fs/9p/vfs_addr.c

   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 static void v9fs_upload_to_server(struct netfs_io_subrequest *subreq)
  30 {
  31         struct p9_fid *fid = subreq->rreq->netfs_priv;
  32         int err, len;
  33
  34         trace_netfs_sreq(subreq, netfs_sreq_trace_submit);
  35         len = p9_client_write(fid, subreq->start, &subreq->io_iter, &err);
  36         netfs_write_subrequest_terminated(subreq, len ?: err, false);
  37 }
  38
  39 static void v9fs_upload_to_server_worker(struct work_struct *work)
  40 {
  41         struct netfs_io_subrequest *subreq =
  42                 container_of(work, struct netfs_io_subrequest, work);
  43
  44         v9fs_upload_to_server(subreq);
  45 }
  46
  47 /*
  48  * Set up write requests for a writeback slice.  We need to add a write request
  49  * for each write we want to make.
  50  */
  51 static void v9fs_create_write_requests(struct netfs_io_request *wreq, loff_t start, size_t len)
  52 {
  53         struct netfs_io_subrequest *subreq;
  54
  55         subreq = netfs_create_write_request(wreq, NETFS_UPLOAD_TO_SERVER,
  56                                             start, len, v9fs_upload_to_server_worker);
  57         if (subreq)
  58                 netfs_queue_write_request(subreq);
  59 }
  60
  61 /**
  62  * v9fs_issue_read - Issue a read from 9P
  63  * @subreq: The read to make
  64  */
  65 static void v9fs_issue_read(struct netfs_io_subrequest *subreq)
  66 {
  67         struct netfs_io_request *rreq = subreq->rreq;
  68         struct p9_fid *fid = rreq->netfs_priv;
  69         int total, err;
  70
  71         total = p9_client_read(fid, subreq->start + subreq->transferred,
  72                                &subreq->io_iter, &err);
  73
  74         /* if we just extended the file size, any portion not in
  75          * cache won't be on server and is zeroes */
  76         __set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags);
  77
  78         netfs_subreq_terminated(subreq, err ?: total, false);
  79 }
  80
  81 /**
  82  * v9fs_init_request - Initialise a request
  83  * @rreq: The read request
  84  * @file: The file being read from
  85  */
  86 static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file)
  87 {
  88         struct p9_fid *fid;
  89         bool writing = (rreq->origin == NETFS_READ_FOR_WRITE ||
  90                         rreq->origin == NETFS_WRITEBACK ||
  91                         rreq->origin == NETFS_WRITETHROUGH ||
  92                         rreq->origin == NETFS_LAUNDER_WRITE ||
  93                         rreq->origin == NETFS_UNBUFFERED_WRITE ||
  94                         rreq->origin == NETFS_DIO_WRITE);
  95
  96         if (file) {
  97                 fid = file->private_data;
  98                 if (!fid)
  99                         goto no_fid;
 100                 p9_fid_get(fid);
 101         } else {
 102                 fid = v9fs_fid_find_inode(rreq->inode, writing, INVALID_UID, true);
 103                 if (!fid)
 104                         goto no_fid;
 105         }
 106
 107         /* we might need to read from a fid that was opened write-only
 108          * for read-modify-write of page cache, use the writeback fid
 109          * for that */
 110         WARN_ON(rreq->origin == NETFS_READ_FOR_WRITE && !(fid->mode & P9_ORDWR));
 111         rreq->netfs_priv = fid;
 112         return 0;
 113
 114 no_fid:
 115         WARN_ONCE(1, "folio expected an open fid inode->i_ino=%lx\n",
 116                   rreq->inode->i_ino);
 117         return -EINVAL;
 118 }
 119
 120 /**
 121  * v9fs_free_request - Cleanup request initialized by v9fs_init_rreq
 122  * @rreq: The I/O request to clean up
 123  */
 124 static void v9fs_free_request(struct netfs_io_request *rreq)
 125 {
 126         struct p9_fid *fid = rreq->netfs_priv;
 127
 128         p9_fid_put(fid);
 129 }
 130
 131 const struct netfs_request_ops v9fs_req_ops = {
 132         .init_request           = v9fs_init_request,
 133         .free_request           = v9fs_free_request,
 134         .issue_read             = v9fs_issue_read,
 135         .create_write_requests  = v9fs_create_write_requests,
 136 };
 137
 138 const struct address_space_operations v9fs_addr_operations = {
 139         .read_folio             = netfs_read_folio,
 140         .readahead              = netfs_readahead,
 141         .dirty_folio            = netfs_dirty_folio,
 142         .release_folio          = netfs_release_folio,
 143         .invalidate_folio       = netfs_invalidate_folio,
 144         .launder_folio          = netfs_launder_folio,
 145         .direct_IO              = noop_direct_IO,
 146         .writepages             = netfs_writepages,
 147 };