write.c

jffs2源代码基于2。6内核

	uint32_t writtenlen = 0;

       	D1(printk(KERN_DEBUG "jffs2_write_inode_range(): Ino #%u, ofs 0x%x, len 0x%x\n",
		  f->inocache->ino, offset, writelen));
		
	while(writelen) {
		struct jffs2_full_dnode *fn;
		unsigned char *comprbuf = NULL;
		uint16_t comprtype = JFFS2_COMPR_NONE;
		uint32_t phys_ofs, alloclen;
		uint32_t datalen, cdatalen;
		int retried = 0;

	retry:
		D2(printk(KERN_DEBUG "jffs2_commit_write() loop: 0x%x to write to 0x%x\n", writelen, offset));

		ret = jffs2_reserve_space(c, sizeof(*ri) + JFFS2_MIN_DATA_LEN, &phys_ofs, &alloclen, ALLOC_NORMAL);
		if (ret) {
			D1(printk(KERN_DEBUG "jffs2_reserve_space returned %d\n", ret));
			break;
		}
		down(&f->sem);
		datalen = min_t(uint32_t, writelen, PAGE_CACHE_SIZE - (offset & (PAGE_CACHE_SIZE-1)));
		cdatalen = min_t(uint32_t, alloclen - sizeof(*ri), datalen);

		comprtype = jffs2_compress(c, f, buf, &comprbuf, &datalen, &cdatalen);

		ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
		ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
		ri->totlen = cpu_to_je32(sizeof(*ri) + cdatalen);
		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->isize = cpu_to_je32(max(je32_to_cpu(ri->isize), offset + datalen));
		ri->offset = cpu_to_je32(offset);
		ri->csize = cpu_to_je32(cdatalen);
		ri->dsize = cpu_to_je32(datalen);
		ri->compr = comprtype & 0xff;
		ri->usercompr = (comprtype >> 8 ) & 0xff;
		ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
		ri->data_crc = cpu_to_je32(crc32(0, comprbuf, cdatalen));

		fn = jffs2_write_dnode(c, f, ri, comprbuf, cdatalen, phys_ofs, ALLOC_NORETRY);

		jffs2_free_comprbuf(comprbuf, buf);

		if (IS_ERR(fn)) {
			ret = PTR_ERR(fn);
			up(&f->sem);
			jffs2_complete_reservation(c);
			if (!retried) {
				/* Write error to be retried */
				retried = 1;
				D1(printk(KERN_DEBUG "Retrying node write in jffs2_write_inode_range()\n"));
				goto retry;
			}
			break;
		}
		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) {
			/* Eep */
			D1(printk(KERN_DEBUG "Eep. add_full_dnode_to_inode() failed in commit_write, returned %d\n", ret));
			jffs2_mark_node_obsolete(c, fn->raw);
			jffs2_free_full_dnode(fn);

			up(&f->sem);
			jffs2_complete_reservation(c);
			break;
		}
		up(&f->sem);
		jffs2_complete_reservation(c);
		if (!datalen) {
			printk(KERN_WARNING "Eep. We didn't actually write any data in jffs2_write_inode_range()\n");
			ret = -EIO;
			break;
		}
		D1(printk(KERN_DEBUG "increasing writtenlen by %d\n", datalen));
		writtenlen += datalen;
		offset += datalen;
		writelen -= datalen;
		buf += datalen;
	}
	*retlen = writtenlen;
	return ret;
}

int jffs2_do_create(struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f, struct jffs2_inode_info *f, struct jffs2_raw_inode *ri, const char *name, int namelen)
{
	struct jffs2_raw_dirent *rd;
	struct jffs2_full_dnode *fn;
	struct jffs2_full_dirent *fd;
	uint32_t alloclen, phys_ofs;
	int ret;

	/* Try to reserve enough space for both node and dirent. 
	 * Just the node will do for now, though 
	 */
	ret = jffs2_reserve_space(c, sizeof(*ri), &phys_ofs, &alloclen, ALLOC_NORMAL);
	D1(printk(KERN_DEBUG "jffs2_do_create(): reserved 0x%x bytes\n", alloclen));
	if (ret) {
		up(&f->sem);
		return ret;
	}

	ri->data_crc = cpu_to_je32(0);
	ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));

	fn = jffs2_write_dnode(c, f, ri, NULL, 0, phys_ofs, ALLOC_NORMAL);

	D1(printk(KERN_DEBUG "jffs2_do_create created file with mode 0x%x\n",
		  jemode_to_cpu(ri->mode)));

	if (IS_ERR(fn)) {
		D1(printk(KERN_DEBUG "jffs2_write_dnode() failed\n"));
		/* Eeek. Wave bye bye */
		up(&f->sem);
		jffs2_complete_reservation(c);
		return PTR_ERR(fn);
	}
	/* No data here. Only a metadata node, which will be 
	   obsoleted by the first data write
	*/
	f->metadata = fn;

	up(&f->sem);
	jffs2_complete_reservation(c);
	ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &phys_ofs, &alloclen, ALLOC_NORMAL);
		
	if (ret) {
		/* Eep. */
		D1(printk(KERN_DEBUG "jffs2_reserve_space() for dirent failed\n"));
		return ret;
	}

	rd = jffs2_alloc_raw_dirent();
	if (!rd) {
		/* Argh. Now we treat it like a normal delete */
		jffs2_complete_reservation(c);
		return -ENOMEM;
	}

	down(&dir_f->sem);

	rd->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	rd->nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
	rd->totlen = cpu_to_je32(sizeof(*rd) + namelen);
	rd->hdr_crc = cpu_to_je32(crc32(0, rd, sizeof(struct jffs2_unknown_node)-4));

	rd->pino = cpu_to_je32(dir_f->inocache->ino);
	rd->version = cpu_to_je32(++dir_f->highest_version);
	rd->ino = ri->ino;
	rd->mctime = ri->ctime;
	rd->nsize = namelen;
	rd->type = DT_REG;
	rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
	rd->name_crc = cpu_to_je32(crc32(0, name, namelen));

	fd = jffs2_write_dirent(c, dir_f, rd, name, namelen, phys_ofs, ALLOC_NORMAL);

	jffs2_free_raw_dirent(rd);
	
	if (IS_ERR(fd)) {
		/* dirent failed to write. Delete the inode normally 
		   as if it were the final unlink() */
		jffs2_complete_reservation(c);
		up(&dir_f->sem);
		return PTR_ERR(fd);
	}

	/* Link the fd into the inode's list, obsoleting an old
	   one if necessary. */
	jffs2_add_fd_to_list(c, fd, &dir_f->dents);

	jffs2_complete_reservation(c);
	up(&dir_f->sem);

	return 0;
}


int jffs2_do_unlink(struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f,
		    const char *name, int namelen, struct jffs2_inode_info *dead_f)
{
	struct jffs2_raw_dirent *rd;
	struct jffs2_full_dirent *fd;
	uint32_t alloclen, phys_ofs;
	int ret;

	if (1 /* alternative branch needs testing */ || 
	    !jffs2_can_mark_obsolete(c)) {
		/* We can't mark stuff obsolete on the medium. We need to write a deletion dirent */

		rd = jffs2_alloc_raw_dirent();
		if (!rd)
			return -ENOMEM;

		ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &phys_ofs, &alloclen, ALLOC_DELETION);
		if (ret) {
			jffs2_free_raw_dirent(rd);
			return ret;
		}

		down(&dir_f->sem);

		/* Build a deletion node */
		rd->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
		rd->nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
		rd->totlen = cpu_to_je32(sizeof(*rd) + namelen);
		rd->hdr_crc = cpu_to_je32(crc32(0, rd, sizeof(struct jffs2_unknown_node)-4));
		
		rd->pino = cpu_to_je32(dir_f->inocache->ino);
		rd->version = cpu_to_je32(++dir_f->highest_version);
		rd->ino = cpu_to_je32(0);
		rd->mctime = cpu_to_je32(get_seconds());
		rd->nsize = namelen;
		rd->type = DT_UNKNOWN;
		rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
		rd->name_crc = cpu_to_je32(crc32(0, name, namelen));

		fd = jffs2_write_dirent(c, dir_f, rd, name, namelen, phys_ofs, ALLOC_DELETION);
		
		jffs2_free_raw_dirent(rd);

		if (IS_ERR(fd)) {
			jffs2_complete_reservation(c);
			up(&dir_f->sem);
			return PTR_ERR(fd);
		}

		/* File it. This will mark the old one obsolete. */
		jffs2_add_fd_to_list(c, fd, &dir_f->dents);
		up(&dir_f->sem);
	} else {
		struct jffs2_full_dirent **prev = &dir_f->dents;
		uint32_t nhash = full_name_hash(name, namelen);

		down(&dir_f->sem);

		while ((*prev) && (*prev)->nhash <= nhash) {
			if ((*prev)->nhash == nhash && 
			    !memcmp((*prev)->name, name, namelen) &&
			    !(*prev)->name[namelen]) {
				struct jffs2_full_dirent *this = *prev;

				D1(printk(KERN_DEBUG "Marking old dirent node (ino #%u) @%08x obsolete\n",
					  this->ino, ref_offset(this->raw)));

				*prev = this->next;
				jffs2_mark_node_obsolete(c, (this->raw));
				jffs2_free_full_dirent(this);
				break;
			}
			prev = &((*prev)->next);
		}
		up(&dir_f->sem);
	}

	/* dead_f is NULL if this was a rename not a real unlink */
	/* Also catch the !f->inocache case, where there was a dirent
	   pointing to an inode which didn't exist. */
	if (dead_f && dead_f->inocache) { 

		down(&dead_f->sem);

		while (dead_f->dents) {
			/* There can be only deleted ones */
			fd = dead_f->dents;
			
			dead_f->dents = fd->next;
			
			if (fd->ino) {
				printk(KERN_WARNING "Deleting inode #%u with active dentry \"%s\"->ino #%u\n",
				       dead_f->inocache->ino, fd->name, fd->ino);
			} else {
				D1(printk(KERN_DEBUG "Removing deletion dirent for \"%s\" from dir ino #%u\n", fd->name, dead_f->inocache->ino));
			}
			jffs2_mark_node_obsolete(c, fd->raw);
			jffs2_free_full_dirent(fd);
		}

		dead_f->inocache->nlink--;
		/* NB: Caller must set inode nlink if appropriate */
		up(&dead_f->sem);
	}

	jffs2_complete_reservation(c);

	return 0;
}


int jffs2_do_link (struct jffs2_sb_info *c, struct jffs2_inode_info *dir_f, uint32_t ino, uint8_t type, const char *name, int namelen)
{
	struct jffs2_raw_dirent *rd;
	struct jffs2_full_dirent *fd;
	uint32_t alloclen, phys_ofs;
	int ret;

	rd = jffs2_alloc_raw_dirent();
	if (!rd)
		return -ENOMEM;

	ret = jffs2_reserve_space(c, sizeof(*rd)+namelen, &phys_ofs, &alloclen, ALLOC_NORMAL);
	if (ret) {
		jffs2_free_raw_dirent(rd);
		return ret;
	}
	
	down(&dir_f->sem);

	/* Build a deletion node */
	rd->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	rd->nodetype = cpu_to_je16(JFFS2_NODETYPE_DIRENT);
	rd->totlen = cpu_to_je32(sizeof(*rd) + namelen);
	rd->hdr_crc = cpu_to_je32(crc32(0, rd, sizeof(struct jffs2_unknown_node)-4));

	rd->pino = cpu_to_je32(dir_f->inocache->ino);
	rd->version = cpu_to_je32(++dir_f->highest_version);
	rd->ino = cpu_to_je32(ino);
	rd->mctime = cpu_to_je32(get_seconds());
	rd->nsize = namelen;

	rd->type = type;

	rd->node_crc = cpu_to_je32(crc32(0, rd, sizeof(*rd)-8));
	rd->name_crc = cpu_to_je32(crc32(0, name, namelen));

	fd = jffs2_write_dirent(c, dir_f, rd, name, namelen, phys_ofs, ALLOC_NORMAL);
	
	jffs2_free_raw_dirent(rd);

	if (IS_ERR(fd)) {
		jffs2_complete_reservation(c);
		up(&dir_f->sem);
		return PTR_ERR(fd);
	}

	/* File it. This will mark the old one obsolete. */
	jffs2_add_fd_to_list(c, fd, &dir_f->dents);

	jffs2_complete_reservation(c);
	up(&dir_f->sem);

	return 0;
}