fs/jffs2/file.c - linux - Git at Google

 /*
  * 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, unsigned flags,
 			struct page **pagep, void **fsdata);
 static int jffs2_readpage (struct file *filp, struct page *pg);

 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_acl =	jffs2_get_acl,
 	.set_acl =	jffs2_set_acl,
 	.setattr =	jffs2_setattr,
 	.listxattr =	jffs2_listxattr,
 };

 const struct address_space_operations jffs2_file_address_operations =
 {
 	.readpage =	jffs2_readpage,
 	.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_do_readpage_unlock(void *data, struct page *pg)
 {
 	int ret = jffs2_do_readpage_nolock(data, pg);
 	unlock_page(pg);
 	return ret;
 }


 static int jffs2_readpage (struct file *filp, struct page *pg)
 {
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
 	int ret;

 	mutex_lock(&f->sem);
 	ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
 	mutex_unlock(&f->sem);
 	return ret;
 }

 static int jffs2_write_begin(struct file *filp, struct address_space *mapping,
 			loff_t pos, unsigned len, unsigned flags,
 			struct page **pagep, void **fsdata)
 {
 	struct page *pg;
 	struct inode *inode = mapping->host;
 	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
 	pgoff_t index = pos >> PAGE_SHIFT;
 	uint32_t pageofs = index << PAGE_SHIFT;
 	int ret = 0;

 	pg = grab_cache_page_write_begin(mapping, index, flags);
 	if (!pg)
 		return -ENOMEM;
 	*pagep = pg;

 	jffs2_dbg(1, "%s()\n", __func__);

 	if (pageofs > inode->i_size) {
 		/* Make new hole frag from old EOF to new page */
 		struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
 		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_page;

 		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_page;
 		}
 		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_page;
 		}
 		jffs2_complete_reservation(c);
 		inode->i_size = pageofs;
 		mutex_unlock(&f->sem);
 	}

 	/*
 	 * 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)
 			goto out_page;
 	}
 	jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
 	return ret;

 out_page:
 	unlock_page(pg);
 	put_page(pg);
 	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;
 }
	/*
	* 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, unsigned flags,
	struct page pagep, void fsdata);
	static int jffs2_readpage (struct file filp, struct page pg);

	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_acl = jffs2_get_acl,
	.set_acl = jffs2_set_acl,
	.setattr = jffs2_setattr,
	.listxattr = jffs2_listxattr,
	};

	const struct address_space_operations jffs2_file_address_operations =
	{
	.readpage = jffs2_readpage,
	.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_do_readpage_unlock(void data, struct page pg)
	{
	int ret = jffs2_do_readpage_nolock(data, pg);
	unlock_page(pg);
	return ret;
	}


	static int jffs2_readpage (struct file filp, struct page pg)
	{
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(pg->mapping->host);
	int ret;

	mutex_lock(&f->sem);
	ret = jffs2_do_readpage_unlock(pg->mapping->host, pg);
	mutex_unlock(&f->sem);
	return ret;
	}

	static int jffs2_write_begin(struct file filp, struct address_space mapping,
	loff_t pos, unsigned len, unsigned flags,
	struct page pagep, void fsdata)
	{
	struct page *pg;
	struct inode *inode = mapping->host;
	struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode);
	pgoff_t index = pos >> PAGE_SHIFT;
	uint32_t pageofs = index << PAGE_SHIFT;
	int ret = 0;

	pg = grab_cache_page_write_begin(mapping, index, flags);
	if (!pg)
	return -ENOMEM;
	*pagep = pg;

	jffs2_dbg(1, "%s()\n", __func__);

	if (pageofs > inode->i_size) {
	/* Make new hole frag from old EOF to new page */
	struct jffs2_sb_info *c = JFFS2_SB_INFO(inode->i_sb);
	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_page;

	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_page;
	}
	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_page;
	}
	jffs2_complete_reservation(c);
	inode->i_size = pageofs;
	mutex_unlock(&f->sem);
	}

	/*
	* 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)
	goto out_page;
	}
	jffs2_dbg(1, "end write_begin(). pg->flags %lx\n", pg->flags);
	return ret;

	out_page:
	unlock_page(pg);
	put_page(pg);
	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;
	}