/* 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 <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/slab.h> #include <linux/fs.h> #include <linux/pagemap.h> #include <linux/writeback.h> #include "internal.h" static int afs_readpage(struct file *file, struct page *page); static void afs_invalidatepage(struct page *page, unsigned long offset); static int afs_releasepage(struct page *page, gfp_t gfp_flags); static int afs_launder_page(struct page *page); 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 = do_sync_read, .write = do_sync_write, .aio_read = generic_file_aio_read, .aio_write = afs_file_write, .mmap = generic_file_readonly_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, }; 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, }; /* * 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 key *key; int ret; _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode); key = afs_request_key(vnode->volume->cell); if (IS_ERR(key)) { _leave(" = %ld [key]", PTR_ERR(key)); return PTR_ERR(key); } ret = afs_validate(vnode, key); if (ret < 0) { _leave(" = %d [val]", ret); return ret; } file->private_data = key; _leave(" = 0"); return 0; } /* * 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); _enter("{%x:%u},", vnode->fid.vid, vnode->fid.vnode); key_put(file->private_data); _leave(" = 0"); return 0; } /* * 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); } /* * AFS read page from file, directory or symlink */ static int afs_readpage(struct file *file, struct page *page) { struct afs_vnode *vnode; struct inode *inode; struct key *key; size_t len; off_t offset; int ret; inode = page->mapping->host; ASSERT(file != NULL); key = file->private_data; ASSERT(key != NULL); _enter("{%x},{%lu},{%lu}", key_serial(key), inode->i_ino, page->index); vnode = AFS_FS_I(inode); 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: offset = page->index << PAGE_CACHE_SHIFT; len = min_t(size_t, i_size_read(inode) - offset, PAGE_SIZE); /* read the contents of the file from the server into the * page */ ret = afs_vnode_fetch_data(vnode, key, offset, len, page); 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)); goto error; } SetPageUptodate(page); /* send the page to the cache */ #ifdef CONFIG_AFS_FSCACHE if (PageFsCache(page) && fscache_write_page(vnode->cache, page, GFP_KERNEL) != 0) { fscache_uncache_page(vnode->cache, page); BUG_ON(PageFsCache(page)); } #endif unlock_page(page); } _leave(" = 0"); return 0; error: SetPageError(page); unlock_page(page); _leave(" = %d", ret); 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 afs_vnode *vnode; int ret = 0; _enter(",{%lu},,%d", mapping->host->i_ino, nr_pages); vnode = AFS_FS_I(mapping->host); if (vnode->flags & AFS_VNODE_DELETED) { _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; } /* load the missing pages from the network */ ret = read_cache_pages(mapping, pages, (void *) afs_readpage, file); _leave(" = %d [netting]", ret); return ret; } /* * write back a dirty page */ static int afs_launder_page(struct page *page) { _enter("{%lu}", page->index); return 0; } /* * 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 long offset) { struct afs_writeback *wb = (struct afs_writeback *) page_private(page); _enter("{%lu},%lu", page->index, offset); BUG_ON(!PageLocked(page)); /* we clean up only if the entire page is being invalidated */ if (offset == 0) { #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); ClearPageFsCache(page); } #endif if (PagePrivate(page)) { if (wb && !PageWriteback(page)) { set_page_private(page, 0); afs_put_writeback(wb); } if (!page_private(page)) 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_writeback *wb = (struct afs_writeback *) page_private(page); struct afs_vnode *vnode = AFS_FS_I(page->mapping->host); _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 (PageFsCache(page)) { if (fscache_check_page_write(vnode->cache, page)) { if (!(gfp_flags & __GFP_WAIT)) { _leave(" = F [cache busy]"); return 0; } fscache_wait_on_page_write(vnode->cache, page); } fscache_uncache_page(vnode->cache, page); ClearPageFsCache(page); } #endif if (PagePrivate(page)) { if (wb) { set_page_private(page, 0); afs_put_writeback(wb); } ClearPagePrivate(page); } /* indicate that the page can be released */ _leave(" = T"); return 1; }