1 files changed, 541 insertions, 0 deletions

diff --git a/fs/xfs/xfs_attr_remote.c b/fs/xfs/xfs_attr_remote.c
new file mode 100644
index 000000000000..dee84466dcc9
--- /dev/null
+++ b/fs/xfs/xfs_attr_remote.c
@@ -0,0 +1,541 @@
+/*
+ * 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_error.h"
+#include "xfs_da_btree.h"
+#include "xfs_bmap_btree.h"
+#include "xfs_dinode.h"
+#include "xfs_inode.h"
+#include "xfs_alloc.h"
+#include "xfs_inode_item.h"
+#include "xfs_bmap.h"
+#include "xfs_attr.h"
+#include "xfs_attr_leaf.h"
+#include "xfs_attr_remote.h"
+#include "xfs_trans_space.h"
+#include "xfs_trace.h"
+#include "xfs_cksum.h"
+#include "xfs_buf_item.h"
+
+#define ATTR_RMTVALUE_MAPSIZE	1	/* # of map entries at once */
+
+/*
+ * Each contiguous block has a header, so it is not just a simple attribute
+ * length to FSB conversion.
+ */
+static int
+xfs_attr3_rmt_blocks(
+	struct xfs_mount *mp,
+	int		attrlen)
+{
+	int		buflen = XFS_ATTR3_RMT_BUF_SPACE(mp,
+							 mp->m_sb.sb_blocksize);
+	return (attrlen + buflen - 1) / buflen;
+}
+
+static bool
+xfs_attr3_rmt_verify(
+	struct xfs_buf		*bp)
+{
+	struct xfs_mount	*mp = bp->b_target->bt_mount;
+	struct xfs_attr3_rmt_hdr *rmt = bp->b_addr;
+
+	if (!xfs_sb_version_hascrc(&mp->m_sb))
+		return false;
+	if (rmt->rm_magic != cpu_to_be32(XFS_ATTR3_RMT_MAGIC))
+		return false;
+	if (!uuid_equal(&rmt->rm_uuid, &mp->m_sb.sb_uuid))
+		return false;
+	if (bp->b_bn != be64_to_cpu(rmt->rm_blkno))
+		return false;
+	if (be32_to_cpu(rmt->rm_offset) +
+				be32_to_cpu(rmt->rm_bytes) >= XATTR_SIZE_MAX)
+		return false;
+	if (rmt->rm_owner == 0)
+		return false;
+
+	return true;
+}
+
+static void
+xfs_attr3_rmt_read_verify(
+	struct xfs_buf	*bp)
+{
+	struct xfs_mount *mp = bp->b_target->bt_mount;
+
+	/* no verification of non-crc buffers */
+	if (!xfs_sb_version_hascrc(&mp->m_sb))
+		return;
+
+	if (!xfs_verify_cksum(bp->b_addr, BBTOB(bp->b_length),
+			      XFS_ATTR3_RMT_CRC_OFF) ||
+	    !xfs_attr3_rmt_verify(bp)) {
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+		xfs_buf_ioerror(bp, EFSCORRUPTED);
+	}
+}
+
+static void
+xfs_attr3_rmt_write_verify(
+	struct xfs_buf	*bp)
+{
+	struct xfs_mount *mp = bp->b_target->bt_mount;
+	struct xfs_buf_log_item	*bip = bp->b_fspriv;
+
+	/* no verification of non-crc buffers */
+	if (!xfs_sb_version_hascrc(&mp->m_sb))
+		return;
+
+	if (!xfs_attr3_rmt_verify(bp)) {
+		XFS_CORRUPTION_ERROR(__func__, XFS_ERRLEVEL_LOW, mp, bp->b_addr);
+		xfs_buf_ioerror(bp, EFSCORRUPTED);
+		return;
+	}
+
+	if (bip) {
+		struct xfs_attr3_rmt_hdr *rmt = bp->b_addr;
+		rmt->rm_lsn = cpu_to_be64(bip->bli_item.li_lsn);
+	}
+	xfs_update_cksum(bp->b_addr, BBTOB(bp->b_length),
+			 XFS_ATTR3_RMT_CRC_OFF);
+}
+
+const struct xfs_buf_ops xfs_attr3_rmt_buf_ops = {
+	.verify_read = xfs_attr3_rmt_read_verify,
+	.verify_write = xfs_attr3_rmt_write_verify,
+};
+
+static int
+xfs_attr3_rmt_hdr_set(
+	struct xfs_mount	*mp,
+	xfs_ino_t		ino,
+	uint32_t		offset,
+	uint32_t		size,
+	struct xfs_buf		*bp)
+{
+	struct xfs_attr3_rmt_hdr *rmt = bp->b_addr;
+
+	if (!xfs_sb_version_hascrc(&mp->m_sb))
+		return 0;
+
+	rmt->rm_magic = cpu_to_be32(XFS_ATTR3_RMT_MAGIC);
+	rmt->rm_offset = cpu_to_be32(offset);
+	rmt->rm_bytes = cpu_to_be32(size);
+	uuid_copy(&rmt->rm_uuid, &mp->m_sb.sb_uuid);
+	rmt->rm_owner = cpu_to_be64(ino);
+	rmt->rm_blkno = cpu_to_be64(bp->b_bn);
+	bp->b_ops = &xfs_attr3_rmt_buf_ops;
+
+	return sizeof(struct xfs_attr3_rmt_hdr);
+}
+
+/*
+ * Checking of the remote attribute header is split into two parts. the verifier
+ * does CRC, location and bounds checking, the unpacking function checks the
+ * attribute parameters and owner.
+ */
+static bool
+xfs_attr3_rmt_hdr_ok(
+	struct xfs_mount	*mp,
+	xfs_ino_t		ino,
+	uint32_t		offset,
+	uint32_t		size,
+	struct xfs_buf		*bp)
+{
+	struct xfs_attr3_rmt_hdr *rmt = bp->b_addr;
+
+	if (offset != be32_to_cpu(rmt->rm_offset))
+		return false;
+	if (size != be32_to_cpu(rmt->rm_bytes))
+		return false;
+	if (ino != be64_to_cpu(rmt->rm_owner))
+		return false;
+
+	/* ok */
+	return true;
+}
+
+/*
+ * Read the value associated with an attribute from the out-of-line buffer
+ * that we stored it in.
+ */
+int
+xfs_attr_rmtval_get(
+	struct xfs_da_args	*args)
+{
+	struct xfs_bmbt_irec	map[ATTR_RMTVALUE_MAPSIZE];
+	struct xfs_mount	*mp = args->dp->i_mount;
+	struct xfs_buf		*bp;
+	xfs_daddr_t		dblkno;
+	xfs_dablk_t		lblkno = args->rmtblkno;
+	void			*dst = args->value;
+	int			valuelen = args->valuelen;
+	int			nmap;
+	int			error;
+	int			blkcnt;
+	int			i;
+	int			offset = 0;
+
+	trace_xfs_attr_rmtval_get(args);
+
+	ASSERT(!(args->flags & ATTR_KERNOVAL));
+
+	while (valuelen > 0) {
+		nmap = ATTR_RMTVALUE_MAPSIZE;
+		error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
+				       args->rmtblkcnt, map, &nmap,
+				       XFS_BMAPI_ATTRFORK);
+		if (error)
+			return error;
+		ASSERT(nmap >= 1);
+
+		for (i = 0; (i < nmap) && (valuelen > 0); i++) {
+			int	byte_cnt;
+			char	*src;
+
+			ASSERT((map[i].br_startblock != DELAYSTARTBLOCK) &&
+			       (map[i].br_startblock != HOLESTARTBLOCK));
+			dblkno = XFS_FSB_TO_DADDR(mp, map[i].br_startblock);
+			blkcnt = XFS_FSB_TO_BB(mp, map[i].br_blockcount);
+			error = xfs_trans_read_buf(mp, NULL, mp->m_ddev_targp,
+						   dblkno, blkcnt, 0, &bp,
+						   &xfs_attr3_rmt_buf_ops);
+			if (error)
+				return error;
+
+			byte_cnt = min_t(int, valuelen, BBTOB(bp->b_length));
+			byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, byte_cnt);
+
+			src = bp->b_addr;
+			if (xfs_sb_version_hascrc(&mp->m_sb)) {
+				if (!xfs_attr3_rmt_hdr_ok(mp, args->dp->i_ino,
+							offset, byte_cnt, bp)) {
+					xfs_alert(mp,
+"remote attribute header does not match required off/len/owner (0x%x/Ox%x,0x%llx)",
+						offset, byte_cnt, args->dp->i_ino);
+					xfs_buf_relse(bp);
+					return EFSCORRUPTED;
+
+				}
+
+				src += sizeof(struct xfs_attr3_rmt_hdr);
+			}
+
+			memcpy(dst, src, byte_cnt);
+			xfs_buf_relse(bp);
+
+			offset += byte_cnt;
+			dst += byte_cnt;
+			valuelen -= byte_cnt;
+
+			lblkno += map[i].br_blockcount;
+		}
+	}
+	ASSERT(valuelen == 0);
+	return 0;
+}
+
+/*
+ * Write the value associated with an attribute into the out-of-line buffer
+ * that we have defined for it.
+ */
+int
+xfs_attr_rmtval_set(
+	struct xfs_da_args	*args)
+{
+	struct xfs_inode	*dp = args->dp;
+	struct xfs_mount	*mp = dp->i_mount;
+	struct xfs_bmbt_irec	map;
+	struct xfs_buf		*bp;
+	xfs_daddr_t		dblkno;
+	xfs_dablk_t		lblkno;
+	xfs_fileoff_t		lfileoff = 0;
+	void			*src = args->value;
+	int			blkcnt;
+	int			valuelen;
+	int			nmap;
+	int			error;
+	int			hdrcnt = 0;
+	bool			crcs = xfs_sb_version_hascrc(&mp->m_sb);
+	int			offset = 0;
+
+	trace_xfs_attr_rmtval_set(args);
+
+	/*
+	 * Find a "hole" in the attribute address space large enough for
+	 * us to drop the new attribute's value into. Because CRC enable
+	 * attributes have headers, we can't just do a straight byte to FSB
+	 * conversion. We calculate the worst case block count in this case
+	 * and we may not need that many, so we have to handle this when
+	 * allocating the blocks below. 
+	 */
+	if (!crcs)
+		blkcnt = XFS_B_TO_FSB(mp, args->valuelen);
+	else
+		blkcnt = xfs_attr3_rmt_blocks(mp, args->valuelen);
+
+	error = xfs_bmap_first_unused(args->trans, args->dp, blkcnt, &lfileoff,
+						   XFS_ATTR_FORK);
+	if (error)
+		return error;
+
+	/* Start with the attribute data. We'll allocate the rest afterwards. */
+	if (crcs)
+		blkcnt = XFS_B_TO_FSB(mp, args->valuelen);
+
+	args->rmtblkno = lblkno = (xfs_dablk_t)lfileoff;
+	args->rmtblkcnt = blkcnt;
+
+	/*
+	 * Roll through the "value", allocating blocks on disk as required.
+	 */
+	while (blkcnt > 0) {
+		int	committed;
+
+		/*
+		 * Allocate a single extent, up to the size of the value.
+		 */
+		xfs_bmap_init(args->flist, args->firstblock);
+		nmap = 1;
+		error = xfs_bmapi_write(args->trans, dp, (xfs_fileoff_t)lblkno,
+				  blkcnt,
+				  XFS_BMAPI_ATTRFORK | XFS_BMAPI_METADATA,
+				  args->firstblock, args->total, &map, &nmap,
+				  args->flist);
+		if (!error) {
+			error = xfs_bmap_finish(&args->trans, args->flist,
+						&committed);
+		}
+		if (error) {
+			ASSERT(committed);
+			args->trans = NULL;
+			xfs_bmap_cancel(args->flist);
+			return(error);
+		}
+
+		/*
+		 * bmap_finish() may have committed the last trans and started
+		 * a new one.  We need the inode to be in all transactions.
+		 */
+		if (committed)
+			xfs_trans_ijoin(args->trans, dp, 0);
+
+		ASSERT(nmap == 1);
+		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
+		       (map.br_startblock != HOLESTARTBLOCK));
+		lblkno += map.br_blockcount;
+		blkcnt -= map.br_blockcount;
+		hdrcnt++;
+
+		/*
+		 * If we have enough blocks for the attribute data, calculate
+		 * how many extra blocks we need for headers. We might run
+		 * through this multiple times in the case that the additional
+		 * headers in the blocks needed for the data fragments spills
+		 * into requiring more blocks. e.g. for 512 byte blocks, we'll
+		 * spill for another block every 9 headers we require in this
+		 * loop.
+		 */
+		if (crcs && blkcnt == 0) {
+			int total_len;
+
+			total_len = args->valuelen +
+				    hdrcnt * sizeof(struct xfs_attr3_rmt_hdr);
+			blkcnt = XFS_B_TO_FSB(mp, total_len);
+			blkcnt -= args->rmtblkcnt;
+			args->rmtblkcnt += blkcnt;
+		}
+
+		/*
+		 * Start the next trans in the chain.
+		 */
+		error = xfs_trans_roll(&args->trans, dp);
+		if (error)
+			return (error);
+	}
+
+	/*
+	 * Roll through the "value", copying the attribute value to the
+	 * already-allocated blocks.  Blocks are written synchronously
+	 * so that we can know they are all on disk before we turn off
+	 * the INCOMPLETE flag.
+	 */
+	lblkno = args->rmtblkno;
+	valuelen = args->valuelen;
+	while (valuelen > 0) {
+		int	byte_cnt;
+		char	*buf;
+
+		/*
+		 * Try to remember where we decided to put the value.
+		 */
+		xfs_bmap_init(args->flist, args->firstblock);
+		nmap = 1;
+		error = xfs_bmapi_read(dp, (xfs_fileoff_t)lblkno,
+				       args->rmtblkcnt, &map, &nmap,
+				       XFS_BMAPI_ATTRFORK);
+		if (error)
+			return(error);
+		ASSERT(nmap == 1);
+		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
+		       (map.br_startblock != HOLESTARTBLOCK));
+
+		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
+		blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
+
+		bp = xfs_buf_get(mp->m_ddev_targp, dblkno, blkcnt, 0);
+		if (!bp)
+			return ENOMEM;
+		bp->b_ops = &xfs_attr3_rmt_buf_ops;
+
+		byte_cnt = BBTOB(bp->b_length);
+		byte_cnt = XFS_ATTR3_RMT_BUF_SPACE(mp, byte_cnt);
+		if (valuelen < byte_cnt)
+			byte_cnt = valuelen;
+
+		buf = bp->b_addr;
+		buf += xfs_attr3_rmt_hdr_set(mp, dp->i_ino, offset,
+					     byte_cnt, bp);
+		memcpy(buf, src, byte_cnt);
+
+		if (byte_cnt < BBTOB(bp->b_length))
+			xfs_buf_zero(bp, byte_cnt,
+				     BBTOB(bp->b_length) - byte_cnt);
+
+		error = xfs_bwrite(bp);	/* GROT: NOTE: synchronous write */
+		xfs_buf_relse(bp);
+		if (error)
+			return error;
+
+		src += byte_cnt;
+		valuelen -= byte_cnt;
+		offset += byte_cnt;
+		hdrcnt--;
+
+		lblkno += map.br_blockcount;
+	}
+	ASSERT(valuelen == 0);
+	ASSERT(hdrcnt == 0);
+	return 0;
+}
+
+/*
+ * Remove the value associated with an attribute by deleting the
+ * out-of-line buffer that it is stored on.
+ */
+int
+xfs_attr_rmtval_remove(xfs_da_args_t *args)
+{
+	xfs_mount_t *mp;
+	xfs_bmbt_irec_t map;
+	xfs_buf_t *bp;
+	xfs_daddr_t dblkno;
+	xfs_dablk_t lblkno;
+	int valuelen, blkcnt, nmap, error, done, committed;
+
+	trace_xfs_attr_rmtval_remove(args);
+
+	mp = args->dp->i_mount;
+
+	/*
+	 * Roll through the "value", invalidating the attribute value's
+	 * blocks.
+	 */
+	lblkno = args->rmtblkno;
+	valuelen = args->rmtblkcnt;
+	while (valuelen > 0) {
+		/*
+		 * Try to remember where we decided to put the value.
+		 */
+		nmap = 1;
+		error = xfs_bmapi_read(args->dp, (xfs_fileoff_t)lblkno,
+				       args->rmtblkcnt, &map, &nmap,
+				       XFS_BMAPI_ATTRFORK);
+		if (error)
+			return(error);
+		ASSERT(nmap == 1);
+		ASSERT((map.br_startblock != DELAYSTARTBLOCK) &&
+		       (map.br_startblock != HOLESTARTBLOCK));
+
+		dblkno = XFS_FSB_TO_DADDR(mp, map.br_startblock),
+		blkcnt = XFS_FSB_TO_BB(mp, map.br_blockcount);
+
+		/*
+		 * If the "remote" value is in the cache, remove it.
+		 */
+		bp = xfs_incore(mp->m_ddev_targp, dblkno, blkcnt, XBF_TRYLOCK);
+		if (bp) {
+			xfs_buf_stale(bp);
+			xfs_buf_relse(bp);
+			bp = NULL;
+		}
+
+		valuelen -= map.br_blockcount;
+
+		lblkno += map.br_blockcount;
+	}
+
+	/*
+	 * Keep de-allocating extents until the remote-value region is gone.
+	 */
+	lblkno = args->rmtblkno;
+	blkcnt = args->rmtblkcnt;
+	done = 0;
+	while (!done) {
+		xfs_bmap_init(args->flist, args->firstblock);
+		error = xfs_bunmapi(args->trans, args->dp, lblkno, blkcnt,
+				    XFS_BMAPI_ATTRFORK | XFS_BMAPI_METADATA,
+				    1, args->firstblock, args->flist,
+				    &done);
+		if (!error) {
+			error = xfs_bmap_finish(&args->trans, args->flist,
+						&committed);
+		}
+		if (error) {
+			ASSERT(committed);
+			args->trans = NULL;
+			xfs_bmap_cancel(args->flist);
+			return error;
+		}
+
+		/*
+		 * bmap_finish() may have committed the last trans and started
+		 * a new one.  We need the inode to be in all transactions.
+		 */
+		if (committed)
+			xfs_trans_ijoin(args->trans, args->dp, 0);
+
+		/*
+		 * Close out trans and start the next one in the chain.
+		 */
+		error = xfs_trans_roll(&args->trans, args->dp);
+		if (error)
+			return (error);
+	}
+	return(0);
+}
+