自学教程：C++ xfs_dir2_block_tail_p函数代码示例

/* * Log the block tail. */static voidxfs_dir2_block_log_tail(	xfs_trans_t		*tp,		/* transaction structure */	struct xfs_buf		*bp)		/* block buffer */{	xfs_dir2_data_hdr_t	*hdr = bp->b_addr;	xfs_dir2_block_tail_t	*btp;	btp = xfs_dir2_block_tail_p(tp->t_mountp->m_dir_geo, hdr);	xfs_trans_log_buf(tp, bp, (uint)((char *)btp - (char *)hdr),		(uint)((char *)(btp + 1) - (char *)hdr - 1));}

/* * Log the block tail. */static voidxfs_dir2_block_log_tail(	xfs_trans_t		*tp,		/* transaction structure */	xfs_dabuf_t		*bp)		/* block buffer */{	xfs_dir2_block_t	*block;		/* directory block structure */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_mount_t		*mp;		/* filesystem mount point */	mp = tp->t_mountp;	block = bp->data;	btp = xfs_dir2_block_tail_p(mp, block);	xfs_da_log_buf(tp, bp, (uint)((char *)btp - (char *)block),		(uint)((char *)(btp + 1) - (char *)block - 1));}

/* * Log leaf entries from the block. */static voidxfs_dir2_block_log_leaf(	xfs_trans_t		*tp,		/* transaction structure */	struct xfs_buf		*bp,		/* block buffer */	int			first,		/* index of first logged leaf */	int			last)		/* index of last logged leaf */{	xfs_dir2_data_hdr_t	*hdr = bp->b_addr;	xfs_dir2_leaf_entry_t	*blp;	xfs_dir2_block_tail_t	*btp;	btp = xfs_dir2_block_tail_p(tp->t_mountp->m_dir_geo, hdr);	blp = xfs_dir2_block_leaf_p(btp);	xfs_trans_log_buf(tp, bp, (uint)((char *)&blp[first] - (char *)hdr),		(uint)((char *)&blp[last + 1] - (char *)hdr - 1));}

/* * Replace an entry in a V2 block directory. * Change the inode number to the new value. */int						/* error */xfs_dir2_block_replace(	xfs_da_args_t		*args)		/* directory operation args */{	xfs_dir2_data_hdr_t	*hdr;		/* block header */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */	struct xfs_buf		*bp;		/* block buffer */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_inode_t		*dp;		/* incore inode */	int			ent;		/* leaf entry index */	int			error;		/* error return value */	xfs_mount_t		*mp;		/* filesystem mount point */	trace_xfs_dir2_block_replace(args);	/*	 * Lookup the entry in the directory.  Get buffer and entry index.	 * This will always succeed since the caller has already done a lookup.	 */	if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent))) {		return error;	}	dp = args->dp;	mp = dp->i_mount;	hdr = bp->b_addr;	btp = xfs_dir2_block_tail_p(args->geo, hdr);	blp = xfs_dir2_block_leaf_p(btp);	/*	 * Point to the data entry we need to change.	 */	dep = (xfs_dir2_data_entry_t *)((char *)hdr +			xfs_dir2_dataptr_to_off(args->geo,						be32_to_cpu(blp[ent].address)));	ASSERT(be64_to_cpu(dep->inumber) != args->inumber);	/*	 * Change the inode number to the new value.	 */	dep->inumber = cpu_to_be64(args->inumber);	dp->d_ops->data_put_ftype(dep, args->filetype);	xfs_dir2_data_log_entry(args, bp, dep);	xfs_dir3_data_check(dp, bp);	return 0;}

/* * Look up an entry in the block.  This is the external routine, * xfs_dir2_block_lookup_int does the real work. */int						/* error */xfs_dir2_block_lookup(	xfs_da_args_t		*args)		/* dir lookup arguments */{	xfs_dir2_data_hdr_t	*hdr;		/* block header */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */	struct xfs_buf		*bp;		/* block buffer */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_inode_t		*dp;		/* incore inode */	int			ent;		/* entry index */	int			error;		/* error return value */	xfs_mount_t		*mp;		/* filesystem mount point */	trace_xfs_dir2_block_lookup(args);	/*	 * Get the buffer, look up the entry.	 * If not found (ENOENT) then return, have no buffer.	 */	if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent)))		return error;	dp = args->dp;	mp = dp->i_mount;	hdr = bp->b_addr;	xfs_dir3_data_check(dp, bp);	btp = xfs_dir2_block_tail_p(args->geo, hdr);	blp = xfs_dir2_block_leaf_p(btp);	/*	 * Get the offset from the leaf entry, to point to the data.	 */	dep = (xfs_dir2_data_entry_t *)((char *)hdr +			xfs_dir2_dataptr_to_off(args->geo,						be32_to_cpu(blp[ent].address)));	/*	 * Fill in inode number, CI name if appropriate, release the block.	 */	args->inumber = be64_to_cpu(dep->inumber);	args->filetype = dp->d_ops->data_get_ftype(dep);	error = xfs_dir_cilookup_result(args, dep->name, dep->namelen);	xfs_trans_brelse(args->trans, bp);	return error;}

/* * Log leaf entries from the block. */static voidxfs_dir2_block_log_leaf(	xfs_trans_t		*tp,		/* transaction structure */	xfs_dabuf_t		*bp,		/* block buffer */	int			first,		/* index of first logged leaf */	int			last)		/* index of last logged leaf */{	xfs_dir2_block_t	*block;		/* directory block structure */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_mount_t		*mp;		/* filesystem mount point */	mp = tp->t_mountp;	block = bp->data;	btp = xfs_dir2_block_tail_p(mp, block);	blp = xfs_dir2_block_leaf_p(btp);	xfs_da_log_buf(tp, bp, (uint)((char *)&blp[first] - (char *)block),		(uint)((char *)&blp[last + 1] - (char *)block - 1));}

/* * Look up an entry in the block.  This is the external routine, * xfs_dir2_block_lookup_int does the real work. */int						/* error */xfs_dir2_block_lookup(	xfs_da_args_t		*args)		/* dir lookup arguments */{	xfs_dir2_block_t	*block;		/* block structure */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */	xfs_dabuf_t		*bp;		/* block buffer */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_inode_t		*dp;		/* incore inode */	int			ent;		/* entry index */	int			error;		/* error return value */	xfs_mount_t		*mp;		/* filesystem mount point */	xfs_dir2_trace_args("block_lookup", args);	/*	 * Get the buffer, look up the entry.	 * If not found (ENOENT) then return, have no buffer.	 */	if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent)))		return error;	dp = args->dp;	mp = dp->i_mount;	block = bp->data;	xfs_dir2_data_check(dp, bp);	btp = xfs_dir2_block_tail_p(mp, block);	blp = xfs_dir2_block_leaf_p(btp);	/*	 * Get the offset from the leaf entry, to point to the data.	 */	dep = (xfs_dir2_data_entry_t *)	      ((char *)block + xfs_dir2_dataptr_to_off(mp, be32_to_cpu(blp[ent].address)));	/*	 * Fill in inode number, release the block.	 */	args->inumber = be64_to_cpu(dep->inumber);	xfs_da_brelse(args->trans, bp);	return XFS_ERROR(EEXIST);}

/* * Add an entry to a block directory. */int						/* error */xfs_dir2_block_addname(	xfs_da_args_t		*args)		/* directory op arguments */{	xfs_dir2_data_hdr_t	*hdr;		/* block header */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */	struct xfs_buf		*bp;		/* buffer for block */	xfs_dir2_block_tail_t	*btp;		/* block tail */	int			compact;	/* need to compact leaf ents */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_inode_t		*dp;		/* directory inode */	xfs_dir2_data_unused_t	*dup;		/* block unused entry */	int			error;		/* error return value */	xfs_dir2_data_unused_t	*enddup=NULL;	/* unused at end of data */	xfs_dahash_t		hash;		/* hash value of found entry */	int			high;		/* high index for binary srch */	int			highstale;	/* high stale index */	int			lfloghigh=0;	/* last final leaf to log */	int			lfloglow=0;	/* first final leaf to log */	int			len;		/* length of the new entry */	int			low;		/* low index for binary srch */	int			lowstale;	/* low stale index */	int			mid=0;		/* midpoint for binary srch */	int			needlog;	/* need to log header */	int			needscan;	/* need to rescan freespace */	__be16			*tagp;		/* pointer to tag value */	xfs_trans_t		*tp;		/* transaction structure */	trace_xfs_dir2_block_addname(args);	dp = args->dp;	tp = args->trans;	/* Read the (one and only) directory block into bp. */	error = xfs_dir3_block_read(tp, dp, &bp);	if (error)		return error;	len = dp->d_ops->data_entsize(args->namelen);	/*	 * Set up pointers to parts of the block.	 */	hdr = bp->b_addr;	btp = xfs_dir2_block_tail_p(args->geo, hdr);	blp = xfs_dir2_block_leaf_p(btp);	/*	 * Find out if we can reuse stale entries or whether we need extra	 * space for entry and new leaf.	 */	xfs_dir2_block_need_space(dp, hdr, btp, blp, &tagp, &dup,				  &enddup, &compact, len);	/*	 * Done everything we need for a space check now.	 */	if (args->op_flags & XFS_DA_OP_JUSTCHECK) {		xfs_trans_brelse(tp, bp);		if (!dup)			return -ENOSPC;		return 0;	}	/*	 * If we don't have space for the new entry & leaf ...	 */	if (!dup) {		/* Don't have a space reservation: return no-space.  */		if (args->total == 0)			return -ENOSPC;		/*		 * Convert to the next larger format.		 * Then add the new entry in that format.		 */		error = xfs_dir2_block_to_leaf(args, bp);		if (error)			return error;		return xfs_dir2_leaf_addname(args);	}	needlog = needscan = 0;	/*	 * If need to compact the leaf entries, do it now.	 */	if (compact) {		xfs_dir2_block_compact(args, bp, hdr, btp, blp, &needlog,				      &lfloghigh, &lfloglow);		/* recalculate blp post-compaction */		blp = xfs_dir2_block_leaf_p(btp);	} else if (btp->stale) {		/*		 * Set leaf logging boundaries to impossible state.		 * For the no-stale case they're set explicitly.		 */		lfloglow = be32_to_cpu(btp->count);//.........这里部分代码省略.........

//.........这里部分代码省略.........	error = xfs_dir2_grow_inode(args, XFS_DIR2_DATA_SPACE, &blkno);	if (error) {		kmem_free(sfp);		return error;	}	/*	 * Initialize the data block, then convert it to block format.	 */	error = xfs_dir3_data_init(args, blkno, &bp);	if (error) {		kmem_free(sfp);		return error;	}	xfs_dir3_block_init(mp, tp, bp, dp);	hdr = bp->b_addr;	/*	 * Compute size of block "tail" area.	 */	i = (uint)sizeof(*btp) +	    (sfp->count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t);	/*	 * The whole thing is initialized to free by the init routine.	 * Say we're using the leaf and tail area.	 */	dup = dp->d_ops->data_unused_p(hdr);	needlog = needscan = 0;	xfs_dir2_data_use_free(args, bp, dup, args->geo->blksize - i,			       i, &needlog, &needscan);	ASSERT(needscan == 0);	/*	 * Fill in the tail.	 */	btp = xfs_dir2_block_tail_p(args->geo, hdr);	btp->count = cpu_to_be32(sfp->count + 2);	/* ., .. */	btp->stale = 0;	blp = xfs_dir2_block_leaf_p(btp);	endoffset = (uint)((char *)blp - (char *)hdr);	/*	 * Remove the freespace, we'll manage it.	 */	xfs_dir2_data_use_free(args, bp, dup,		(xfs_dir2_data_aoff_t)((char *)dup - (char *)hdr),		be16_to_cpu(dup->length), &needlog, &needscan);	/*	 * Create entry for .	 */	dep = dp->d_ops->data_dot_entry_p(hdr);	dep->inumber = cpu_to_be64(dp->i_ino);	dep->namelen = 1;	dep->name[0] = '.';	dp->d_ops->data_put_ftype(dep, XFS_DIR3_FT_DIR);	tagp = dp->d_ops->data_entry_tag_p(dep);	*tagp = cpu_to_be16((char *)dep - (char *)hdr);	xfs_dir2_data_log_entry(args, bp, dep);	blp[0].hashval = cpu_to_be32(xfs_dir_hash_dot);	blp[0].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(				(char *)dep - (char *)hdr));	/*	 * Create entry for ..	 */	dep = dp->d_ops->data_dotdot_entry_p(hdr);	dep->inumber = cpu_to_be64(dp->d_ops->sf_get_parent_ino(sfp));	dep->namelen = 2;	dep->name[0] = dep->name[1] = '.';	dp->d_ops->data_put_ftype(dep, XFS_DIR3_FT_DIR);

/* * Readdir for block directories. */int						/* error */xfs_dir2_block_getdents(	xfs_inode_t		*dp,		/* incore inode */	void			*dirent,	xfs_off_t		*offset,	filldir_t		filldir){	xfs_dir2_data_hdr_t	*hdr;		/* block header */	struct xfs_buf		*bp;		/* buffer for block */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_dir2_data_unused_t	*dup;		/* block unused entry */	char			*endptr;	/* end of the data entries */	int			error;		/* error return value */	xfs_mount_t		*mp;		/* filesystem mount point */	char			*ptr;		/* current data entry */	int			wantoff;	/* starting block offset */	xfs_off_t		cook;	mp = dp->i_mount;	/*	 * 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;	error = xfs_dir2_block_read(NULL, dp, &bp);	if (error)		return error;	/*	 * Extract the byte offset we start at from the seek pointer.	 * We'll skip entries before this.	 */	wantoff = xfs_dir2_dataptr_to_off(mp, *offset);	hdr = bp->b_addr;	xfs_dir2_data_check(dp, bp);	/*	 * Set up values for the loop.	 */	btp = xfs_dir2_block_tail_p(mp, hdr);	ptr = (char *)(hdr + 1);	endptr = (char *)xfs_dir2_block_leaf_p(btp);	/*	 * Loop over the data portion of the block.	 * Each object is a real entry (dep) or an unused one (dup).	 */	while (ptr < endptr) {		dup = (xfs_dir2_data_unused_t *)ptr;		/*		 * Unused, skip it.		 */		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;		/*		 * Bump pointer for the next iteration.		 */		ptr += xfs_dir2_data_entsize(dep->namelen);		/*		 * The entry is before the desired starting point, skip it.		 */		if ((char *)dep - (char *)hdr < wantoff)			continue;		cook = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,					    (char *)dep - (char *)hdr);		/*		 * If it didn't fit, set the final offset to here & return.		 */		if (filldir(dirent, (char *)dep->name, dep->namelen,			    cook & 0x7fffffff, be64_to_cpu(dep->inumber),			    DT_UNKNOWN)) {			*offset = cook & 0x7fffffff;			xfs_trans_brelse(NULL, bp);			return 0;		}	}	/*	 * Reached the end of the block.	 * Set the offset to a non-existent block 1 and return.	 */	*offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0) &			0x7fffffff;	xfs_trans_brelse(NULL, bp);	return 0;}

int						/*       */xfs_dir2_block_to_sf(	xfs_da_args_t		*args,		/*                     */	xfs_dabuf_t		*bp,		/*              */	int			size,		/*                          */	xfs_dir2_sf_hdr_t	*sfhp)		/*                         */{	xfs_dir2_data_hdr_t	*hdr;		/*              */	xfs_dir2_block_tail_t	*btp;		/*                    */	xfs_dir2_data_entry_t	*dep;		/*                    */	xfs_inode_t		*dp;		/*                        */	xfs_dir2_data_unused_t	*dup;		/*                     */	char			*endptr;	/*                     */	int			error;		/*                    */	int			logflags;	/*                     */	xfs_mount_t		*mp;		/*                        */	char			*ptr;		/*                      */	xfs_dir2_sf_entry_t	*sfep;		/*                 */	xfs_dir2_sf_hdr_t	*sfp;		/*                            */	trace_xfs_dir2_block_to_sf(args);	dp = args->dp;	mp = dp->i_mount;	/*                                                                                      */	hdr = kmem_alloc(mp->m_dirblksize, KM_SLEEP);	memcpy(hdr, 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;	}	/*                                                                                                                                      */	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;	/*                                                          */	sfp = (xfs_dir2_sf_hdr_t *)dp->i_df.if_u1.if_data;	memcpy(sfp, sfhp, xfs_dir2_sf_hdr_size(sfhp->i8count));	dp->i_d.di_size = size;	/*                                              */	btp = xfs_dir2_block_tail_p(mp, hdr);	ptr = (char *)(hdr + 1);	endptr = (char *)xfs_dir2_block_leaf_p(btp);	sfep = xfs_dir2_sf_firstentry(sfp);	/*                                                                                                        */	while (ptr < endptr) {		/*                                          */		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;		/*              */		if (dep->namelen == 1 && dep->name[0] == '.')			ASSERT(be64_to_cpu(dep->inumber) == dp->i_ino);		/*                                                         */		else if (dep->namelen == 2 &&			 dep->name[0] == '.' && dep->name[1] == '.')			ASSERT(be64_to_cpu(dep->inumber) ==			       xfs_dir2_sf_get_parent_ino(sfp));		/*                                             */		else {			sfep->namelen = dep->namelen;			xfs_dir2_sf_put_offset(sfep,				(xfs_dir2_data_aoff_t)				((char *)dep - (char *)hdr));			memcpy(sfep->name, dep->name, dep->namelen);			xfs_dir2_sfe_put_ino(sfp, sfep,					     be64_to_cpu(dep->inumber));//.........这里部分代码省略.........

/* * 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 */	struct xfs_buf		*bp,	int			size,		/* shortform directory size */	xfs_dir2_sf_hdr_t	*sfhp)		/* shortform directory hdr */{	xfs_dir2_data_hdr_t	*hdr;		/* block header */	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_hdr_t	*sfp;		/* shortform directory header */	trace_xfs_dir2_block_to_sf(args);	dp = args->dp;	mp = dp->i_mount;	/*	 * Make a copy of the block data, so we can shrink the inode	 * and add local data.	 */	hdr = kmem_alloc(mp->m_dirblksize, KM_SLEEP);	memcpy(hdr, bp->b_addr, 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_hdr_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, hdr);	ptr = (char *)xfs_dir3_data_entry_p(hdr);	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_parent_ino(sfp));		/*		 * 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 *)hdr));//.........这里部分代码省略.........

/* * Remove an entry from a block format directory. * If that makes the block small enough to fit in shortform, transform it. */int						/* error */xfs_dir2_block_removename(	xfs_da_args_t		*args)		/* directory operation args */{	xfs_dir2_data_hdr_t	*hdr;		/* block header */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf pointer */	struct xfs_buf		*bp;		/* block buffer */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_inode_t		*dp;		/* incore inode */	int			ent;		/* block leaf entry index */	int			error;		/* error return value */	int			needlog;	/* need to log block header */	int			needscan;	/* need to fixup bestfree */	xfs_dir2_sf_hdr_t	sfh;		/* shortform header */	int			size;		/* shortform size */	xfs_trans_t		*tp;		/* transaction pointer */	trace_xfs_dir2_block_removename(args);	/*	 * Look up the entry in the block.  Gets the buffer and entry index.	 * It will always be there, the vnodeops level does a lookup first.	 */	if ((error = xfs_dir2_block_lookup_int(args, &bp, &ent))) {		return error;	}	dp = args->dp;	tp = args->trans;	hdr = bp->b_addr;	btp = xfs_dir2_block_tail_p(args->geo, hdr);	blp = xfs_dir2_block_leaf_p(btp);	/*	 * Point to the data entry using the leaf entry.	 */	dep = (xfs_dir2_data_entry_t *)((char *)hdr +			xfs_dir2_dataptr_to_off(args->geo,						be32_to_cpu(blp[ent].address)));	/*	 * Mark the data entry's space free.	 */	needlog = needscan = 0;	xfs_dir2_data_make_free(args, bp,		(xfs_dir2_data_aoff_t)((char *)dep - (char *)hdr),		dp->d_ops->data_entsize(dep->namelen), &needlog, &needscan);	/*	 * Fix up the block tail.	 */	be32_add_cpu(&btp->stale, 1);	xfs_dir2_block_log_tail(tp, bp);	/*	 * Remove the leaf entry by marking it stale.	 */	blp[ent].address = cpu_to_be32(XFS_DIR2_NULL_DATAPTR);	xfs_dir2_block_log_leaf(tp, bp, ent, ent);	/*	 * Fix up bestfree, log the header if necessary.	 */	if (needscan)		xfs_dir2_data_freescan(dp, hdr, &needlog);	if (needlog)		xfs_dir2_data_log_header(args, bp);	xfs_dir3_data_check(dp, bp);	/*	 * See if the size as a shortform is good enough.	 */	size = xfs_dir2_block_sfsize(dp, hdr, &sfh);	if (size > XFS_IFORK_DSIZE(dp))		return 0;	/*	 * If it works, do the conversion.	 */	return xfs_dir2_block_to_sf(args, bp, size, &sfh);}

/* * Internal block lookup routine. */static int					/* error */xfs_dir2_block_lookup_int(	xfs_da_args_t		*args,		/* dir lookup arguments */	xfs_dabuf_t		**bpp,		/* returned block buffer */	int			*entno)		/* returned entry number */{	xfs_dir2_dataptr_t	addr;		/* data entry address */	xfs_dir2_block_t	*block;		/* block structure */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */	xfs_dabuf_t		*bp;		/* block buffer */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_inode_t		*dp;		/* incore inode */	int			error;		/* error return value */	xfs_dahash_t		hash;		/* found hash value */	int			high;		/* binary search high index */	int			low;		/* binary search low index */	int			mid;		/* binary search current idx */	xfs_mount_t		*mp;		/* filesystem mount point */	xfs_trans_t		*tp;		/* transaction pointer */	dp = args->dp;	tp = args->trans;	mp = dp->i_mount;	/*	 * Read the buffer, return error if we can't get it.	 */	if ((error =	    xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &bp, XFS_DATA_FORK))) {		return error;	}	ASSERT(bp != NULL);	block = bp->data;	xfs_dir2_data_check(dp, bp);	btp = xfs_dir2_block_tail_p(mp, block);	blp = xfs_dir2_block_leaf_p(btp);	/*	 * Loop doing a binary search for our hash value.	 * Find our entry, ENOENT if it's not there.	 */	for (low = 0, high = be32_to_cpu(btp->count) - 1; ; ) {		ASSERT(low <= high);		mid = (low + high) >> 1;		if ((hash = be32_to_cpu(blp[mid].hashval)) == args->hashval)			break;		if (hash < args->hashval)			low = mid + 1;		else			high = mid - 1;		if (low > high) {			ASSERT(args->oknoent);			xfs_da_brelse(tp, bp);			return XFS_ERROR(ENOENT);		}	}	/*	 * Back up to the first one with the right hash value.	 */	while (mid > 0 && be32_to_cpu(blp[mid - 1].hashval) == args->hashval) {		mid--;	}	/*	 * Now loop forward through all the entries with the	 * right hash value looking for our name.	 */	do {		if ((addr = be32_to_cpu(blp[mid].address)) == XFS_DIR2_NULL_DATAPTR)			continue;		/*		 * Get pointer to the entry from the leaf.		 */		dep = (xfs_dir2_data_entry_t *)			((char *)block + xfs_dir2_dataptr_to_off(mp, addr));		/*		 * Compare, if it's right give back buffer & entry number.		 */		if (dep->namelen == args->namelen &&		    dep->name[0] == args->name[0] &&		    memcmp(dep->name, args->name, args->namelen) == 0) {			*bpp = bp;			*entno = mid;			return 0;		}	} while (++mid < be32_to_cpu(btp->count) && be32_to_cpu(blp[mid].hashval) == hash);	/*	 * No match, release the buffer and return ENOENT.	 */	ASSERT(args->oknoent);	xfs_da_brelse(tp, bp);	return XFS_ERROR(ENOENT);}

/* * Readdir for block directories. */STATIC intxfs_dir2_block_getdents(	struct xfs_da_args	*args,	struct dir_context	*ctx){	struct xfs_inode	*dp = args->dp;	/* incore directory inode */	xfs_dir2_data_hdr_t	*hdr;		/* block header */	struct xfs_buf		*bp;		/* buffer for block */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_dir2_data_unused_t	*dup;		/* block unused entry */	char			*endptr;	/* end of the data entries */	int			error;		/* error return value */	char			*ptr;		/* current data entry */	int			wantoff;	/* starting block offset */	xfs_off_t		cook;	struct xfs_da_geometry	*geo = args->geo;	int			lock_mode;	/*	 * If the block number in the offset is out of range, we're done.	 */	if (xfs_dir2_dataptr_to_db(geo, ctx->pos) > geo->datablk)		return 0;	lock_mode = xfs_ilock_data_map_shared(dp);	error = xfs_dir3_block_read(NULL, dp, &bp);	xfs_iunlock(dp, lock_mode);	if (error)		return error;	/*	 * Extract the byte offset we start at from the seek pointer.	 * We'll skip entries before this.	 */	wantoff = xfs_dir2_dataptr_to_off(geo, ctx->pos);	hdr = bp->b_addr;	xfs_dir3_data_check(dp, bp);	/*	 * Set up values for the loop.	 */	btp = xfs_dir2_block_tail_p(geo, hdr);	ptr = (char *)dp->d_ops->data_entry_p(hdr);	endptr = (char *)xfs_dir2_block_leaf_p(btp);	/*	 * Loop over the data portion of the block.	 * Each object is a real entry (dep) or an unused one (dup).	 */	while (ptr < endptr) {		__uint8_t filetype;		dup = (xfs_dir2_data_unused_t *)ptr;		/*		 * Unused, skip it.		 */		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;		/*		 * Bump pointer for the next iteration.		 */		ptr += dp->d_ops->data_entsize(dep->namelen);		/*		 * The entry is before the desired starting point, skip it.		 */		if ((char *)dep - (char *)hdr < wantoff)			continue;		cook = xfs_dir2_db_off_to_dataptr(geo, geo->datablk,					    (char *)dep - (char *)hdr);		ctx->pos = cook & 0x7fffffff;		filetype = dp->d_ops->data_get_ftype(dep);		/*		 * If it didn't fit, set the final offset to here & return.		 */		if (!dir_emit(ctx, (char *)dep->name, dep->namelen,			    be64_to_cpu(dep->inumber),			    xfs_dir3_get_dtype(dp->i_mount, filetype))) {			xfs_trans_brelse(NULL, bp);			return 0;		}	}	/*	 * Reached the end of the block.	 * Set the offset to a non-existent block 1 and return.	 */	ctx->pos = xfs_dir2_db_off_to_dataptr(geo, geo->datablk + 1, 0) &								0x7fffffff;	xfs_trans_brelse(NULL, bp);	return 0;//.........这里部分代码省略.........

/* * Convert a V2 leaf directory to a V2 block directory if possible. */int						/* error */xfs_dir2_leaf_to_block(	xfs_da_args_t		*args,		/* operation arguments */	xfs_dabuf_t		*lbp,		/* leaf buffer */	xfs_dabuf_t		*dbp)		/* data buffer */{	__be16			*bestsp;	/* leaf bests table */	xfs_dir2_block_t	*block;		/* block structure */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_inode_t		*dp;		/* incore directory inode */	xfs_dir2_data_unused_t	*dup;		/* unused data entry */	int			error;		/* error return value */	int			from;		/* leaf from index */	xfs_dir2_leaf_t		*leaf;		/* leaf structure */	xfs_dir2_leaf_entry_t	*lep;		/* leaf entry */	xfs_dir2_leaf_tail_t	*ltp;		/* leaf tail structure */	xfs_mount_t		*mp;		/* file system mount point */	int			needlog;	/* need to log data header */	int			needscan;	/* need to scan for bestfree */	xfs_dir2_sf_hdr_t	sfh;		/* shortform header */	int			size;		/* bytes used */	__be16			*tagp;		/* end of entry (tag) */	int			to;		/* block/leaf to index */	xfs_trans_t		*tp;		/* transaction pointer */	trace_xfs_dir2_leaf_to_block(args);	dp = args->dp;	tp = args->trans;	mp = dp->i_mount;	leaf = lbp->data;	ASSERT(be16_to_cpu(leaf->hdr.info.magic) == XFS_DIR2_LEAF1_MAGIC);	ltp = xfs_dir2_leaf_tail_p(mp, leaf);	/*	 * If there are data blocks other than the first one, take this	 * opportunity to remove trailing empty data blocks that may have	 * been left behind during no-space-reservation operations.	 * These will show up in the leaf bests table.	 */	while (dp->i_d.di_size > mp->m_dirblksize) {		bestsp = xfs_dir2_leaf_bests_p(ltp);		if (be16_to_cpu(bestsp[be32_to_cpu(ltp->bestcount) - 1]) ==		    mp->m_dirblksize - (uint)sizeof(block->hdr)) {			if ((error =			    xfs_dir2_leaf_trim_data(args, lbp,				    (xfs_dir2_db_t)(be32_to_cpu(ltp->bestcount) - 1))))				goto out;		} else {			error = 0;			goto out;		}	}	/*	 * Read the data block if we don't already have it, give up if it fails.	 */	if (dbp == NULL &&	    (error = xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &dbp,		    XFS_DATA_FORK))) {		goto out;	}	block = dbp->data;	ASSERT(be32_to_cpu(block->hdr.magic) == XFS_DIR2_DATA_MAGIC);	/*	 * Size of the "leaf" area in the block.	 */	size = (uint)sizeof(block->tail) +	       (uint)sizeof(*lep) * (be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale));	/*	 * Look at the last data entry.	 */	tagp = (__be16 *)((char *)block + mp->m_dirblksize) - 1;	dup = (xfs_dir2_data_unused_t *)((char *)block + be16_to_cpu(*tagp));	/*	 * If it's not free or is too short we can't do it.	 */	if (be16_to_cpu(dup->freetag) != XFS_DIR2_DATA_FREE_TAG ||	    be16_to_cpu(dup->length) < size) {		error = 0;		goto out;	}	/*	 * Start converting it to block form.	 */	block->hdr.magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);	needlog = 1;	needscan = 0;	/*	 * Use up the space at the end of the block (blp/btp).	 */	xfs_dir2_data_use_free(tp, dbp, dup, mp->m_dirblksize - size, size,		&needlog, &needscan);	/*	 * Initialize the block tail.	 */	btp = xfs_dir2_block_tail_p(mp, block);	btp->count = cpu_to_be32(be16_to_cpu(leaf->hdr.count) - be16_to_cpu(leaf->hdr.stale));	btp->stale = 0;//.........这里部分代码省略.........

/* * Add an entry to a block directory. */int						/* error */xfs_dir2_block_addname(	xfs_da_args_t		*args)		/* directory op arguments */{	xfs_dir2_data_free_t	*bf;		/* bestfree table in block */	xfs_dir2_block_t	*block;		/* directory block structure */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */	xfs_dabuf_t		*bp;		/* buffer for block */	xfs_dir2_block_tail_t	*btp;		/* block tail */	int			compact;	/* need to compact leaf ents */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_inode_t		*dp;		/* directory inode */	xfs_dir2_data_unused_t	*dup;		/* block unused entry */	int			error;		/* error return value */	xfs_dir2_data_unused_t	*enddup=NULL;	/* unused at end of data */	xfs_dahash_t		hash;		/* hash value of found entry */	int			high;		/* high index for binary srch */	int			highstale;	/* high stale index */	int			lfloghigh=0;	/* last final leaf to log */	int			lfloglow=0;	/* first final leaf to log */	int			len;		/* length of the new entry */	int			low;		/* low index for binary srch */	int			lowstale;	/* low stale index */	int			mid=0;		/* midpoint for binary srch */	xfs_mount_t		*mp;		/* filesystem mount point */	int			needlog;	/* need to log header */	int			needscan;	/* need to rescan freespace */	__be16			*tagp;		/* pointer to tag value */	xfs_trans_t		*tp;		/* transaction structure */	trace_xfs_dir2_block_addname(args);	dp = args->dp;	tp = args->trans;	mp = dp->i_mount;	/*	 * Read the (one and only) directory block into dabuf bp.	 */	if ((error =	    xfs_da_read_buf(tp, dp, mp->m_dirdatablk, -1, &bp, XFS_DATA_FORK))) {		return error;	}	ASSERT(bp != NULL);	block = bp->data;	/*	 * Check the magic number, corrupted if wrong.	 */	if (unlikely(be32_to_cpu(block->hdr.magic) != XFS_DIR2_BLOCK_MAGIC)) {		XFS_CORRUPTION_ERROR("xfs_dir2_block_addname",				     XFS_ERRLEVEL_LOW, mp, block);		xfs_da_brelse(tp, bp);		return XFS_ERROR(EFSCORRUPTED);	}	len = xfs_dir2_data_entsize(args->namelen);	/*	 * Set up pointers to parts of the block.	 */	bf = block->hdr.bestfree;	btp = xfs_dir2_block_tail_p(mp, block);	blp = xfs_dir2_block_leaf_p(btp);	/*	 * No stale entries?  Need space for entry and new leaf.	 */	if (!btp->stale) {		/*		 * Tag just before the first leaf entry.		 */		tagp = (__be16 *)blp - 1;		/*		 * Data object just before the first leaf entry.		 */		enddup = (xfs_dir2_data_unused_t *)((char *)block + be16_to_cpu(*tagp));		/*		 * If it's not free then can't do this add without cleaning up:		 * the space before the first leaf entry needs to be free so it		 * can be expanded to hold the pointer to the new entry.		 */		if (be16_to_cpu(enddup->freetag) != XFS_DIR2_DATA_FREE_TAG)			dup = enddup = NULL;		/*		 * Check out the biggest freespace and see if it's the same one.		 */		else {			dup = (xfs_dir2_data_unused_t *)			      ((char *)block + be16_to_cpu(bf[0].offset));			if (dup == enddup) {				/*				 * It is the biggest freespace, is it too small				 * to hold the new leaf too?				 */				if (be16_to_cpu(dup->length) < len + (uint)sizeof(*blp)) {					/*					 * Yes, we use the second-largest					 * entry instead if it works.					 */					if (be16_to_cpu(bf[1].length) >= len)						dup = (xfs_dir2_data_unused_t *)//.........这里部分代码省略.........

//.........这里部分代码省略.........	 */	error = xfs_dir2_grow_inode(args, XFS_DIR2_DATA_SPACE, &blkno);	if (error) {		kmem_free(buf);		return error;	}	/*	 * Initialize the data block.	 */	error = xfs_dir2_data_init(args, blkno, &bp);	if (error) {		kmem_free(buf);		return error;	}	block = bp->data;	block->hdr.magic = cpu_to_be32(XFS_DIR2_BLOCK_MAGIC);	/*	 * Compute size of block "tail" area.	 */	i = (uint)sizeof(*btp) +	    (sfp->hdr.count + 2) * (uint)sizeof(xfs_dir2_leaf_entry_t);	/*	 * The whole thing is initialized to free by the init routine.	 * Say we're using the leaf and tail area.	 */	dup = (xfs_dir2_data_unused_t *)block->u;	needlog = needscan = 0;	xfs_dir2_data_use_free(tp, bp, dup, mp->m_dirblksize - i, i, &needlog,		&needscan);	ASSERT(needscan == 0);	/*	 * Fill in the tail.	 */	btp = xfs_dir2_block_tail_p(mp, block);	btp->count = cpu_to_be32(sfp->hdr.count + 2);	/* ., .. */	btp->stale = 0;	blp = xfs_dir2_block_leaf_p(btp);	endoffset = (uint)((char *)blp - (char *)block);	/*	 * Remove the freespace, we'll manage it.	 */	xfs_dir2_data_use_free(tp, bp, dup,		(xfs_dir2_data_aoff_t)((char *)dup - (char *)block),		be16_to_cpu(dup->length), &needlog, &needscan);	/*	 * Create entry for .	 */	dep = (xfs_dir2_data_entry_t *)	      ((char *)block + XFS_DIR2_DATA_DOT_OFFSET);	dep->inumber = cpu_to_be64(dp->i_ino);	dep->namelen = 1;	dep->name[0] = '.';	tagp = xfs_dir2_data_entry_tag_p(dep);	*tagp = cpu_to_be16((char *)dep - (char *)block);	xfs_dir2_data_log_entry(tp, bp, dep);	blp[0].hashval = cpu_to_be32(xfs_dir_hash_dot);	blp[0].address = cpu_to_be32(xfs_dir2_byte_to_dataptr(mp,				(char *)dep - (char *)block));	/*	 * Create entry for ..	 */	dep = (xfs_dir2_data_entry_t *)		((char *)block + XFS_DIR2_DATA_DOTDOT_OFFSET);	dep->inumber = cpu_to_be64(xfs_dir2_sf_get_inumber(sfp, &sfp->hdr.parent));	dep->namelen = 2;	dep->name[0] = dep->name[1] = '.';

/* * Internal block lookup routine. */static int					/* error */xfs_dir2_block_lookup_int(	xfs_da_args_t		*args,		/* dir lookup arguments */	struct xfs_buf		**bpp,		/* returned block buffer */	int			*entno)		/* returned entry number */{	xfs_dir2_dataptr_t	addr;		/* data entry address */	xfs_dir2_data_hdr_t	*hdr;		/* block header */	xfs_dir2_leaf_entry_t	*blp;		/* block leaf entries */	struct xfs_buf		*bp;		/* block buffer */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_inode_t		*dp;		/* incore inode */	int			error;		/* error return value */	xfs_dahash_t		hash;		/* found hash value */	int			high;		/* binary search high index */	int			low;		/* binary search low index */	int			mid;		/* binary search current idx */	xfs_mount_t		*mp;		/* filesystem mount point */	xfs_trans_t		*tp;		/* transaction pointer */	enum xfs_dacmp		cmp;		/* comparison result */	dp = args->dp;	tp = args->trans;	mp = dp->i_mount;	error = xfs_dir3_block_read(tp, dp, &bp);	if (error)		return error;	hdr = bp->b_addr;	xfs_dir3_data_check(dp, bp);	btp = xfs_dir2_block_tail_p(args->geo, hdr);	blp = xfs_dir2_block_leaf_p(btp);	/*	 * Loop doing a binary search for our hash value.	 * Find our entry, ENOENT if it's not there.	 */	for (low = 0, high = be32_to_cpu(btp->count) - 1; ; ) {		ASSERT(low <= high);		mid = (low + high) >> 1;		if ((hash = be32_to_cpu(blp[mid].hashval)) == args->hashval)			break;		if (hash < args->hashval)			low = mid + 1;		else			high = mid - 1;		if (low > high) {			ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);			xfs_trans_brelse(tp, bp);			return -ENOENT;		}	}	/*	 * Back up to the first one with the right hash value.	 */	while (mid > 0 && be32_to_cpu(blp[mid - 1].hashval) == args->hashval) {		mid--;	}	/*	 * Now loop forward through all the entries with the	 * right hash value looking for our name.	 */	do {		if ((addr = be32_to_cpu(blp[mid].address)) == XFS_DIR2_NULL_DATAPTR)			continue;		/*		 * Get pointer to the entry from the leaf.		 */		dep = (xfs_dir2_data_entry_t *)			((char *)hdr + xfs_dir2_dataptr_to_off(args->geo, addr));		/*		 * Compare name and if it's an exact match, return the index		 * and buffer. If it's the first case-insensitive match, store		 * the index and buffer and continue looking for an exact match.		 */		cmp = mp->m_dirnameops->compname(args, dep->name, dep->namelen);		if (cmp != XFS_CMP_DIFFERENT && cmp != args->cmpresult) {			args->cmpresult = cmp;			*bpp = bp;			*entno = mid;			if (cmp == XFS_CMP_EXACT)				return 0;		}	} while (++mid < be32_to_cpu(btp->count) &&			be32_to_cpu(blp[mid].hashval) == hash);	ASSERT(args->op_flags & XFS_DA_OP_OKNOENT);	/*	 * Here, we can only be doing a lookup (not a rename or replace).	 * If a case-insensitive match was found earlier, return success.	 */	if (args->cmpresult == XFS_CMP_CASE)		return 0;	/*	 * No match, release the buffer and return ENOENT.	 *///.........这里部分代码省略.........

/* * Check the consistency of the data block. * The input can also be a block-format directory. * Return 0 is the buffer is good, otherwise an error. */int__xfs_dir3_data_check(	struct xfs_inode	*dp,		/* incore inode pointer */	struct xfs_buf		*bp)		/* data block's buffer */{	xfs_dir2_dataptr_t	addr;		/* addr for leaf lookup */	xfs_dir2_data_free_t	*bf;		/* bestfree table */	xfs_dir2_block_tail_t	*btp=NULL;	/* block tail */	int			count;		/* count of entries found */	xfs_dir2_data_hdr_t	*hdr;		/* data block header */	xfs_dir2_data_entry_t	*dep;		/* data entry */	xfs_dir2_data_free_t	*dfp;		/* bestfree entry */	xfs_dir2_data_unused_t	*dup;		/* unused entry */	char			*endp;		/* end of useful data */	int			freeseen;	/* mask of bestfrees seen */	xfs_dahash_t		hash;		/* hash of current name */	int			i;		/* leaf index */	int			lastfree;	/* last entry was unused */	xfs_dir2_leaf_entry_t	*lep=NULL;	/* block leaf entries */	xfs_mount_t		*mp;		/* filesystem mount point */	char			*p;		/* current data position */	int			stale;		/* count of stale leaves */	struct xfs_name		name;	const struct xfs_dir_ops *ops;	struct xfs_da_geometry	*geo;	mp = bp->b_target->bt_mount;	geo = mp->m_dir_geo;	/*	 * We can be passed a null dp here from a verifier, so we need to go the	 * hard way to get them.	 */	ops = xfs_dir_get_ops(mp, dp);	hdr = bp->b_addr;	p = (char *)ops->data_entry_p(hdr);	switch (hdr->magic) {	case cpu_to_be32(XFS_DIR3_BLOCK_MAGIC):	case cpu_to_be32(XFS_DIR2_BLOCK_MAGIC):		btp = xfs_dir2_block_tail_p(geo, hdr);		lep = xfs_dir2_block_leaf_p(btp);		endp = (char *)lep;		/*		 * The number of leaf entries is limited by the size of the		 * block and the amount of space used by the data entries.		 * We don't know how much space is used by the data entries yet,		 * so just ensure that the count falls somewhere inside the		 * block right now.		 */		XFS_WANT_CORRUPTED_RETURN(mp, be32_to_cpu(btp->count) <			((char *)btp - p) / sizeof(struct xfs_dir2_leaf_entry));		break;	case cpu_to_be32(XFS_DIR3_DATA_MAGIC):	case cpu_to_be32(XFS_DIR2_DATA_MAGIC):		endp = (char *)hdr + geo->blksize;		break;	default:		XFS_ERROR_REPORT("Bad Magic", XFS_ERRLEVEL_LOW, mp);		return -EFSCORRUPTED;	}	/*	 * Account for zero bestfree entries.	 */	bf = ops->data_bestfree_p(hdr);	count = lastfree = freeseen = 0;	if (!bf[0].length) {		XFS_WANT_CORRUPTED_RETURN(mp, !bf[0].offset);		freeseen |= 1 << 0;	}	if (!bf[1].length) {		XFS_WANT_CORRUPTED_RETURN(mp, !bf[1].offset);		freeseen |= 1 << 1;	}	if (!bf[2].length) {		XFS_WANT_CORRUPTED_RETURN(mp, !bf[2].offset);		freeseen |= 1 << 2;	}	XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[0].length) >=						be16_to_cpu(bf[1].length));	XFS_WANT_CORRUPTED_RETURN(mp, be16_to_cpu(bf[1].length) >=						be16_to_cpu(bf[2].length));	/*	 * Loop over the data/unused entries.	 */	while (p < endp) {		dup = (xfs_dir2_data_unused_t *)p;		/*		 * If it's unused, look for the space in the bestfree table.		 * If we find it, account for that, else make sure it		 * doesn't need to be there.//.........这里部分代码省略.........

//.........这里部分代码省略.........	 * opportunity to remove trailing empty data blocks that may have	 * been left behind during no-space-reservation operations.	 * These will show up in the leaf bests table.	 */	while (dp->i_d.di_size > args->geo->blksize) {		int hdrsz;		hdrsz = dp->d_ops->data_entry_offset;		bestsp = xfs_dir2_leaf_bests_p(ltp);		if (be16_to_cpu(bestsp[be32_to_cpu(ltp->bestcount) - 1]) ==					    args->geo->blksize - hdrsz) {			if ((error =			    xfs_dir2_leaf_trim_data(args, lbp,				    (xfs_dir2_db_t)(be32_to_cpu(ltp->bestcount) - 1))))				return error;		} else			return 0;	}	/*	 * Read the data block if we don't already have it, give up if it fails.	 */	if (!dbp) {		error = xfs_dir3_data_read(tp, dp, args->geo->datablk, -1, &dbp);		if (error)			return error;	}	hdr = dbp->b_addr;	ASSERT(hdr->magic == cpu_to_be32(XFS_DIR2_DATA_MAGIC) ||	       hdr->magic == cpu_to_be32(XFS_DIR3_DATA_MAGIC));	/*	 * Size of the "leaf" area in the block.	 */	size = (uint)sizeof(xfs_dir2_block_tail_t) +	       (uint)sizeof(*lep) * (leafhdr.count - leafhdr.stale);	/*	 * Look at the last data entry.	 */	tagp = (__be16 *)((char *)hdr + args->geo->blksize) - 1;	dup = (xfs_dir2_data_unused_t *)((char *)hdr + be16_to_cpu(*tagp));	/*	 * If it's not free or is too short we can't do it.	 */	if (be16_to_cpu(dup->freetag) != XFS_DIR2_DATA_FREE_TAG ||	    be16_to_cpu(dup->length) < size)		return 0;	/*	 * Start converting it to block form.	 */	xfs_dir3_block_init(mp, tp, dbp, dp);	needlog = 1;	needscan = 0;	/*	 * Use up the space at the end of the block (blp/btp).	 */	xfs_dir2_data_use_free(args, dbp, dup, args->geo->blksize - size, size,		&needlog, &needscan);	/*	 * Initialize the block tail.	 */	btp = xfs_dir2_block_tail_p(args->geo, hdr);	btp->count = cpu_to_be32(leafhdr.count - leafhdr.stale);	btp->stale = 0;	xfs_dir2_block_log_tail(tp, dbp);	/*	 * Initialize the block leaf area.  We compact out stale entries.	 */	lep = xfs_dir2_block_leaf_p(btp);	for (from = to = 0; from < leafhdr.count; from++) {		if (ents[from].address == cpu_to_be32(XFS_DIR2_NULL_DATAPTR))			continue;		lep[to++] = ents[from];	}	ASSERT(to == be32_to_cpu(btp->count));	xfs_dir2_block_log_leaf(tp, dbp, 0, be32_to_cpu(btp->count) - 1);	/*	 * Scan the bestfree if we need it and log the data block header.	 */	if (needscan)		xfs_dir2_data_freescan(dp, hdr, &needlog);	if (needlog)		xfs_dir2_data_log_header(args, dbp);	/*	 * Pitch the old leaf block.	 */	error = xfs_da_shrink_inode(args, args->geo->leafblk, lbp);	if (error)		return error;	/*	 * Now see if the resulting block can be shrunken to shortform.	 */	size = xfs_dir2_block_sfsize(dp, hdr, &sfh);	if (size > XFS_IFORK_DSIZE(dp))		return 0;	return xfs_dir2_block_to_sf(args, dbp, size, &sfh);}

int						/*                  */xfs_dir2_block_sfsize(	xfs_inode_t		*dp,		/*                      */	xfs_dir2_data_hdr_t	*hdr,		/*                      */	xfs_dir2_sf_hdr_t	*sfhp)		/*                            */{	xfs_dir2_dataptr_t	addr;		/*                    */	xfs_dir2_leaf_entry_t	*blp;		/*                        */	xfs_dir2_block_tail_t	*btp;		/*                        */	int			count;		/*                       */	xfs_dir2_data_entry_t	*dep;		/*                         */	int			i;		/*                   */	int			i8count;	/*                            */	int			isdot;		/*              */	int			isdotdot;	/*               */	xfs_mount_t		*mp;		/*                         */	int			namelen;	/*                  */	xfs_ino_t		parent = 0;	/*                     */	int			size=0;		/*                     */	mp = dp->i_mount;	count = i8count = namelen = 0;	btp = xfs_dir2_block_tail_p(mp, hdr);	blp = xfs_dir2_block_leaf_p(btp);	/*                                                                       */	for (i = 0; i < be32_to_cpu(btp->count); i++) {		if ((addr = be32_to_cpu(blp[i].address)) == XFS_DIR2_NULL_DATAPTR)			continue;		/*                                                   */		dep = (xfs_dir2_data_entry_t *)		      ((char *)hdr + xfs_dir2_dataptr_to_off(mp, addr));		/*                                                                                                                                                  */		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);		/*                                                             */		size = xfs_dir2_sf_hdr_size(i8count) +		/*        */		       count +					/*         */		       count * (uint)sizeof(xfs_dir2_sf_off_t) + /*        */		       namelen +				/*      */		       (i8count ?				/*         */				(uint)sizeof(xfs_dir2_ino8_t) * count :				(uint)sizeof(xfs_dir2_ino4_t) * count);		if (size > XFS_IFORK_DSIZE(dp))			return size;		/*                         */	}	/*                                             */	sfhp->count = count;	sfhp->i8count = i8count;	xfs_dir2_sf_put_parent_ino(sfhp, parent);	return size;}

/* * 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_data_hdr_t	*hdr,		/* 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, hdr);	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 *)hdr + 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_parent_ino(sfhp, parent);	return size;}

/* * Readdir for block directories. */int						/* error */xfs_dir2_block_getdents(	xfs_inode_t		*dp,		/* incore inode */	void			*dirent,	xfs_off_t		*offset,	filldir_t		filldir){	xfs_dir2_block_t	*block;		/* directory block structure */	xfs_dabuf_t		*bp;		/* buffer for block */	xfs_dir2_block_tail_t	*btp;		/* block tail */	xfs_dir2_data_entry_t	*dep;		/* block data entry */	xfs_dir2_data_unused_t	*dup;		/* block unused entry */	char			*endptr;	/* end of the data entries */	int			error;		/* error return value */	xfs_mount_t		*mp;		/* filesystem mount point */	char			*ptr;		/* current data entry */	int			wantoff;	/* starting block offset */	xfs_ino_t		ino;	xfs_off_t		cook;	mp = dp->i_mount;	/*	 * 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;	}	/*	 * Can't read the block, give up, else get dabuf in bp.	 */	error = xfs_da_read_buf(NULL, dp, mp->m_dirdatablk, -1,				&bp, XFS_DATA_FORK);	if (error)		return error;	ASSERT(bp != NULL);	/*	 * Extract the byte offset we start at from the seek pointer.	 * We'll skip entries before this.	 */	wantoff = xfs_dir2_dataptr_to_off(mp, *offset);	block = bp->data;	xfs_dir2_data_check(dp, bp);	/*	 * Set up values for the loop.	 */	btp = xfs_dir2_block_tail_p(mp, block);	ptr = (char *)block->u;	endptr = (char *)xfs_dir2_block_leaf_p(btp);	/*	 * Loop over the data portion of the block.	 * Each object is a real entry (dep) or an unused one (dup).	 */	while (ptr < endptr) {		dup = (xfs_dir2_data_unused_t *)ptr;		/*		 * Unused, skip it.		 */		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;		/*		 * Bump pointer for the next iteration.		 */		ptr += xfs_dir2_data_entsize(dep->namelen);		/*		 * The entry is before the desired starting point, skip it.		 */		if ((char *)dep - (char *)block < wantoff)			continue;		cook = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk,					    (char *)dep - (char *)block);		ino = be64_to_cpu(dep->inumber);#if XFS_BIG_INUMS		ino += mp->m_inoadd;#endif		/*		 * If it didn't fit, set the final offset to here & return.		 */		if (filldir(dirent, dep->name, dep->namelen, cook,			    ino, DT_UNKNOWN)) {			*offset = cook;			xfs_da_brelse(NULL, bp);			return 0;		}	}	/*	 * Reached the end of the block.	 * Set the offset to a non-existent block 1 and return.//.........这里部分代码省略.........