xattr.c

jfs-2.4-1.1.7.tar.gz jfs 2.4－1.1.7 源码

	} else if (ji->ea.flag & DXD_INLINE) {
		if (min_size <= sizeof (ji->i_inline_ea)) {
			ea_buf->flag = EA_INLINE;
			ea_buf->max_size = sizeof (ji->i_inline_ea);
			ea_buf->xattr = (struct jfs_ea_list *) ji->i_inline_ea;
			goto size_check;
		}
		current_blocks = 0;
	} else {
		if (!(ji->ea.flag & DXD_EXTENT)) {
			jfs_error(sb, "ea_get: invalid ea.flag)");
			return -EIO;
		}
		current_blocks = (ea_size + sb->s_blocksize - 1) >>
		    sb->s_blocksize_bits;
	}
	size = max(min_size, ea_size);

	if (size > PSIZE) {
		/*
		 * To keep the rest of the code simple.  Allocate a
		 * contiguous buffer to work with
		 */
		ea_buf->xattr = kmalloc(size, GFP_KERNEL);
		if (ea_buf->xattr == NULL)
			return -ENOMEM;

		ea_buf->flag = EA_MALLOC;
		ea_buf->max_size = (size + sb->s_blocksize - 1) &
		    ~(sb->s_blocksize - 1);

		if (ea_size == 0)
			return 0;

		if ((rc = ea_read(inode, ea_buf->xattr))) {
			kfree(ea_buf->xattr);
			ea_buf->xattr = NULL;
			return rc;
		}
		goto size_check;
	}
	blocks_needed = (min_size + sb->s_blocksize - 1) >>
	    sb->s_blocksize_bits;

	if (blocks_needed > current_blocks) {
		rc = dbAlloc(inode, INOHINT(inode), (s64) blocks_needed,
			     &blkno);
		if (rc)
			return rc;

		DXDlength(&ea_buf->new_ea, blocks_needed);
		DXDaddress(&ea_buf->new_ea, blkno);
		ea_buf->new_ea.flag = DXD_EXTENT;
		DXDsize(&ea_buf->new_ea, min_size);

		ea_buf->flag = EA_EXTENT | EA_NEW;

		ea_buf->mp = get_metapage(inode, blkno,
					  blocks_needed << sb->s_blocksize_bits,
					  1);
		if (ea_buf->mp == NULL) {
			dbFree(inode, blkno, (s64) blocks_needed);
			return -EIO;
		}
		ea_buf->xattr = ea_buf->mp->data;
		ea_buf->max_size = (min_size + sb->s_blocksize - 1) &
		    ~(sb->s_blocksize - 1);
		if (ea_size == 0)
			return 0;
		if ((rc = ea_read(inode, ea_buf->xattr))) {
			discard_metapage(ea_buf->mp);
			dbFree(inode, blkno, (s64) blocks_needed);
			return rc;
		}
		goto size_check;
	}
	ea_buf->flag = EA_EXTENT;
	ea_buf->mp = read_metapage(inode, addressDXD(&ji->ea),
				   lengthDXD(&ji->ea) << sb->s_blocksize_bits,
				   1);
	if (ea_buf->mp == NULL)
		return -EIO;
	ea_buf->xattr = ea_buf->mp->data;
	ea_buf->max_size = (ea_size + sb->s_blocksize - 1) &
	    ~(sb->s_blocksize - 1);

      size_check:
	if (EALIST_SIZE(ea_buf->xattr) != ea_size) {
		printk(KERN_ERR "ea_get: invalid extended attribute\n");
		dump_mem("xattr", ea_buf->xattr, ea_size);
		ea_release(inode, ea_buf);
		return -EIO;
	}

	return ea_size;
}

static void ea_release(struct inode *inode, struct ea_buffer *ea_buf)
{
	if (ea_buf->flag & EA_MALLOC)
		kfree(ea_buf->xattr);
	else if (ea_buf->flag & EA_EXTENT) {
		assert(ea_buf->mp);
		release_metapage(ea_buf->mp);

		if (ea_buf->flag & EA_NEW)
			dbFree(inode, addressDXD(&ea_buf->new_ea),
			       lengthDXD(&ea_buf->new_ea));
	}
}

static int ea_put(struct inode *inode, struct ea_buffer *ea_buf, int new_size)
{
	struct jfs_inode_info *ji = JFS_IP(inode);
	unsigned long old_blocks, new_blocks;
	int rc = 0;
	tid_t tid;

	if (new_size == 0) {
		ea_release(inode, ea_buf);
		ea_buf = 0;
	} else if (ea_buf->flag & EA_INLINE) {
		assert(new_size <= sizeof (ji->i_inline_ea));
		ji->mode2 &= ~INLINEEA;
		ea_buf->new_ea.flag = DXD_INLINE;
		DXDsize(&ea_buf->new_ea, new_size);
		DXDaddress(&ea_buf->new_ea, 0);
		DXDlength(&ea_buf->new_ea, 0);
	} else if (ea_buf->flag & EA_MALLOC) {
		rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
		kfree(ea_buf->xattr);
	} else if (ea_buf->flag & EA_NEW) {
		/* We have already allocated a new dxd */
		flush_metapage(ea_buf->mp);
	} else {
		/* ->xattr must point to original ea's metapage */
		rc = ea_write(inode, ea_buf->xattr, new_size, &ea_buf->new_ea);
		discard_metapage(ea_buf->mp);
	}
	if (rc)
		return rc;

	tid = txBegin(inode->i_sb, 0);
	down(&ji->commit_sem);

	old_blocks = new_blocks = 0;

	if (ji->ea.flag & DXD_EXTENT) {
		invalidate_dxd_metapages(inode, ji->ea);
		old_blocks = lengthDXD(&ji->ea);
	}

	if (ea_buf) {
		txEA(tid, inode, &ji->ea, &ea_buf->new_ea);
		if (ea_buf->new_ea.flag & DXD_EXTENT) {
			new_blocks = lengthDXD(&ea_buf->new_ea);
			if (ji->ea.flag & DXD_INLINE)
				ji->mode2 |= INLINEEA;
		}
		ji->ea = ea_buf->new_ea;
	} else {
		txEA(tid, inode, &ji->ea, 0);
		if (ji->ea.flag & DXD_INLINE)
			ji->mode2 |= INLINEEA;
		ji->ea.flag = 0;
		ji->ea.size = 0;
	}

	inode->i_blocks += LBLK2PBLK(inode->i_sb, new_blocks - old_blocks);
	rc = txCommit(tid, 1, &inode, 0);
	txEnd(tid);
	up(&ji->commit_sem);

	return rc;
}

static int can_set_xattr(struct inode *inode, const char *name,
			 void *value, size_t value_len)
{
	if (IS_RDONLY(inode))
		return -EROFS;

	if (IS_IMMUTABLE(inode) || IS_APPEND(inode) || S_ISLNK(inode->i_mode))
		return -EPERM;

	if((strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN) != 0) &&
	   (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) != 0))
		return -EOPNOTSUPP;

	if (!S_ISREG(inode->i_mode) &&
	    (!S_ISDIR(inode->i_mode) || inode->i_mode &S_ISVTX))
		return -EPERM;

	return permission(inode, MAY_WRITE);
}

int __jfs_setxattr(struct inode *inode, const char *name, void *value,
		   size_t value_len, int flags)
{
	struct jfs_ea_list *ealist;
	struct jfs_ea *ea, *old_ea = NULL, *next_ea = NULL;
	struct ea_buffer ea_buf;
	int old_ea_size = 0;
	int xattr_size;
	int new_size;
	int namelen = strlen(name);
	char *os2name = NULL;
	int found = 0;
	int rc;
	int length;

	if ((rc = can_set_xattr(inode, name, value, value_len)))
		return rc;

	if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
		os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
				  GFP_KERNEL);
		if (!os2name)
			return -ENOMEM;
		strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
		name = os2name;
		namelen -= XATTR_OS2_PREFIX_LEN;
	}

	xattr_size = ea_get(inode, &ea_buf, 0);
	if (xattr_size < 0) {
		rc = xattr_size;
		goto out;
	}

      again:
	ealist = (struct jfs_ea_list *) ea_buf.xattr;
	new_size = sizeof (struct jfs_ea_list);

	if (xattr_size) {
		for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist);
		     ea = NEXT_EA(ea)) {
			if ((namelen == ea->namelen) &&
			    (memcmp(name, ea->name, namelen) == 0)) {
				found = 1;
				if (flags & XATTR_CREATE) {
					rc = -EEXIST;
					goto release;
				}
				old_ea = ea;
				old_ea_size = EA_SIZE(ea);
				next_ea = NEXT_EA(ea);
			} else
				new_size += EA_SIZE(ea);
		}
	}

	if (!found) {
		if (flags & XATTR_REPLACE) {
			rc = -ENODATA;
			goto release;
		}
		if (value == NULL) {
			rc = 0;
			goto release;
		}
	}
	if (value)
		new_size += sizeof (struct jfs_ea) + namelen + 1 + value_len;

	if (new_size > ea_buf.max_size) {
		/*
		 * We need to allocate more space for merged ea list.
		 * We should only have loop to again: once.
		 */
		ea_release(inode, &ea_buf);
		xattr_size = ea_get(inode, &ea_buf, new_size);
		if (xattr_size < 0) {
			rc = xattr_size;
			goto out;
		}
		goto again;
	}

	/* Remove old ea of the same name */
	if (found) {
		/* number of bytes following target EA */
		length = (char *) END_EALIST(ealist) - (char *) next_ea;
		if (length > 0)
			memmove(old_ea, next_ea, length);
		xattr_size -= old_ea_size;
	}

	/* Add new entry to the end */
	if (value) {
		if (xattr_size == 0)
			/* Completely new ea list */
			xattr_size = sizeof (struct jfs_ea_list);

		ea = (struct jfs_ea *) ((char *) ealist + xattr_size);
		ea->flag = 0;
		ea->namelen = namelen;
		ea->valuelen = (cpu_to_le16(value_len));
		memcpy(ea->name, name, namelen);
		ea->name[namelen] = 0;
		if (value_len)
			memcpy(&ea->name[namelen + 1], value, value_len);
		xattr_size += EA_SIZE(ea);
	}

	/* DEBUG - If we did this right, these number match */
	if (xattr_size != new_size) {
		printk(KERN_ERR
		       "jfs_xsetattr: xattr_size = %d, new_size = %d\n",
		       xattr_size, new_size);

		rc = -EINVAL;
		goto release;
	}

	/*
	 * If we're left with an empty list, there's no ea
	 */
	if (new_size == sizeof (struct jfs_ea_list))
		new_size = 0;

	ealist->size = cpu_to_le32(new_size);

	rc = ea_put(inode, &ea_buf, new_size);

	goto out;
      release:
	ea_release(inode, &ea_buf);
      out:
	if (os2name)
		kfree(os2name);

	return rc;
}

int jfs_setxattr(struct dentry *dentry, const char *name, void *value,
		 size_t value_len, int flags)
{
	if (value == NULL) {	/* empty EA, do not remove */
		value = "";
		value_len = 0;
	}

	return __jfs_setxattr(dentry->d_inode, name, value, value_len, flags);
}

static inline int can_get_xattr(struct inode *inode, const char *name)
{
	if(strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN) == 0)
		return 0;
	return permission(inode, MAY_READ);
}

ssize_t __jfs_getxattr(struct inode *inode, const char *name, void *data,
		       size_t buf_size)
{
	struct jfs_ea_list *ealist;
	struct jfs_ea *ea;
	struct ea_buffer ea_buf;
	int xattr_size;
	ssize_t size;
	int namelen = strlen(name);
	char *os2name = NULL;
	int rc;
	char *value;

	if ((rc = can_get_xattr(inode, name)))
		return rc;

	if (strncmp(name, XATTR_OS2_PREFIX, XATTR_OS2_PREFIX_LEN) == 0) {
		os2name = kmalloc(namelen - XATTR_OS2_PREFIX_LEN + 1,
				  GFP_KERNEL);
		if (!os2name)
			return -ENOMEM;
		strcpy(os2name, name + XATTR_OS2_PREFIX_LEN);
		name = os2name;
		namelen -= XATTR_OS2_PREFIX_LEN;
	}

	xattr_size = ea_get(inode, &ea_buf, 0);
	if (xattr_size < 0) {
		size = xattr_size;
		goto out;
	}

	if (xattr_size == 0)
		goto not_found;

	ealist = (struct jfs_ea_list *) ea_buf.xattr;

	/* Find the named attribute */
	for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea))
		if ((namelen == ea->namelen) &&
		    memcmp(name, ea->name, namelen) == 0) {
			/* Found it */
			size = le16_to_cpu(ea->valuelen);
			if (!data)
				goto release;
			else if (size > buf_size) {
				size = -ERANGE;
				goto release;
			}
			value = ((char *) &ea->name) + ea->namelen + 1;
			memcpy(data, value, size);
			goto release;
		}
      not_found:
	size = -ENODATA;
      release:
	ea_release(inode, &ea_buf);
      out:
	if (os2name)
		kfree(os2name);

	return size;
}

ssize_t jfs_getxattr(struct dentry *dentry, const char *name, void *data,
		     size_t buf_size)
{
	return __jfs_getxattr(dentry->d_inode, name, data, buf_size);
}

ssize_t jfs_listxattr(struct dentry * dentry, char *data, size_t buf_size)
{
	struct inode *inode = dentry->d_inode;
	char *buffer;
	ssize_t size = 0;
	int xattr_size;
	struct jfs_ea_list *ealist;
	struct jfs_ea *ea;
	struct ea_buffer ea_buf;

	xattr_size = ea_get(inode, &ea_buf, 0);
	if (xattr_size < 0) {
		size = xattr_size;
		goto out;
	}

	if (xattr_size == 0)
		goto release;

	ealist = (struct jfs_ea_list *) ea_buf.xattr;

	/* compute required size of list */
	for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea))
		size += name_size(ea) + 1;

	if (!data)
		goto release;

	if (size > buf_size) {
		size = -ERANGE;
		goto release;
	}

	/* Copy attribute names to buffer */
	buffer = data;
	for (ea = FIRST_EA(ealist); ea < END_EALIST(ealist); ea = NEXT_EA(ea)) {
		int namelen = copy_name(buffer, ea);
		buffer += namelen + 1;
	}

      release:
	ea_release(inode, &ea_buf);
      out:
	return size;
}

int jfs_removexattr(struct dentry *dentry, const char *name)
{
	return __jfs_setxattr(dentry->d_inode, name, 0, 0, XATTR_REPLACE);
}

#endif	/* JFS_XATTR */