WSL2-Linux-Kernel/fs/jffs2/file.c

343 строки
9.4 KiB
C

/*
* JFFS2 -- Journalling Flash File System, Version 2.
*
* Copyright © 2001-2007 Red Hat, Inc.
* Copyright © 2004-2010 David Woodhouse <dwmw2@infradead.org>
*
* Created by David Woodhouse <dwmw2@infradead.org>
*
* For licensing information, see the file 'LICENCE' in this directory.
*
*/
#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
#include <linux/kernel.h>
#include <linux/fs.h>
#include <linux/time.h>
#include <linux/pagemap.h>
#include <linux/highmem.h>
#include <linux/crc32.h>
#include <linux/jffs2.h>
#include "nodelist.h"
static int jffs2_write_end(struct file *filp, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *pg, void *fsdata);
static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
loff_t pos, unsigned len,
struct page **pagep, void **fsdata);
static int jffs2_read_folio(struct file *filp, struct folio *folio);
int jffs2_fsync(struct file *filp, loff_t start, loff_t end, int datasync)
{
struct inode *inode = filp->f_mapping->host;
struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
int ret;
ret = file_write_and_wait_range(filp, start, end);
if (ret)
return ret;
inode_lock(inode);
/* Trigger GC to flush any pending writes for this inode */
jffs2_flush_wbuf_gc(c, inode->i_ino);
inode_unlock(inode);
return 0;
}
const struct file_operations jffs2_file_operations =
{
.llseek = generic_file_llseek,
.open = generic_file_open,
.read_iter = generic_file_read_iter,
.write_iter = generic_file_write_iter,
.unlocked_ioctl=jffs2_ioctl,
.mmap = generic_file_readonly_mmap,
.fsync = jffs2_fsync,
.splice_read = generic_file_splice_read,
.splice_write = iter_file_splice_write,
};
/* jffs2_file_inode_operations */
const struct inode_operations jffs2_file_inode_operations =
{
.get_inode_acl = jffs2_get_acl,
.set_acl = jffs2_set_acl,
.setattr = jffs2_setattr,
.listxattr = jffs2_listxattr,
};
const struct address_space_operations jffs2_file_address_operations =
{
.read_folio = jffs2_read_folio,
.write_begin = jffs2_write_begin,
.write_end = jffs2_write_end,
};
static int jffs2_do_readpage_nolock (struct inode *inode, struct page *pg)
{
struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
unsigned char *pg_buf;
int ret;
jffs2_dbg(2, "%s(): ino #%lu, page at offset 0x%lx\n",
__func__, inode->i_ino, pg->index << PAGE_SHIFT);
BUG_ON(!PageLocked(pg));
pg_buf = kmap(pg);
/* FIXME: Can kmap fail? */
ret = jffs2_read_inode_range(c, f, pg_buf, pg->index << PAGE_SHIFT,
PAGE_SIZE);
if (ret) {
ClearPageUptodate(pg);
SetPageError(pg);
} else {
SetPageUptodate(pg);
ClearPageError(pg);
}
flush_dcache_page(pg);
kunmap(pg);
jffs2_dbg(2, "readpage finished\n");
return ret;
}
int __jffs2_read_folio(struct file *file, struct folio *folio)
{
int ret = jffs2_do_readpage_nolock(folio->mapping->host, &folio->page);
folio_unlock(folio);
return ret;
}
static int jffs2_read_folio(struct file *file, struct folio *folio)
{
struct jffs2_inode_info *f = JFFS2_INODE_INFO(folio->mapping->host);
int ret;
mutex_lock(&f->sem);
ret = __jffs2_read_folio(file, folio);
mutex_unlock(&f->sem);
return ret;
}
static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
loff_t pos, unsigned len,
struct page **pagep, void **fsdata)
{
struct page *pg;
struct inode *inode = mapping->host;
struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
pgoff_t index = pos >> PAGE_SHIFT;
uint32_t pageofs = index << PAGE_SHIFT;
int ret = 0;
jffs2_dbg(1, "%s()\n", __func__);
if (pageofs > inode->i_size) {
/* Make new hole frag from old EOF to new page */
struct jffs2_raw_inode ri;
struct jffs2_full_dnode *fn;
uint32_t alloc_len;
jffs2_dbg(1, "Writing new hole frag 0x%x-0x%x between current EOF and new page\n",
(unsigned int)inode->i_size, pageofs);
ret = jffs2_reserve_space(c, sizeof(ri), &alloc_len,
ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
if (ret)
goto out_err;
mutex_lock(&f->sem);
memset(&ri, 0, sizeof(ri));
ri.magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
ri.nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
ri.totlen = cpu_to_je32(sizeof(ri));
ri.hdr_crc = cpu_to_je32(crc32(0, &ri, sizeof(struct jffs2_unknown_node)-4));
ri.ino = cpu_to_je32(f->inocache->ino);
ri.version = cpu_to_je32(++f->highest_version);
ri.mode = cpu_to_jemode(inode->i_mode);
ri.uid = cpu_to_je16(i_uid_read(inode));
ri.gid = cpu_to_je16(i_gid_read(inode));
ri.isize = cpu_to_je32(max((uint32_t)inode->i_size, pageofs));
ri.atime = ri.ctime = ri.mtime = cpu_to_je32(JFFS2_NOW());
ri.offset = cpu_to_je32(inode->i_size);
ri.dsize = cpu_to_je32(pageofs - inode->i_size);
ri.csize = cpu_to_je32(0);
ri.compr = JFFS2_COMPR_ZERO;
ri.node_crc = cpu_to_je32(crc32(0, &ri, sizeof(ri)-8));
ri.data_crc = cpu_to_je32(0);
fn = jffs2_write_dnode(c, f, &ri, NULL, 0, ALLOC_NORMAL);
if (IS_ERR(fn)) {
ret = PTR_ERR(fn);
jffs2_complete_reservation(c);
mutex_unlock(&f->sem);
goto out_err;
}
ret = jffs2_add_full_dnode_to_inode(c, f, fn);
if (f->metadata) {
jffs2_mark_node_obsolete(c, f->metadata->raw);
jffs2_free_full_dnode(f->metadata);
f->metadata = NULL;
}
if (ret) {
jffs2_dbg(1, "Eep. add_full_dnode_to_inode() failed in write_begin, returned %d\n",
ret);
jffs2_mark_node_obsolete(c, fn->raw);
jffs2_free_full_dnode(fn);
jffs2_complete_reservation(c);
mutex_unlock(&f->sem);
goto out_err;
}
jffs2_complete_reservation(c);
inode->i_size = pageofs;
mutex_unlock(&f->sem);
}
/*
* While getting a page and reading data in, lock c->alloc_sem until
* the page is Uptodate. Otherwise GC task may attempt to read the same
* page in read_cache_page(), which causes a deadlock.
*/
mutex_lock(&c->alloc_sem);
pg = grab_cache_page_write_begin(mapping, index);
if (!pg) {
ret = -ENOMEM;
goto release_sem;
}
*pagep = pg;
/*
* Read in the page if it wasn't already present. Cannot optimize away
* the whole page write case until jffs2_write_end can handle the
* case of a short-copy.
*/
if (!PageUptodate(pg)) {
mutex_lock(&f->sem);
ret = jffs2_do_readpage_nolock(inode, pg);
mutex_unlock(&f->sem);
if (ret) {
unlock_page(pg);
put_page(pg);
goto release_sem;
}
}
jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
release_sem:
mutex_unlock(&c->alloc_sem);
out_err:
return ret;
}
static int jffs2_write_end(struct file *filp, struct address_space *mapping,
loff_t pos, unsigned len, unsigned copied,
struct page *pg, void *fsdata)
{
/* Actually commit the write from the page cache page we're looking at.
* For now, we write the full page out each time. It sucks, but it's simple
*/
struct inode *inode = mapping->host;
struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
struct jffs2_raw_inode *ri;
unsigned start = pos & (PAGE_SIZE - 1);
unsigned end = start + copied;
unsigned aligned_start = start & ~3;
int ret = 0;
uint32_t writtenlen = 0;
jffs2_dbg(1, "%s(): ino #%lu, page at 0x%lx, range %d-%d, flags %lx\n",
__func__, inode->i_ino, pg->index << PAGE_SHIFT,
start, end, pg->flags);
/* We need to avoid deadlock with page_cache_read() in
jffs2_garbage_collect_pass(). So the page must be
up to date to prevent page_cache_read() from trying
to re-lock it. */
BUG_ON(!PageUptodate(pg));
if (end == PAGE_SIZE) {
/* When writing out the end of a page, write out the
_whole_ page. This helps to reduce the number of
nodes in files which have many short writes, like
syslog files. */
aligned_start = 0;
}
ri = jffs2_alloc_raw_inode();
if (!ri) {
jffs2_dbg(1, "%s(): Allocation of raw inode failed\n",
__func__);
unlock_page(pg);
put_page(pg);
return -ENOMEM;
}
/* Set the fields that the generic jffs2_write_inode_range() code can't find */
ri->ino = cpu_to_je32(inode->i_ino);
ri->mode = cpu_to_jemode(inode->i_mode);
ri->uid = cpu_to_je16(i_uid_read(inode));
ri->gid = cpu_to_je16(i_gid_read(inode));
ri->isize = cpu_to_je32((uint32_t)inode->i_size);
ri->atime = ri->ctime = ri->mtime = cpu_to_je32(JFFS2_NOW());
/* In 2.4, it was already kmapped by generic_file_write(). Doesn't
hurt to do it again. The alternative is ifdefs, which are ugly. */
kmap(pg);
ret = jffs2_write_inode_range(c, f, ri, page_address(pg) + aligned_start,
(pg->index << PAGE_SHIFT) + aligned_start,
end - aligned_start, &writtenlen);
kunmap(pg);
if (ret) {
/* There was an error writing. */
SetPageError(pg);
}
/* Adjust writtenlen for the padding we did, so we don't confuse our caller */
writtenlen -= min(writtenlen, (start - aligned_start));
if (writtenlen) {
if (inode->i_size < pos + writtenlen) {
inode->i_size = pos + writtenlen;
inode->i_blocks = (inode->i_size + 511) >> 9;
inode->i_ctime = inode->i_mtime = ITIME(je32_to_cpu(ri->ctime));
}
}
jffs2_free_raw_inode(ri);
if (start+writtenlen < end) {
/* generic_file_write has written more to the page cache than we've
actually written to the medium. Mark the page !Uptodate so that
it gets reread */
jffs2_dbg(1, "%s(): Not all bytes written. Marking page !uptodate\n",
__func__);
SetPageError(pg);
ClearPageUptodate(pg);
}
jffs2_dbg(1, "%s() returning %d\n",
__func__, writtenlen > 0 ? writtenlen : ret);
unlock_page(pg);
put_page(pg);
return writtenlen > 0 ? writtenlen : ret;
}