xfs: split out attribute listing code into separate file

The attribute listing code is not used by userspace, so like the
directory readdir code, split it out into a separate file to
minimise the differences between the filesystem shared with libxfs
in userspace.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Mark Tinguely <tinguely@sgi.com>
Signed-off-by: Ben Myers <bpm@sgi.com>

1 files changed, 655 insertions, 0 deletions

diff --git a/fs/xfs/xfs_attr_list.c b/fs/xfs/xfs_attr_list.c
new file mode 100644
index 000000000000..cbc80d485177
--- /dev/null
+++ b/fs/xfs/xfs_attr_list.c
@@ -0,0 +1,655 @@
+/*
+ * 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_types.h"
+#include "xfs_bit.h"
+#include "xfs_log.h"
+#include "xfs_trans.h"
+#include "xfs_sb.h"
+#include "xfs_ag.h"
+#include "xfs_mount.h"
+#include "xfs_da_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_alloc_btree.h"
+#include "xfs_ialloc_btree.h"
+#include "xfs_alloc.h"
+#include "xfs_btree.h"
+#include "xfs_attr_sf.h"
+#include "xfs_attr_remote.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_inode_item.h"
+#include "xfs_bmap.h"
+#include "xfs_attr.h"
+#include "xfs_attr_leaf.h"
+#include "xfs_error.h"
+#include "xfs_trace.h"
+#include "xfs_buf_item.h"
+#include "xfs_cksum.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 XFS_ERROR(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;
+
+	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, context->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, context->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 XFS_ERROR(EFSCORRUPTED);
+			}
+
+			xfs_da3_node_hdr_from_disk(&nodehdr, node);
+			btree = xfs_da3_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, context->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.dp = context->dp;
+				args.whichfork = XFS_ATTR_FORK;
+				args.valuelen = 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 XFS_ERROR(error);
+
+	error = xfs_attr3_leaf_list_int(bp, context);
+	xfs_trans_brelse(NULL, bp);
+	return XFS_ERROR(error);
+}
+
+int
+xfs_attr_list_int(
+	xfs_attr_list_context_t *context)
+{
+	int error;
+	xfs_inode_t *dp = context->dp;
+
+	XFS_STATS_INC(xs_attr_list);
+
+	if (XFS_FORCED_SHUTDOWN(dp->i_mount))
+		return EIO;
+
+	xfs_ilock(dp, XFS_ILOCK_SHARED);
+
+	/*
+	 * Decide on what work routines to call based on the inode size.
+	 */
+	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, XFS_ILOCK_SHARED);
+
+	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(XFS_ERROR(EINVAL));
+	if ((cursor->initted == 0) &&
+	    (cursor->hashval || cursor->blkno || cursor->offset))
+		return XFS_ERROR(EINVAL);
+
+	/*
+	 * Check for a properly aligned buffer.
+	 */
+	if (((long)buffer) & (sizeof(int)-1))
+		return XFS_ERROR(EFAULT);
+	if (flags & ATTR_KERNOVAL)
+		bufsize = 0;
+
+	/*
+	 * Initialize the output buffer.
+	 */
+	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;
+}