fs/xfs/xfs_attr_list.c - kernel/msm-4.9 - Gitiles

 /*
  * Copyright (c) 2000-2005 Silicon Graphics, Inc.
  * Copyright (c) 2013 Red Hat, 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_format.h"
 #include "xfs_log_format.h"
 #include "xfs_trans_resv.h"
 #include "xfs_bit.h"
 #include "xfs_sb.h"
 #include "xfs_ag.h"
 #include "xfs_mount.h"
 #include "xfs_da_format.h"
 #include "xfs_da_btree.h"
 #include "xfs_inode.h"
 #include "xfs_trans.h"
 #include "xfs_inode_item.h"
 #include "xfs_bmap.h"
 #include "xfs_attr.h"
 #include "xfs_attr_sf.h"
 #include "xfs_attr_remote.h"
 #include "xfs_attr_leaf.h"
 #include "xfs_error.h"
 #include "xfs_trace.h"
 #include "xfs_buf_item.h"
 #include "xfs_cksum.h"
 #include "xfs_dinode.h"
 #include "xfs_dir2.h"

 STATIC int
 xfs_attr_shortform_compare(const void *a, const void *b)
 {
 	xfs_attr_sf_sort_t *sa, *sb;

 	sa = (xfs_attr_sf_sort_t *)a;
 	sb = (xfs_attr_sf_sort_t *)b;
 	if (sa->hash < sb->hash) {
 		return -1;
 	} else if (sa->hash > sb->hash) {
 		return 1;
 	} else {
 		return sa->entno - sb->entno;
 	}
 }

 #define XFS_ISRESET_CURSOR(cursor) \
 	(!((cursor)->initted) && !((cursor)->hashval) && \
 	 !((cursor)->blkno) && !((cursor)->offset))
 /*
  * Copy out entries of shortform attribute lists for attr_list().
  * Shortform attribute lists are not stored in hashval sorted order.
  * If the output buffer is not large enough to hold them all, then we
  * we have to calculate each entries' hashvalue and sort them before
  * we can begin returning them to the user.
  */
 int
 xfs_attr_shortform_list(xfs_attr_list_context_t *context)
 {
 	attrlist_cursor_kern_t *cursor;
 	xfs_attr_sf_sort_t *sbuf, *sbp;
 	xfs_attr_shortform_t *sf;
 	xfs_attr_sf_entry_t *sfe;
 	xfs_inode_t *dp;
 	int sbsize, nsbuf, count, i;
 	int error;

 	ASSERT(context != NULL);
 	dp = context->dp;
 	ASSERT(dp != NULL);
 	ASSERT(dp->i_afp != NULL);
 	sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
 	ASSERT(sf != NULL);
 	if (!sf->hdr.count)
 		return 0;
 	cursor = context->cursor;
 	ASSERT(cursor != NULL);

 	trace_xfs_attr_list_sf(context);

 	/*
 	 * If the buffer is large enough and the cursor is at the start,
 	 * do not bother with sorting since we will return everything in
 	 * one buffer and another call using the cursor won't need to be
 	 * made.
 	 * Note the generous fudge factor of 16 overhead bytes per entry.
 	 * If bufsize is zero then put_listent must be a search function
 	 * and can just scan through what we have.
 	 */
 	if (context->bufsize == 0 ||
 	    (XFS_ISRESET_CURSOR(cursor) &&
              (dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
 		for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
 			error = context->put_listent(context,
 					   sfe->flags,
 					   sfe->nameval,
 					   (int)sfe->namelen,
 					   (int)sfe->valuelen,
 					   &sfe->nameval[sfe->namelen]);

 			/*
 			 * Either search callback finished early or
 			 * didn't fit it all in the buffer after all.
 			 */
 			if (context->seen_enough)
 				break;

 			if (error)
 				return error;
 			sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
 		}
 		trace_xfs_attr_list_sf_all(context);
 		return 0;
 	}

 	/* do no more for a search callback */
 	if (context->bufsize == 0)
 		return 0;

 	/*
 	 * It didn't all fit, so we have to sort everything on hashval.
 	 */
 	sbsize = sf->hdr.count * sizeof(*sbuf);
 	sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP | KM_NOFS);

 	/*
 	 * Scan the attribute list for the rest of the entries, storing
 	 * the relevant info from only those that match into a buffer.
 	 */
 	nsbuf = 0;
 	for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
 		if (unlikely(
 		    ((char *)sfe < (char *)sf) ||
 		    ((char *)sfe >= ((char *)sf + dp->i_afp->if_bytes)))) {
 			XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
 					     XFS_ERRLEVEL_LOW,
 					     context->dp->i_mount, sfe);
 			kmem_free(sbuf);
 			return -EFSCORRUPTED;
 		}

 		sbp->entno = i;
 		sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
 		sbp->name = sfe->nameval;
 		sbp->namelen = sfe->namelen;
 		/* These are bytes, and both on-disk, don't endian-flip */
 		sbp->valuelen = sfe->valuelen;
 		sbp->flags = sfe->flags;
 		sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
 		sbp++;
 		nsbuf++;
 	}

 	/*
 	 * Sort the entries on hash then entno.
 	 */
 	xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);

 	/*
 	 * Re-find our place IN THE SORTED LIST.
 	 */
 	count = 0;
 	cursor->initted = 1;
 	cursor->blkno = 0;
 	for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
 		if (sbp->hash == cursor->hashval) {
 			if (cursor->offset == count) {
 				break;
 			}
 			count++;
 		} else if (sbp->hash > cursor->hashval) {
 			break;
 		}
 	}
 	if (i == nsbuf) {
 		kmem_free(sbuf);
 		return 0;
 	}

 	/*
 	 * Loop putting entries into the user buffer.
 	 */
 	for ( ; i < nsbuf; i++, sbp++) {
 		if (cursor->hashval != sbp->hash) {
 			cursor->hashval = sbp->hash;
 			cursor->offset = 0;
 		}
 		error = context->put_listent(context,
 					sbp->flags,
 					sbp->name,
 					sbp->namelen,
 					sbp->valuelen,
 					&sbp->name[sbp->namelen]);
 		if (error)
 			return error;
 		if (context->seen_enough)
 			break;
 		cursor->offset++;
 	}

 	kmem_free(sbuf);
 	return 0;
 }

 STATIC int
 xfs_attr_node_list(xfs_attr_list_context_t *context)
 {
 	attrlist_cursor_kern_t *cursor;
 	xfs_attr_leafblock_t *leaf;
 	xfs_da_intnode_t *node;
 	struct xfs_attr3_icleaf_hdr leafhdr;
 	struct xfs_da3_icnode_hdr nodehdr;
 	struct xfs_da_node_entry *btree;
 	int error, i;
 	struct xfs_buf *bp;
 	struct xfs_inode	*dp = context->dp;

 	trace_xfs_attr_node_list(context);

 	cursor = context->cursor;
 	cursor->initted = 1;

 	/*
 	 * Do all sorts of validation on the passed-in cursor structure.
 	 * If anything is amiss, ignore the cursor and look up the hashval
 	 * starting from the btree root.
 	 */
 	bp = NULL;
 	if (cursor->blkno > 0) {
 		error = xfs_da3_node_read(NULL, dp, cursor->blkno, -1,
 					      &bp, XFS_ATTR_FORK);
 		if ((error != 0) && (error != -EFSCORRUPTED))
 			return error;
 		if (bp) {
 			struct xfs_attr_leaf_entry *entries;

 			node = bp->b_addr;
 			switch (be16_to_cpu(node->hdr.info.magic)) {
 			case XFS_DA_NODE_MAGIC:
 			case XFS_DA3_NODE_MAGIC:
 				trace_xfs_attr_list_wrong_blk(context);
 				xfs_trans_brelse(NULL, bp);
 				bp = NULL;
 				break;
 			case XFS_ATTR_LEAF_MAGIC:
 			case XFS_ATTR3_LEAF_MAGIC:
 				leaf = bp->b_addr;
 				xfs_attr3_leaf_hdr_from_disk(&leafhdr, leaf);
 				entries = xfs_attr3_leaf_entryp(leaf);
 				if (cursor->hashval > be32_to_cpu(
 						entries[leafhdr.count - 1].hashval)) {
 					trace_xfs_attr_list_wrong_blk(context);
 					xfs_trans_brelse(NULL, bp);
 					bp = NULL;
 				} else if (cursor->hashval <= be32_to_cpu(
 						entries[0].hashval)) {
 					trace_xfs_attr_list_wrong_blk(context);
 					xfs_trans_brelse(NULL, bp);
 					bp = NULL;
 				}
 				break;
 			default:
 				trace_xfs_attr_list_wrong_blk(context);
 				xfs_trans_brelse(NULL, bp);
 				bp = NULL;
 			}
 		}
 	}

 	/*
 	 * We did not find what we expected given the cursor's contents,
 	 * so we start from the top and work down based on the hash value.
 	 * Note that start of node block is same as start of leaf block.
 	 */
 	if (bp == NULL) {
 		cursor->blkno = 0;
 		for (;;) {
 			__uint16_t magic;

 			error = xfs_da3_node_read(NULL, dp,
 						      cursor->blkno, -1, &bp,
 						      XFS_ATTR_FORK);
 			if (error)
 				return error;
 			node = bp->b_addr;
 			magic = be16_to_cpu(node->hdr.info.magic);
 			if (magic == XFS_ATTR_LEAF_MAGIC ||
 			    magic == XFS_ATTR3_LEAF_MAGIC)
 				break;
 			if (magic != XFS_DA_NODE_MAGIC &&
 			    magic != XFS_DA3_NODE_MAGIC) {
 				XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
 						     XFS_ERRLEVEL_LOW,
 						     context->dp->i_mount,
 						     node);
 				xfs_trans_brelse(NULL, bp);
 				return -EFSCORRUPTED;
 			}

 			dp->d_ops->node_hdr_from_disk(&nodehdr, node);
 			btree = dp->d_ops->node_tree_p(node);
 			for (i = 0; i < nodehdr.count; btree++, i++) {
 				if (cursor->hashval
 						<= be32_to_cpu(btree->hashval)) {
 					cursor->blkno = be32_to_cpu(btree->before);
 					trace_xfs_attr_list_node_descend(context,
 									 btree);
 					break;
 				}
 			}
 			if (i == nodehdr.count) {
 				xfs_trans_brelse(NULL, bp);
 				return 0;
 			}
 			xfs_trans_brelse(NULL, bp);
 		}
 	}
 	ASSERT(bp != NULL);

 	/*
 	 * Roll upward through the blocks, processing each leaf block in
 	 * order.  As long as there is space in the result buffer, keep
 	 * adding the information.
 	 */
 	for (;;) {
 		leaf = bp->b_addr;
 		error = xfs_attr3_leaf_list_int(bp, context);
 		if (error) {
 			xfs_trans_brelse(NULL, bp);
 			return error;
 		}
 		xfs_attr3_leaf_hdr_from_disk(&leafhdr, leaf);
 		if (context->seen_enough || leafhdr.forw == 0)
 			break;
 		cursor->blkno = leafhdr.forw;
 		xfs_trans_brelse(NULL, bp);
 		error = xfs_attr3_leaf_read(NULL, dp, cursor->blkno, -1, &bp);
 		if (error)
 			return error;
 	}
 	xfs_trans_brelse(NULL, bp);
 	return 0;
 }

 /*
  * Copy out attribute list entries for attr_list(), for leaf attribute lists.
  */
 int
 xfs_attr3_leaf_list_int(
 	struct xfs_buf			*bp,
 	struct xfs_attr_list_context	*context)
 {
 	struct attrlist_cursor_kern	*cursor;
 	struct xfs_attr_leafblock	*leaf;
 	struct xfs_attr3_icleaf_hdr	ichdr;
 	struct xfs_attr_leaf_entry	*entries;
 	struct xfs_attr_leaf_entry	*entry;
 	int				retval;
 	int				i;

 	trace_xfs_attr_list_leaf(context);

 	leaf = bp->b_addr;
 	xfs_attr3_leaf_hdr_from_disk(&ichdr, leaf);
 	entries = xfs_attr3_leaf_entryp(leaf);

 	cursor = context->cursor;
 	cursor->initted = 1;

 	/*
 	 * Re-find our place in the leaf block if this is a new syscall.
 	 */
 	if (context->resynch) {
 		entry = &entries[0];
 		for (i = 0; i < ichdr.count; entry++, i++) {
 			if (be32_to_cpu(entry->hashval) == cursor->hashval) {
 				if (cursor->offset == context->dupcnt) {
 					context->dupcnt = 0;
 					break;
 				}
 				context->dupcnt++;
 			} else if (be32_to_cpu(entry->hashval) >
 					cursor->hashval) {
 				context->dupcnt = 0;
 				break;
 			}
 		}
 		if (i == ichdr.count) {
 			trace_xfs_attr_list_notfound(context);
 			return 0;
 		}
 	} else {
 		entry = &entries[0];
 		i = 0;
 	}
 	context->resynch = 0;

 	/*
 	 * We have found our place, start copying out the new attributes.
 	 */
 	retval = 0;
 	for (; i < ichdr.count; entry++, i++) {
 		if (be32_to_cpu(entry->hashval) != cursor->hashval) {
 			cursor->hashval = be32_to_cpu(entry->hashval);
 			cursor->offset = 0;
 		}

 		if (entry->flags & XFS_ATTR_INCOMPLETE)
 			continue;		/* skip incomplete entries */

 		if (entry->flags & XFS_ATTR_LOCAL) {
 			xfs_attr_leaf_name_local_t *name_loc =
 				xfs_attr3_leaf_name_local(leaf, i);

 			retval = context->put_listent(context,
 						entry->flags,
 						name_loc->nameval,
 						(int)name_loc->namelen,
 						be16_to_cpu(name_loc->valuelen),
 						&name_loc->nameval[name_loc->namelen]);
 			if (retval)
 				return retval;
 		} else {
 			xfs_attr_leaf_name_remote_t *name_rmt =
 				xfs_attr3_leaf_name_remote(leaf, i);

 			int valuelen = be32_to_cpu(name_rmt->valuelen);

 			if (context->put_value) {
 				xfs_da_args_t args;

 				memset((char *)&args, 0, sizeof(args));
 				args.geo = context->dp->i_mount->m_attr_geo;
 				args.dp = context->dp;
 				args.whichfork = XFS_ATTR_FORK;
 				args.valuelen = valuelen;
 				args.rmtvaluelen = valuelen;
 				args.value = kmem_alloc(valuelen, KM_SLEEP | KM_NOFS);
 				args.rmtblkno = be32_to_cpu(name_rmt->valueblk);
 				args.rmtblkcnt = xfs_attr3_rmt_blocks(
 							args.dp->i_mount, valuelen);
 				retval = xfs_attr_rmtval_get(&args);
 				if (retval)
 					return retval;
 				retval = context->put_listent(context,
 						entry->flags,
 						name_rmt->name,
 						(int)name_rmt->namelen,
 						valuelen,
 						args.value);
 				kmem_free(args.value);
 			} else {
 				retval = context->put_listent(context,
 						entry->flags,
 						name_rmt->name,
 						(int)name_rmt->namelen,
 						valuelen,
 						NULL);
 			}
 			if (retval)
 				return retval;
 		}
 		if (context->seen_enough)
 			break;
 		cursor->offset++;
 	}
 	trace_xfs_attr_list_leaf_end(context);
 	return retval;
 }

 /*
  * Copy out attribute entries for attr_list(), for leaf attribute lists.
  */
 STATIC int
 xfs_attr_leaf_list(xfs_attr_list_context_t *context)
 {
 	int error;
 	struct xfs_buf *bp;

 	trace_xfs_attr_leaf_list(context);

 	context->cursor->blkno = 0;
 	error = xfs_attr3_leaf_read(NULL, context->dp, 0, -1, &bp);
 	if (error)
 		return error;

 	error = xfs_attr3_leaf_list_int(bp, context);
 	xfs_trans_brelse(NULL, bp);
 	return error;
 }

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

 	XFS_STATS_INC(xs_attr_list);

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

 	/*
 	 * Decide on what work routines to call based on the inode size.
 	 */
 	lock_mode = xfs_ilock_attr_map_shared(dp);
 	if (!xfs_inode_hasattr(dp)) {
 		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, lock_mode);
 	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.
  */
 STATIC int
 xfs_attr_put_listent(
 	xfs_attr_list_context_t *context,
 	int		flags,
 	unsigned char	*name,
 	int		namelen,
 	int		valuelen,
 	unsigned char	*value)
 {
 	struct attrlist *alist = (struct attrlist *)context->alist;
 	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(*alist));
 	ASSERT(context->firstu <= context->bufsize);

 	/*
 	 * Only list entries in the right namespace.
 	 */
 	if (((context->flags & ATTR_SECURE) == 0) !=
 	    ((flags & XFS_ATTR_SECURE) == 0))
 		return 0;
 	if (((context->flags & ATTR_ROOT) == 0) !=
 	    ((flags & XFS_ATTR_ROOT) == 0))
 		return 0;

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

 	aep = (attrlist_ent_t *)&context->alist[context->firstu];
 	aep->a_valuelen = valuelen;
 	memcpy(aep->a_name, name, namelen);
 	aep->a_name[namelen] = 0;
 	alist->al_offset[context->count++] = context->firstu;
 	alist->al_count = context->count;
 	trace_xfs_attr_list_add(context);
 	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;
 	struct attrlist *alist;
 	int error;

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

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

 	/*
 	 * Initialize the output buffer.
 	 */
 	memset(&context, 0, sizeof(context));
 	context.dp = dp;
 	context.cursor = cursor;
 	context.resynch = 1;
 	context.flags = flags;
 	context.alist = buffer;
 	context.bufsize = (bufsize & ~(sizeof(int)-1));  /* align */
 	context.firstu = context.bufsize;
 	context.put_listent = xfs_attr_put_listent;

 	alist = (struct attrlist *)context.alist;
 	alist->al_count = 0;
 	alist->al_more = 0;
 	alist->al_offset[0] = context.bufsize;

 	error = xfs_attr_list_int(&context);
 	ASSERT(error <= 0);
 	return error;
 }
	/*
	* Copyright (c) 2000-2005 Silicon Graphics, Inc.
	* Copyright (c) 2013 Red Hat, 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_format.h"
	#include "xfs_log_format.h"
	#include "xfs_trans_resv.h"
	#include "xfs_bit.h"
	#include "xfs_sb.h"
	#include "xfs_ag.h"
	#include "xfs_mount.h"
	#include "xfs_da_format.h"
	#include "xfs_da_btree.h"
	#include "xfs_inode.h"
	#include "xfs_trans.h"
	#include "xfs_inode_item.h"
	#include "xfs_bmap.h"
	#include "xfs_attr.h"
	#include "xfs_attr_sf.h"
	#include "xfs_attr_remote.h"
	#include "xfs_attr_leaf.h"
	#include "xfs_error.h"
	#include "xfs_trace.h"
	#include "xfs_buf_item.h"
	#include "xfs_cksum.h"
	#include "xfs_dinode.h"
	#include "xfs_dir2.h"

	STATIC int
	xfs_attr_shortform_compare(const void a, const void b)
	{
	xfs_attr_sf_sort_t sa, sb;

	sa = (xfs_attr_sf_sort_t *)a;
	sb = (xfs_attr_sf_sort_t *)b;
	if (sa->hash < sb->hash) {
	return -1;
	} else if (sa->hash > sb->hash) {
	return 1;
	} else {
	return sa->entno - sb->entno;
	}
	}

	#define XFS_ISRESET_CURSOR(cursor) \
	(!((cursor)->initted) && !((cursor)->hashval) && \
	!((cursor)->blkno) && !((cursor)->offset))
	/*
	* Copy out entries of shortform attribute lists for attr_list().
	* Shortform attribute lists are not stored in hashval sorted order.
	* If the output buffer is not large enough to hold them all, then we
	* we have to calculate each entries' hashvalue and sort them before
	* we can begin returning them to the user.
	*/
	int
	xfs_attr_shortform_list(xfs_attr_list_context_t *context)
	{
	attrlist_cursor_kern_t *cursor;
	xfs_attr_sf_sort_t sbuf, sbp;
	xfs_attr_shortform_t *sf;
	xfs_attr_sf_entry_t *sfe;
	xfs_inode_t *dp;
	int sbsize, nsbuf, count, i;
	int error;

	ASSERT(context != NULL);
	dp = context->dp;
	ASSERT(dp != NULL);
	ASSERT(dp->i_afp != NULL);
	sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
	ASSERT(sf != NULL);
	if (!sf->hdr.count)
	return 0;
	cursor = context->cursor;
	ASSERT(cursor != NULL);

	trace_xfs_attr_list_sf(context);

	/*
	* If the buffer is large enough and the cursor is at the start,
	* do not bother with sorting since we will return everything in
	* one buffer and another call using the cursor won't need to be
	* made.
	* Note the generous fudge factor of 16 overhead bytes per entry.
	* If bufsize is zero then put_listent must be a search function
	* and can just scan through what we have.
	*/
	if (context->bufsize == 0 \|\|
	(XFS_ISRESET_CURSOR(cursor) &&
	(dp->i_afp->if_bytes + sf->hdr.count * 16) < context->bufsize)) {
	for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
	error = context->put_listent(context,
	sfe->flags,
	sfe->nameval,
	(int)sfe->namelen,
	(int)sfe->valuelen,
	&sfe->nameval[sfe->namelen]);

	/*
	* Either search callback finished early or
	* didn't fit it all in the buffer after all.
	*/
	if (context->seen_enough)
	break;

	if (error)
	return error;
	sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
	}
	trace_xfs_attr_list_sf_all(context);
	return 0;
	}

	/* do no more for a search callback */
	if (context->bufsize == 0)
	return 0;

	/*
	* It didn't all fit, so we have to sort everything on hashval.
	*/
	sbsize = sf->hdr.count * sizeof(*sbuf);
	sbp = sbuf = kmem_alloc(sbsize, KM_SLEEP \| KM_NOFS);

	/*
	* Scan the attribute list for the rest of the entries, storing
	* the relevant info from only those that match into a buffer.
	*/
	nsbuf = 0;
	for (i = 0, sfe = &sf->list[0]; i < sf->hdr.count; i++) {
	if (unlikely(
	((char )sfe < (char )sf) \|\|
	((char )sfe >= ((char )sf + dp->i_afp->if_bytes)))) {
	XFS_CORRUPTION_ERROR("xfs_attr_shortform_list",
	XFS_ERRLEVEL_LOW,
	context->dp->i_mount, sfe);
	kmem_free(sbuf);
	return -EFSCORRUPTED;
	}

	sbp->entno = i;
	sbp->hash = xfs_da_hashname(sfe->nameval, sfe->namelen);
	sbp->name = sfe->nameval;
	sbp->namelen = sfe->namelen;
	/* These are bytes, and both on-disk, don't endian-flip */
	sbp->valuelen = sfe->valuelen;
	sbp->flags = sfe->flags;
	sfe = XFS_ATTR_SF_NEXTENTRY(sfe);
	sbp++;
	nsbuf++;
	}

	/*
	* Sort the entries on hash then entno.
	*/
	xfs_sort(sbuf, nsbuf, sizeof(*sbuf), xfs_attr_shortform_compare);

	/*
	* Re-find our place IN THE SORTED LIST.
	*/
	count = 0;
	cursor->initted = 1;
	cursor->blkno = 0;
	for (sbp = sbuf, i = 0; i < nsbuf; i++, sbp++) {
	if (sbp->hash == cursor->hashval) {
	if (cursor->offset == count) {
	break;
	}
	count++;
	} else if (sbp->hash > cursor->hashval) {
	break;
	}
	}
	if (i == nsbuf) {
	kmem_free(sbuf);
	return 0;
	}

	/*
	* Loop putting entries into the user buffer.
	*/
	for ( ; i < nsbuf; i++, sbp++) {
	if (cursor->hashval != sbp->hash) {
	cursor->hashval = sbp->hash;
	cursor->offset = 0;
	}
	error = context->put_listent(context,
	sbp->flags,
	sbp->name,
	sbp->namelen,
	sbp->valuelen,
	&sbp->name[sbp->namelen]);
	if (error)
	return error;
	if (context->seen_enough)
	break;
	cursor->offset++;
	}

	kmem_free(sbuf);
	return 0;
	}

	STATIC int
	xfs_attr_node_list(xfs_attr_list_context_t *context)
	{
	attrlist_cursor_kern_t *cursor;
	xfs_attr_leafblock_t *leaf;
	xfs_da_intnode_t *node;
	struct xfs_attr3_icleaf_hdr leafhdr;
	struct xfs_da3_icnode_hdr nodehdr;
	struct xfs_da_node_entry *btree;
	int error, i;
	struct xfs_buf *bp;
	struct xfs_inode *dp = context->dp;

	trace_xfs_attr_node_list(context);

	cursor = context->cursor;
	cursor->initted = 1;

	/*
	* Do all sorts of validation on the passed-in cursor structure.
	* If anything is amiss, ignore the cursor and look up the hashval
	* starting from the btree root.
	*/
	bp = NULL;
	if (cursor->blkno > 0) {
	error = xfs_da3_node_read(NULL, dp, cursor->blkno, -1,
	&bp, XFS_ATTR_FORK);
	if ((error != 0) && (error != -EFSCORRUPTED))
	return error;
	if (bp) {
	struct xfs_attr_leaf_entry *entries;

	node = bp->b_addr;
	switch (be16_to_cpu(node->hdr.info.magic)) {
	case XFS_DA_NODE_MAGIC:
	case XFS_DA3_NODE_MAGIC:
	trace_xfs_attr_list_wrong_blk(context);
	xfs_trans_brelse(NULL, bp);
	bp = NULL;
	break;
	case XFS_ATTR_LEAF_MAGIC:
	case XFS_ATTR3_LEAF_MAGIC:
	leaf = bp->b_addr;
	xfs_attr3_leaf_hdr_from_disk(&leafhdr, leaf);
	entries = xfs_attr3_leaf_entryp(leaf);
	if (cursor->hashval > be32_to_cpu(
	entries[leafhdr.count - 1].hashval)) {
	trace_xfs_attr_list_wrong_blk(context);
	xfs_trans_brelse(NULL, bp);
	bp = NULL;
	} else if (cursor->hashval <= be32_to_cpu(
	entries[0].hashval)) {
	trace_xfs_attr_list_wrong_blk(context);
	xfs_trans_brelse(NULL, bp);
	bp = NULL;
	}
	break;
	default:
	trace_xfs_attr_list_wrong_blk(context);
	xfs_trans_brelse(NULL, bp);
	bp = NULL;
	}
	}
	}

	/*
	* We did not find what we expected given the cursor's contents,
	* so we start from the top and work down based on the hash value.
	* Note that start of node block is same as start of leaf block.
	*/
	if (bp == NULL) {
	cursor->blkno = 0;
	for (;;) {
	__uint16_t magic;

	error = xfs_da3_node_read(NULL, dp,
	cursor->blkno, -1, &bp,
	XFS_ATTR_FORK);
	if (error)
	return error;
	node = bp->b_addr;
	magic = be16_to_cpu(node->hdr.info.magic);
	if (magic == XFS_ATTR_LEAF_MAGIC \|\|
	magic == XFS_ATTR3_LEAF_MAGIC)
	break;
	if (magic != XFS_DA_NODE_MAGIC &&
	magic != XFS_DA3_NODE_MAGIC) {
	XFS_CORRUPTION_ERROR("xfs_attr_node_list(3)",
	XFS_ERRLEVEL_LOW,
	context->dp->i_mount,
	node);
	xfs_trans_brelse(NULL, bp);
	return -EFSCORRUPTED;
	}

	dp->d_ops->node_hdr_from_disk(&nodehdr, node);
	btree = dp->d_ops->node_tree_p(node);
	for (i = 0; i < nodehdr.count; btree++, i++) {
	if (cursor->hashval
	<= be32_to_cpu(btree->hashval)) {
	cursor->blkno = be32_to_cpu(btree->before);
	trace_xfs_attr_list_node_descend(context,
	btree);
	break;
	}
	}
	if (i == nodehdr.count) {
	xfs_trans_brelse(NULL, bp);
	return 0;
	}
	xfs_trans_brelse(NULL, bp);
	}
	}
	ASSERT(bp != NULL);

	/*
	* Roll upward through the blocks, processing each leaf block in
	* order. As long as there is space in the result buffer, keep
	* adding the information.
	*/
	for (;;) {
	leaf = bp->b_addr;
	error = xfs_attr3_leaf_list_int(bp, context);
	if (error) {
	xfs_trans_brelse(NULL, bp);
	return error;
	}
	xfs_attr3_leaf_hdr_from_disk(&leafhdr, leaf);
	if (context->seen_enough \|\| leafhdr.forw == 0)
	break;
	cursor->blkno = leafhdr.forw;
	xfs_trans_brelse(NULL, bp);
	error = xfs_attr3_leaf_read(NULL, dp, cursor->blkno, -1, &bp);
	if (error)
	return error;
	}
	xfs_trans_brelse(NULL, bp);
	return 0;
	}

	/*
	* Copy out attribute list entries for attr_list(), for leaf attribute lists.
	*/
	int
	xfs_attr3_leaf_list_int(
	struct xfs_buf *bp,
	struct xfs_attr_list_context *context)
	{
	struct attrlist_cursor_kern *cursor;
	struct xfs_attr_leafblock *leaf;
	struct xfs_attr3_icleaf_hdr ichdr;
	struct xfs_attr_leaf_entry *entries;
	struct xfs_attr_leaf_entry *entry;
	int retval;
	int i;

	trace_xfs_attr_list_leaf(context);

	leaf = bp->b_addr;
	xfs_attr3_leaf_hdr_from_disk(&ichdr, leaf);
	entries = xfs_attr3_leaf_entryp(leaf);

	cursor = context->cursor;
	cursor->initted = 1;

	/*
	* Re-find our place in the leaf block if this is a new syscall.
	*/
	if (context->resynch) {
	entry = &entries[0];
	for (i = 0; i < ichdr.count; entry++, i++) {
	if (be32_to_cpu(entry->hashval) == cursor->hashval) {
	if (cursor->offset == context->dupcnt) {
	context->dupcnt = 0;
	break;
	}
	context->dupcnt++;
	} else if (be32_to_cpu(entry->hashval) >
	cursor->hashval) {
	context->dupcnt = 0;
	break;
	}
	}
	if (i == ichdr.count) {
	trace_xfs_attr_list_notfound(context);
	return 0;
	}
	} else {
	entry = &entries[0];
	i = 0;
	}
	context->resynch = 0;

	/*
	* We have found our place, start copying out the new attributes.
	*/
	retval = 0;
	for (; i < ichdr.count; entry++, i++) {
	if (be32_to_cpu(entry->hashval) != cursor->hashval) {
	cursor->hashval = be32_to_cpu(entry->hashval);
	cursor->offset = 0;
	}

	if (entry->flags & XFS_ATTR_INCOMPLETE)
	continue; /* skip incomplete entries */

	if (entry->flags & XFS_ATTR_LOCAL) {
	xfs_attr_leaf_name_local_t *name_loc =
	xfs_attr3_leaf_name_local(leaf, i);

	retval = context->put_listent(context,
	entry->flags,
	name_loc->nameval,
	(int)name_loc->namelen,
	be16_to_cpu(name_loc->valuelen),
	&name_loc->nameval[name_loc->namelen]);
	if (retval)
	return retval;
	} else {
	xfs_attr_leaf_name_remote_t *name_rmt =
	xfs_attr3_leaf_name_remote(leaf, i);

	int valuelen = be32_to_cpu(name_rmt->valuelen);

	if (context->put_value) {
	xfs_da_args_t args;

	memset((char *)&args, 0, sizeof(args));
	args.geo = context->dp->i_mount->m_attr_geo;
	args.dp = context->dp;
	args.whichfork = XFS_ATTR_FORK;
	args.valuelen = valuelen;
	args.rmtvaluelen = valuelen;
	args.value = kmem_alloc(valuelen, KM_SLEEP \| KM_NOFS);
	args.rmtblkno = be32_to_cpu(name_rmt->valueblk);
	args.rmtblkcnt = xfs_attr3_rmt_blocks(
	args.dp->i_mount, valuelen);
	retval = xfs_attr_rmtval_get(&args);
	if (retval)
	return retval;
	retval = context->put_listent(context,
	entry->flags,
	name_rmt->name,
	(int)name_rmt->namelen,
	valuelen,
	args.value);
	kmem_free(args.value);
	} else {
	retval = context->put_listent(context,
	entry->flags,
	name_rmt->name,
	(int)name_rmt->namelen,
	valuelen,
	NULL);
	}
	if (retval)
	return retval;
	}
	if (context->seen_enough)
	break;
	cursor->offset++;
	}
	trace_xfs_attr_list_leaf_end(context);
	return retval;
	}

	/*
	* Copy out attribute entries for attr_list(), for leaf attribute lists.
	*/
	STATIC int
	xfs_attr_leaf_list(xfs_attr_list_context_t *context)
	{
	int error;
	struct xfs_buf *bp;

	trace_xfs_attr_leaf_list(context);

	context->cursor->blkno = 0;
	error = xfs_attr3_leaf_read(NULL, context->dp, 0, -1, &bp);
	if (error)
	return error;

	error = xfs_attr3_leaf_list_int(bp, context);
	xfs_trans_brelse(NULL, bp);
	return error;
	}

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

	XFS_STATS_INC(xs_attr_list);

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

	/*
	* Decide on what work routines to call based on the inode size.
	*/
	lock_mode = xfs_ilock_attr_map_shared(dp);
	if (!xfs_inode_hasattr(dp)) {
	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, lock_mode);
	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.
	*/
	STATIC int
	xfs_attr_put_listent(
	xfs_attr_list_context_t *context,
	int flags,
	unsigned char *name,
	int namelen,
	int valuelen,
	unsigned char *value)
	{
	struct attrlist alist = (struct attrlist )context->alist;
	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(*alist));
	ASSERT(context->firstu <= context->bufsize);

	/*
	* Only list entries in the right namespace.
	*/
	if (((context->flags & ATTR_SECURE) == 0) !=
	((flags & XFS_ATTR_SECURE) == 0))
	return 0;
	if (((context->flags & ATTR_ROOT) == 0) !=
	((flags & XFS_ATTR_ROOT) == 0))
	return 0;

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

	aep = (attrlist_ent_t *)&context->alist[context->firstu];
	aep->a_valuelen = valuelen;
	memcpy(aep->a_name, name, namelen);
	aep->a_name[namelen] = 0;
	alist->al_offset[context->count++] = context->firstu;
	alist->al_count = context->count;
	trace_xfs_attr_list_add(context);
	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;
	struct attrlist *alist;
	int error;

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

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

	/*
	* Initialize the output buffer.
	*/
	memset(&context, 0, sizeof(context));
	context.dp = dp;
	context.cursor = cursor;
	context.resynch = 1;
	context.flags = flags;
	context.alist = buffer;
	context.bufsize = (bufsize & ~(sizeof(int)-1)); /* align */
	context.firstu = context.bufsize;
	context.put_listent = xfs_attr_put_listent;

	alist = (struct attrlist *)context.alist;
	alist->al_count = 0;
	alist->al_more = 0;
	alist->al_offset[0] = context.bufsize;

	error = xfs_attr_list_int(&context);
	ASSERT(error <= 0);
	return error;
	}