fs/jffs2/fs.c

Source file repositories/reference/linux-study-clean/fs/jffs2/fs.c

File Facts

System
Linux kernel
Corpus path
fs/jffs2/fs.c
Extension
.c
Size
19971 bytes
Lines
743
Domain
Core OS
Bucket
VFS And Filesystem Core
Inferred role
Core OS: implementation source
Status
source implementation candidate

Why This File Exists

Core operating-system implementation surface: boot, tasks, memory, VFS, syscall-facing interfaces, synchronization, credentials, and isolation.

Dependency Surface

Detected Declarations

Annotated Snippet

if (!mdata) {
			mutex_unlock(&f->sem);
			return -ENOMEM;
		}
		ret = jffs2_read_dnode(c, f, f->metadata, mdata, 0, mdatalen);
		if (ret) {
			mutex_unlock(&f->sem);
			kfree(mdata);
			return ret;
		}
		mutex_unlock(&f->sem);
		jffs2_dbg(1, "%s(): Writing %d bytes of symlink target\n",
			  __func__, mdatalen);
	}

	ri = jffs2_alloc_raw_inode();
	if (!ri) {
		if (S_ISLNK(inode->i_mode))
			kfree(mdata);
		return -ENOMEM;
	}

	ret = jffs2_reserve_space(c, sizeof(*ri) + mdatalen, &alloclen,
				  ALLOC_NORMAL, JFFS2_SUMMARY_INODE_SIZE);
	if (ret) {
		jffs2_free_raw_inode(ri);
		if (S_ISLNK(inode->i_mode))
			 kfree(mdata);
		return ret;
	}
	mutex_lock(&f->sem);
	ivalid = iattr->ia_valid;

	ri->magic = cpu_to_je16(JFFS2_MAGIC_BITMASK);
	ri->nodetype = cpu_to_je16(JFFS2_NODETYPE_INODE);
	ri->totlen = cpu_to_je32(sizeof(*ri) + mdatalen);
	ri->hdr_crc = cpu_to_je32(crc32(0, ri, sizeof(struct jffs2_unknown_node)-4));

	ri->ino = cpu_to_je32(inode->i_ino);
	ri->version = cpu_to_je32(++f->highest_version);

	ri->uid = cpu_to_je16((ivalid & ATTR_UID)?
		from_kuid(&init_user_ns, iattr->ia_uid):i_uid_read(inode));
	ri->gid = cpu_to_je16((ivalid & ATTR_GID)?
		from_kgid(&init_user_ns, iattr->ia_gid):i_gid_read(inode));

	if (ivalid & ATTR_MODE)
		ri->mode = cpu_to_jemode(iattr->ia_mode);
	else
		ri->mode = cpu_to_jemode(inode->i_mode);


	ri->isize = cpu_to_je32((ivalid & ATTR_SIZE)?iattr->ia_size:inode->i_size);
	ri->atime = cpu_to_je32(I_SEC((ivalid & ATTR_ATIME)?iattr->ia_atime:inode_get_atime(inode)));
	ri->mtime = cpu_to_je32(I_SEC((ivalid & ATTR_MTIME)?iattr->ia_mtime:inode_get_mtime(inode)));
	ri->ctime = cpu_to_je32(I_SEC((ivalid & ATTR_CTIME)?iattr->ia_ctime:inode_get_ctime(inode)));

	ri->offset = cpu_to_je32(0);
	ri->csize = ri->dsize = cpu_to_je32(mdatalen);
	ri->compr = JFFS2_COMPR_NONE;
	if (ivalid & ATTR_SIZE && inode->i_size < iattr->ia_size) {
		/* It's an extension. Make it a hole node */
		ri->compr = JFFS2_COMPR_ZERO;
		ri->dsize = cpu_to_je32(iattr->ia_size - inode->i_size);
		ri->offset = cpu_to_je32(inode->i_size);
	} else if (ivalid & ATTR_SIZE && !iattr->ia_size) {
		/* For truncate-to-zero, treat it as deletion because
		   it'll always be obsoleting all previous nodes */
		alloc_type = ALLOC_DELETION;
	}
	ri->node_crc = cpu_to_je32(crc32(0, ri, sizeof(*ri)-8));
	if (mdatalen)
		ri->data_crc = cpu_to_je32(crc32(0, mdata, mdatalen));
	else
		ri->data_crc = cpu_to_je32(0);

	new_metadata = jffs2_write_dnode(c, f, ri, mdata, mdatalen, alloc_type);
	if (S_ISLNK(inode->i_mode))
		kfree(mdata);

	if (IS_ERR(new_metadata)) {
		jffs2_complete_reservation(c);
		jffs2_free_raw_inode(ri);
		mutex_unlock(&f->sem);
		return PTR_ERR(new_metadata);
	}
	/* It worked. Update the inode */
	inode_set_atime_to_ts(inode, ITIME(je32_to_cpu(ri->atime)));
	inode_set_ctime_to_ts(inode, ITIME(je32_to_cpu(ri->ctime)));
	inode_set_mtime_to_ts(inode, ITIME(je32_to_cpu(ri->mtime)));

Annotation

Implementation Notes