blob: 86a62420e02c6571306483b18acf110dc5a55e61 [file] [log] [blame]
// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2022-2023 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <djwong@kernel.org>
*/
#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_btree.h"
#include "xfs_log_format.h"
#include "xfs_trans.h"
#include "xfs_sb.h"
#include "xfs_inode.h"
#include "xfs_alloc.h"
#include "xfs_alloc_btree.h"
#include "xfs_ialloc.h"
#include "xfs_ialloc_btree.h"
#include "xfs_rmap.h"
#include "xfs_rmap_btree.h"
#include "xfs_refcount_btree.h"
#include "xfs_extent_busy.h"
#include "xfs_ag.h"
#include "xfs_ag_resv.h"
#include "xfs_quota.h"
#include "xfs_qm.h"
#include "xfs_bmap.h"
#include "xfs_da_format.h"
#include "xfs_da_btree.h"
#include "xfs_attr.h"
#include "xfs_attr_remote.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/repair.h"
#include "scrub/bitmap.h"
#include "scrub/reap.h"
/*
* Disposal of Blocks from Old Metadata
*
* Now that we've constructed a new btree to replace the damaged one, we want
* to dispose of the blocks that (we think) the old btree was using.
* Previously, we used the rmapbt to collect the extents (bitmap) with the
* rmap owner corresponding to the tree we rebuilt, collected extents for any
* blocks with the same rmap owner that are owned by another data structure
* (sublist), and subtracted sublist from bitmap. In theory the extents
* remaining in bitmap are the old btree's blocks.
*
* Unfortunately, it's possible that the btree was crosslinked with other
* blocks on disk. The rmap data can tell us if there are multiple owners, so
* if the rmapbt says there is an owner of this block other than @oinfo, then
* the block is crosslinked. Remove the reverse mapping and continue.
*
* If there is one rmap record, we can free the block, which removes the
* reverse mapping but doesn't add the block to the free space. Our repair
* strategy is to hope the other metadata objects crosslinked on this block
* will be rebuilt (atop different blocks), thereby removing all the cross
* links.
*
* If there are no rmap records at all, we also free the block. If the btree
* being rebuilt lives in the free space (bnobt/cntbt/rmapbt) then there isn't
* supposed to be a rmap record and everything is ok. For other btrees there
* had to have been an rmap entry for the block to have ended up on @bitmap,
* so if it's gone now there's something wrong and the fs will shut down.
*
* Note: If there are multiple rmap records with only the same rmap owner as
* the btree we're trying to rebuild and the block is indeed owned by another
* data structure with the same rmap owner, then the block will be in sublist
* and therefore doesn't need disposal. If there are multiple rmap records
* with only the same rmap owner but the block is not owned by something with
* the same rmap owner, the block will be freed.
*
* The caller is responsible for locking the AG headers for the entire rebuild
* operation so that nothing else can sneak in and change the AG state while
* we're not looking. We must also invalidate any buffers associated with
* @bitmap.
*/
/* Information about reaping extents after a repair. */
struct xreap_state {
struct xfs_scrub *sc;
/* Reverse mapping owner and metadata reservation type. */
const struct xfs_owner_info *oinfo;
enum xfs_ag_resv_type resv;
/* If true, roll the transaction before reaping the next extent. */
bool force_roll;
/* Number of deferred reaps attached to the current transaction. */
unsigned int deferred;
/* Number of invalidated buffers logged to the current transaction. */
unsigned int invalidated;
/* Number of deferred reaps queued during the whole reap sequence. */
unsigned long long total_deferred;
};
/* Put a block back on the AGFL. */
STATIC int
xreap_put_freelist(
struct xfs_scrub *sc,
xfs_agblock_t agbno)
{
struct xfs_buf *agfl_bp;
int error;
/* Make sure there's space on the freelist. */
error = xrep_fix_freelist(sc, true);
if (error)
return error;
/*
* Since we're "freeing" a lost block onto the AGFL, we have to
* create an rmap for the block prior to merging it or else other
* parts will break.
*/
error = xfs_rmap_alloc(sc->tp, sc->sa.agf_bp, sc->sa.pag, agbno, 1,
&XFS_RMAP_OINFO_AG);
if (error)
return error;
/* Put the block on the AGFL. */
error = xfs_alloc_read_agfl(sc->sa.pag, sc->tp, &agfl_bp);
if (error)
return error;
error = xfs_alloc_put_freelist(sc->sa.pag, sc->tp, sc->sa.agf_bp,
agfl_bp, agbno, 0);
if (error)
return error;
xfs_extent_busy_insert(sc->tp, sc->sa.pag, agbno, 1,
XFS_EXTENT_BUSY_SKIP_DISCARD);
return 0;
}
/* Are there any uncommitted reap operations? */
static inline bool xreap_dirty(const struct xreap_state *rs)
{
if (rs->force_roll)
return true;
if (rs->deferred)
return true;
if (rs->invalidated)
return true;
if (rs->total_deferred)
return true;
return false;
}
#define XREAP_MAX_BINVAL (2048)
/*
* Decide if we want to roll the transaction after reaping an extent. We don't
* want to overrun the transaction reservation, so we prohibit more than
* 128 EFIs per transaction. For the same reason, we limit the number
* of buffer invalidations to 2048.
*/
static inline bool xreap_want_roll(const struct xreap_state *rs)
{
if (rs->force_roll)
return true;
if (rs->deferred > XREP_MAX_ITRUNCATE_EFIS)
return true;
if (rs->invalidated > XREAP_MAX_BINVAL)
return true;
return false;
}
static inline void xreap_reset(struct xreap_state *rs)
{
rs->total_deferred += rs->deferred;
rs->deferred = 0;
rs->invalidated = 0;
rs->force_roll = false;
}
#define XREAP_MAX_DEFER_CHAIN (2048)
/*
* Decide if we want to finish the deferred ops that are attached to the scrub
* transaction. We don't want to queue huge chains of deferred ops because
* that can consume a lot of log space and kernel memory. Hence we trigger a
* xfs_defer_finish if there are more than 2048 deferred reap operations or the
* caller did some real work.
*/
static inline bool
xreap_want_defer_finish(const struct xreap_state *rs)
{
if (rs->force_roll)
return true;
if (rs->total_deferred > XREAP_MAX_DEFER_CHAIN)
return true;
return false;
}
static inline void xreap_defer_finish_reset(struct xreap_state *rs)
{
rs->total_deferred = 0;
rs->deferred = 0;
rs->invalidated = 0;
rs->force_roll = false;
}
/* Try to invalidate the incore buffers for an extent that we're freeing. */
STATIC void
xreap_agextent_binval(
struct xreap_state *rs,
xfs_agblock_t agbno,
xfs_extlen_t *aglenp)
{
struct xfs_scrub *sc = rs->sc;
struct xfs_perag *pag = sc->sa.pag;
struct xfs_mount *mp = sc->mp;
xfs_agnumber_t agno = sc->sa.pag->pag_agno;
xfs_agblock_t agbno_next = agbno + *aglenp;
xfs_agblock_t bno = agbno;
/*
* Avoid invalidating AG headers and post-EOFS blocks because we never
* own those.
*/
if (!xfs_verify_agbno(pag, agbno) ||
!xfs_verify_agbno(pag, agbno_next - 1))
return;
/*
* If there are incore buffers for these blocks, invalidate them. We
* assume that the lack of any other known owners means that the buffer
* can be locked without risk of deadlocking. The buffer cache cannot
* detect aliasing, so employ nested loops to scan for incore buffers
* of any plausible size.
*/
while (bno < agbno_next) {
xfs_agblock_t fsbcount;
xfs_agblock_t max_fsbs;
/*
* Max buffer size is the max remote xattr buffer size, which
* is one fs block larger than 64k.
*/
max_fsbs = min_t(xfs_agblock_t, agbno_next - bno,
xfs_attr3_rmt_blocks(mp, XFS_XATTR_SIZE_MAX));
for (fsbcount = 1; fsbcount < max_fsbs; fsbcount++) {
struct xfs_buf *bp = NULL;
xfs_daddr_t daddr;
int error;
daddr = XFS_AGB_TO_DADDR(mp, agno, bno);
error = xfs_buf_incore(mp->m_ddev_targp, daddr,
XFS_FSB_TO_BB(mp, fsbcount),
XBF_LIVESCAN, &bp);
if (error)
continue;
xfs_trans_bjoin(sc->tp, bp);
xfs_trans_binval(sc->tp, bp);
rs->invalidated++;
/*
* Stop invalidating if we've hit the limit; we should
* still have enough reservation left to free however
* far we've gotten.
*/
if (rs->invalidated > XREAP_MAX_BINVAL) {
*aglenp -= agbno_next - bno;
goto out;
}
}
bno++;
}
out:
trace_xreap_agextent_binval(sc->sa.pag, agbno, *aglenp);
}
/*
* Figure out the longest run of blocks that we can dispose of with a single
* call. Cross-linked blocks should have their reverse mappings removed, but
* single-owner extents can be freed. AGFL blocks can only be put back one at
* a time.
*/
STATIC int
xreap_agextent_select(
struct xreap_state *rs,
xfs_agblock_t agbno,
xfs_agblock_t agbno_next,
bool *crosslinked,
xfs_extlen_t *aglenp)
{
struct xfs_scrub *sc = rs->sc;
struct xfs_btree_cur *cur;
xfs_agblock_t bno = agbno + 1;
xfs_extlen_t len = 1;
int error;
/*
* Determine if there are any other rmap records covering the first
* block of this extent. If so, the block is crosslinked.
*/
cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, sc->sa.agf_bp,
sc->sa.pag);
error = xfs_rmap_has_other_keys(cur, agbno, 1, rs->oinfo,
crosslinked);
if (error)
goto out_cur;
/* AGFL blocks can only be deal with one at a time. */
if (rs->resv == XFS_AG_RESV_AGFL)
goto out_found;
/*
* Figure out how many of the subsequent blocks have the same crosslink
* status.
*/
while (bno < agbno_next) {
bool also_crosslinked;
error = xfs_rmap_has_other_keys(cur, bno, 1, rs->oinfo,
&also_crosslinked);
if (error)
goto out_cur;
if (*crosslinked != also_crosslinked)
break;
len++;
bno++;
}
out_found:
*aglenp = len;
trace_xreap_agextent_select(sc->sa.pag, agbno, len, *crosslinked);
out_cur:
xfs_btree_del_cursor(cur, error);
return error;
}
/*
* Dispose of as much of the beginning of this AG extent as possible. The
* number of blocks disposed of will be returned in @aglenp.
*/
STATIC int
xreap_agextent_iter(
struct xreap_state *rs,
xfs_agblock_t agbno,
xfs_extlen_t *aglenp,
bool crosslinked)
{
struct xfs_scrub *sc = rs->sc;
xfs_fsblock_t fsbno;
int error = 0;
fsbno = XFS_AGB_TO_FSB(sc->mp, sc->sa.pag->pag_agno, agbno);
/*
* If there are other rmappings, this block is cross linked and must
* not be freed. Remove the reverse mapping and move on. Otherwise,
* we were the only owner of the block, so free the extent, which will
* also remove the rmap.
*
* XXX: XFS doesn't support detecting the case where a single block
* metadata structure is crosslinked with a multi-block structure
* because the buffer cache doesn't detect aliasing problems, so we
* can't fix 100% of crosslinking problems (yet). The verifiers will
* blow on writeout, the filesystem will shut down, and the admin gets
* to run xfs_repair.
*/
if (crosslinked) {
trace_xreap_dispose_unmap_extent(sc->sa.pag, agbno, *aglenp);
rs->force_roll = true;
return xfs_rmap_free(sc->tp, sc->sa.agf_bp, sc->sa.pag, agbno,
*aglenp, rs->oinfo);
}
trace_xreap_dispose_free_extent(sc->sa.pag, agbno, *aglenp);
/*
* Invalidate as many buffers as we can, starting at agbno. If this
* function sets *aglenp to zero, the transaction is full of logged
* buffer invalidations, so we need to return early so that we can
* roll and retry.
*/
xreap_agextent_binval(rs, agbno, aglenp);
if (*aglenp == 0) {
ASSERT(xreap_want_roll(rs));
return 0;
}
/* Put blocks back on the AGFL one at a time. */
if (rs->resv == XFS_AG_RESV_AGFL) {
ASSERT(*aglenp == 1);
error = xreap_put_freelist(sc, agbno);
if (error)
return error;
rs->force_roll = true;
return 0;
}
/*
* Use deferred frees to get rid of the old btree blocks to try to
* minimize the window in which we could crash and lose the old blocks.
*/
error = __xfs_free_extent_later(sc->tp, fsbno, *aglenp, rs->oinfo,
rs->resv, true);
if (error)
return error;
rs->deferred++;
return 0;
}
/*
* Break an AG metadata extent into sub-extents by fate (crosslinked, not
* crosslinked), and dispose of each sub-extent separately.
*/
STATIC int
xreap_agmeta_extent(
uint64_t fsbno,
uint64_t len,
void *priv)
{
struct xreap_state *rs = priv;
struct xfs_scrub *sc = rs->sc;
xfs_agblock_t agbno = fsbno;
xfs_agblock_t agbno_next = agbno + len;
int error = 0;
ASSERT(len <= XFS_MAX_BMBT_EXTLEN);
ASSERT(sc->ip == NULL);
while (agbno < agbno_next) {
xfs_extlen_t aglen;
bool crosslinked;
error = xreap_agextent_select(rs, agbno, agbno_next,
&crosslinked, &aglen);
if (error)
return error;
error = xreap_agextent_iter(rs, agbno, &aglen, crosslinked);
if (error)
return error;
if (xreap_want_defer_finish(rs)) {
error = xrep_defer_finish(sc);
if (error)
return error;
xreap_defer_finish_reset(rs);
} else if (xreap_want_roll(rs)) {
error = xrep_roll_ag_trans(sc);
if (error)
return error;
xreap_reset(rs);
}
agbno += aglen;
}
return 0;
}
/* Dispose of every block of every AG metadata extent in the bitmap. */
int
xrep_reap_agblocks(
struct xfs_scrub *sc,
struct xagb_bitmap *bitmap,
const struct xfs_owner_info *oinfo,
enum xfs_ag_resv_type type)
{
struct xreap_state rs = {
.sc = sc,
.oinfo = oinfo,
.resv = type,
};
int error;
ASSERT(xfs_has_rmapbt(sc->mp));
ASSERT(sc->ip == NULL);
error = xagb_bitmap_walk(bitmap, xreap_agmeta_extent, &rs);
if (error)
return error;
if (xreap_dirty(&rs))
return xrep_defer_finish(sc);
return 0;
}