xfs_attr.c

linux 内核源代码

	if ((error = xfs_trans_reserve(args.trans,
				      XFS_ATTRRM_SPACE_RES(mp),
				      XFS_ATTRRM_LOG_RES(mp),
				      0, XFS_TRANS_PERM_LOG_RES,
				      XFS_ATTRRM_LOG_COUNT))) {
		xfs_trans_cancel(args.trans, 0);
		return(error);
	}

	xfs_ilock(dp, XFS_ILOCK_EXCL);
	/*
	 * No need to make quota reservations here. We expect to release some
	 * blocks not allocate in the common case.
	 */
	xfs_trans_ijoin(args.trans, dp, XFS_ILOCK_EXCL);
	xfs_trans_ihold(args.trans, dp);

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	if (XFS_IFORK_Q(dp) == 0 ||
	    (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
	     dp->i_d.di_anextents == 0)) {
		error = XFS_ERROR(ENOATTR);
		goto out;
	}
	if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
		ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
		error = xfs_attr_shortform_remove(&args);
		if (error) {
			goto out;
		}
	} else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
		error = xfs_attr_leaf_removename(&args);
	} else {
		error = xfs_attr_node_removename(&args);
	}
	if (error) {
		goto out;
	}

	/*
	 * If this is a synchronous mount, make sure that the
	 * transaction goes to disk before returning to the user.
	 */
	if (mp->m_flags & XFS_MOUNT_WSYNC) {
		xfs_trans_set_sync(args.trans);
	}

	/*
	 * Commit the last in the sequence of transactions.
	 */
	xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
	error = xfs_trans_commit(args.trans, XFS_TRANS_RELEASE_LOG_RES);
	xfs_iunlock(dp, XFS_ILOCK_EXCL);

	/*
	 * Hit the inode change time.
	 */
	if (!error && (flags & ATTR_KERNOTIME) == 0) {
		xfs_ichgtime(dp, XFS_ICHGTIME_CHG);
	}

	return(error);

out:
	if (args.trans)
		xfs_trans_cancel(args.trans,
			XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
	xfs_iunlock(dp, XFS_ILOCK_EXCL);
	return(error);
}

int
xfs_attr_remove(
	xfs_inode_t	*dp,
	const char	*name,
	int		flags)
{
	int		namelen;

	namelen = strlen(name);
	if (namelen >= MAXNAMELEN)
		return EFAULT;		/* match IRIX behaviour */

	XFS_STATS_INC(xs_attr_remove);

	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
		return (EIO);

	xfs_ilock(dp, XFS_ILOCK_SHARED);
	if (XFS_IFORK_Q(dp) == 0 ||
		   (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
		    dp->i_d.di_anextents == 0)) {
		xfs_iunlock(dp, XFS_ILOCK_SHARED);
		return(XFS_ERROR(ENOATTR));
	}
	xfs_iunlock(dp, XFS_ILOCK_SHARED);

	return xfs_attr_remove_int(dp, name, namelen, flags);
}

int								/* error */
xfs_attr_list_int(xfs_attr_list_context_t *context)
{
	int error;
	xfs_inode_t *dp = context->dp;

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	if (XFS_IFORK_Q(dp) == 0 ||
	    (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
	     dp->i_d.di_anextents == 0)) {
		error = 0;
	} else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
		error = xfs_attr_shortform_list(context);
	} else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
		error = xfs_attr_leaf_list(context);
	} else {
		error = xfs_attr_node_list(context);
	}
	return error;
}

#define	ATTR_ENTBASESIZE		/* minimum bytes used by an attr */ \
	(((struct attrlist_ent *) 0)->a_name - (char *) 0)
#define	ATTR_ENTSIZE(namelen)		/* actual bytes used by an attr */ \
	((ATTR_ENTBASESIZE + (namelen) + 1 + sizeof(u_int32_t)-1) \
	 & ~(sizeof(u_int32_t)-1))

/*
 * Format an attribute and copy it out to the user's buffer.
 * Take care to check values and protect against them changing later,
 * we may be reading them directly out of a user buffer.
 */
/*ARGSUSED*/
STATIC int
xfs_attr_put_listent(xfs_attr_list_context_t *context, attrnames_t *namesp,
		     char *name, int namelen,
		     int valuelen, char *value)
{
	attrlist_ent_t *aep;
	int arraytop;

	ASSERT(!(context->flags & ATTR_KERNOVAL));
	ASSERT(context->count >= 0);
	ASSERT(context->count < (ATTR_MAX_VALUELEN/8));
	ASSERT(context->firstu >= sizeof(*context->alist));
	ASSERT(context->firstu <= context->bufsize);

	arraytop = sizeof(*context->alist) +
			context->count * sizeof(context->alist->al_offset[0]);
	context->firstu -= ATTR_ENTSIZE(namelen);
	if (context->firstu < arraytop) {
		xfs_attr_trace_l_c("buffer full", context);
		context->alist->al_more = 1;
		context->seen_enough = 1;
		return 1;
	}

	aep = (attrlist_ent_t *)&(((char *)context->alist)[ context->firstu ]);
	aep->a_valuelen = valuelen;
	memcpy(aep->a_name, name, namelen);
	aep->a_name[ namelen ] = 0;
	context->alist->al_offset[ context->count++ ] = context->firstu;
	context->alist->al_count = context->count;
	xfs_attr_trace_l_c("add", context);
	return 0;
}

STATIC int
xfs_attr_kern_list(xfs_attr_list_context_t *context, attrnames_t *namesp,
		     char *name, int namelen,
		     int valuelen, char *value)
{
	char *offset;
	int arraytop;

	ASSERT(context->count >= 0);

	arraytop = context->count + namesp->attr_namelen + namelen + 1;
	if (arraytop > context->firstu) {
		context->count = -1;	/* insufficient space */
		return 1;
	}
	offset = (char *)context->alist + context->count;
	strncpy(offset, namesp->attr_name, namesp->attr_namelen);
	offset += namesp->attr_namelen;
	strncpy(offset, name, namelen);			/* real name */
	offset += namelen;
	*offset = '\0';
	context->count += namesp->attr_namelen + namelen + 1;
	return 0;
}

/*ARGSUSED*/
STATIC int
xfs_attr_kern_list_sizes(xfs_attr_list_context_t *context, attrnames_t *namesp,
		     char *name, int namelen,
		     int valuelen, char *value)
{
	context->count += namesp->attr_namelen + namelen + 1;
	return 0;
}

/*
 * Generate a list of extended attribute names and optionally
 * also value lengths.  Positive return value follows the XFS
 * convention of being an error, zero or negative return code
 * is the length of the buffer returned (negated), indicating
 * success.
 */
int
xfs_attr_list(
	xfs_inode_t	*dp,
	char		*buffer,
	int		bufsize,
	int		flags,
	attrlist_cursor_kern_t *cursor)
{
	xfs_attr_list_context_t context;
	int error;

	XFS_STATS_INC(xs_attr_list);

	/*
	 * Validate the cursor.
	 */
	if (cursor->pad1 || cursor->pad2)
		return(XFS_ERROR(EINVAL));
	if ((cursor->initted == 0) &&
	    (cursor->hashval || cursor->blkno || cursor->offset))
		return XFS_ERROR(EINVAL);

	/*
	 * Check for a properly aligned buffer.
	 */
	if (((long)buffer) & (sizeof(int)-1))
		return XFS_ERROR(EFAULT);
	if (flags & ATTR_KERNOVAL)
		bufsize = 0;

	/*
	 * Initialize the output buffer.
	 */
	context.dp = dp;
	context.cursor = cursor;
	context.count = 0;
	context.dupcnt = 0;
	context.resynch = 1;
	context.flags = flags;
	context.seen_enough = 0;
	context.alist = (attrlist_t *)buffer;
	context.put_value = 0;

	if (flags & ATTR_KERNAMELS) {
		context.bufsize = bufsize;
		context.firstu = context.bufsize;
		if (flags & ATTR_KERNOVAL)
			context.put_listent = xfs_attr_kern_list_sizes;
		else
			context.put_listent = xfs_attr_kern_list;
	} else {
		context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
		context.firstu = context.bufsize;
		context.alist->al_count = 0;
		context.alist->al_more = 0;
		context.alist->al_offset[0] = context.bufsize;
		context.put_listent = xfs_attr_put_listent;
	}

	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
		return EIO;

	xfs_ilock(dp, XFS_ILOCK_SHARED);
	xfs_attr_trace_l_c("syscall start", &context);

	error = xfs_attr_list_int(&context);

	xfs_iunlock(dp, XFS_ILOCK_SHARED);
	xfs_attr_trace_l_c("syscall end", &context);

	if (context.flags & (ATTR_KERNOVAL|ATTR_KERNAMELS)) {
		/* must return negated buffer size or the error */
		if (context.count < 0)
			error = XFS_ERROR(ERANGE);
		else
			error = -context.count;
	} else
		ASSERT(error >= 0);

	return error;
}

int								/* error */
xfs_attr_inactive(xfs_inode_t *dp)
{
	xfs_trans_t *trans;
	xfs_mount_t *mp;
	int error;

	mp = dp->i_mount;
	ASSERT(! XFS_NOT_DQATTACHED(mp, dp));

	xfs_ilock(dp, XFS_ILOCK_SHARED);
	if ((XFS_IFORK_Q(dp) == 0) ||
	    (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) ||
	    (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
	     dp->i_d.di_anextents == 0)) {
		xfs_iunlock(dp, XFS_ILOCK_SHARED);
		return(0);
	}
	xfs_iunlock(dp, XFS_ILOCK_SHARED);

	/*
	 * Start our first transaction of the day.
	 *
	 * All future transactions during this code must be "chained" off
	 * this one via the trans_dup() call.  All transactions will contain
	 * the inode, and the inode will always be marked with trans_ihold().
	 * Since the inode will be locked in all transactions, we must log
	 * the inode in every transaction to let it float upward through
	 * the log.
	 */
	trans = xfs_trans_alloc(mp, XFS_TRANS_ATTRINVAL);
	if ((error = xfs_trans_reserve(trans, 0, XFS_ATTRINVAL_LOG_RES(mp), 0,
				      XFS_TRANS_PERM_LOG_RES,
				      XFS_ATTRINVAL_LOG_COUNT))) {
		xfs_trans_cancel(trans, 0);
		return(error);
	}
	xfs_ilock(dp, XFS_ILOCK_EXCL);

	/*
	 * No need to make quota reservations here. We expect to release some
	 * blocks, not allocate, in the common case.
	 */
	xfs_trans_ijoin(trans, dp, XFS_ILOCK_EXCL);
	xfs_trans_ihold(trans, dp);

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	if ((XFS_IFORK_Q(dp) == 0) ||
	    (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) ||
	    (dp->i_d.di_aformat == XFS_DINODE_FMT_EXTENTS &&
	     dp->i_d.di_anextents == 0)) {
		error = 0;
		goto out;
	}
	error = xfs_attr_root_inactive(&trans, dp);
	if (error)
		goto out;
	/*
	 * signal synchronous inactive transactions unless this
	 * is a synchronous mount filesystem in which case we
	 * know that we're here because we've been called out of
	 * xfs_inactive which means that the last reference is gone
	 * and the unlink transaction has already hit the disk so
	 * async inactive transactions are safe.
	 */
	if ((error = xfs_itruncate_finish(&trans, dp, 0LL, XFS_ATTR_FORK,
				(!(mp->m_flags & XFS_MOUNT_WSYNC)
				 ? 1 : 0))))
		goto out;

	/*
	 * Commit the last in the sequence of transactions.
	 */
	xfs_trans_log_inode(trans, dp, XFS_ILOG_CORE);
	error = xfs_trans_commit(trans, XFS_TRANS_RELEASE_LOG_RES);
	xfs_iunlock(dp, XFS_ILOCK_EXCL);

	return(error);

out:
	xfs_trans_cancel(trans, XFS_TRANS_RELEASE_LOG_RES|XFS_TRANS_ABORT);
	xfs_iunlock(dp, XFS_ILOCK_EXCL);
	return(error);
}



/*========================================================================
 * External routines when attribute list is inside the inode
 *========================================================================*/

/*
 * Add a name to the shortform attribute list structure
 * This is the external routine.
 */
STATIC int
xfs_attr_shortform_addname(xfs_da_args_t *args)
{
	int newsize, forkoff, retval;

	retval = xfs_attr_shortform_lookup(args);
	if ((args->flags & ATTR_REPLACE) && (retval == ENOATTR)) {
		return(retval);
	} else if (retval == EEXIST) {
		if (args->flags & ATTR_CREATE)
			return(retval);
		retval = xfs_attr_shortform_remove(args);
		ASSERT(retval == 0);
	}

	if (args->namelen >= XFS_ATTR_SF_ENTSIZE_MAX ||
	    args->valuelen >= XFS_ATTR_SF_ENTSIZE_MAX)
		return(XFS_ERROR(ENOSPC));

	newsize = XFS_ATTR_SF_TOTSIZE(args->dp);
	newsize += XFS_ATTR_SF_ENTSIZE_BYNAME(args->namelen, args->valuelen);

	forkoff = xfs_attr_shortform_bytesfit(args->dp, newsize);
	if (!forkoff)
		return(XFS_ERROR(ENOSPC));

	xfs_attr_shortform_add(args, forkoff);
	return(0);
}


/*========================================================================
 * External routines when attribute list is one block
 *========================================================================*/

/*
 * Add a name to the leaf attribute list structure
 *
 * This leaf block cannot have a "remote" value, we only call this routine
 * if bmap_one_block() says there is only one block (ie: no remote blks).
 */
int
xfs_attr_leaf_addname(xfs_da_args_t *args)
{
	xfs_inode_t *dp;
	xfs_dabuf_t *bp;
	int retval, error, committed, forkoff;

	/*
	 * Read the (only) block in the attribute list in.
	 */
	dp = args->dp;
	args->blkno = 0;
	error = xfs_da_read_buf(args->trans, args->dp, args->blkno, -1, &bp,
					     XFS_ATTR_FORK);
	if (error)
		return(error);
	ASSERT(bp != NULL);

	/*
	 * Look up the given attribute in the leaf block.  Figure out if
	 * the given flags produce an error or call for an atomic rename.
	 */
	retval = xfs_attr_leaf_lookup_int(bp, args);
	if ((args->flags & ATTR_REPLACE) && (retval == ENOATTR)) {
		xfs_da_brelse(args->trans, bp);
		return(retval);
	} else if (retval == EEXIST) {
		if (args->flags & ATTR_CREATE) {	/* pure create op */
			xfs_da_brelse(args->trans, bp);
			return(retval);
		}
		args->rename = 1;			/* an atomic rename */
		args->blkno2 = args->blkno;		/* set 2nd entry info*/
		args->index2 = args->index;
		args->rmtblkno2 = args->rmtblkno;
		args->rmtblkcnt2 = args->rmtblkcnt;
	}

	/*
	 * Add the attribute to the leaf block, transitioning to a Btree
	 * if required.
	 */
	retval = xfs_attr_leaf_add(bp, args);
	xfs_da_buf_done(bp);
	if (retval == ENOSPC) {
		/*
		 * Promote the attribute list to the Btree format, then
		 * Commit that transaction so that the node_addname() call
		 * can manage its own transactions.
		 */
		XFS_BMAP_INIT(args->flist, args->firstblock);
		error = xfs_attr_leaf_to_node(args);
		if (!error) {
			error = xfs_bmap_finish(&args->trans, args->flist,
						&committed);
		}
		if (error) {
			ASSERT(committed);
			args->trans = NULL;
			xfs_bmap_cancel(args->flist);
			return(error);
		}

		/*
		 * bmap_finish() may have committed the last trans and started