linux/fs/xfs/scrub/bmap.c

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/*
* Copyright (C) 2017 Oracle. All Rights Reserved.
*
* Author: Darrick J. Wong <darrick.wong@oracle.com>
*
* 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; either version 2
* of the License, or (at your option) any later version.
*
* 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_shared.h"
#include "xfs_format.h"
#include "xfs_trans_resv.h"
#include "xfs_mount.h"
#include "xfs_defer.h"
#include "xfs_btree.h"
#include "xfs_bit.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_inode.h"
#include "xfs_inode_fork.h"
#include "xfs_alloc.h"
#include "xfs_rtalloc.h"
#include "xfs_bmap.h"
#include "xfs_bmap_util.h"
#include "xfs_bmap_btree.h"
#include "xfs_rmap.h"
#include "scrub/xfs_scrub.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/btree.h"
#include "scrub/trace.h"
/* Set us up with an inode's bmap. */
int
xfs_scrub_setup_inode_bmap(
struct xfs_scrub_context *sc,
struct xfs_inode *ip)
{
struct xfs_mount *mp = sc->mp;
int error;
error = xfs_scrub_get_inode(sc, ip);
if (error)
goto out;
sc->ilock_flags = XFS_IOLOCK_EXCL | XFS_MMAPLOCK_EXCL;
xfs_ilock(sc->ip, sc->ilock_flags);
/*
* We don't want any ephemeral data fork updates sitting around
* while we inspect block mappings, so wait for directio to finish
* and flush dirty data if we have delalloc reservations.
*/
if (S_ISREG(VFS_I(sc->ip)->i_mode) &&
sc->sm->sm_type == XFS_SCRUB_TYPE_BMBTD) {
inode_dio_wait(VFS_I(sc->ip));
error = filemap_write_and_wait(VFS_I(sc->ip)->i_mapping);
if (error)
goto out;
}
/* Got the inode, lock it and we're ready to go. */
error = xfs_scrub_trans_alloc(sc->sm, mp, &sc->tp);
if (error)
goto out;
sc->ilock_flags |= XFS_ILOCK_EXCL;
xfs_ilock(sc->ip, XFS_ILOCK_EXCL);
out:
/* scrub teardown will unlock and release the inode */
return error;
}
/*
* Inode fork block mapping (BMBT) scrubber.
* More complex than the others because we have to scrub
* all the extents regardless of whether or not the fork
* is in btree format.
*/
struct xfs_scrub_bmap_info {
struct xfs_scrub_context *sc;
xfs_fileoff_t lastoff;
bool is_rt;
bool is_shared;
int whichfork;
};
/* Cross-reference a single rtdev extent record. */
STATIC void
xfs_scrub_bmap_rt_extent_xref(
struct xfs_scrub_bmap_info *info,
struct xfs_inode *ip,
struct xfs_btree_cur *cur,
struct xfs_bmbt_irec *irec)
{
if (info->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
return;
}
/* Cross-reference a single datadev extent record. */
STATIC void
xfs_scrub_bmap_extent_xref(
struct xfs_scrub_bmap_info *info,
struct xfs_inode *ip,
struct xfs_btree_cur *cur,
struct xfs_bmbt_irec *irec)
{
struct xfs_mount *mp = info->sc->mp;
xfs_agnumber_t agno;
xfs_agblock_t agbno;
xfs_extlen_t len;
int error;
if (info->sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
return;
agno = XFS_FSB_TO_AGNO(mp, irec->br_startblock);
agbno = XFS_FSB_TO_AGBNO(mp, irec->br_startblock);
len = irec->br_blockcount;
error = xfs_scrub_ag_init(info->sc, agno, &info->sc->sa);
if (!xfs_scrub_fblock_process_error(info->sc, info->whichfork,
irec->br_startoff, &error))
return;
xfs_scrub_xref_is_used_space(info->sc, agbno, len);
xfs_scrub_ag_free(info->sc, &info->sc->sa);
}
/* Scrub a single extent record. */
STATIC int
xfs_scrub_bmap_extent(
struct xfs_inode *ip,
struct xfs_btree_cur *cur,
struct xfs_scrub_bmap_info *info,
struct xfs_bmbt_irec *irec)
{
struct xfs_mount *mp = info->sc->mp;
struct xfs_buf *bp = NULL;
int error = 0;
if (cur)
xfs_btree_get_block(cur, 0, &bp);
/*
* Check for out-of-order extents. This record could have come
* from the incore list, for which there is no ordering check.
*/
if (irec->br_startoff < info->lastoff)
xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
irec->br_startoff);
/* There should never be a "hole" extent in either extent list. */
if (irec->br_startblock == HOLESTARTBLOCK)
xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
irec->br_startoff);
/*
* Check for delalloc extents. We never iterate the ones in the
* in-core extent scan, and we should never see these in the bmbt.
*/
if (isnullstartblock(irec->br_startblock))
xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
irec->br_startoff);
/* Make sure the extent points to a valid place. */
if (irec->br_startblock + irec->br_blockcount <= irec->br_startblock)
xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
irec->br_startoff);
if (info->is_rt &&
(!xfs_verify_rtbno(mp, irec->br_startblock) ||
!xfs_verify_rtbno(mp, irec->br_startblock +
irec->br_blockcount - 1)))
xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
irec->br_startoff);
if (!info->is_rt &&
(!xfs_verify_fsbno(mp, irec->br_startblock) ||
!xfs_verify_fsbno(mp, irec->br_startblock +
irec->br_blockcount - 1)))
xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
irec->br_startoff);
/* We don't allow unwritten extents on attr forks. */
if (irec->br_state == XFS_EXT_UNWRITTEN &&
info->whichfork == XFS_ATTR_FORK)
xfs_scrub_fblock_set_corrupt(info->sc, info->whichfork,
irec->br_startoff);
if (info->is_rt)
xfs_scrub_bmap_rt_extent_xref(info, ip, cur, irec);
else
xfs_scrub_bmap_extent_xref(info, ip, cur, irec);
info->lastoff = irec->br_startoff + irec->br_blockcount;
return error;
}
/* Scrub a bmbt record. */
STATIC int
xfs_scrub_bmapbt_rec(
struct xfs_scrub_btree *bs,
union xfs_btree_rec *rec)
{
struct xfs_bmbt_irec irec;
struct xfs_scrub_bmap_info *info = bs->private;
struct xfs_inode *ip = bs->cur->bc_private.b.ip;
struct xfs_buf *bp = NULL;
struct xfs_btree_block *block;
uint64_t owner;
int i;
/*
* Check the owners of the btree blocks up to the level below
* the root since the verifiers don't do that.
*/
if (xfs_sb_version_hascrc(&bs->cur->bc_mp->m_sb) &&
bs->cur->bc_ptrs[0] == 1) {
for (i = 0; i < bs->cur->bc_nlevels - 1; i++) {
block = xfs_btree_get_block(bs->cur, i, &bp);
owner = be64_to_cpu(block->bb_u.l.bb_owner);
if (owner != ip->i_ino)
xfs_scrub_fblock_set_corrupt(bs->sc,
info->whichfork, 0);
}
}
/* Set up the in-core record and scrub it. */
xfs: use a b+tree for the in-core extent list Replace the current linear list and the indirection array for the in-core extent list with a b+tree to avoid the need for larger memory allocations for the indirection array when lots of extents are present. The current extent list implementations leads to heavy pressure on the memory allocator when modifying files with a high extent count, and can lead to high latencies because of that. The replacement is a b+tree with a few quirks. The leaf nodes directly store the extent record in two u64 values. The encoding is a little bit different from the existing in-core extent records so that the start offset and length which are required for lookups can be retreived with simple mask operations. The inner nodes store a 64-bit key containing the start offset in the first half of the node, and the pointers to the next lower level in the second half. In either case we walk the node from the beginninig to the end and do a linear search, as that is more efficient for the low number of cache lines touched during a search (2 for the inner nodes, 4 for the leaf nodes) than a binary search. We store termination markers (zero length for the leaf nodes, an otherwise impossible high bit for the inner nodes) to terminate the key list / records instead of storing a count to use the available cache lines as efficiently as possible. One quirk of the algorithm is that while we normally split a node half and half like usual btree implementations we just spill over entries added at the very end of the list to a new node on its own. This means we get a 100% fill grade for the common cases of bulk insertion when reading an inode into memory, and when only sequentially appending to a file. The downside is a slightly higher chance of splits on the first random insertions. Both insert and removal manually recurse into the lower levels, but the bulk deletion of the whole tree is still implemented as a recursive function call, although one limited by the overall depth and with very little stack usage in every iteration. For the first few extents we dynamically grow the list from a single extent to the next powers of two until we have a first full leaf block and that building the actual tree. The code started out based on the generic lib/btree.c code from Joern Engel based on earlier work from Peter Zijlstra, but has since been rewritten beyond recognition. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-11-04 01:34:46 +08:00
xfs_bmbt_disk_get_all(&rec->bmbt, &irec);
return xfs_scrub_bmap_extent(ip, bs->cur, info, &irec);
}
/* Scan the btree records. */
STATIC int
xfs_scrub_bmap_btree(
struct xfs_scrub_context *sc,
int whichfork,
struct xfs_scrub_bmap_info *info)
{
struct xfs_owner_info oinfo;
struct xfs_mount *mp = sc->mp;
struct xfs_inode *ip = sc->ip;
struct xfs_btree_cur *cur;
int error;
cur = xfs_bmbt_init_cursor(mp, sc->tp, ip, whichfork);
xfs_rmap_ino_bmbt_owner(&oinfo, ip->i_ino, whichfork);
error = xfs_scrub_btree(sc, cur, xfs_scrub_bmapbt_rec, &oinfo, info);
xfs_btree_del_cursor(cur, error ? XFS_BTREE_ERROR :
XFS_BTREE_NOERROR);
return error;
}
/*
* Scrub an inode fork's block mappings.
*
* First we scan every record in every btree block, if applicable.
* Then we unconditionally scan the incore extent cache.
*/
STATIC int
xfs_scrub_bmap(
struct xfs_scrub_context *sc,
int whichfork)
{
struct xfs_bmbt_irec irec;
struct xfs_scrub_bmap_info info = { NULL };
struct xfs_mount *mp = sc->mp;
struct xfs_inode *ip = sc->ip;
struct xfs_ifork *ifp;
xfs_fileoff_t endoff;
struct xfs_iext_cursor icur;
int error = 0;
ifp = XFS_IFORK_PTR(ip, whichfork);
info.is_rt = whichfork == XFS_DATA_FORK && XFS_IS_REALTIME_INODE(ip);
info.whichfork = whichfork;
info.is_shared = whichfork == XFS_DATA_FORK && xfs_is_reflink_inode(ip);
info.sc = sc;
switch (whichfork) {
case XFS_COW_FORK:
/* Non-existent CoW forks are ignorable. */
if (!ifp)
goto out;
/* No CoW forks on non-reflink inodes/filesystems. */
if (!xfs_is_reflink_inode(ip)) {
xfs_scrub_ino_set_corrupt(sc, sc->ip->i_ino, NULL);
goto out;
}
break;
case XFS_ATTR_FORK:
if (!ifp)
goto out;
if (!xfs_sb_version_hasattr(&mp->m_sb) &&
!xfs_sb_version_hasattr2(&mp->m_sb))
xfs_scrub_ino_set_corrupt(sc, sc->ip->i_ino, NULL);
break;
default:
ASSERT(whichfork == XFS_DATA_FORK);
break;
}
/* Check the fork values */
switch (XFS_IFORK_FORMAT(ip, whichfork)) {
case XFS_DINODE_FMT_UUID:
case XFS_DINODE_FMT_DEV:
case XFS_DINODE_FMT_LOCAL:
/* No mappings to check. */
goto out;
case XFS_DINODE_FMT_EXTENTS:
if (!(ifp->if_flags & XFS_IFEXTENTS)) {
xfs_scrub_fblock_set_corrupt(sc, whichfork, 0);
goto out;
}
break;
case XFS_DINODE_FMT_BTREE:
if (whichfork == XFS_COW_FORK) {
xfs_scrub_fblock_set_corrupt(sc, whichfork, 0);
goto out;
}
error = xfs_scrub_bmap_btree(sc, whichfork, &info);
if (error)
goto out;
break;
default:
xfs_scrub_fblock_set_corrupt(sc, whichfork, 0);
goto out;
}
if (sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT)
goto out;
/* Now try to scrub the in-memory extent list. */
if (!(ifp->if_flags & XFS_IFEXTENTS)) {
error = xfs_iread_extents(sc->tp, ip, whichfork);
if (!xfs_scrub_fblock_process_error(sc, whichfork, 0, &error))
goto out;
}
/* Find the offset of the last extent in the mapping. */
error = xfs_bmap_last_offset(ip, &endoff, whichfork);
if (!xfs_scrub_fblock_process_error(sc, whichfork, 0, &error))
goto out;
/* Scrub extent records. */
info.lastoff = 0;
ifp = XFS_IFORK_PTR(ip, whichfork);
for_each_xfs_iext(ifp, &icur, &irec) {
if (xfs_scrub_should_terminate(sc, &error))
break;
if (isnullstartblock(irec.br_startblock))
continue;
if (irec.br_startoff >= endoff) {
xfs_scrub_fblock_set_corrupt(sc, whichfork,
irec.br_startoff);
goto out;
}
error = xfs_scrub_bmap_extent(ip, NULL, &info, &irec);
if (error)
goto out;
}
out:
return error;
}
/* Scrub an inode's data fork. */
int
xfs_scrub_bmap_data(
struct xfs_scrub_context *sc)
{
return xfs_scrub_bmap(sc, XFS_DATA_FORK);
}
/* Scrub an inode's attr fork. */
int
xfs_scrub_bmap_attr(
struct xfs_scrub_context *sc)
{
return xfs_scrub_bmap(sc, XFS_ATTR_FORK);
}
/* Scrub an inode's CoW fork. */
int
xfs_scrub_bmap_cow(
struct xfs_scrub_context *sc)
{
if (!xfs_is_reflink_inode(sc->ip))
return -ENOENT;
return xfs_scrub_bmap(sc, XFS_COW_FORK);
}