/* AFS filesystem file handling * * Copyright (C) 2002, 2007 Red Hat, Inc. All Rights Reserved. * Written by David Howells (dhowells@redhat.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version * 2 of the License, or (at your option) any later version. */ #include #include #include #include #include #include #include #include #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, .flush = afs_flush, .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, .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, .listxattr = afs_listxattr, }; 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 (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("{%x:%u},", 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; } 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; _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode); 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(" = 0"); return 0; } /* * 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)) { 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 /* * Fetch file data from the volume. */ int afs_fetch_data(struct afs_vnode *vnode, struct key *key, struct afs_read *desc) { struct afs_fs_cursor fc; int ret; _enter("%s{%x:%u.%u},%x,,,", vnode->volume->name, vnode->fid.vid, vnode->fid.vnode, vnode->fid.unique, key_serial(key)); ret = -ERESTARTSYS; if (afs_begin_vnode_operation(&fc, vnode, key)) { while (afs_select_fileserver(&fc)) { fc.cb_break = vnode->cb_break + vnode->cb_s_break; afs_fs_fetch_data(&fc, desc); } afs_check_for_remote_deletion(&fc, fc.vnode); afs_vnode_commit_status(&fc, vnode, fc.cb_break); ret = afs_end_vnode_operation(&fc); } _leave(" = %d", ret); return ret; } /* * 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"); default: go_on: req = kzalloc(sizeof(struct afs_read) + sizeof(struct page *), 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_call *call, struct afs_read *req) { #ifdef CONFIG_AFS_FSCACHE struct afs_vnode *vnode = call->reply[0]; #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 = list_entry(pages->prev, struct page, lru); 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(sizeof(struct afs_read) + sizeof(struct page *) * n, GFP_NOFS); if (!req) return -ENOMEM; refcount_set(&req->usage, 1); 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 = list_entry(pages->prev, struct page, lru); 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; } /* * 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) { struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); unsigned long priv; _enter("{%lu},%u,%u", page->index, offset, length); BUG_ON(!PageLocked(page)); /* we clean up only if the entire page is being invalidated */ if (offset == 0 && length == PAGE_SIZE) { #ifdef CONFIG_AFS_FSCACHE 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)) { priv = page_private(page); trace_afs_page_dirty(vnode, tracepoint_string("inval"), page->index, priv); set_page_private(page, 0); ClearPagePrivate(page); } } _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("{{%x:%u}[%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 = page_private(page); trace_afs_page_dirty(vnode, tracepoint_string("rel"), page->index, priv); set_page_private(page, 0); ClearPagePrivate(page); } /* 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; }