// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2022-2023 Oracle. All Rights Reserved.
* Author: Darrick J. Wong <[email protected]>
*/
#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.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 "xfs_defer.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/repair.h"
#include "scrub/bitmap.h"
#include "scrub/agb_bitmap.h"
#include "scrub/fsb_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/inode for the entire
* rebuild operation so that nothing else can sneak in and change the incore
* 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, 0);
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;
}
/*
* Compute the maximum length of a buffer cache scan (in units of sectors),
* given a quantity of fs blocks.
*/
xfs_daddr_t
xrep_bufscan_max_sectors(
struct xfs_mount *mp,
xfs_extlen_t fsblocks)
{
int max_fsbs;
/* Remote xattr values are the largest buffers that we support. */
max_fsbs = xfs_attr3_max_rmt_blocks(mp);
return XFS_FSB_TO_BB(mp, min_t(xfs_extlen_t, fsblocks, max_fsbs));
}
/*
* Return an incore buffer from a sector scan, or NULL if there are no buffers
* left to return.
*/
struct xfs_buf *
xrep_bufscan_advance(
struct xfs_mount *mp,
struct xrep_bufscan *scan)
{
scan->__sector_count += scan->daddr_step;
while (scan->__sector_count <= scan->max_sectors) {
struct xfs_buf *bp = NULL;
int error;
error = xfs_buf_incore(mp->m_ddev_targp, scan->daddr,
scan->__sector_count, XBF_LIVESCAN, &bp);
if (!error)
return bp;
scan->__sector_count += scan->daddr_step;
}
return NULL;
}
/* 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) {
struct xrep_bufscan scan = {
.daddr = XFS_AGB_TO_DADDR(mp, agno, bno),
.max_sectors = xrep_bufscan_max_sectors(mp,
agbno_next - bno),
.daddr_step = XFS_FSB_TO_BB(mp, 1),
};
struct xfs_buf *bp;
while ((bp = xrep_bufscan_advance(mp, &scan)) != NULL) {
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;
if (rs->oinfo == &XFS_RMAP_OINFO_COW) {
/*
* If we're unmapping CoW staging extents, remove the
* records from the refcountbt, which will remove the
* rmap record as well.
*/
xfs_refcount_free_cow_extent(sc->tp, fsbno, *aglenp);
return 0;
}
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;
}
/*
* If we're getting rid of CoW staging extents, use deferred work items
* to remove the refcountbt records (which removes the rmap records)
* and free the extent. We're not worried about the system going down
* here because log recovery walks the refcount btree to clean out the
* CoW staging extents.
*/
if (rs->oinfo == &XFS_RMAP_OINFO_COW) {
ASSERT(rs->resv == XFS_AG_RESV_NONE);
xfs_refcount_free_cow_extent(sc->tp, fsbno, *aglenp);
error = xfs_free_extent_later(sc->tp, fsbno, *aglenp, NULL,
rs->resv, XFS_FREE_EXTENT_SKIP_DISCARD);
if (error)
return error;
rs->force_roll = true;
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.
* Add a defer ops barrier every other extent to avoid stressing the
* system with large EFIs.
*/
error = xfs_free_extent_later(sc->tp, fsbno, *aglenp, rs->oinfo,
rs->resv, XFS_FREE_EXTENT_SKIP_DISCARD);
if (error)
return error;
rs->deferred++;
if (rs->deferred % 2 == 0)
xfs_defer_add_barrier(sc->tp);
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(
uint32_t agbno,
uint32_t len,
void *priv)
{
struct xreap_state *rs = priv;
struct xfs_scrub *sc = rs->sc;
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;
}
/*
* Break a file metadata extent into sub-extents by fate (crosslinked, not
* crosslinked), and dispose of each sub-extent separately. The extent must
* not cross an AG boundary.
*/
STATIC int
xreap_fsmeta_extent(
uint64_t fsbno,
uint64_t len,
void *priv)
{
struct xreap_state *rs = priv;
struct xfs_scrub *sc = rs->sc;
xfs_agnumber_t agno = XFS_FSB_TO_AGNO(sc->mp, fsbno);
xfs_agblock_t agbno = XFS_FSB_TO_AGBNO(sc->mp, fsbno);
xfs_agblock_t agbno_next = agbno + len;
int error = 0;
ASSERT(len <= XFS_MAX_BMBT_EXTLEN);
ASSERT(sc->ip != NULL);
ASSERT(!sc->sa.pag);
/*
* We're reaping blocks after repairing file metadata, which means that
* we have to init the xchk_ag structure ourselves.
*/
sc->sa.pag = xfs_perag_get(sc->mp, agno);
if (!sc->sa.pag)
return -EFSCORRUPTED;
error = xfs_alloc_read_agf(sc->sa.pag, sc->tp, 0, &sc->sa.agf_bp);
if (error)
goto out_pag;
while (agbno < agbno_next) {
xfs_extlen_t aglen;
bool crosslinked;
error = xreap_agextent_select(rs, agbno, agbno_next,
&crosslinked, &aglen);
if (error)
goto out_agf;
error = xreap_agextent_iter(rs, agbno, &aglen, crosslinked);
if (error)
goto out_agf;
if (xreap_want_defer_finish(rs)) {
/*
* Holds the AGF buffer across the deferred chain
* processing.
*/
error = xrep_defer_finish(sc);
if (error)
goto out_agf;
xreap_defer_finish_reset(rs);
} else if (xreap_want_roll(rs)) {
/*
* Hold the AGF buffer across the transaction roll so
* that we don't have to reattach it to the scrub
* context.
*/
xfs_trans_bhold(sc->tp, sc->sa.agf_bp);
error = xfs_trans_roll_inode(&sc->tp, sc->ip);
xfs_trans_bjoin(sc->tp, sc->sa.agf_bp);
if (error)
goto out_agf;
xreap_reset(rs);
}
agbno += aglen;
}
out_agf:
xfs_trans_brelse(sc->tp, sc->sa.agf_bp);
sc->sa.agf_bp = NULL;
out_pag:
xfs_perag_put(sc->sa.pag);
sc->sa.pag = NULL;
return error;
}
/*
* Dispose of every block of every fs metadata extent in the bitmap.
* Do not use this to dispose of the mappings in an ondisk inode fork.
*/
int
xrep_reap_fsblocks(
struct xfs_scrub *sc,
struct xfsb_bitmap *bitmap,
const struct xfs_owner_info *oinfo)
{
struct xreap_state rs = {
.sc = sc,
.oinfo = oinfo,
.resv = XFS_AG_RESV_NONE,
};
int error;
ASSERT(xfs_has_rmapbt(sc->mp));
ASSERT(sc->ip != NULL);
error = xfsb_bitmap_walk(bitmap, xreap_fsmeta_extent, &rs);
if (error)
return error;
if (xreap_dirty(&rs))
return xrep_defer_finish(sc);
return 0;
}
/*
* Metadata files are not supposed to share blocks with anything else.
* If blocks are shared, we remove the reverse mapping (thus reducing the
* crosslink factor); if blocks are not shared, we also need to free them.
*
* This first step determines the longest subset of the passed-in imap
* (starting at its beginning) that is either crosslinked or not crosslinked.
* The blockcount will be adjust down as needed.
*/
STATIC int
xreap_bmapi_select(
struct xfs_scrub *sc,
struct xfs_inode *ip,
int whichfork,
struct xfs_bmbt_irec *imap,
bool *crosslinked)
{
struct xfs_owner_info oinfo;
struct xfs_btree_cur *cur;
xfs_filblks_t len = 1;
xfs_agblock_t bno;
xfs_agblock_t agbno;
xfs_agblock_t agbno_next;
int error;
agbno = XFS_FSB_TO_AGBNO(sc->mp, imap->br_startblock);
agbno_next = agbno + imap->br_blockcount;
cur = xfs_rmapbt_init_cursor(sc->mp, sc->tp, sc->sa.agf_bp,
sc->sa.pag);
xfs_rmap_ino_owner(&oinfo, ip->i_ino, whichfork, imap->br_startoff);
error = xfs_rmap_has_other_keys(cur, agbno, 1, &oinfo, crosslinked);
if (error)
goto out_cur;
bno = agbno + 1;
while (bno < agbno_next) {
bool also_crosslinked;
oinfo.oi_offset++;
error = xfs_rmap_has_other_keys(cur, bno, 1, &oinfo,
&also_crosslinked);
if (error)
goto out_cur;
if (also_crosslinked != *crosslinked)
break;
len++;
bno++;
}
imap->br_blockcount = len;
trace_xreap_bmapi_select(sc->sa.pag, agbno, len, *crosslinked);
out_cur:
xfs_btree_del_cursor(cur, error);
return error;
}
/*
* Decide if this buffer can be joined to a transaction. This is true for most
* buffers, but there are two cases that we want to catch: large remote xattr
* value buffers are not logged and can overflow the buffer log item dirty
* bitmap size; and oversized cached buffers if things have really gone
* haywire.
*/
static inline bool
xreap_buf_loggable(
const struct xfs_buf *bp)
{
int i;
for (i = 0; i < bp->b_map_count; i++) {
int chunks;
int map_size;
chunks = DIV_ROUND_UP(BBTOB(bp->b_maps[i].bm_len),
XFS_BLF_CHUNK);
map_size = DIV_ROUND_UP(chunks, NBWORD);
if (map_size > XFS_BLF_DATAMAP_SIZE)
return false;
}
return true;
}
/*
* Invalidate any buffers for this file mapping. The @imap blockcount may be
* adjusted downward if we need to roll the transaction.
*/
STATIC int
xreap_bmapi_binval(
struct xfs_scrub *sc,
struct xfs_inode *ip,
int whichfork,
struct xfs_bmbt_irec *imap)
{
struct xfs_mount *mp = sc->mp;
struct xfs_perag *pag = sc->sa.pag;
int bmap_flags = xfs_bmapi_aflag(whichfork);
xfs_fileoff_t off;
xfs_fileoff_t max_off;
xfs_extlen_t scan_blocks;
xfs_agnumber_t agno = sc->sa.pag->pag_agno;
xfs_agblock_t bno;
xfs_agblock_t agbno;
xfs_agblock_t agbno_next;
unsigned int invalidated = 0;
int error;
/*
* Avoid invalidating AG headers and post-EOFS blocks because we never
* own those.
*/
agbno = bno = XFS_FSB_TO_AGBNO(sc->mp, imap->br_startblock);
agbno_next = agbno + imap->br_blockcount;
if (!xfs_verify_agbno(pag, agbno) ||
!xfs_verify_agbno(pag, agbno_next - 1))
return 0;
/*
* Buffers for file blocks can span multiple contiguous mappings. This
* means that for each block in the mapping, there could exist an
* xfs_buf indexed by that block with any length up to the maximum
* buffer size (remote xattr values) or to the next hole in the fork.
* To set up our binval scan, first we need to figure out the location
* of the next hole.
*/
off = imap->br_startoff + imap->br_blockcount;
max_off = off + xfs_attr3_max_rmt_blocks(mp);
while (off < max_off) {
struct xfs_bmbt_irec hmap;
int nhmaps = 1;
error = xfs_bmapi_read(ip, off, max_off - off, &hmap,
&nhmaps, bmap_flags);
if (error)
return error;
if (nhmaps != 1 || hmap.br_startblock == DELAYSTARTBLOCK) {
ASSERT(0);
return -EFSCORRUPTED;
}
if (!xfs_bmap_is_real_extent(&hmap))
break;
off = hmap.br_startoff + hmap.br_blockcount;
}
scan_blocks = off - imap->br_startoff;
trace_xreap_bmapi_binval_scan(sc, imap, scan_blocks);
/*
* If there are incore buffers for these blocks, invalidate them. If
* we can't (try)lock the buffer we assume it's owned by someone else
* and leave it alone. The buffer cache cannot detect aliasing, so
* employ nested loops to detect incore buffers of any plausible size.
*/
while (bno < agbno_next) {
struct xrep_bufscan scan = {
.daddr = XFS_AGB_TO_DADDR(mp, agno, bno),
.max_sectors = xrep_bufscan_max_sectors(mp,
scan_blocks),
.daddr_step = XFS_FSB_TO_BB(mp, 1),
};
struct xfs_buf *bp;
while ((bp = xrep_bufscan_advance(mp, &scan)) != NULL) {
if (xreap_buf_loggable(bp)) {
xfs_trans_bjoin(sc->tp, bp);
xfs_trans_binval(sc->tp, bp);
} else {
xfs_buf_stale(bp);
xfs_buf_relse(bp);
}
invalidated++;
/*
* Stop invalidating if we've hit the limit; we should
* still have enough reservation left to free however
* much of the mapping we've seen so far.
*/
if (invalidated > XREAP_MAX_BINVAL) {
imap->br_blockcount = agbno_next - bno;
goto out;
}
}
bno++;
scan_blocks--;
}
out:
trace_xreap_bmapi_binval(sc->sa.pag, agbno, imap->br_blockcount);
return 0;
}
/*
* Dispose of as much of the beginning of this file fork mapping as possible.
* The number of blocks disposed of is returned in @imap->br_blockcount.
*/
STATIC int
xrep_reap_bmapi_iter(
struct xfs_scrub *sc,
struct xfs_inode *ip,
int whichfork,
struct xfs_bmbt_irec *imap,
bool crosslinked)
{
int error;
if (crosslinked) {
/*
* If there are other rmappings, this block is cross linked and
* must not be freed. Remove the reverse mapping, leave the
* buffer cache in its possibly confused state, and move on.
* We don't want to risk discarding valid data buffers from
* anybody else who thinks they own the block, even though that
* runs the risk of stale buffer warnings in the future.
*/
trace_xreap_dispose_unmap_extent(sc->sa.pag,
XFS_FSB_TO_AGBNO(sc->mp, imap->br_startblock),
imap->br_blockcount);
/*
* Schedule removal of the mapping from the fork. We use
* deferred log intents in this function to control the exact
* sequence of metadata updates.
*/
xfs_bmap_unmap_extent(sc->tp, ip, whichfork, imap);
xfs_trans_mod_dquot_byino(sc->tp, ip, XFS_TRANS_DQ_BCOUNT,
-(int64_t)imap->br_blockcount);
xfs_rmap_unmap_extent(sc->tp, ip, whichfork, imap);
return 0;
}
/*
* If the block is not crosslinked, we can invalidate all the incore
* buffers for the extent, and then free the extent. This is a bit of
* a mess since we don't detect discontiguous buffers that are indexed
* by a block starting before the first block of the extent but overlap
* anyway.
*/
trace_xreap_dispose_free_extent(sc->sa.pag,
XFS_FSB_TO_AGBNO(sc->mp, imap->br_startblock),
imap->br_blockcount);
/*
* Invalidate as many buffers as we can, starting at the beginning of
* this mapping. If this function sets blockcount to zero, the
* transaction is full of logged buffer invalidations, so we need to
* return early so that we can roll and retry.
*/
error = xreap_bmapi_binval(sc, ip, whichfork, imap);
if (error || imap->br_blockcount == 0)
return error;
/*
* Schedule removal of the mapping from the fork. We use deferred log
* intents in this function to control the exact sequence of metadata
* updates.
*/
xfs_bmap_unmap_extent(sc->tp, ip, whichfork, imap);
xfs_trans_mod_dquot_byino(sc->tp, ip, XFS_TRANS_DQ_BCOUNT,
-(int64_t)imap->br_blockcount);
return xfs_free_extent_later(sc->tp, imap->br_startblock,
imap->br_blockcount, NULL, XFS_AG_RESV_NONE,
XFS_FREE_EXTENT_SKIP_DISCARD);
}
/*
* Dispose of as much of this file extent as we can. Upon successful return,
* the imap will reflect the mapping that was removed from the fork.
*/
STATIC int
xreap_ifork_extent(
struct xfs_scrub *sc,
struct xfs_inode *ip,
int whichfork,
struct xfs_bmbt_irec *imap)
{
xfs_agnumber_t agno;
bool crosslinked;
int error;
ASSERT(sc->sa.pag == NULL);
trace_xreap_ifork_extent(sc, ip, whichfork, imap);
agno = XFS_FSB_TO_AGNO(sc->mp, imap->br_startblock);
sc->sa.pag = xfs_perag_get(sc->mp, agno);
if (!sc->sa.pag)
return -EFSCORRUPTED;
error = xfs_alloc_read_agf(sc->sa.pag, sc->tp, 0, &sc->sa.agf_bp);
if (error)
goto out_pag;
/*
* Decide the fate of the blocks at the beginning of the mapping, then
* update the mapping to use it with the unmap calls.
*/
error = xreap_bmapi_select(sc, ip, whichfork, imap, &crosslinked);
if (error)
goto out_agf;
error = xrep_reap_bmapi_iter(sc, ip, whichfork, imap, crosslinked);
if (error)
goto out_agf;
out_agf:
xfs_trans_brelse(sc->tp, sc->sa.agf_bp);
sc->sa.agf_bp = NULL;
out_pag:
xfs_perag_put(sc->sa.pag);
sc->sa.pag = NULL;
return error;
}
/*
* Dispose of each block mapped to the given fork of the given file. Callers
* must hold ILOCK_EXCL, and ip can only be sc->ip or sc->tempip. The fork
* must not have any delalloc reservations.
*/
int
xrep_reap_ifork(
struct xfs_scrub *sc,
struct xfs_inode *ip,
int whichfork)
{
xfs_fileoff_t off = 0;
int bmap_flags = xfs_bmapi_aflag(whichfork);
int error;
ASSERT(xfs_has_rmapbt(sc->mp));
ASSERT(ip == sc->ip || ip == sc->tempip);
ASSERT(whichfork == XFS_ATTR_FORK || !XFS_IS_REALTIME_INODE(ip));
while (off < XFS_MAX_FILEOFF) {
struct xfs_bmbt_irec imap;
int nimaps = 1;
/* Read the next extent, skip past holes and delalloc. */
error = xfs_bmapi_read(ip, off, XFS_MAX_FILEOFF - off, &imap,
&nimaps, bmap_flags);
if (error)
return error;
if (nimaps != 1 || imap.br_startblock == DELAYSTARTBLOCK) {
ASSERT(0);
return -EFSCORRUPTED;
}
/*
* If this is a real space mapping, reap as much of it as we
* can in a single transaction.
*/
if (xfs_bmap_is_real_extent(&imap)) {
error = xreap_ifork_extent(sc, ip, whichfork, &imap);
if (error)
return error;
error = xfs_defer_finish(&sc->tp);
if (error)
return error;
}
off = imap.br_startoff + imap.br_blockcount;
}
return 0;
}
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