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![Linus Torvalds](/assets/img/avatar_default.png)
- fix possible uninitialized memory usage for setattr - fix fscache reading hole in a file just after it's been grown - split net/9p/trans_fd.c in its own module like other transports that module defaults to 9P_NET and is autoloaded if required so users should not be impacted - add Christian Schoenebeck to 9p reviewers - some more trivial cleanup -----BEGIN PGP SIGNATURE----- iQIzBAABCAAdFiEE/IPbcYBuWt0zoYhOq06b7GqY5nAFAmHgt18ACgkQq06b7GqY 5nAdUA//ZHFTIcnbTiVkqbw0YztxedTOhdGCWcYsszux0pNQ/ZCjbP5NxESWiFxs raYWcvE98Xvq4fbs8b+m7YKBJzWF+Km/v1MKfgvZZWFLZR3MfWiL8iojlsaUgG9U rBmEUyaTWw2COIvFN7EqnwT5mwzNCli5d3AzaAmgffWsHEi/+EVU35YX70ySUkjW nVf08oX3dBB425oArXOZApOZSVRsUr5YDSuQGiFHBL+hvPTrvPumu/AXbjLbTbmf NuUxu1Akw8/jhWNATLHzjCdzJzBSfF0zRs+oH9Qt8MKkUrlTfjxc/2MbQYL1p1IN 84XxiG02ebw+Mx05cydP9/Ll7gOo2p6ORGXMHcoPIAMy6zFiCKo3TRdKDgmYDauC K8c3v+osNwl2GFn1+2XoQIWnqXb7bJ1debkFtWVEGOPd/Yr6CYCZyfiZamoPJXUO TjkoLAJXJGKlV66ZCuVeAsySdUxdtwbj2WxTliDUWtxvQ+m1jt06S3f/TbA7a9bB 8aBhx7FKzQ/UL8zhm4+3WLPlWkoSUXhFSZZUknvhuaHFV/S1xglXox5OAQJrJMy+ qOzmOjCg14T1TC2WkJlEsedLUH8ACU+XueAPT6uqSdA4rvQEVzk32zTm/GfFu3Q3 0RhcGlW5kAAYBTBLXvmKsjyW2OmPCSycgbWCu3E8A/1gubbRE40= =o2Lc -----END PGP SIGNATURE----- Merge tag '9p-for-5.17-rc1' of git://github.com/martinetd/linux Pull 9p updates from Dominique Martinet: "Fixes, split 9p_net_fd, and new reviewer: - fix possible uninitialized memory usage for setattr - fix fscache reading hole in a file just after it's been grown - split net/9p/trans_fd.c in its own module like other transports. The new transport module defaults to 9P_NET and is autoloaded if required so users should not be impacted - add Christian Schoenebeck to 9p reviewers - some more trivial cleanup" * tag '9p-for-5.17-rc1' of git://github.com/martinetd/linux: 9p: fix enodata when reading growing file net/9p: show error message if user 'msize' cannot be satisfied MAINTAINERS: 9p: add Christian Schoenebeck as reviewer 9p: only copy valid iattrs in 9P2000.L setattr implementation 9p: Use BUG_ON instead of if condition followed by BUG. net/p9: load default transports 9p/xen: autoload when xenbus service is available 9p/trans_fd: split into dedicated module fs: 9p: remove unneeded variable 9p/trans_virtio: Fix typo in the comment for p9_virtio_create()
400 lines
10 KiB
C
400 lines
10 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* This file contians vfs address (mmap) ops for 9P2000.
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*
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* Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com>
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* Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov>
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*/
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#include <linux/module.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/stat.h>
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#include <linux/string.h>
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#include <linux/inet.h>
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#include <linux/pagemap.h>
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#include <linux/idr.h>
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#include <linux/sched.h>
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#include <linux/swap.h>
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#include <linux/uio.h>
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#include <linux/netfs.h>
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#include <net/9p/9p.h>
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#include <net/9p/client.h>
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#include "v9fs.h"
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#include "v9fs_vfs.h"
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#include "cache.h"
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#include "fid.h"
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/**
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* v9fs_req_issue_op - Issue a read from 9P
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* @subreq: The read to make
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*/
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static void v9fs_req_issue_op(struct netfs_read_subrequest *subreq)
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{
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struct netfs_read_request *rreq = subreq->rreq;
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struct p9_fid *fid = rreq->netfs_priv;
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struct iov_iter to;
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loff_t pos = subreq->start + subreq->transferred;
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size_t len = subreq->len - subreq->transferred;
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int total, err;
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iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len);
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total = p9_client_read(fid, pos, &to, &err);
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/* if we just extended the file size, any portion not in
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* cache won't be on server and is zeroes */
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__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
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netfs_subreq_terminated(subreq, err ?: total, false);
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}
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/**
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* v9fs_init_rreq - Initialise a read request
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* @rreq: The read request
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* @file: The file being read from
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*/
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static void v9fs_init_rreq(struct netfs_read_request *rreq, struct file *file)
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{
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struct p9_fid *fid = file->private_data;
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refcount_inc(&fid->count);
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rreq->netfs_priv = fid;
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}
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/**
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* v9fs_req_cleanup - Cleanup request initialized by v9fs_init_rreq
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* @mapping: unused mapping of request to cleanup
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* @priv: private data to cleanup, a fid, guaranted non-null.
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*/
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static void v9fs_req_cleanup(struct address_space *mapping, void *priv)
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{
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struct p9_fid *fid = priv;
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p9_client_clunk(fid);
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}
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/**
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* v9fs_is_cache_enabled - Determine if caching is enabled for an inode
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* @inode: The inode to check
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*/
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static bool v9fs_is_cache_enabled(struct inode *inode)
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{
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struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(inode));
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return fscache_cookie_enabled(cookie) && cookie->cache_priv;
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}
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/**
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* v9fs_begin_cache_operation - Begin a cache operation for a read
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* @rreq: The read request
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*/
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static int v9fs_begin_cache_operation(struct netfs_read_request *rreq)
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{
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#ifdef CONFIG_9P_FSCACHE
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struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode));
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return fscache_begin_read_operation(&rreq->cache_resources, cookie);
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#else
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return -ENOBUFS;
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#endif
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}
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static const struct netfs_read_request_ops v9fs_req_ops = {
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.init_rreq = v9fs_init_rreq,
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.is_cache_enabled = v9fs_is_cache_enabled,
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.begin_cache_operation = v9fs_begin_cache_operation,
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.issue_op = v9fs_req_issue_op,
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.cleanup = v9fs_req_cleanup,
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};
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/**
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* v9fs_vfs_readpage - read an entire page in from 9P
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* @file: file being read
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* @page: structure to page
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*
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*/
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static int v9fs_vfs_readpage(struct file *file, struct page *page)
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{
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struct folio *folio = page_folio(page);
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return netfs_readpage(file, folio, &v9fs_req_ops, NULL);
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}
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/**
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* v9fs_vfs_readahead - read a set of pages from 9P
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* @ractl: The readahead parameters
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*/
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static void v9fs_vfs_readahead(struct readahead_control *ractl)
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{
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netfs_readahead(ractl, &v9fs_req_ops, NULL);
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}
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/**
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* v9fs_release_page - release the private state associated with a page
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* @page: The page to be released
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* @gfp: The caller's allocation restrictions
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*
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* Returns 1 if the page can be released, false otherwise.
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*/
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static int v9fs_release_page(struct page *page, gfp_t gfp)
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{
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struct folio *folio = page_folio(page);
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struct inode *inode = folio_inode(folio);
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if (folio_test_private(folio))
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return 0;
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#ifdef CONFIG_9P_FSCACHE
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if (folio_test_fscache(folio)) {
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if (current_is_kswapd() || !(gfp & __GFP_FS))
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return 0;
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folio_wait_fscache(folio);
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}
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#endif
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fscache_note_page_release(v9fs_inode_cookie(V9FS_I(inode)));
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return 1;
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}
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/**
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* v9fs_invalidate_page - Invalidate a page completely or partially
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* @page: The page to be invalidated
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* @offset: offset of the invalidated region
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* @length: length of the invalidated region
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*/
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static void v9fs_invalidate_page(struct page *page, unsigned int offset,
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unsigned int length)
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{
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struct folio *folio = page_folio(page);
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folio_wait_fscache(folio);
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}
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static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error,
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bool was_async)
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{
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struct v9fs_inode *v9inode = priv;
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__le32 version;
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if (IS_ERR_VALUE(transferred_or_error) &&
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transferred_or_error != -ENOBUFS) {
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version = cpu_to_le32(v9inode->qid.version);
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fscache_invalidate(v9fs_inode_cookie(v9inode), &version,
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i_size_read(&v9inode->vfs_inode), 0);
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}
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}
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static int v9fs_vfs_write_folio_locked(struct folio *folio)
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{
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struct inode *inode = folio_inode(folio);
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struct v9fs_inode *v9inode = V9FS_I(inode);
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struct fscache_cookie *cookie = v9fs_inode_cookie(v9inode);
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loff_t start = folio_pos(folio);
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loff_t i_size = i_size_read(inode);
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struct iov_iter from;
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size_t len = folio_size(folio);
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int err;
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if (start >= i_size)
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return 0; /* Simultaneous truncation occurred */
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len = min_t(loff_t, i_size - start, len);
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iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len);
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/* We should have writeback_fid always set */
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BUG_ON(!v9inode->writeback_fid);
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folio_wait_fscache(folio);
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folio_start_writeback(folio);
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p9_client_write(v9inode->writeback_fid, start, &from, &err);
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if (err == 0 &&
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fscache_cookie_enabled(cookie) &&
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test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) {
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folio_start_fscache(folio);
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fscache_write_to_cache(v9fs_inode_cookie(v9inode),
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folio_mapping(folio), start, len, i_size,
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v9fs_write_to_cache_done, v9inode,
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true);
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}
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folio_end_writeback(folio);
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return err;
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}
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static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc)
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{
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struct folio *folio = page_folio(page);
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int retval;
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p9_debug(P9_DEBUG_VFS, "folio %p\n", folio);
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retval = v9fs_vfs_write_folio_locked(folio);
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if (retval < 0) {
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if (retval == -EAGAIN) {
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folio_redirty_for_writepage(wbc, folio);
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retval = 0;
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} else {
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mapping_set_error(folio_mapping(folio), retval);
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}
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} else
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retval = 0;
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folio_unlock(folio);
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return retval;
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}
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/**
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* v9fs_launder_page - Writeback a dirty page
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* @page: The page to be cleaned up
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*
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* Returns 0 on success.
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*/
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static int v9fs_launder_page(struct page *page)
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{
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struct folio *folio = page_folio(page);
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int retval;
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if (folio_clear_dirty_for_io(folio)) {
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retval = v9fs_vfs_write_folio_locked(folio);
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if (retval)
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return retval;
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}
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folio_wait_fscache(folio);
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return 0;
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}
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/**
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* v9fs_direct_IO - 9P address space operation for direct I/O
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* @iocb: target I/O control block
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* @iter: The data/buffer to use
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*
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* The presence of v9fs_direct_IO() in the address space ops vector
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* allowes open() O_DIRECT flags which would have failed otherwise.
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*
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* In the non-cached mode, we shunt off direct read and write requests before
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* the VFS gets them, so this method should never be called.
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*
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* Direct IO is not 'yet' supported in the cached mode. Hence when
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* this routine is called through generic_file_aio_read(), the read/write fails
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* with an error.
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*
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*/
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static ssize_t
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v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
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{
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struct file *file = iocb->ki_filp;
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loff_t pos = iocb->ki_pos;
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ssize_t n;
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int err = 0;
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if (iov_iter_rw(iter) == WRITE) {
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n = p9_client_write(file->private_data, pos, iter, &err);
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if (n) {
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struct inode *inode = file_inode(file);
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loff_t i_size = i_size_read(inode);
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if (pos + n > i_size)
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inode_add_bytes(inode, pos + n - i_size);
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}
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} else {
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n = p9_client_read(file->private_data, pos, iter, &err);
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}
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return n ? n : err;
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}
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static int v9fs_write_begin(struct file *filp, struct address_space *mapping,
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loff_t pos, unsigned int len, unsigned int flags,
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struct page **subpagep, void **fsdata)
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{
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int retval;
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struct folio *folio;
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struct v9fs_inode *v9inode = V9FS_I(mapping->host);
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p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
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BUG_ON(!v9inode->writeback_fid);
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/* Prefetch area to be written into the cache if we're caching this
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* file. We need to do this before we get a lock on the page in case
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* there's more than one writer competing for the same cache block.
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*/
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retval = netfs_write_begin(filp, mapping, pos, len, flags, &folio, fsdata,
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&v9fs_req_ops, NULL);
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if (retval < 0)
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return retval;
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*subpagep = &folio->page;
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return retval;
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}
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static int v9fs_write_end(struct file *filp, struct address_space *mapping,
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loff_t pos, unsigned int len, unsigned int copied,
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struct page *subpage, void *fsdata)
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{
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loff_t last_pos = pos + copied;
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struct folio *folio = page_folio(subpage);
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struct inode *inode = mapping->host;
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struct v9fs_inode *v9inode = V9FS_I(inode);
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p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping);
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if (!folio_test_uptodate(folio)) {
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if (unlikely(copied < len)) {
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copied = 0;
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goto out;
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}
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folio_mark_uptodate(folio);
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}
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/*
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* No need to use i_size_read() here, the i_size
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* cannot change under us because we hold the i_mutex.
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*/
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if (last_pos > inode->i_size) {
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inode_add_bytes(inode, last_pos - inode->i_size);
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i_size_write(inode, last_pos);
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fscache_update_cookie(v9fs_inode_cookie(v9inode), NULL, &last_pos);
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}
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folio_mark_dirty(folio);
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out:
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folio_unlock(folio);
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folio_put(folio);
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return copied;
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}
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#ifdef CONFIG_9P_FSCACHE
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/*
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* Mark a page as having been made dirty and thus needing writeback. We also
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* need to pin the cache object to write back to.
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*/
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static int v9fs_set_page_dirty(struct page *page)
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{
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struct v9fs_inode *v9inode = V9FS_I(page->mapping->host);
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return fscache_set_page_dirty(page, v9fs_inode_cookie(v9inode));
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}
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#else
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#define v9fs_set_page_dirty __set_page_dirty_nobuffers
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#endif
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const struct address_space_operations v9fs_addr_operations = {
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.readpage = v9fs_vfs_readpage,
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.readahead = v9fs_vfs_readahead,
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.set_page_dirty = v9fs_set_page_dirty,
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.writepage = v9fs_vfs_writepage,
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.write_begin = v9fs_write_begin,
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.write_end = v9fs_write_end,
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.releasepage = v9fs_release_page,
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.invalidatepage = v9fs_invalidate_page,
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.launder_page = v9fs_launder_page,
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.direct_IO = v9fs_direct_IO,
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};
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