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linux/fs/xfs/scrub/dabtree.c
Darrick J. Wong 88accf1722 xfs: scrub should use ECHRNG to signal that the drain is needed 
In the previous patch, we added jump labels to the intent drain code so
that regular filesystem operations need not pay the price of checking
for someone (scrub) waiting on intents to drain from some part of the
filesystem when that someone isn't running.

However, I observed that xfs/285 now spends a lot more time pushing the
AIL from the inode btree scrubber than it used to.  This is because the
inobt scrubber will try push the AIL to try to get logged inode cores
written to the filesystem when it sees a weird discrepancy between the
ondisk inode and the inobt records.  This AIL push is triggered when the
setup function sees TRY_HARDER is set; and the requisite EDEADLOCK
return is initiated when the discrepancy is seen.

The solution to this performance slow down is to use a different result
code (ECHRNG) for scrub code to signal that it needs to wait for
deferred intent work items to drain out of some part of the filesystem.
When this happens, set a new scrub state flag (XCHK_NEED_DRAIN) so that
setup functions will activate the jump label.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
2023-04-11 19:00:00 -07:00

598 lines
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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Copyright (C) 2017-2023 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_log_format.h"
#include "xfs_trans.h"
#include "xfs_inode.h"
#include "xfs_dir2.h"
#include "xfs_dir2_priv.h"
#include "xfs_attr_leaf.h"
#include "scrub/scrub.h"
#include "scrub/common.h"
#include "scrub/trace.h"
#include "scrub/dabtree.h"
/* Directory/Attribute Btree */
/*
* Check for da btree operation errors. See the section about handling
* operational errors in common.c.
*/
bool
xchk_da_process_error(
struct xchk_da_btree *ds,
int level,
int *error)
{
struct xfs_scrub *sc = ds->sc;
if (*error == 0)
return true;
switch (*error) {
case -EDEADLOCK:
case -ECHRNG:
/* Used to restart an op with deadlock avoidance. */
trace_xchk_deadlock_retry(sc->ip, sc->sm, *error);
break;
case -EFSBADCRC:
case -EFSCORRUPTED:
/* Note the badness but don't abort. */
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
*error = 0;
fallthrough;
default:
trace_xchk_file_op_error(sc, ds->dargs.whichfork,
xfs_dir2_da_to_db(ds->dargs.geo,
ds->state->path.blk[level].blkno),
*error, __return_address);
break;
}
return false;
}
/*
* Check for da btree corruption. See the section about handling
* operational errors in common.c.
*/
void
xchk_da_set_corrupt(
struct xchk_da_btree *ds,
int level)
{
struct xfs_scrub *sc = ds->sc;
sc->sm->sm_flags |= XFS_SCRUB_OFLAG_CORRUPT;
trace_xchk_fblock_error(sc, ds->dargs.whichfork,
xfs_dir2_da_to_db(ds->dargs.geo,
ds->state->path.blk[level].blkno),
__return_address);
}
static struct xfs_da_node_entry *
xchk_da_btree_node_entry(
struct xchk_da_btree *ds,
int level)
{
struct xfs_da_state_blk *blk = &ds->state->path.blk[level];
struct xfs_da3_icnode_hdr hdr;
ASSERT(blk->magic == XFS_DA_NODE_MAGIC);
xfs_da3_node_hdr_from_disk(ds->sc->mp, &hdr, blk->bp->b_addr);
return hdr.btree + blk->index;
}
/* Scrub a da btree hash (key). */
int
xchk_da_btree_hash(
struct xchk_da_btree *ds,
int level,
__be32 *hashp)
{
struct xfs_da_node_entry *entry;
xfs_dahash_t hash;
xfs_dahash_t parent_hash;
/* Is this hash in order? */
hash = be32_to_cpu(*hashp);
if (hash < ds->hashes[level])
xchk_da_set_corrupt(ds, level);
ds->hashes[level] = hash;
if (level == 0)
return 0;
/* Is this hash no larger than the parent hash? */
entry = xchk_da_btree_node_entry(ds, level - 1);
parent_hash = be32_to_cpu(entry->hashval);
if (parent_hash < hash)
xchk_da_set_corrupt(ds, level);
return 0;
}
/*
* Check a da btree pointer. Returns true if it's ok to use this
* pointer.
*/
STATIC bool
xchk_da_btree_ptr_ok(
struct xchk_da_btree *ds,
int level,
xfs_dablk_t blkno)
{
if (blkno < ds->lowest || (ds->highest != 0 && blkno >= ds->highest)) {
xchk_da_set_corrupt(ds, level);
return false;
}
return true;
}
/*
* The da btree scrubber can handle leaf1 blocks as a degenerate
* form of leafn blocks. Since the regular da code doesn't handle
* leaf1, we must multiplex the verifiers.
*/
static void
xchk_da_btree_read_verify(
struct xfs_buf *bp)
{
struct xfs_da_blkinfo *info = bp->b_addr;
switch (be16_to_cpu(info->magic)) {
case XFS_DIR2_LEAF1_MAGIC:
case XFS_DIR3_LEAF1_MAGIC:
bp->b_ops = &xfs_dir3_leaf1_buf_ops;
bp->b_ops->verify_read(bp);
return;
default:
/*
* xfs_da3_node_buf_ops already know how to handle
* DA*_NODE, ATTR*_LEAF, and DIR*_LEAFN blocks.
*/
bp->b_ops = &xfs_da3_node_buf_ops;
bp->b_ops->verify_read(bp);
return;
}
}
static void
xchk_da_btree_write_verify(
struct xfs_buf *bp)
{
struct xfs_da_blkinfo *info = bp->b_addr;
switch (be16_to_cpu(info->magic)) {
case XFS_DIR2_LEAF1_MAGIC:
case XFS_DIR3_LEAF1_MAGIC:
bp->b_ops = &xfs_dir3_leaf1_buf_ops;
bp->b_ops->verify_write(bp);
return;
default:
/*
* xfs_da3_node_buf_ops already know how to handle
* DA*_NODE, ATTR*_LEAF, and DIR*_LEAFN blocks.
*/
bp->b_ops = &xfs_da3_node_buf_ops;
bp->b_ops->verify_write(bp);
return;
}
}
static void *
xchk_da_btree_verify(
struct xfs_buf *bp)
{
struct xfs_da_blkinfo *info = bp->b_addr;
switch (be16_to_cpu(info->magic)) {
case XFS_DIR2_LEAF1_MAGIC:
case XFS_DIR3_LEAF1_MAGIC:
bp->b_ops = &xfs_dir3_leaf1_buf_ops;
return bp->b_ops->verify_struct(bp);
default:
bp->b_ops = &xfs_da3_node_buf_ops;
return bp->b_ops->verify_struct(bp);
}
}
static const struct xfs_buf_ops xchk_da_btree_buf_ops = {
.name = "xchk_da_btree",
.verify_read = xchk_da_btree_read_verify,
.verify_write = xchk_da_btree_write_verify,
.verify_struct = xchk_da_btree_verify,
};
/* Check a block's sibling. */
STATIC int
xchk_da_btree_block_check_sibling(
struct xchk_da_btree *ds,
int level,
int direction,
xfs_dablk_t sibling)
{
struct xfs_da_state_path *path = &ds->state->path;
struct xfs_da_state_path *altpath = &ds->state->altpath;
int retval;
int plevel;
int error;
memcpy(altpath, path, sizeof(ds->state->altpath));
/*
* If the pointer is null, we shouldn't be able to move the upper
* level pointer anywhere.
*/
if (sibling == 0) {
error = xfs_da3_path_shift(ds->state, altpath, direction,
false, &retval);
if (error == 0 && retval == 0)
xchk_da_set_corrupt(ds, level);
error = 0;
goto out;
}
/* Move the alternate cursor one block in the direction given. */
error = xfs_da3_path_shift(ds->state, altpath, direction, false,
&retval);
if (!xchk_da_process_error(ds, level, &error))
goto out;
if (retval) {
xchk_da_set_corrupt(ds, level);
goto out;
}
if (altpath->blk[level].bp)
xchk_buffer_recheck(ds->sc, altpath->blk[level].bp);
/* Compare upper level pointer to sibling pointer. */
if (altpath->blk[level].blkno != sibling)
xchk_da_set_corrupt(ds, level);
out:
/* Free all buffers in the altpath that aren't referenced from path. */
for (plevel = 0; plevel < altpath->active; plevel++) {
if (altpath->blk[plevel].bp == NULL ||
(plevel < path->active &&
altpath->blk[plevel].bp == path->blk[plevel].bp))
continue;
xfs_trans_brelse(ds->dargs.trans, altpath->blk[plevel].bp);
altpath->blk[plevel].bp = NULL;
}
return error;
}
/* Check a block's sibling pointers. */
STATIC int
xchk_da_btree_block_check_siblings(
struct xchk_da_btree *ds,
int level,
struct xfs_da_blkinfo *hdr)
{
xfs_dablk_t forw;
xfs_dablk_t back;
int error = 0;
forw = be32_to_cpu(hdr->forw);
back = be32_to_cpu(hdr->back);
/* Top level blocks should not have sibling pointers. */
if (level == 0) {
if (forw != 0 || back != 0)
xchk_da_set_corrupt(ds, level);
return 0;
}
/*
* Check back (left) and forw (right) pointers. These functions
* absorb error codes for us.
*/
error = xchk_da_btree_block_check_sibling(ds, level, 0, back);
if (error)
goto out;
error = xchk_da_btree_block_check_sibling(ds, level, 1, forw);
out:
memset(&ds->state->altpath, 0, sizeof(ds->state->altpath));
return error;
}
/* Load a dir/attribute block from a btree. */
STATIC int
xchk_da_btree_block(
struct xchk_da_btree *ds,
int level,
xfs_dablk_t blkno)
{
struct xfs_da_state_blk *blk;
struct xfs_da_intnode *node;
struct xfs_da_node_entry *btree;
struct xfs_da3_blkinfo *hdr3;
struct xfs_da_args *dargs = &ds->dargs;
struct xfs_inode *ip = ds->dargs.dp;
xfs_ino_t owner;
int *pmaxrecs;
struct xfs_da3_icnode_hdr nodehdr;
int error = 0;
blk = &ds->state->path.blk[level];
ds->state->path.active = level + 1;
/* Release old block. */
if (blk->bp) {
xfs_trans_brelse(dargs->trans, blk->bp);
blk->bp = NULL;
}
/* Check the pointer. */
blk->blkno = blkno;
if (!xchk_da_btree_ptr_ok(ds, level, blkno))
goto out_nobuf;
/* Read the buffer. */
error = xfs_da_read_buf(dargs->trans, dargs->dp, blk->blkno,
XFS_DABUF_MAP_HOLE_OK, &blk->bp, dargs->whichfork,
&xchk_da_btree_buf_ops);
if (!xchk_da_process_error(ds, level, &error))
goto out_nobuf;
if (blk->bp)
xchk_buffer_recheck(ds->sc, blk->bp);
/*
* We didn't find a dir btree root block, which means that
* there's no LEAF1/LEAFN tree (at least not where it's supposed
* to be), so jump out now.
*/
if (ds->dargs.whichfork == XFS_DATA_FORK && level == 0 &&
blk->bp == NULL)
goto out_nobuf;
/* It's /not/ ok for attr trees not to have a da btree. */
if (blk->bp == NULL) {
xchk_da_set_corrupt(ds, level);
goto out_nobuf;
}
hdr3 = blk->bp->b_addr;
blk->magic = be16_to_cpu(hdr3->hdr.magic);
pmaxrecs = &ds->maxrecs[level];
/* We only started zeroing the header on v5 filesystems. */
if (xfs_has_crc(ds->sc->mp) && hdr3->hdr.pad)
xchk_da_set_corrupt(ds, level);
/* Check the owner. */
if (xfs_has_crc(ip->i_mount)) {
owner = be64_to_cpu(hdr3->owner);
if (owner != ip->i_ino)
xchk_da_set_corrupt(ds, level);
}
/* Check the siblings. */
error = xchk_da_btree_block_check_siblings(ds, level, &hdr3->hdr);
if (error)
goto out;
/* Interpret the buffer. */
switch (blk->magic) {
case XFS_ATTR_LEAF_MAGIC:
case XFS_ATTR3_LEAF_MAGIC:
xfs_trans_buf_set_type(dargs->trans, blk->bp,
XFS_BLFT_ATTR_LEAF_BUF);
blk->magic = XFS_ATTR_LEAF_MAGIC;
blk->hashval = xfs_attr_leaf_lasthash(blk->bp, pmaxrecs);
if (ds->tree_level != 0)
xchk_da_set_corrupt(ds, level);
break;
case XFS_DIR2_LEAFN_MAGIC:
case XFS_DIR3_LEAFN_MAGIC:
xfs_trans_buf_set_type(dargs->trans, blk->bp,
XFS_BLFT_DIR_LEAFN_BUF);
blk->magic = XFS_DIR2_LEAFN_MAGIC;
blk->hashval = xfs_dir2_leaf_lasthash(ip, blk->bp, pmaxrecs);
if (ds->tree_level != 0)
xchk_da_set_corrupt(ds, level);
break;
case XFS_DIR2_LEAF1_MAGIC:
case XFS_DIR3_LEAF1_MAGIC:
xfs_trans_buf_set_type(dargs->trans, blk->bp,
XFS_BLFT_DIR_LEAF1_BUF);
blk->magic = XFS_DIR2_LEAF1_MAGIC;
blk->hashval = xfs_dir2_leaf_lasthash(ip, blk->bp, pmaxrecs);
if (ds->tree_level != 0)
xchk_da_set_corrupt(ds, level);
break;
case XFS_DA_NODE_MAGIC:
case XFS_DA3_NODE_MAGIC:
xfs_trans_buf_set_type(dargs->trans, blk->bp,
XFS_BLFT_DA_NODE_BUF);
blk->magic = XFS_DA_NODE_MAGIC;
node = blk->bp->b_addr;
xfs_da3_node_hdr_from_disk(ip->i_mount, &nodehdr, node);
btree = nodehdr.btree;
*pmaxrecs = nodehdr.count;
blk->hashval = be32_to_cpu(btree[*pmaxrecs - 1].hashval);
if (level == 0) {
if (nodehdr.level >= XFS_DA_NODE_MAXDEPTH) {
xchk_da_set_corrupt(ds, level);
goto out_freebp;
}
ds->tree_level = nodehdr.level;
} else {
if (ds->tree_level != nodehdr.level) {
xchk_da_set_corrupt(ds, level);
goto out_freebp;
}
}
/* XXX: Check hdr3.pad32 once we know how to fix it. */
break;
default:
xchk_da_set_corrupt(ds, level);
goto out_freebp;
}
/*
* If we've been handed a block that is below the dabtree root, does
* its hashval match what the parent block expected to see?
*/
if (level > 0) {
struct xfs_da_node_entry *key;
key = xchk_da_btree_node_entry(ds, level - 1);
if (be32_to_cpu(key->hashval) != blk->hashval) {
xchk_da_set_corrupt(ds, level);
goto out_freebp;
}
}
out:
return error;
out_freebp:
xfs_trans_brelse(dargs->trans, blk->bp);
blk->bp = NULL;
out_nobuf:
blk->blkno = 0;
return error;
}
/* Visit all nodes and leaves of a da btree. */
int
xchk_da_btree(
struct xfs_scrub *sc,
int whichfork,
xchk_da_btree_rec_fn scrub_fn,
void *private)
{
struct xchk_da_btree *ds;
struct xfs_mount *mp = sc->mp;
struct xfs_da_state_blk *blks;
struct xfs_da_node_entry *key;
xfs_dablk_t blkno;
int level;
int error;
/* Skip short format data structures; no btree to scan. */
if (!xfs_ifork_has_extents(xfs_ifork_ptr(sc->ip, whichfork)))
return 0;
/* Set up initial da state. */
ds = kzalloc(sizeof(struct xchk_da_btree), XCHK_GFP_FLAGS);
if (!ds)
return -ENOMEM;
ds->dargs.dp = sc->ip;
ds->dargs.whichfork = whichfork;
ds->dargs.trans = sc->tp;
ds->dargs.op_flags = XFS_DA_OP_OKNOENT;
ds->state = xfs_da_state_alloc(&ds->dargs);
ds->sc = sc;
ds->private = private;
if (whichfork == XFS_ATTR_FORK) {
ds->dargs.geo = mp->m_attr_geo;
ds->lowest = 0;
ds->highest = 0;
} else {
ds->dargs.geo = mp->m_dir_geo;
ds->lowest = ds->dargs.geo->leafblk;
ds->highest = ds->dargs.geo->freeblk;
}
blkno = ds->lowest;
level = 0;
/* Find the root of the da tree, if present. */
blks = ds->state->path.blk;
error = xchk_da_btree_block(ds, level, blkno);
if (error)
goto out_state;
/*
* We didn't find a block at ds->lowest, which means that there's
* no LEAF1/LEAFN tree (at least not where it's supposed to be),
* so jump out now.
*/
if (blks[level].bp == NULL)
goto out_state;
blks[level].index = 0;
while (level >= 0 && level < XFS_DA_NODE_MAXDEPTH) {
/* Handle leaf block. */
if (blks[level].magic != XFS_DA_NODE_MAGIC) {
/* End of leaf, pop back towards the root. */
if (blks[level].index >= ds->maxrecs[level]) {
if (level > 0)
blks[level - 1].index++;
ds->tree_level++;
level--;
continue;
}
/* Dispatch record scrubbing. */
error = scrub_fn(ds, level);
if (error)
break;
if (xchk_should_terminate(sc, &error) ||
(sc->sm->sm_flags & XFS_SCRUB_OFLAG_CORRUPT))
break;
blks[level].index++;
continue;
}
/* End of node, pop back towards the root. */
if (blks[level].index >= ds->maxrecs[level]) {
if (level > 0)
blks[level - 1].index++;
ds->tree_level++;
level--;
continue;
}
/* Hashes in order for scrub? */
key = xchk_da_btree_node_entry(ds, level);
error = xchk_da_btree_hash(ds, level, &key->hashval);
if (error)
goto out;
/* Drill another level deeper. */
blkno = be32_to_cpu(key->before);
level++;
if (level >= XFS_DA_NODE_MAXDEPTH) {
/* Too deep! */
xchk_da_set_corrupt(ds, level - 1);
break;
}
ds->tree_level--;
error = xchk_da_btree_block(ds, level, blkno);
if (error)
goto out;
if (blks[level].bp == NULL)
goto out;
blks[level].index = 0;
}
out:
/* Release all the buffers we're tracking. */
for (level = 0; level < XFS_DA_NODE_MAXDEPTH; level++) {
if (blks[level].bp == NULL)
continue;
xfs_trans_brelse(sc->tp, blks[level].bp);
blks[level].bp = NULL;
}
out_state:
xfs_da_state_free(ds->state);
kfree(ds);
return error;
}
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