xfs_dir2_sf.c

linux 内核源代码

}

/*
 * Add the new entry the "hard" way.
 * The caller has already converted to 8 byte inode numbers if necessary,
 * in which case we need to leave the i8count at 1.
 * Find a hole that the new entry will fit into, and copy
 * the first part of the entries, the new entry, and the last part of
 * the entries.
 */
/* ARGSUSED */
static void
xfs_dir2_sf_addname_hard(
	xfs_da_args_t		*args,		/* operation arguments */
	int			objchange,	/* changing inode number size */
	int			new_isize)	/* new directory size */
{
	int			add_datasize;	/* data size need for new ent */
	char			*buf;		/* buffer for old */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			eof;		/* reached end of old dir */
	int			nbytes;		/* temp for byte copies */
	xfs_dir2_data_aoff_t	new_offset;	/* next offset value */
	xfs_dir2_data_aoff_t	offset;		/* current offset value */
	int			old_isize;	/* previous di_size */
	xfs_dir2_sf_entry_t	*oldsfep;	/* entry in original dir */
	xfs_dir2_sf_t		*oldsfp;	/* original shortform dir */
	xfs_dir2_sf_entry_t	*sfep;		/* entry in new dir */
	xfs_dir2_sf_t		*sfp;		/* new shortform dir */

	/*
	 * Copy the old directory to the stack buffer.
	 */
	dp = args->dp;

	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	old_isize = (int)dp->i_d.di_size;
	buf = kmem_alloc(old_isize, KM_SLEEP);
	oldsfp = (xfs_dir2_sf_t *)buf;
	memcpy(oldsfp, sfp, old_isize);
	/*
	 * Loop over the old directory finding the place we're going
	 * to insert the new entry.
	 * If it's going to end up at the end then oldsfep will point there.
	 */
	for (offset = XFS_DIR2_DATA_FIRST_OFFSET,
	      oldsfep = xfs_dir2_sf_firstentry(oldsfp),
	      add_datasize = xfs_dir2_data_entsize(args->namelen),
	      eof = (char *)oldsfep == &buf[old_isize];
	     !eof;
	     offset = new_offset + xfs_dir2_data_entsize(oldsfep->namelen),
	      oldsfep = xfs_dir2_sf_nextentry(oldsfp, oldsfep),
	      eof = (char *)oldsfep == &buf[old_isize]) {
		new_offset = xfs_dir2_sf_get_offset(oldsfep);
		if (offset + add_datasize <= new_offset)
			break;
	}
	/*
	 * Get rid of the old directory, then allocate space for
	 * the new one.  We do this so xfs_idata_realloc won't copy
	 * the data.
	 */
	xfs_idata_realloc(dp, -old_isize, XFS_DATA_FORK);
	xfs_idata_realloc(dp, new_isize, XFS_DATA_FORK);
	/*
	 * Reset the pointer since the buffer was reallocated.
	 */
	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	/*
	 * Copy the first part of the directory, including the header.
	 */
	nbytes = (int)((char *)oldsfep - (char *)oldsfp);
	memcpy(sfp, oldsfp, nbytes);
	sfep = (xfs_dir2_sf_entry_t *)((char *)sfp + nbytes);
	/*
	 * Fill in the new entry, and update the header counts.
	 */
	sfep->namelen = args->namelen;
	xfs_dir2_sf_put_offset(sfep, offset);
	memcpy(sfep->name, args->name, sfep->namelen);
	xfs_dir2_sf_put_inumber(sfp, &args->inumber,
		xfs_dir2_sf_inumberp(sfep));
	sfp->hdr.count++;
#if XFS_BIG_INUMS
	if (args->inumber > XFS_DIR2_MAX_SHORT_INUM && !objchange)
		sfp->hdr.i8count++;
#endif
	/*
	 * If there's more left to copy, do that.
	 */
	if (!eof) {
		sfep = xfs_dir2_sf_nextentry(sfp, sfep);
		memcpy(sfep, oldsfep, old_isize - nbytes);
	}
	kmem_free(buf, old_isize);
	dp->i_d.di_size = new_isize;
	xfs_dir2_sf_check(args);
}

/*
 * Decide if the new entry will fit at all.
 * If it will fit, pick between adding the new entry to the end (easy)
 * or somewhere else (hard).
 * Return 0 (won't fit), 1 (easy), 2 (hard).
 */
/*ARGSUSED*/
static int					/* pick result */
xfs_dir2_sf_addname_pick(
	xfs_da_args_t		*args,		/* operation arguments */
	int			objchange,	/* inode # size changes */
	xfs_dir2_sf_entry_t	**sfepp,	/* out(1): new entry ptr */
	xfs_dir2_data_aoff_t	*offsetp)	/* out(1): new offset */
{
	xfs_inode_t		*dp;		/* incore directory inode */
	int			holefit;	/* found hole it will fit in */
	int			i;		/* entry number */
	xfs_mount_t		*mp;		/* filesystem mount point */
	xfs_dir2_data_aoff_t	offset;		/* data block offset */
	xfs_dir2_sf_entry_t	*sfep;		/* shortform entry */
	xfs_dir2_sf_t		*sfp;		/* shortform structure */
	int			size;		/* entry's data size */
	int			used;		/* data bytes used */

	dp = args->dp;
	mp = dp->i_mount;

	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	size = xfs_dir2_data_entsize(args->namelen);
	offset = XFS_DIR2_DATA_FIRST_OFFSET;
	sfep = xfs_dir2_sf_firstentry(sfp);
	holefit = 0;
	/*
	 * Loop over sf entries.
	 * Keep track of data offset and whether we've seen a place
	 * to insert the new entry.
	 */
	for (i = 0; i < sfp->hdr.count; i++) {
		if (!holefit)
			holefit = offset + size <= xfs_dir2_sf_get_offset(sfep);
		offset = xfs_dir2_sf_get_offset(sfep) +
			 xfs_dir2_data_entsize(sfep->namelen);
		sfep = xfs_dir2_sf_nextentry(sfp, sfep);
	}
	/*
	 * Calculate data bytes used excluding the new entry, if this
	 * was a data block (block form directory).
	 */
	used = offset +
	       (sfp->hdr.count + 3) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
	       (uint)sizeof(xfs_dir2_block_tail_t);
	/*
	 * If it won't fit in a block form then we can't insert it,
	 * we'll go back, convert to block, then try the insert and convert
	 * to leaf.
	 */
	if (used + (holefit ? 0 : size) > mp->m_dirblksize)
		return 0;
	/*
	 * If changing the inode number size, do it the hard way.
	 */
#if XFS_BIG_INUMS
	if (objchange) {
		return 2;
	}
#else
	ASSERT(objchange == 0);
#endif
	/*
	 * If it won't fit at the end then do it the hard way (use the hole).
	 */
	if (used + size > mp->m_dirblksize)
		return 2;
	/*
	 * Do it the easy way.
	 */
	*sfepp = sfep;
	*offsetp = offset;
	return 1;
}

#ifdef DEBUG
/*
 * Check consistency of shortform directory, assert if bad.
 */
static void
xfs_dir2_sf_check(
	xfs_da_args_t		*args)		/* operation arguments */
{
	xfs_inode_t		*dp;		/* incore directory inode */
	int			i;		/* entry number */
	int			i8count;	/* number of big inode#s */
	xfs_ino_t		ino;		/* entry inode number */
	int			offset;		/* data offset */
	xfs_dir2_sf_entry_t	*sfep;		/* shortform dir entry */
	xfs_dir2_sf_t		*sfp;		/* shortform structure */

	dp = args->dp;

	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	offset = XFS_DIR2_DATA_FIRST_OFFSET;
	ino = xfs_dir2_sf_get_inumber(sfp, &sfp->hdr.parent);
	i8count = ino > XFS_DIR2_MAX_SHORT_INUM;

	for (i = 0, sfep = xfs_dir2_sf_firstentry(sfp);
	     i < sfp->hdr.count;
	     i++, sfep = xfs_dir2_sf_nextentry(sfp, sfep)) {
		ASSERT(xfs_dir2_sf_get_offset(sfep) >= offset);
		ino = xfs_dir2_sf_get_inumber(sfp, xfs_dir2_sf_inumberp(sfep));
		i8count += ino > XFS_DIR2_MAX_SHORT_INUM;
		offset =
			xfs_dir2_sf_get_offset(sfep) +
			xfs_dir2_data_entsize(sfep->namelen);
	}
	ASSERT(i8count == sfp->hdr.i8count);
	ASSERT(XFS_BIG_INUMS || i8count == 0);
	ASSERT((char *)sfep - (char *)sfp == dp->i_d.di_size);
	ASSERT(offset +
	       (sfp->hdr.count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t) +
	       (uint)sizeof(xfs_dir2_block_tail_t) <=
	       dp->i_mount->m_dirblksize);
}
#endif	/* DEBUG */

/*
 * Create a new (shortform) directory.
 */
int					/* error, always 0 */
xfs_dir2_sf_create(
	xfs_da_args_t	*args,		/* operation arguments */
	xfs_ino_t	pino)		/* parent inode number */
{
	xfs_inode_t	*dp;		/* incore directory inode */
	int		i8count;	/* parent inode is an 8-byte number */
	xfs_dir2_sf_t	*sfp;		/* shortform structure */
	int		size;		/* directory size */

	xfs_dir2_trace_args_i("sf_create", args, pino);
	dp = args->dp;

	ASSERT(dp != NULL);
	ASSERT(dp->i_d.di_size == 0);
	/*
	 * If it's currently a zero-length extent file,
	 * convert it to local format.
	 */
	if (dp->i_d.di_format == XFS_DINODE_FMT_EXTENTS) {
		dp->i_df.if_flags &= ~XFS_IFEXTENTS;	/* just in case */
		dp->i_d.di_format = XFS_DINODE_FMT_LOCAL;
		xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE);
		dp->i_df.if_flags |= XFS_IFINLINE;
	}
	ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
	ASSERT(dp->i_df.if_bytes == 0);
	i8count = pino > XFS_DIR2_MAX_SHORT_INUM;
	size = xfs_dir2_sf_hdr_size(i8count);
	/*
	 * Make a buffer for the data.
	 */
	xfs_idata_realloc(dp, size, XFS_DATA_FORK);
	/*
	 * Fill in the header,
	 */
	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	sfp->hdr.i8count = i8count;
	/*
	 * Now can put in the inode number, since i8count is set.
	 */
	xfs_dir2_sf_put_inumber(sfp, &pino, &sfp->hdr.parent);
	sfp->hdr.count = 0;
	dp->i_d.di_size = size;
	xfs_dir2_sf_check(args);
	xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA);
	return 0;
}

int						/* error */
xfs_dir2_sf_getdents(
	xfs_inode_t		*dp,		/* incore directory inode */
	void			*dirent,
	xfs_off_t		*offset,
	filldir_t		filldir)
{
	int			i;		/* shortform entry number */
	xfs_mount_t		*mp;		/* filesystem mount point */
	xfs_dir2_dataptr_t	off;		/* current entry's offset */
	xfs_dir2_sf_entry_t	*sfep;		/* shortform directory entry */
	xfs_dir2_sf_t		*sfp;		/* shortform structure */
	xfs_dir2_dataptr_t	dot_offset;
	xfs_dir2_dataptr_t	dotdot_offset;
	xfs_ino_t		ino;

	mp = dp->i_mount;

	ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
	/*
	 * Give up if the directory is way too short.
	 */
	if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
		ASSERT(XFS_FORCED_SHUTDOWN(mp));
		return XFS_ERROR(EIO);
	}

	ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
	ASSERT(dp->i_df.if_u1.if_data != NULL);

	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;

	ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->hdr.i8count));

	/*
	 * If the block number in the offset is out of range, we're done.
	 */
	if (xfs_dir2_dataptr_to_db(mp, *offset) > mp->m_dirdatablk)
		return 0;

	/*
	 * Precalculate offsets for . and .. as we will always need them.
	 *
	 * XXX(hch): the second argument is sometimes 0 and sometimes
	 * mp->m_dirdatablk.
	 */
	dot_offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
					     XFS_DIR2_DATA_DOT_OFFSET);
	dotdot_offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
						XFS_DIR2_DATA_DOTDOT_OFFSET);

	/*
	 * Put . entry unless we're starting past it.
	 */
	if (*offset <= dot_offset) {
		ino = dp->i_ino;
#if XFS_BIG_INUMS
		ino += mp->m_inoadd;
#endif
		if (filldir(dirent, ".", 1, dot_offset, ino, DT_DIR)) {
			*offset = dot_offset;
			return 0;
		}
	}

	/*
	 * Put .. entry unless we're starting past it.
	 */
	if (*offset <= dotdot_offset) {
		ino = xfs_dir2_sf_get_inumber(sfp, &sfp->hdr.parent);
#if XFS_BIG_INUMS
		ino += mp->m_inoadd;
#endif
		if (filldir(dirent, "..", 2, dotdot_offset, ino, DT_DIR)) {
			*offset = dotdot_offset;
			return 0;
		}
	}

	/*
	 * Loop while there are more entries and put'ing works.
	 */
	sfep = xfs_dir2_sf_firstentry(sfp);
	for (i = 0; i < sfp->hdr.count; i++) {
		off = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,
				xfs_dir2_sf_get_offset(sfep));

		if (*offset > off) {
			sfep = xfs_dir2_sf_nextentry(sfp, sfep);
			continue;
		}

		ino = xfs_dir2_sf_get_inumber(sfp, xfs_dir2_sf_inumberp(sfep));
#if XFS_BIG_INUMS
		ino += mp->m_inoadd;
#endif

		if (filldir(dirent, sfep->name, sfep->namelen,
					    off, ino, DT_UNKNOWN)) {
			*offset = off;
			return 0;
		}
		sfep = xfs_dir2_sf_nextentry(sfp, sfep);
	}

	*offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0);
	return 0;
}

/*
 * Lookup an entry in a shortform directory.
 * Returns EEXIST if found, ENOENT if not found.
 */
int						/* error */
xfs_dir2_sf_lookup(
	xfs_da_args_t		*args)		/* operation arguments */
{
	xfs_inode_t		*dp;		/* incore directory inode */
	int			i;		/* entry index */
	xfs_dir2_sf_entry_t	*sfep;		/* shortform directory entry */
	xfs_dir2_sf_t		*sfp;		/* shortform structure */

	xfs_dir2_trace_args("sf_lookup", args);
	xfs_dir2_sf_check(args);
	dp = args->dp;

	ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
	/*
	 * Bail out if the directory is way too short.
	 */
	if (dp->i_d.di_size < offsetof(xfs_dir2_sf_hdr_t, parent)) {
		ASSERT(XFS_FORCED_SHUTDOWN(dp->i_mount));
		return XFS_ERROR(EIO);
	}
	ASSERT(dp->i_df.if_bytes == dp->i_d.di_size);
	ASSERT(dp->i_df.if_u1.if_data != NULL);
	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	ASSERT(dp->i_d.di_size >= xfs_dir2_sf_hdr_size(sfp->hdr.i8count));
	/*
	 * Special case for .
	 */
	if (args->namelen == 1 && args->name[0] == '.') {
		args->inumber = dp->i_ino;
		return XFS_ERROR(EEXIST);
	}