1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * This file contians vfs address (mmap) ops for 9P2000. 4 * 5 * Copyright (C) 2005 by Eric Van Hensbergen <ericvh@gmail.com> 6 * Copyright (C) 2002 by Ron Minnich <rminnich@lanl.gov> 7 */ 8 9 #include <linux/module.h> 10 #include <linux/errno.h> 11 #include <linux/fs.h> 12 #include <linux/file.h> 13 #include <linux/stat.h> 14 #include <linux/string.h> 15 #include <linux/pagemap.h> 16 #include <linux/sched.h> 17 #include <linux/swap.h> 18 #include <linux/uio.h> 19 #include <linux/netfs.h> 20 #include <net/9p/9p.h> 21 #include <net/9p/client.h> 22 #include <trace/events/netfs.h> 23 24 #include "v9fs.h" 25 #include "v9fs_vfs.h" 26 #include "cache.h" 27 #include "fid.h" 28 29 /* 30 * Writeback calls this when it finds a folio that needs uploading. This isn't 31 * called if writeback only has copy-to-cache to deal with. 32 */ 33 static void v9fs_begin_writeback(struct netfs_io_request *wreq) 34 { 35 struct p9_fid *fid; 36 37 fid = v9fs_fid_find_inode(wreq->inode, true, INVALID_UID, true); 38 if (!fid) { 39 WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n", 40 wreq->inode->i_ino); 41 return; 42 } 43 44 wreq->wsize = fid->clnt->msize - P9_IOHDRSZ; 45 if (fid->iounit) 46 wreq->wsize = min(wreq->wsize, fid->iounit); 47 wreq->netfs_priv = fid; 48 wreq->io_streams[0].avail = true; 49 } 50 51 /* 52 * Issue a subrequest to write to the server. 53 */ 54 static void v9fs_issue_write(struct netfs_io_subrequest *subreq) 55 { 56 struct p9_fid *fid = subreq->rreq->netfs_priv; 57 int err, len; 58 59 len = p9_client_write(fid, subreq->start, &subreq->io_iter, &err); 60 netfs_write_subrequest_terminated(subreq, len ?: err, false); 61 } 62 63 /** 64 * v9fs_issue_read - Issue a read from 9P 65 * @subreq: The read to make 66 */ 67 static void v9fs_issue_read(struct netfs_io_subrequest *subreq) 68 { 69 struct netfs_io_request *rreq = subreq->rreq; 70 struct p9_fid *fid = rreq->netfs_priv; 71 unsigned long long pos = subreq->start + subreq->transferred; 72 int total, err; 73 74 total = p9_client_read(fid, pos, &subreq->io_iter, &err); 75 76 /* if we just extended the file size, any portion not in 77 * cache won't be on server and is zeroes */ 78 if (subreq->rreq->origin != NETFS_DIO_READ) 79 __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); 80 if (pos + total >= i_size_read(rreq->inode)) 81 __set_bit(NETFS_SREQ_HIT_EOF, &subreq->flags); 82 83 if (!err) 84 subreq->transferred += total; 85 86 netfs_read_subreq_terminated(subreq, err, false); 87 } 88 89 /** 90 * v9fs_init_request - Initialise a request 91 * @rreq: The read request 92 * @file: The file being read from 93 */ 94 static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file) 95 { 96 struct p9_fid *fid; 97 bool writing = (rreq->origin == NETFS_READ_FOR_WRITE || 98 rreq->origin == NETFS_WRITETHROUGH || 99 rreq->origin == NETFS_UNBUFFERED_WRITE || 100 rreq->origin == NETFS_DIO_WRITE); 101 102 if (rreq->origin == NETFS_WRITEBACK) 103 return 0; /* We don't get the write handle until we find we 104 * have actually dirty data and not just 105 * copy-to-cache data. 106 */ 107 108 if (file) { 109 fid = file->private_data; 110 if (!fid) 111 goto no_fid; 112 p9_fid_get(fid); 113 } else { 114 fid = v9fs_fid_find_inode(rreq->inode, writing, INVALID_UID, true); 115 if (!fid) 116 goto no_fid; 117 } 118 119 rreq->wsize = fid->clnt->msize - P9_IOHDRSZ; 120 if (fid->iounit) 121 rreq->wsize = min(rreq->wsize, fid->iounit); 122 123 /* we might need to read from a fid that was opened write-only 124 * for read-modify-write of page cache, use the writeback fid 125 * for that */ 126 WARN_ON(rreq->origin == NETFS_READ_FOR_WRITE && !(fid->mode & P9_ORDWR)); 127 rreq->netfs_priv = fid; 128 return 0; 129 130 no_fid: 131 WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n", 132 rreq->inode->i_ino); 133 return -EINVAL; 134 } 135 136 /** 137 * v9fs_free_request - Cleanup request initialized by v9fs_init_rreq 138 * @rreq: The I/O request to clean up 139 */ 140 static void v9fs_free_request(struct netfs_io_request *rreq) 141 { 142 struct p9_fid *fid = rreq->netfs_priv; 143 144 p9_fid_put(fid); 145 } 146 147 const struct netfs_request_ops v9fs_req_ops = { 148 .init_request = v9fs_init_request, 149 .free_request = v9fs_free_request, 150 .issue_read = v9fs_issue_read, 151 .begin_writeback = v9fs_begin_writeback, 152 .issue_write = v9fs_issue_write, 153 }; 154 155 const struct address_space_operations v9fs_addr_operations = { 156 .read_folio = netfs_read_folio, 157 .readahead = netfs_readahead, 158 .dirty_folio = netfs_dirty_folio, 159 .release_folio = netfs_release_folio, 160 .invalidate_folio = netfs_invalidate_folio, 161 .direct_IO = noop_direct_IO, 162 .writepages = netfs_writepages, 163 }; 164