mirror of https://github.com/Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
360 lines
9.3 KiB
360 lines
9.3 KiB
// SPDX-License-Identifier: GPL-2.0-only |
|
/* |
|
* This file contians vfs address (mmap) ops for 9P2000. |
|
* |
|
* Copyright (C) 2005 by Eric Van Hensbergen <[email protected]> |
|
* Copyright (C) 2002 by Ron Minnich <[email protected]> |
|
*/ |
|
|
|
#include <linux/module.h> |
|
#include <linux/errno.h> |
|
#include <linux/fs.h> |
|
#include <linux/file.h> |
|
#include <linux/stat.h> |
|
#include <linux/string.h> |
|
#include <linux/inet.h> |
|
#include <linux/pagemap.h> |
|
#include <linux/idr.h> |
|
#include <linux/sched.h> |
|
#include <linux/swap.h> |
|
#include <linux/uio.h> |
|
#include <linux/netfs.h> |
|
#include <net/9p/9p.h> |
|
#include <net/9p/client.h> |
|
|
|
#include "v9fs.h" |
|
#include "v9fs_vfs.h" |
|
#include "cache.h" |
|
#include "fid.h" |
|
|
|
/** |
|
* v9fs_issue_read - Issue a read from 9P |
|
* @subreq: The read to make |
|
*/ |
|
static void v9fs_issue_read(struct netfs_io_subrequest *subreq) |
|
{ |
|
struct netfs_io_request *rreq = subreq->rreq; |
|
struct p9_fid *fid = rreq->netfs_priv; |
|
struct iov_iter to; |
|
loff_t pos = subreq->start + subreq->transferred; |
|
size_t len = subreq->len - subreq->transferred; |
|
int total, err; |
|
|
|
iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len); |
|
|
|
total = p9_client_read(fid, pos, &to, &err); |
|
|
|
/* if we just extended the file size, any portion not in |
|
* cache won't be on server and is zeroes */ |
|
__set_bit(NETFS_SREQ_CLEAR_TAIL, &subreq->flags); |
|
|
|
netfs_subreq_terminated(subreq, err ?: total, false); |
|
} |
|
|
|
/** |
|
* v9fs_init_request - Initialise a read request |
|
* @rreq: The read request |
|
* @file: The file being read from |
|
*/ |
|
static int v9fs_init_request(struct netfs_io_request *rreq, struct file *file) |
|
{ |
|
struct inode *inode = file_inode(file); |
|
struct v9fs_inode *v9inode = V9FS_I(inode); |
|
struct p9_fid *fid = file->private_data; |
|
|
|
BUG_ON(!fid); |
|
|
|
/* we might need to read from a fid that was opened write-only |
|
* for read-modify-write of page cache, use the writeback fid |
|
* for that */ |
|
if (rreq->origin == NETFS_READ_FOR_WRITE && |
|
(fid->mode & O_ACCMODE) == O_WRONLY) { |
|
fid = v9inode->writeback_fid; |
|
BUG_ON(!fid); |
|
} |
|
|
|
p9_fid_get(fid); |
|
rreq->netfs_priv = fid; |
|
return 0; |
|
} |
|
|
|
/** |
|
* v9fs_free_request - Cleanup request initialized by v9fs_init_rreq |
|
* @rreq: The I/O request to clean up |
|
*/ |
|
static void v9fs_free_request(struct netfs_io_request *rreq) |
|
{ |
|
struct p9_fid *fid = rreq->netfs_priv; |
|
|
|
p9_fid_put(fid); |
|
} |
|
|
|
/** |
|
* v9fs_begin_cache_operation - Begin a cache operation for a read |
|
* @rreq: The read request |
|
*/ |
|
static int v9fs_begin_cache_operation(struct netfs_io_request *rreq) |
|
{ |
|
#ifdef CONFIG_9P_FSCACHE |
|
struct fscache_cookie *cookie = v9fs_inode_cookie(V9FS_I(rreq->inode)); |
|
|
|
return fscache_begin_read_operation(&rreq->cache_resources, cookie); |
|
#else |
|
return -ENOBUFS; |
|
#endif |
|
} |
|
|
|
const struct netfs_request_ops v9fs_req_ops = { |
|
.init_request = v9fs_init_request, |
|
.free_request = v9fs_free_request, |
|
.begin_cache_operation = v9fs_begin_cache_operation, |
|
.issue_read = v9fs_issue_read, |
|
}; |
|
|
|
/** |
|
* v9fs_release_folio - release the private state associated with a folio |
|
* @folio: The folio to be released |
|
* @gfp: The caller's allocation restrictions |
|
* |
|
* Returns true if the page can be released, false otherwise. |
|
*/ |
|
|
|
static bool v9fs_release_folio(struct folio *folio, gfp_t gfp) |
|
{ |
|
struct inode *inode = folio_inode(folio); |
|
|
|
if (folio_test_private(folio)) |
|
return false; |
|
#ifdef CONFIG_9P_FSCACHE |
|
if (folio_test_fscache(folio)) { |
|
if (current_is_kswapd() || !(gfp & __GFP_FS)) |
|
return false; |
|
folio_wait_fscache(folio); |
|
} |
|
#endif |
|
fscache_note_page_release(v9fs_inode_cookie(V9FS_I(inode))); |
|
return true; |
|
} |
|
|
|
static void v9fs_invalidate_folio(struct folio *folio, size_t offset, |
|
size_t length) |
|
{ |
|
folio_wait_fscache(folio); |
|
} |
|
|
|
static void v9fs_write_to_cache_done(void *priv, ssize_t transferred_or_error, |
|
bool was_async) |
|
{ |
|
struct v9fs_inode *v9inode = priv; |
|
__le32 version; |
|
|
|
if (IS_ERR_VALUE(transferred_or_error) && |
|
transferred_or_error != -ENOBUFS) { |
|
version = cpu_to_le32(v9inode->qid.version); |
|
fscache_invalidate(v9fs_inode_cookie(v9inode), &version, |
|
i_size_read(&v9inode->netfs.inode), 0); |
|
} |
|
} |
|
|
|
static int v9fs_vfs_write_folio_locked(struct folio *folio) |
|
{ |
|
struct inode *inode = folio_inode(folio); |
|
struct v9fs_inode *v9inode = V9FS_I(inode); |
|
struct fscache_cookie *cookie = v9fs_inode_cookie(v9inode); |
|
loff_t start = folio_pos(folio); |
|
loff_t i_size = i_size_read(inode); |
|
struct iov_iter from; |
|
size_t len = folio_size(folio); |
|
int err; |
|
|
|
if (start >= i_size) |
|
return 0; /* Simultaneous truncation occurred */ |
|
|
|
len = min_t(loff_t, i_size - start, len); |
|
|
|
iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len); |
|
|
|
/* We should have writeback_fid always set */ |
|
BUG_ON(!v9inode->writeback_fid); |
|
|
|
folio_wait_fscache(folio); |
|
folio_start_writeback(folio); |
|
|
|
p9_client_write(v9inode->writeback_fid, start, &from, &err); |
|
|
|
if (err == 0 && |
|
fscache_cookie_enabled(cookie) && |
|
test_bit(FSCACHE_COOKIE_IS_CACHING, &cookie->flags)) { |
|
folio_start_fscache(folio); |
|
fscache_write_to_cache(v9fs_inode_cookie(v9inode), |
|
folio_mapping(folio), start, len, i_size, |
|
v9fs_write_to_cache_done, v9inode, |
|
true); |
|
} |
|
|
|
folio_end_writeback(folio); |
|
return err; |
|
} |
|
|
|
static int v9fs_vfs_writepage(struct page *page, struct writeback_control *wbc) |
|
{ |
|
struct folio *folio = page_folio(page); |
|
int retval; |
|
|
|
p9_debug(P9_DEBUG_VFS, "folio %p\n", folio); |
|
|
|
retval = v9fs_vfs_write_folio_locked(folio); |
|
if (retval < 0) { |
|
if (retval == -EAGAIN) { |
|
folio_redirty_for_writepage(wbc, folio); |
|
retval = 0; |
|
} else { |
|
mapping_set_error(folio_mapping(folio), retval); |
|
} |
|
} else |
|
retval = 0; |
|
|
|
folio_unlock(folio); |
|
return retval; |
|
} |
|
|
|
static int v9fs_launder_folio(struct folio *folio) |
|
{ |
|
int retval; |
|
|
|
if (folio_clear_dirty_for_io(folio)) { |
|
retval = v9fs_vfs_write_folio_locked(folio); |
|
if (retval) |
|
return retval; |
|
} |
|
folio_wait_fscache(folio); |
|
return 0; |
|
} |
|
|
|
/** |
|
* v9fs_direct_IO - 9P address space operation for direct I/O |
|
* @iocb: target I/O control block |
|
* @iter: The data/buffer to use |
|
* |
|
* The presence of v9fs_direct_IO() in the address space ops vector |
|
* allowes open() O_DIRECT flags which would have failed otherwise. |
|
* |
|
* In the non-cached mode, we shunt off direct read and write requests before |
|
* the VFS gets them, so this method should never be called. |
|
* |
|
* Direct IO is not 'yet' supported in the cached mode. Hence when |
|
* this routine is called through generic_file_aio_read(), the read/write fails |
|
* with an error. |
|
* |
|
*/ |
|
static ssize_t |
|
v9fs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) |
|
{ |
|
struct file *file = iocb->ki_filp; |
|
loff_t pos = iocb->ki_pos; |
|
ssize_t n; |
|
int err = 0; |
|
|
|
if (iov_iter_rw(iter) == WRITE) { |
|
n = p9_client_write(file->private_data, pos, iter, &err); |
|
if (n) { |
|
struct inode *inode = file_inode(file); |
|
loff_t i_size = i_size_read(inode); |
|
|
|
if (pos + n > i_size) |
|
inode_add_bytes(inode, pos + n - i_size); |
|
} |
|
} else { |
|
n = p9_client_read(file->private_data, pos, iter, &err); |
|
} |
|
return n ? n : err; |
|
} |
|
|
|
static int v9fs_write_begin(struct file *filp, struct address_space *mapping, |
|
loff_t pos, unsigned int len, |
|
struct page **subpagep, void **fsdata) |
|
{ |
|
int retval; |
|
struct folio *folio; |
|
struct v9fs_inode *v9inode = V9FS_I(mapping->host); |
|
|
|
p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); |
|
|
|
BUG_ON(!v9inode->writeback_fid); |
|
|
|
/* Prefetch area to be written into the cache if we're caching this |
|
* file. We need to do this before we get a lock on the page in case |
|
* there's more than one writer competing for the same cache block. |
|
*/ |
|
retval = netfs_write_begin(&v9inode->netfs, filp, mapping, pos, len, &folio, fsdata); |
|
if (retval < 0) |
|
return retval; |
|
|
|
*subpagep = &folio->page; |
|
return retval; |
|
} |
|
|
|
static int v9fs_write_end(struct file *filp, struct address_space *mapping, |
|
loff_t pos, unsigned int len, unsigned int copied, |
|
struct page *subpage, void *fsdata) |
|
{ |
|
loff_t last_pos = pos + copied; |
|
struct folio *folio = page_folio(subpage); |
|
struct inode *inode = mapping->host; |
|
struct v9fs_inode *v9inode = V9FS_I(inode); |
|
|
|
p9_debug(P9_DEBUG_VFS, "filp %p, mapping %p\n", filp, mapping); |
|
|
|
if (!folio_test_uptodate(folio)) { |
|
if (unlikely(copied < len)) { |
|
copied = 0; |
|
goto out; |
|
} |
|
|
|
folio_mark_uptodate(folio); |
|
} |
|
|
|
/* |
|
* No need to use i_size_read() here, the i_size |
|
* cannot change under us because we hold the i_mutex. |
|
*/ |
|
if (last_pos > inode->i_size) { |
|
inode_add_bytes(inode, last_pos - inode->i_size); |
|
i_size_write(inode, last_pos); |
|
fscache_update_cookie(v9fs_inode_cookie(v9inode), NULL, &last_pos); |
|
} |
|
folio_mark_dirty(folio); |
|
out: |
|
folio_unlock(folio); |
|
folio_put(folio); |
|
|
|
return copied; |
|
} |
|
|
|
#ifdef CONFIG_9P_FSCACHE |
|
/* |
|
* Mark a page as having been made dirty and thus needing writeback. We also |
|
* need to pin the cache object to write back to. |
|
*/ |
|
static bool v9fs_dirty_folio(struct address_space *mapping, struct folio *folio) |
|
{ |
|
struct v9fs_inode *v9inode = V9FS_I(mapping->host); |
|
|
|
return fscache_dirty_folio(mapping, folio, v9fs_inode_cookie(v9inode)); |
|
} |
|
#else |
|
#define v9fs_dirty_folio filemap_dirty_folio |
|
#endif |
|
|
|
const struct address_space_operations v9fs_addr_operations = { |
|
.read_folio = netfs_read_folio, |
|
.readahead = netfs_readahead, |
|
.dirty_folio = v9fs_dirty_folio, |
|
.writepage = v9fs_vfs_writepage, |
|
.write_begin = v9fs_write_begin, |
|
.write_end = v9fs_write_end, |
|
.release_folio = v9fs_release_folio, |
|
.invalidate_folio = v9fs_invalidate_folio, |
|
.launder_folio = v9fs_launder_folio, |
|
.direct_IO = v9fs_direct_IO, |
|
};
|
|
|