xfs_attr.c

来自「Linux Kernel 2.6.9 for OMAP1710」· C语言 代码 · 共 2,474 行 · 第 1/5 页

	memset((char *)&args, 0, sizeof(args));
	args.name = name;
	args.namelen = namelen;
	args.flags = flags;
	args.hashval = xfs_da_hashname(args.name, args.namelen);
	args.dp = dp;
	args.firstblock = &firstblock;
	args.flist = &flist;
	args.total = 0;
	args.whichfork = XFS_ATTR_FORK;

	/*
	 * Attach the dquots to the inode.
	 */
	if ((error = XFS_QM_DQATTACH(mp, dp, 0)))
		return (error);

	/*
	 * 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.
	 */
	args.trans = xfs_trans_alloc(mp, XFS_TRANS_ATTR_RM);

	/*
	 * Root fork attributes can use reserved data blocks for this
	 * operation if necessary
	 */

	if (flags & ATTR_ROOT)
		args.trans->t_flags |= XFS_TRANS_RESERVE;

	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,
				 NULL);
	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);
}

/*
 * 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(bhv_desc_t *bdp, char *buffer, int bufsize, int flags,
		      attrlist_cursor_kern_t *cursor, struct cred *cred)
{
	xfs_attr_list_context_t context;
	xfs_inode_t *dp;
	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 = XFS_BHVTOI(bdp);
	context.cursor = cursor;
	context.count = 0;
	context.dupcnt = 0;
	context.resynch = 1;
	context.flags = flags;
	if (!(flags & ATTR_KERNAMELS)) {
		context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
		context.firstu = context.bufsize;
		context.alist = (attrlist_t *)buffer;
		context.alist->al_count = 0;
		context.alist->al_more = 0;
		context.alist->al_offset[0] = context.bufsize;
	}
	else {
		context.bufsize = bufsize;
		context.firstu = context.bufsize;
		context.alist = (attrlist_t *)buffer;
	}

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

	xfs_ilock(dp, XFS_ILOCK_SHARED);
	if (!(flags & ATTR_SECURE) &&
	     (error = xfs_iaccess(dp, S_IRUSR, cred))) {
		xfs_iunlock(dp, XFS_ILOCK_SHARED);
		return(XFS_ERROR(error));
	}

	/*
	 * Decide on what work routines to call based on the inode size.
	 */
	xfs_attr_trace_l_c("syscall start", &context);
	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);
	}
	xfs_iunlock(dp, XFS_ILOCK_SHARED);
	xfs_attr_trace_l_c("syscall end", &context);

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

	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,
				 NULL);
	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, 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);
	}

	newsize = XFS_ATTR_SF_TOTSIZE(args->dp);
	newsize += XFS_ATTR_SF_ENTSIZE_BYNAME(args->namelen, args->valuelen);
	if ((newsize <= XFS_IFORK_ASIZE(args->dp)) &&
	    (args->namelen < XFS_ATTR_SF_ENTSIZE_MAX) &&
	    (args->valuelen < XFS_ATTR_SF_ENTSIZE_MAX)) {
		retval = xfs_attr_shortform_add(args);
		ASSERT(retval == 0);
	} else {
		return(XFS_ERROR(ENOSPC));
	}
	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;

	/*
	 * 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,
						*args->firstblock, &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
		 * a new one.  We need the inode to be in all transactions.
		 */
		if (committed) {
			xfs_trans_ijoin(args->trans, dp, XFS_ILOCK_EXCL);
			xfs_trans_ihold(args->trans, dp);
		}

		/*
		 * Commit the current trans (including the inode) and start
		 * a new one.
		 */
		if ((error = xfs_attr_rolltrans(&args->trans, dp)))
			return (error);

		/*
		 * Fob the whole rest of the problem off on the Btree code.
		 */
		error = xfs_attr_node_addname(args);
		return(error);
	}

	/*
	 * Commit the transaction that added the attr name so that
	 * later routines can manage their own transactions.
	 */
	if ((error = xfs_attr_rolltrans(&args->trans, dp)))
		return (error);

	/*
	 * If there was an out-of-line value, allocate the blocks we
	 * identified for its storage and copy the value.  This is done
	 * after we create the attribute so that we don't overflow the
	 * maximum size of a transaction and/or hit a deadlock.
	 */
	if (args->rmtblkno > 0) {
		error = xfs_attr_rmtval_set(args);
		if (error)
			return(error);
	}

	/*
	 * If this is an atomic rename operation, we must "flip" the
	 * incomplete flags on the "new" and "old" attribute/value pairs
	 * so that one disappears and one appears atomically.  Then we
	 * must remove the "old" attribute/value pair.
	 */
	if (args->rename) {
		/*
		 * In a separate transaction, set the incomplete flag on the
		 * "old" attr and clear the incomplete flag on the "new" attr.
		 */
		error = xfs_attr_leaf_flipflags(args);
		if (error)
			return(error);

		/*
		 * Dismantle the "old" attribute/value pair by removing
		 * a "remote" value (if it exists).
		 */
		args->index = args->index2;
		args->blkno = args->blkno2;
		args->rmtblkno = args->rmtblkno2;
		args->rmtblkcnt = args->rmtblkcnt2;
		if (args->rmtblkno) {
			error = xfs_attr_rmtval_remove(args);
			if (error)
				return(error);
		}

		/*
		 * Read in the block containing the "old" attr, then
		 * remove the "old" attr from that block (neat, huh!)
		 */
		error = xfs_da_read_buf(args->trans, args->dp, args->blkno, -1,
						     &bp, XFS_ATTR_FORK);
		if (error)
			return(error);
		ASSERT(bp != NULL);
		(void)xfs_attr_leaf_remove(bp, args);

		/*
		 * If the result is small enough, shrink it all into the inode.
		 */