCACHE |
| ret = fscache_read_or_alloc_page(vnode->cache, |
| page, |
| afs_file_readpage_read_complete, |
| NULL, |
| GFP_KERNEL); |
| #else |
| ret = -ENOBUFS; |
| #endif |
| switch (ret) { |
| /* read BIO submitted (page in cache) */ |
| case 0: |
| break; |
| |
| /* page not yet cached */ |
| case -ENODATA: |
| _debug("cache said ENODATA"); |
| goto go_on; |
| |
| /* page will not be cached */ |
| case -ENOBUFS: |
| _debug("cache said ENOBUFS"); |
| |
| fallthrough; |
| default: |
| go_on: |
| req = kzalloc(struct_size(req, array, 1), GFP_KERNEL); |
| if (!req) |
| goto enomem; |
| |
| /* We request a full page. If the page is a partial one at the |
| * end of the file, the server will return a short read and the |
| * unmarshalling code will clear the unfilled space. |
| */ |
| refcount_set(&req->usage, 1); |
| req->pos = (loff_t)page->index << PAGE_SHIFT; |
| req->len = PAGE_SIZE; |
| req->nr_pages = 1; |
| req->pages = req->array; |
| req->pages[0] = page; |
| get_page(page); |
| |
| /* read the contents of the file from the server into the |
| * 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; |
| } |
| |
| #ifdef CONFIG_AFS_FSCACHE |
| fscache_uncache_page(vnode->cache, page); |
| #endif |
| BUG_ON(PageFsCache(page)); |
| |
| if (ret == -EINTR || |
| ret == -ENOMEM || |
| ret == -ERESTARTSYS || |
| ret == -EAGAIN) |
| goto error; |
| goto io_error; |
| } |
| |
| SetPageUptodate(page); |
| |
| /* send the page to the cache */ |
| #ifdef CONFIG_AFS_FSCACHE |
| if (PageFsCache(page) && |
| fscache_write_page(vnode->cache, page, vnode->status.size, |
| GFP_KERNEL) != 0) { |
| fscache_uncache_page(vnode->cache, page); |
| BUG_ON(PageFsCache(page)); |
| } |
| #endif |
| unlock_page(page); |
| } |
| |
| _leave(" = 0"); |
| return 0; |
| |
| io_error: |
| SetPageError(page); |
| goto error; |
| enomem: |
| ret = -ENOMEM; |
| error: |
| unlock_page(page); |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| /* |
| * read page from file, directory or symlink, given a file to nominate the key |
| * to be used |
| */ |
| static int afs_readpage(struct file *file, struct page *page) |
| { |
| struct key *key; |
| int ret; |
| |
| if (file) { |
| key = afs_file_key(file); |
| ASSERT(key != NULL); |
| ret = afs_page_filler(key, page); |
| } else { |
| struct inode *inode = page->mapping->host; |
| key = afs_request_key(AFS_FS_S(inode->i_sb)->cell); |
| if (IS_ERR(key)) { |
| ret = PTR_ERR(key); |
| } else { |
| ret = afs_page_filler(key, page); |
| key_put(key); |
| } |
| } |
| return ret; |
| } |
| |
| /* |
| * Make pages available as they're filled. |
| */ |
| static void afs_readpages_page_done(struct afs_read *req) |
| { |
| #ifdef CONFIG_AFS_FSCACHE |
| struct afs_vnode *vnode = req->vnode; |
| #endif |
| struct page *page = req->pages[req->index]; |
| |
| req->pages[req->index] = NULL; |
| SetPageUptodate(page); |
| |
| /* send the page to the cache */ |
| #ifdef CONFIG_AFS_FSCACHE |
| if (PageFsCache(page) && |
| fscache_write_page(vnode->cache, page, vnode->status.size, |
| GFP_KERNEL) != 0) { |
| fscache_uncache_page(vnode->cache, page); |
| BUG_ON(PageFsCache(page)); |
| } |
| #endif |
| unlock_page(page); |
| put_page(page); |
| } |
| |
| /* |
| * Read a contiguous set of pages. |
| */ |
| static int afs_readpages_one(struct file *file, struct address_space *mapping, |
| struct list_head *pages) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(mapping->host); |
| struct afs_read *req; |
| struct list_head *p; |
| struct page *first, *page; |
| struct key *key = afs_file_key(file); |
| pgoff_t index; |
| int ret, n, i; |
| |
| /* Count the number of contiguous pages at the front of the list. Note |
| * that the list goes prev-wards rather than next-wards. |
| */ |
| first = lru_to_page(pages); |
| index = first->index + 1; |
| n = 1; |
| for (p = first->lru.prev; p != pages; p = p->prev) { |
| page = list_entry(p, struct page, lru); |
| if (page->index != index) |
| break; |
| index++; |
| n++; |
| } |
| |
| req = kzalloc(struct_size(req, array, n), GFP_NOFS); |
| if (!req) |
| return -ENOMEM; |
| |
| refcount_set(&req->usage, 1); |
| req->vnode = vnode; |
| req->page_done = afs_readpages_page_done; |
| req->pos = first->index; |
| req->pos <<= PAGE_SHIFT; |
| req->pages = req->array; |
| |
| /* Transfer the pages to the request. We add them in until one fails |
| * to add to the LRU and then we stop (as that'll make a hole in the |
| * contiguous run. |
| * |
| * Note that it's possible for the file size to change whilst we're |
| * doing this, but we rely on the server returning less than we asked |
| * for if the file shrank. We also rely on this to deal with a partial |
| * page at the end of the file. |
| */ |
| do { |
| page = lru_to_page(pages); |
| list_del(&page->lru); |
| index = page->index; |
| if (add_to_page_cache_lru(page, mapping, index, |
| readahead_gfp_mask(mapping))) { |
| #ifdef CONFIG_AFS_FSCACHE |
| fscache_uncache_page(vnode->cache, page); |
| #endif |
| put_page(page); |
| break; |
| } |
| |
| req->pages[req->nr_pages++] = page; |
| req->len += PAGE_SIZE; |
| } while (req->nr_pages < n); |
| |
| if (req->nr_pages == 0) { |
| kfree(req); |
| return 0; |
| } |
| |
| ret = afs_fetch_data(vnode, key, req); |
| if (ret < 0) |
| goto error; |
| |
| task_io_account_read(PAGE_SIZE * req->nr_pages); |
| afs_put_read(req); |
| return 0; |
| |
| error: |
| if (ret == -ENOENT) { |
| _debug("got NOENT from server" |
| " - marking file deleted and stale"); |
| set_bit(AFS_VNODE_DELETED, &vnode->flags); |
| ret = -ESTALE; |
| } |
| |
| for (i = 0; i < req->nr_pages; i++) { |
| page = req->pages[i]; |
| if (page) { |
| #ifdef CONFIG_AFS_FSCACHE |
| fscache_uncache_page(vnode->cache, page); |
| #endif |
| SetPageError(page); |
| unlock_page(page); |
| } |
| } |
| |
| afs_put_read(req); |
| return ret; |
| } |
| |
| /* |
| * read a set of pages |
| */ |
| static int afs_readpages(struct file *file, struct address_space *mapping, |
| struct list_head *pages, unsigned nr_pages) |
| { |
| struct key *key = afs_file_key(file); |
| struct afs_vnode *vnode; |
| int ret = 0; |
| |
| _enter("{%d},{%lu},,%d", |
| key_serial(key), mapping->host->i_ino, nr_pages); |
| |
| ASSERT(key != NULL); |
| |
| vnode = AFS_FS_I(mapping->host); |
| if (test_bit(AFS_VNODE_DELETED, &vnode->flags)) { |
| _leave(" = -ESTALE"); |
| return -ESTALE; |
| } |
| |
| /* attempt to read as many of the pages as possible */ |
| #ifdef CONFIG_AFS_FSCACHE |
| ret = fscache_read_or_alloc_pages(vnode->cache, |
| mapping, |
| pages, |
| &nr_pages, |
| afs_file_readpage_read_complete, |
| NULL, |
| mapping_gfp_mask(mapping)); |
| #else |
| ret = -ENOBUFS; |
| #endif |
| |
| switch (ret) { |
| /* all pages are being read from the cache */ |
| case 0: |
| BUG_ON(!list_empty(pages)); |
| BUG_ON(nr_pages != 0); |
| _leave(" = 0 [reading all]"); |
| return 0; |
| |
| /* there were pages that couldn't be read from the cache */ |
| case -ENODATA: |
| case -ENOBUFS: |
| break; |
| |
| /* other error */ |
| default: |
| _leave(" = %d", ret); |
| return ret; |
| } |
| |
| while (!list_empty(pages)) { |
| ret = afs_readpages_one(file, mapping, pages); |
| if (ret < 0) |
| break; |
| } |
| |
| _leave(" = %d [netting]", ret); |
| return ret; |
| } |
| |
| /* |
| * Adjust the dirty region of the page on truncation or full invalidation, |
| * getting rid of the markers altogether if the region is entirely invalidated. |
| */ |
| static void afs_invalidate_dirty(struct page *page, unsigned int offset, |
| unsigned int length) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); |
| unsigned long priv; |
| unsigned int f, t, end = offset + length; |
| |
| priv = page_private(page); |
| |
| /* we clean up only if the entire page is being invalidated */ |
| if (offset == 0 && length == thp_size(page)) |
| goto full_invalidate; |
| |
| /* If the page was dirtied by page_mkwrite(), the PTE stays writable |
| * and we don't get another notification to tell us to expand it |
| * again. |
| */ |
| if (afs_is_page_dirty_mmapped(priv)) |
| return; |
| |
| /* We may need to shorten the dirty region */ |
| f = afs_page_dirty_from(priv); |
| t = afs_page_dirty_to(priv); |
| |
| if (t <= offset || f >= end) |
| return; /* Doesn't overlap */ |
| |
| if (f < offset && t > end) |
| return; /* Splits the dirty region - just absorb it */ |
| |
| if (f >= offset && t <= end) |
| goto undirty; |
| |
| if (f < offset) |
| t = offset; |
| else |
| f = end; |
| if (f == t) |
| goto undirty; |
| |
| priv = afs_page_dirty(f, t); |
| set_page_private(page, priv); |
| trace_afs_page_dirty(vnode, tracepoint_string("trunc"), page->index, priv); |
| return; |
| |
| undirty: |
| trace_afs_page_dirty(vnode, tracepoint_string("undirty"), page->index, priv); |
| clear_page_dirty_for_io(page); |
| full_invalidate: |
| priv = (unsigned long)detach_page_private(page); |
| trace_afs_page_dirty(vnode, tracepoint_string("inval"), page->index, priv); |
| } |
| |
| /* |
| * invalidate part or all of a page |
| * - release a page and clean up its private data if offset is 0 (indicating |
| * the entire page) |
| */ |
| static void afs_invalidatepage(struct page *page, unsigned int offset, |
| unsigned int length) |
| { |
| _enter("{%lu},%u,%u", page->index, offset, length); |
| |
| BUG_ON(!PageLocked(page)); |
| |
| #ifdef CONFIG_AFS_FSCACHE |
| /* we clean up only if the entire page is being invalidated */ |
| if (offset == 0 && length == PAGE_SIZE) { |
| if (PageFsCache(page)) { |
| struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); |
| fscache_wait_on_page_write(vnode->cache, page); |
| fscache_uncache_page(vnode->cache, page); |
| } |
| } |
| #endif |
| |
| if (PagePrivate(page)) |
| afs_invalidate_dirty(page, offset, length); |
| |
| _leave(""); |
| } |
| |
| /* |
| * release a page and clean up its private state if it's not busy |
| * - return true if the page can now be released, false if not |
| */ |
| static int afs_releasepage(struct page *page, gfp_t gfp_flags) |
| { |
| struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); |
| unsigned long priv; |
| |
| _enter("{{%llx:%llu}[%lu],%lx},%x", |
| vnode->fid.vid, vnode->fid.vnode, page->index, page->flags, |
| gfp_flags); |
| |
| /* deny if page is being written to the cache and the caller hasn't |
| * elected to wait */ |
| #ifdef CONFIG_AFS_FSCACHE |
| if (!fscache_maybe_release_page(vnode->cache, page, gfp_flags)) { |
| _leave(" = F [cache busy]"); |
| return 0; |
| } |
| #endif |
| |
| if (PagePrivate(page)) { |
| priv = (unsigned long)detach_page_private(page); |
| trace_afs_page_dirty(vnode, tracepoint_string("rel"), |
| page->index, priv); |
| } |
| |
| /* indicate that the page can be released */ |
| _leave(" = T"); |
| return 1; |
| } |
| |
| /* |
| * Handle setting up a memory mapping on an AFS file. |
| */ |
| static int afs_file_mmap(struct file *file, struct vm_area_struct *vma) |
| { |
| int ret; |
| |
| ret = generic_file_mmap(file, vma); |
| if (ret == 0) |
| vma->vm_ops = &afs_vm_ops; |
| return ret; |
| } |