xfs_dir2_sf.c

linux 内核源代码

/*
 * Copyright (c) 2000-2003,2005 Silicon Graphics, Inc.
 * All Rights Reserved.
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it would be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write the Free Software Foundation,
 * Inc.,  51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
 */
#include "xfs.h"
#include "xfs_fs.h"
#include "xfs_types.h"
#include "xfs_log.h"
#include "xfs_inum.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_ag.h"
#include "xfs_dir2.h"
#include "xfs_dmapi.h"
#include "xfs_mount.h"
#include "xfs_da_btree.h"
#include "xfs_bmap_btree.h"
#include "xfs_dir2_sf.h"
#include "xfs_attr_sf.h"
#include "xfs_dinode.h"
#include "xfs_inode.h"
#include "xfs_inode_item.h"
#include "xfs_error.h"
#include "xfs_dir2_data.h"
#include "xfs_dir2_leaf.h"
#include "xfs_dir2_block.h"
#include "xfs_dir2_trace.h"

/*
 * Prototypes for internal functions.
 */
static void xfs_dir2_sf_addname_easy(xfs_da_args_t *args,
				     xfs_dir2_sf_entry_t *sfep,
				     xfs_dir2_data_aoff_t offset,
				     int new_isize);
static void xfs_dir2_sf_addname_hard(xfs_da_args_t *args, int objchange,
				     int new_isize);
static int xfs_dir2_sf_addname_pick(xfs_da_args_t *args, int objchange,
				    xfs_dir2_sf_entry_t **sfepp,
				    xfs_dir2_data_aoff_t *offsetp);
#ifdef DEBUG
static void xfs_dir2_sf_check(xfs_da_args_t *args);
#else
#define	xfs_dir2_sf_check(args)
#endif /* DEBUG */
#if XFS_BIG_INUMS
static void xfs_dir2_sf_toino4(xfs_da_args_t *args);
static void xfs_dir2_sf_toino8(xfs_da_args_t *args);
#endif /* XFS_BIG_INUMS */

/*
 * Given a block directory (dp/block), calculate its size as a shortform (sf)
 * directory and a header for the sf directory, if it will fit it the
 * space currently present in the inode.  If it won't fit, the output
 * size is too big (but not accurate).
 */
int						/* size for sf form */
xfs_dir2_block_sfsize(
	xfs_inode_t		*dp,		/* incore inode pointer */
	xfs_dir2_block_t	*block,		/* block directory data */
	xfs_dir2_sf_hdr_t	*sfhp)		/* output: header for sf form */
{
	xfs_dir2_dataptr_t	addr;		/* data entry address */
	xfs_dir2_leaf_entry_t	*blp;		/* leaf area of the block */
	xfs_dir2_block_tail_t	*btp;		/* tail area of the block */
	int			count;		/* shortform entry count */
	xfs_dir2_data_entry_t	*dep;		/* data entry in the block */
	int			i;		/* block entry index */
	int			i8count;	/* count of big-inode entries */
	int			isdot;		/* entry is "." */
	int			isdotdot;	/* entry is ".." */
	xfs_mount_t		*mp;		/* mount structure pointer */
	int			namelen;	/* total name bytes */
	xfs_ino_t		parent = 0;	/* parent inode number */
	int			size=0;		/* total computed size */

	mp = dp->i_mount;

	count = i8count = namelen = 0;
	btp = xfs_dir2_block_tail_p(mp, block);
	blp = xfs_dir2_block_leaf_p(btp);

	/*
	 * Iterate over the block's data entries by using the leaf pointers.
	 */
	for (i = 0; i < be32_to_cpu(btp->count); i++) {
		if ((addr = be32_to_cpu(blp[i].address)) == XFS_DIR2_NULL_DATAPTR)
			continue;
		/*
		 * Calculate the pointer to the entry at hand.
		 */
		dep = (xfs_dir2_data_entry_t *)
		      ((char *)block + xfs_dir2_dataptr_to_off(mp, addr));
		/*
		 * Detect . and .., so we can special-case them.
		 * . is not included in sf directories.
		 * .. is included by just the parent inode number.
		 */
		isdot = dep->namelen == 1 && dep->name[0] == '.';
		isdotdot =
			dep->namelen == 2 &&
			dep->name[0] == '.' && dep->name[1] == '.';
#if XFS_BIG_INUMS
		if (!isdot)
			i8count += be64_to_cpu(dep->inumber) > XFS_DIR2_MAX_SHORT_INUM;
#endif
		if (!isdot && !isdotdot) {
			count++;
			namelen += dep->namelen;
		} else if (isdotdot)
			parent = be64_to_cpu(dep->inumber);
		/*
		 * Calculate the new size, see if we should give up yet.
		 */
		size = xfs_dir2_sf_hdr_size(i8count) +		/* header */
		       count +					/* namelen */
		       count * (uint)sizeof(xfs_dir2_sf_off_t) + /* offset */
		       namelen +				/* name */
		       (i8count ?				/* inumber */
				(uint)sizeof(xfs_dir2_ino8_t) * count :
				(uint)sizeof(xfs_dir2_ino4_t) * count);
		if (size > XFS_IFORK_DSIZE(dp))
			return size;		/* size value is a failure */
	}
	/*
	 * Create the output header, if it worked.
	 */
	sfhp->count = count;
	sfhp->i8count = i8count;
	xfs_dir2_sf_put_inumber((xfs_dir2_sf_t *)sfhp, &parent, &sfhp->parent);
	return size;
}

/*
 * Convert a block format directory to shortform.
 * Caller has already checked that it will fit, and built us a header.
 */
int						/* error */
xfs_dir2_block_to_sf(
	xfs_da_args_t		*args,		/* operation arguments */
	xfs_dabuf_t		*bp,		/* block buffer */
	int			size,		/* shortform directory size */
	xfs_dir2_sf_hdr_t	*sfhp)		/* shortform directory hdr */
{
	xfs_dir2_block_t	*block;		/* block structure */
	xfs_dir2_block_tail_t	*btp;		/* block tail pointer */
	xfs_dir2_data_entry_t	*dep;		/* data entry pointer */
	xfs_inode_t		*dp;		/* incore directory inode */
	xfs_dir2_data_unused_t	*dup;		/* unused data pointer */
	char			*endptr;	/* end of data entries */
	int			error;		/* error return value */
	int			logflags;	/* inode logging flags */
	xfs_mount_t		*mp;		/* filesystem mount point */
	char			*ptr;		/* current data pointer */
	xfs_dir2_sf_entry_t	*sfep;		/* shortform entry */
	xfs_dir2_sf_t		*sfp;		/* shortform structure */
	xfs_ino_t               temp;

	xfs_dir2_trace_args_sb("block_to_sf", args, size, bp);
	dp = args->dp;
	mp = dp->i_mount;

	/*
	 * Make a copy of the block data, so we can shrink the inode
	 * and add local data.
	 */
	block = kmem_alloc(mp->m_dirblksize, KM_SLEEP);
	memcpy(block, bp->data, mp->m_dirblksize);
	logflags = XFS_ILOG_CORE;
	if ((error = xfs_dir2_shrink_inode(args, mp->m_dirdatablk, bp))) {
		ASSERT(error != ENOSPC);
		goto out;
	}
	/*
	 * The buffer is now unconditionally gone, whether
	 * xfs_dir2_shrink_inode worked or not.
	 *
	 * Convert the inode to local format.
	 */
	dp->i_df.if_flags &= ~XFS_IFEXTENTS;
	dp->i_df.if_flags |= XFS_IFINLINE;
	dp->i_d.di_format = XFS_DINODE_FMT_LOCAL;
	ASSERT(dp->i_df.if_bytes == 0);
	xfs_idata_realloc(dp, size, XFS_DATA_FORK);
	logflags |= XFS_ILOG_DDATA;
	/*
	 * Copy the header into the newly allocate local space.
	 */
	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	memcpy(sfp, sfhp, xfs_dir2_sf_hdr_size(sfhp->i8count));
	dp->i_d.di_size = size;
	/*
	 * Set up to loop over the block's entries.
	 */
	btp = xfs_dir2_block_tail_p(mp, block);
	ptr = (char *)block->u;
	endptr = (char *)xfs_dir2_block_leaf_p(btp);
	sfep = xfs_dir2_sf_firstentry(sfp);
	/*
	 * Loop over the active and unused entries.
	 * Stop when we reach the leaf/tail portion of the block.
	 */
	while (ptr < endptr) {
		/*
		 * If it's unused, just skip over it.
		 */
		dup = (xfs_dir2_data_unused_t *)ptr;
		if (be16_to_cpu(dup->freetag) == XFS_DIR2_DATA_FREE_TAG) {
			ptr += be16_to_cpu(dup->length);
			continue;
		}
		dep = (xfs_dir2_data_entry_t *)ptr;
		/*
		 * Skip .
		 */
		if (dep->namelen == 1 && dep->name[0] == '.')
			ASSERT(be64_to_cpu(dep->inumber) == dp->i_ino);
		/*
		 * Skip .., but make sure the inode number is right.
		 */
		else if (dep->namelen == 2 &&
			 dep->name[0] == '.' && dep->name[1] == '.')
			ASSERT(be64_to_cpu(dep->inumber) ==
			       xfs_dir2_sf_get_inumber(sfp, &sfp->hdr.parent));
		/*
		 * Normal entry, copy it into shortform.
		 */
		else {
			sfep->namelen = dep->namelen;
			xfs_dir2_sf_put_offset(sfep,
				(xfs_dir2_data_aoff_t)
				((char *)dep - (char *)block));
			memcpy(sfep->name, dep->name, dep->namelen);
			temp = be64_to_cpu(dep->inumber);
			xfs_dir2_sf_put_inumber(sfp, &temp,
				xfs_dir2_sf_inumberp(sfep));
			sfep = xfs_dir2_sf_nextentry(sfp, sfep);
		}
		ptr += xfs_dir2_data_entsize(dep->namelen);
	}
	ASSERT((char *)sfep - (char *)sfp == size);
	xfs_dir2_sf_check(args);
out:
	xfs_trans_log_inode(args->trans, dp, logflags);
	kmem_free(block, mp->m_dirblksize);
	return error;
}

/*
 * Add a name to a shortform directory.
 * There are two algorithms, "easy" and "hard" which we decide on
 * before changing anything.
 * Convert to block form if necessary, if the new entry won't fit.
 */
int						/* error */
xfs_dir2_sf_addname(
	xfs_da_args_t		*args)		/* operation arguments */
{
	int			add_entsize;	/* size of the new entry */
	xfs_inode_t		*dp;		/* incore directory inode */
	int			error;		/* error return value */
	int			incr_isize;	/* total change in size */
	int			new_isize;	/* di_size after adding name */
	int			objchange;	/* changing to 8-byte inodes */
	xfs_dir2_data_aoff_t	offset = 0;	/* offset for new entry */
	int			old_isize;	/* di_size before adding name */
	int			pick;		/* which algorithm to use */
	xfs_dir2_sf_t		*sfp;		/* shortform structure */
	xfs_dir2_sf_entry_t	*sfep = NULL;	/* shortform entry */

	xfs_dir2_trace_args("sf_addname", args);
	ASSERT(xfs_dir2_sf_lookup(args) == ENOENT);
	dp = args->dp;
	ASSERT(dp->i_df.if_flags & XFS_IFINLINE);
	/*
	 * Make sure the shortform value has some of its header.
	 */
	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));
	/*
	 * Compute entry (and change in) size.
	 */
	add_entsize = xfs_dir2_sf_entsize_byname(sfp, args->namelen);
	incr_isize = add_entsize;
	objchange = 0;
#if XFS_BIG_INUMS
	/*
	 * Do we have to change to 8 byte inodes?
	 */
	if (args->inumber > XFS_DIR2_MAX_SHORT_INUM && sfp->hdr.i8count == 0) {
		/*
		 * Yes, adjust the entry size and the total size.
		 */
		add_entsize +=
			(uint)sizeof(xfs_dir2_ino8_t) -
			(uint)sizeof(xfs_dir2_ino4_t);
		incr_isize +=
			(sfp->hdr.count + 2) *
			((uint)sizeof(xfs_dir2_ino8_t) -
			 (uint)sizeof(xfs_dir2_ino4_t));
		objchange = 1;
	}
#endif
	old_isize = (int)dp->i_d.di_size;
	new_isize = old_isize + incr_isize;
	/*
	 * Won't fit as shortform any more (due to size),
	 * or the pick routine says it won't (due to offset values).
	 */
	if (new_isize > XFS_IFORK_DSIZE(dp) ||
	    (pick =
	     xfs_dir2_sf_addname_pick(args, objchange, &sfep, &offset)) == 0) {
		/*
		 * Just checking or no space reservation, it doesn't fit.
		 */
		if (args->justcheck || args->total == 0)
			return XFS_ERROR(ENOSPC);
		/*
		 * Convert to block form then add the name.
		 */
		error = xfs_dir2_sf_to_block(args);
		if (error)
			return error;
		return xfs_dir2_block_addname(args);
	}
	/*
	 * Just checking, it fits.
	 */
	if (args->justcheck)
		return 0;
	/*
	 * Do it the easy way - just add it at the end.
	 */
	if (pick == 1)
		xfs_dir2_sf_addname_easy(args, sfep, offset, new_isize);
	/*
	 * Do it the hard way - look for a place to insert the new entry.
	 * Convert to 8 byte inode numbers first if necessary.
	 */
	else {
		ASSERT(pick == 2);
#if XFS_BIG_INUMS
		if (objchange)
			xfs_dir2_sf_toino8(args);
#endif
		xfs_dir2_sf_addname_hard(args, objchange, new_isize);
	}
	xfs_trans_log_inode(args->trans, dp, XFS_ILOG_CORE | XFS_ILOG_DDATA);
	return 0;
}

/*
 * Add the new entry the "easy" way.
 * This is copying the old directory and adding the new entry at the end.
 * Since it's sorted by "offset" we need room after the last offset
 * that's already there, and then room to convert to a block directory.
 * This is already checked by the pick routine.
 */
static void
xfs_dir2_sf_addname_easy(
	xfs_da_args_t		*args,		/* operation arguments */
	xfs_dir2_sf_entry_t	*sfep,		/* pointer to new entry */
	xfs_dir2_data_aoff_t	offset,		/* offset to use for new ent */
	int			new_isize)	/* new directory size */
{
	int			byteoff;	/* byte offset in sf dir */
	xfs_inode_t		*dp;		/* incore directory inode */
	xfs_dir2_sf_t		*sfp;		/* shortform structure */

	dp = args->dp;

	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	byteoff = (int)((char *)sfep - (char *)sfp);
	/*
	 * Grow the in-inode space.
	 */
	xfs_idata_realloc(dp, xfs_dir2_sf_entsize_byname(sfp, args->namelen),
		XFS_DATA_FORK);
	/*
	 * Need to set up again due to realloc of the inode data.
	 */
	sfp = (xfs_dir2_sf_t *)dp->i_df.if_u1.if_data;
	sfep = (xfs_dir2_sf_entry_t *)((char *)sfp + byteoff);
	/*
	 * Fill in the new entry.
	 */
	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));
	/*
	 * Update the header and inode.
	 */
	sfp->hdr.count++;
#if XFS_BIG_INUMS
	if (args->inumber > XFS_DIR2_MAX_SHORT_INUM)
		sfp->hdr.i8count++;
#endif
	dp->i_d.di_size = new_isize;
	xfs_dir2_sf_check(args);