[PATCH 088/110] libxfs: teach buftargs to maintain their own buffer hashtable

Darrick J. Wong
2024-03-26T03:51:23Z

From: Darrick J. Wong <djwong@kernel.org>

Currently, cached buffers are indexed with a single global bcache
structure. This works ok for the limited use case where we only support
reading from the data device, but will fail badly when we want to
support buffers from in-memory btrees. Move the bcache structure into
the buftarg.

As a side effect, we don't need to compare buftarg->bt_bdev anymore
since libxfs is careful enough not to create more than one buftarg per
open fd.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
---
include/libxfs.h | 1 -
libxfs/init.c | 48 +++++++++++++++++++++---------------------------
libxfs/libxfs_io.h | 10 ++++++----
libxfs/logitem.c | 2 +-
libxfs/rdwr.c | 45 +++++++++++++++++++++++++++++----------------
mkfs/xfs_mkfs.c | 2 +-
repair/prefetch.c | 12 ++++++++----
repair/prefetch.h | 1 +
repair/progress.c | 14 +++++++++-----
repair/progress.h | 2 +-
repair/scan.c | 2 +-
repair/xfs_repair.c | 32 +++++++++++++++++---------------
12 files changed, 95 insertions(+), 76 deletions(-)

diff --git a/include/libxfs.h b/include/libxfs.h
index aeec2bc76126..60d3b7968775 100644
--- a/include/libxfs.h
+++ b/include/libxfs.h
@@ -147,7 +147,6 @@ int libxfs_init(struct libxfs_init *);
void libxfs_destroy(struct libxfs_init *li);

extern int libxfs_device_alignment (void);
-extern void libxfs_report(FILE *);

/* check or write log footer: specify device, log size in blocks & uuid */
typedef char *(libxfs_get_block_t)(char *, int, void *);
diff --git a/libxfs/init.c b/libxfs/init.c
index 5641b9bef6bd..f002dc93cd56 100644
--- a/libxfs/init.c
+++ b/libxfs/init.c
@@ -36,7 +36,6 @@ pthread_mutex_t atomic64_lock = PTHREAD_MUTEX_INITIALIZER;

char *progname = "libxfs"; /* default, changed by each tool */

-struct cache *libxfs_bcache; /* global buffer cache */
int libxfs_bhash_size; /* #buckets in bcache */

int use_xfs_buf_lock; /* global flag: use xfs_buf locks for MT */
@@ -267,8 +266,6 @@ libxfs_init(struct libxfs_init *a)

if (!libxfs_bhash_size)
libxfs_bhash_size = LIBXFS_BHASHSIZE(sbp);
- libxfs_bcache = cache_init(a->bcache_flags, libxfs_bhash_size,
- &libxfs_bcache_operations);
use_xfs_buf_lock = a->flags & LIBXFS_USEBUFLOCK;
xfs_dir_startup();
init_caches();
@@ -451,6 +448,7 @@ xfs_set_inode_alloc(
static struct xfs_buftarg *
libxfs_buftarg_alloc(
struct xfs_mount *mp,
+ struct libxfs_init *xi,
struct libxfs_dev *dev,
unsigned long write_fails)
{
@@ -472,6 +470,9 @@ libxfs_buftarg_alloc(
}
pthread_mutex_init(&btp->lock, NULL);

+ btp->bcache = cache_init(xi->bcache_flags, libxfs_bhash_size,
+ &libxfs_bcache_operations);
+
return btp;
}

@@ -568,12 +569,13 @@ libxfs_buftarg_init(
return;
}

- mp->m_ddev_targp = libxfs_buftarg_alloc(mp, &xi->data, dfail);
+ mp->m_ddev_targp = libxfs_buftarg_alloc(mp, xi, &xi->data, dfail);
if (!xi->log.dev || xi->log.dev == xi->data.dev)
mp->m_logdev_targp = mp->m_ddev_targp;
else
- mp->m_logdev_targp = libxfs_buftarg_alloc(mp, &xi->log, lfail);
- mp->m_rtdev_targp = libxfs_buftarg_alloc(mp, &xi->rt, rfail);
+ mp->m_logdev_targp = libxfs_buftarg_alloc(mp, xi, &xi->log,
+ lfail);
+ mp->m_rtdev_targp = libxfs_buftarg_alloc(mp, xi, &xi->rt, rfail);
}

/* Compute maximum possible height for per-AG btree types for this fs. */
@@ -856,7 +858,7 @@ libxfs_flush_mount(
* LOST_WRITE flag to be set in the buftarg. Once that's done,
* instruct the disks to persist their write caches.
*/
- libxfs_bcache_flush();
+ libxfs_bcache_flush(mp);

/* Flush all kernel and disk write caches, and report failures. */
if (mp->m_ddev_targp) {
@@ -882,6 +884,14 @@ libxfs_flush_mount(
return error;
}

+static void
+libxfs_buftarg_free(
+ struct xfs_buftarg *btp)
+{
+ cache_destroy(btp->bcache);
+ kmem_free(btp);
+}
+
/*
* Release any resource obtained during a mount.
*/
@@ -898,7 +908,7 @@ libxfs_umount(
* all incore buffers, then pick up the outcome when we tell the disks
* to persist their write caches.
*/
- libxfs_bcache_purge();
+ libxfs_bcache_purge(mp);
error = libxfs_flush_mount(mp);

/*
@@ -913,10 +923,10 @@ libxfs_umount(
free(mp->m_fsname);
mp->m_fsname = NULL;

- kmem_free(mp->m_rtdev_targp);
+ libxfs_buftarg_free(mp->m_rtdev_targp);
if (mp->m_logdev_targp != mp->m_ddev_targp)
- kmem_free(mp->m_logdev_targp);
- kmem_free(mp->m_ddev_targp);
+ libxfs_buftarg_free(mp->m_logdev_targp);
+ libxfs_buftarg_free(mp->m_ddev_targp);

return error;
}
@@ -932,10 +942,7 @@ libxfs_destroy(

libxfs_close_devices(li);

- /* Free everything from the buffer cache before freeing buffer cache */
- libxfs_bcache_purge();
libxfs_bcache_free();
- cache_destroy(libxfs_bcache);
leaked = destroy_caches();
rcu_unregister_thread();
if (getenv("LIBXFS_LEAK_CHECK") && leaked)
@@ -947,16 +954,3 @@ libxfs_device_alignment(void)
{
return platform_align_blockdev();
}
-
-void
-libxfs_report(FILE *fp)
-{
- time_t t;
- char *c;
-
- cache_report(fp, "libxfs_bcache", libxfs_bcache);
-
- t = time(NULL);
- c = asctime(localtime(&t));
- fprintf(fp, "%s", c);
-}
diff --git a/libxfs/libxfs_io.h b/libxfs/libxfs_io.h
index 259c6a7cf771..7877e17685b8 100644
--- a/libxfs/libxfs_io.h
+++ b/libxfs/libxfs_io.h
@@ -28,6 +28,7 @@ struct xfs_buftarg {
dev_t bt_bdev;
int bt_bdev_fd;
unsigned int flags;
+ struct cache *bcache; /* buffer cache */
};

/* We purged a dirty buffer and lost a write. */
@@ -36,6 +37,8 @@ struct xfs_buftarg {
#define XFS_BUFTARG_CORRUPT_WRITE (1 << 1)
/* Simulate failure after a certain number of writes. */
#define XFS_BUFTARG_INJECT_WRITE_FAIL (1 << 2)
+/* purge buffers when lookups find a size mismatch */
+#define XFS_BUFTARG_MISCOMPARE_PURGE (1 << 3)

/* Simulate the system crashing after a certain number of writes. */
static inline void
@@ -140,7 +143,6 @@ int libxfs_buf_priority(struct xfs_buf *bp);

/* Buffer Cache Interfaces */

-extern struct cache *libxfs_bcache;
extern struct cache_operations libxfs_bcache_operations;

#define LIBXFS_GETBUF_TRYLOCK (1 << 0)
@@ -184,10 +186,10 @@ libxfs_buf_read(

int libxfs_readbuf_verify(struct xfs_buf *bp, const struct xfs_buf_ops *ops);
struct xfs_buf *libxfs_getsb(struct xfs_mount *mp);
-extern void libxfs_bcache_purge(void);
+extern void libxfs_bcache_purge(struct xfs_mount *mp);
extern void libxfs_bcache_free(void);
-extern void libxfs_bcache_flush(void);
-extern int libxfs_bcache_overflowed(void);
+extern void libxfs_bcache_flush(struct xfs_mount *mp);
+extern int libxfs_bcache_overflowed(struct xfs_mount *mp);

/* Buffer (Raw) Interfaces */
int libxfs_bwrite(struct xfs_buf *bp);
diff --git a/libxfs/logitem.c b/libxfs/logitem.c
index 3ce2d7574a37..7757259dfc5e 100644
--- a/libxfs/logitem.c
+++ b/libxfs/logitem.c
@@ -46,7 +46,7 @@ xfs_trans_buf_item_match(
list_for_each_entry(lip, &tp->t_items, li_trans) {
blip = (struct xfs_buf_log_item *)lip;
if (blip->bli_item.li_type == XFS_LI_BUF &&
- blip->bli_buf->b_target->bt_bdev == btp->bt_bdev &&
+ blip->bli_buf->b_target == btp &&
xfs_buf_daddr(blip->bli_buf) == map[0].bm_bn &&
blip->bli_buf->b_length == len) {
ASSERT(blip->bli_buf->b_map_count == nmaps);
diff --git a/libxfs/rdwr.c b/libxfs/rdwr.c
index 153007d5fc86..cf986a7e7820 100644
--- a/libxfs/rdwr.c
+++ b/libxfs/rdwr.c
@@ -198,18 +198,20 @@ libxfs_bhash(cache_key_t key, unsigned int hashsize, unsigned int hashshift)
}

static int
-libxfs_bcompare(struct cache_node *node, cache_key_t key)
+libxfs_bcompare(
+ struct cache_node *node,
+ cache_key_t key)
{
struct xfs_buf *bp = container_of(node, struct xfs_buf,
b_node);
struct xfs_bufkey *bkey = (struct xfs_bufkey *)key;
+ struct cache *bcache = bkey->buftarg->bcache;

- if (bp->b_target->bt_bdev == bkey->buftarg->bt_bdev &&
- bp->b_cache_key == bkey->blkno) {
+ if (bp->b_cache_key == bkey->blkno) {
if (bp->b_length == bkey->bblen)
return CACHE_HIT;
#ifdef IO_BCOMPARE_CHECK
- if (!(libxfs_bcache->c_flags & CACHE_MISCOMPARE_PURGE)) {
+ if (!(bcache->c_flags & CACHE_MISCOMPARE_PURGE)) {
fprintf(stderr,
"%lx: Badness in key lookup (length)\n"
"bp=(bno 0x%llx, len %u bytes) key=(bno 0x%llx, len %u bytes)\n",
@@ -399,11 +401,12 @@ __cache_lookup(
struct xfs_buf **bpp)
{
struct cache_node *cn = NULL;
+ struct cache *bcache = key->buftarg->bcache;
struct xfs_buf *bp;

*bpp = NULL;

- cache_node_get(libxfs_bcache, key, &cn);
+ cache_node_get(bcache, key, &cn);
if (!cn)
return -ENOMEM;
bp = container_of(cn, struct xfs_buf, b_node);
@@ -415,7 +418,7 @@ __cache_lookup(
if (ret) {
ASSERT(ret == EAGAIN);
if (flags & LIBXFS_GETBUF_TRYLOCK) {
- cache_node_put(libxfs_bcache, cn);
+ cache_node_put(bcache, cn);
return -EAGAIN;
}

@@ -434,7 +437,7 @@ __cache_lookup(
bp->b_holder = pthread_self();
}

- cache_node_set_priority(libxfs_bcache, cn,
+ cache_node_set_priority(bcache, cn,
cache_node_get_priority(cn) - CACHE_PREFETCH_PRIORITY);
*bpp = bp;
return 0;
@@ -550,7 +553,7 @@ libxfs_buf_relse(
}

if (!list_empty(&bp->b_node.cn_hash))
- cache_node_put(libxfs_bcache, &bp->b_node);
+ cache_node_put(bp->b_target->bcache, &bp->b_node);
else if (--bp->b_node.cn_count == 0) {
if (bp->b_flags & LIBXFS_B_DIRTY)
libxfs_bwrite(bp);
@@ -606,7 +609,7 @@ libxfs_readbufr(struct xfs_buftarg *btp, xfs_daddr_t blkno, struct xfs_buf *bp,

error = __read_buf(fd, bp->b_addr, bytes, LIBXFS_BBTOOFF64(blkno), flags);
if (!error &&
- bp->b_target->bt_bdev == btp->bt_bdev &&
+ bp->b_target == btp &&
bp->b_cache_key == blkno &&
bp->b_length == len)
bp->b_flags |= LIBXFS_B_UPTODATE;
@@ -1003,21 +1006,31 @@ libxfs_bflush(
}

void
-libxfs_bcache_purge(void)
+libxfs_bcache_purge(struct xfs_mount *mp)
{
- cache_purge(libxfs_bcache);
+ if (!mp)
+ return;
+ cache_purge(mp->m_ddev_targp->bcache);
+ cache_purge(mp->m_logdev_targp->bcache);
+ cache_purge(mp->m_rtdev_targp->bcache);
}

void
-libxfs_bcache_flush(void)
+libxfs_bcache_flush(struct xfs_mount *mp)
{
- cache_flush(libxfs_bcache);
+ if (!mp)
+ return;
+ cache_flush(mp->m_ddev_targp->bcache);
+ cache_flush(mp->m_logdev_targp->bcache);
+ cache_flush(mp->m_rtdev_targp->bcache);
}

int
-libxfs_bcache_overflowed(void)
+libxfs_bcache_overflowed(struct xfs_mount *mp)
{
- return cache_overflowed(libxfs_bcache);
+ return cache_overflowed(mp->m_ddev_targp->bcache) ||
+ cache_overflowed(mp->m_logdev_targp->bcache) ||
+ cache_overflowed(mp->m_rtdev_targp->bcache);
}

struct cache_operations libxfs_bcache_operations = {
@@ -1466,7 +1479,7 @@ libxfs_buf_set_priority(
struct xfs_buf *bp,
int priority)
{
- cache_node_set_priority(libxfs_bcache, &bp->b_node, priority);
+ cache_node_set_priority(bp->b_target->bcache, &bp->b_node, priority);
}

int
diff --git a/mkfs/xfs_mkfs.c b/mkfs/xfs_mkfs.c
index f4a9bf20f391..d6fa48edeab5 100644
--- a/mkfs/xfs_mkfs.c
+++ b/mkfs/xfs_mkfs.c
@@ -4613,7 +4613,7 @@ main(
* Need to drop references to inodes we still hold, first.
*/
libxfs_rtmount_destroy(mp);
- libxfs_bcache_purge();
+ libxfs_bcache_purge(mp);

/*
* Mark the filesystem ok.
diff --git a/repair/prefetch.c b/repair/prefetch.c
index b0dd19775ca8..de36c5fe2cc9 100644
--- a/repair/prefetch.c
+++ b/repair/prefetch.c
@@ -886,10 +886,12 @@ init_prefetch(

prefetch_args_t *
start_inode_prefetch(
+ struct xfs_mount *mp,
xfs_agnumber_t agno,
int dirs_only,
prefetch_args_t *prev_args)
{
+ struct cache *bcache = mp->m_ddev_targp->bcache;
prefetch_args_t *args;
long max_queue;
struct xfs_ino_geometry *igeo = M_IGEO(mp);
@@ -914,7 +916,7 @@ start_inode_prefetch(
* and not any other associated metadata like directories
*/

- max_queue = libxfs_bcache->c_maxcount / thread_count / 8;
+ max_queue = bcache->c_maxcount / thread_count / 8;
if (igeo->inode_cluster_size > mp->m_sb.sb_blocksize)
max_queue = max_queue * igeo->blocks_per_cluster /
igeo->ialloc_blks;
@@ -970,14 +972,16 @@ prefetch_ag_range(
void (*func)(struct workqueue *,
xfs_agnumber_t, void *))
{
+ struct xfs_mount *mp = work->wq_ctx;
int i;
struct prefetch_args *pf_args[2];

- pf_args[start_ag & 1] = start_inode_prefetch(start_ag, dirs_only, NULL);
+ pf_args[start_ag & 1] = start_inode_prefetch(mp, start_ag, dirs_only,
+ NULL);
for (i = start_ag; i < end_ag; i++) {
/* Don't prefetch end_ag */
if (i + 1 < end_ag)
- pf_args[(~i) & 1] = start_inode_prefetch(i + 1,
+ pf_args[(~i) & 1] = start_inode_prefetch(mp, i + 1,
dirs_only, pf_args[i & 1]);
func(work, i, pf_args[i & 1]);
}
@@ -1027,7 +1031,7 @@ do_inode_prefetch(
* filesystem - it's all in the cache. In that case, run a thread per
* CPU to maximise parallelism of the queue to be processed.
*/
- if (check_cache && !libxfs_bcache_overflowed()) {
+ if (check_cache && !libxfs_bcache_overflowed(mp)) {
queue.wq_ctx = mp;
create_work_queue(&queue, mp, platform_nproc());
for (i = 0; i < mp->m_sb.sb_agcount; i++)
diff --git a/repair/prefetch.h b/repair/prefetch.h
index 54ece48ad228..a8c52a1195b6 100644
--- a/repair/prefetch.h
+++ b/repair/prefetch.h
@@ -39,6 +39,7 @@ init_prefetch(

prefetch_args_t *
start_inode_prefetch(
+ struct xfs_mount *mp,
xfs_agnumber_t agno,
int dirs_only,
prefetch_args_t *prev_args);
diff --git a/repair/progress.c b/repair/progress.c
index f6c4d988444e..625dc41c2894 100644
--- a/repair/progress.c
+++ b/repair/progress.c
@@ -383,14 +383,18 @@ timediff(int phase)
** array.
*/
char *
-timestamp(int end, int phase, char *buf)
+timestamp(
+ struct xfs_mount *mp,
+ int end,
+ int phase,
+ char *buf)
{

- time_t now;
- struct tm *tmp;
+ time_t now;
+ struct tm *tmp;

- if (verbose > 1)
- cache_report(stderr, "libxfs_bcache", libxfs_bcache);
+ if (verbose > 1 && mp && mp->m_ddev_targp)
+ cache_report(stderr, "libxfs_bcache", mp->m_ddev_targp->bcache);

now = time(NULL);

diff --git a/repair/progress.h b/repair/progress.h
index 2c1690db1b17..75b751b783b2 100644
--- a/repair/progress.h
+++ b/repair/progress.h
@@ -37,7 +37,7 @@ extern void stop_progress_rpt(void);
extern void summary_report(void);
extern int set_progress_msg(int report, uint64_t total);
extern uint64_t print_final_rpt(void);
-extern char *timestamp(int end, int phase, char *buf);
+extern char *timestamp(struct xfs_mount *mp, int end, int phase, char *buf);
extern char *duration(int val, char *buf);
extern int do_parallel;

diff --git a/repair/scan.c b/repair/scan.c
index 7e6d94cfa670..715be1166fc2 100644
--- a/repair/scan.c
+++ b/repair/scan.c
@@ -42,7 +42,7 @@ struct aghdr_cnts {
void
set_mp(xfs_mount_t *mpp)
{
- libxfs_bcache_purge();
+ libxfs_bcache_purge(mp);
mp = mpp;
}

diff --git a/repair/xfs_repair.c b/repair/xfs_repair.c
index ba9d28330d82..d4f99f36f71d 100644
--- a/repair/xfs_repair.c
+++ b/repair/xfs_repair.c
@@ -942,9 +942,11 @@ repair_capture_writeback(
}

static inline void
-phase_end(int phase)
+phase_end(
+ struct xfs_mount *mp,
+ int phase)
{
- timestamp(PHASE_END, phase, NULL);
+ timestamp(mp, PHASE_END, phase, NULL);

/* Fail if someone injected an post-phase error. */
if (fail_after_phase && phase == fail_after_phase)
@@ -979,8 +981,8 @@ main(int argc, char **argv)

msgbuf = malloc(DURATION_BUF_SIZE);

- timestamp(PHASE_START, 0, NULL);
- phase_end(0);
+ timestamp(temp_mp, PHASE_START, 0, NULL);
+ phase_end(temp_mp, 0);

/* -f forces this, but let's be nice and autodetect it, as well. */
if (!isa_file) {
@@ -1002,7 +1004,7 @@ main(int argc, char **argv)

/* do phase1 to make sure we have a superblock */
phase1(temp_mp);
- phase_end(1);
+ phase_end(temp_mp, 1);

if (no_modify && primary_sb_modified) {
do_warn(_("Primary superblock would have been modified.\n"
@@ -1139,8 +1141,8 @@ main(int argc, char **argv)
unsigned long max_mem;
struct rlimit rlim;

- libxfs_bcache_purge();
- cache_destroy(libxfs_bcache);
+ libxfs_bcache_purge(mp);
+ cache_destroy(mp->m_ddev_targp->bcache);

mem_used = (mp->m_sb.sb_icount >> (10 - 2)) +
(mp->m_sb.sb_dblocks >> (10 + 1)) +
@@ -1200,7 +1202,7 @@ main(int argc, char **argv)
do_log(_(" - block cache size set to %d entries\n"),
libxfs_bhash_size * HASH_CACHE_RATIO);

- libxfs_bcache = cache_init(0, libxfs_bhash_size,
+ mp->m_ddev_targp->bcache = cache_init(0, libxfs_bhash_size,
&libxfs_bcache_operations);
}

@@ -1228,16 +1230,16 @@ main(int argc, char **argv)

/* make sure the per-ag freespace maps are ok so we can mount the fs */
phase2(mp, phase2_threads);
- phase_end(2);
+ phase_end(mp, 2);

if (do_prefetch)
init_prefetch(mp);

phase3(mp, phase2_threads);
- phase_end(3);
+ phase_end(mp, 3);

phase4(mp);
- phase_end(4);
+ phase_end(mp, 4);

if (no_modify) {
printf(_("No modify flag set, skipping phase 5\n"));
@@ -1247,7 +1249,7 @@ main(int argc, char **argv)
} else {
phase5(mp);
}
- phase_end(5);
+ phase_end(mp, 5);

/*
* Done with the block usage maps, toss them...
@@ -1257,10 +1259,10 @@ main(int argc, char **argv)

if (!bad_ino_btree) {
phase6(mp);
- phase_end(6);
+ phase_end(mp, 6);

phase7(mp, phase2_threads);
- phase_end(7);
+ phase_end(mp, 7);
} else {
do_warn(
_("Inode allocation btrees are too corrupted, skipping phases 6 and 7\n"));
@@ -1385,7 +1387,7 @@ _("Note - stripe unit (%d) and width (%d) were copied from a backup superblock.\
* verifiers are run (where we discover the max metadata LSN), reformat
* the log if necessary and unmount.
*/
- libxfs_bcache_flush();
+ libxfs_bcache_flush(mp);
format_log_max_lsn(mp);

if (xfs_sb_version_needsrepair(&mp->m_sb))