diff options
author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-10-07 10:30:35 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-10-07 10:30:35 -0700 |
commit | 102363a39b8d37b5839403e08cfaf900de0cddfa (patch) | |
tree | a8c974f38e3b4cb8e71225ec7e193e926261c966 /fs | |
parent | 4aef108a4d60bb52bf4e8e2ed9444afe2cdfe6a9 (diff) | |
parent | 4e69f490d211ce4e11db60c05c0fcd0ac2f8e61e (diff) | |
download | linux-stable-102363a39b8d37b5839403e08cfaf900de0cddfa.tar.gz linux-stable-102363a39b8d37b5839403e08cfaf900de0cddfa.tar.bz2 linux-stable-102363a39b8d37b5839403e08cfaf900de0cddfa.zip |
Merge tag 'xfs-6.6-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux
Pull xfs fixes from Chandan Babu:
- Prevent filesystem hang when executing fstrim operations on large and
slow storage
* tag 'xfs-6.6-fixes-3' of git://git.kernel.org/pub/scm/fs/xfs/xfs-linux:
xfs: abort fstrim if kernel is suspending
xfs: reduce AGF hold times during fstrim operations
xfs: move log discard work to xfs_discard.c
Diffstat (limited to 'fs')
-rw-r--r-- | fs/xfs/xfs_discard.c | 266 | ||||
-rw-r--r-- | fs/xfs/xfs_discard.h | 6 | ||||
-rw-r--r-- | fs/xfs/xfs_extent_busy.c | 34 | ||||
-rw-r--r-- | fs/xfs/xfs_extent_busy.h | 24 | ||||
-rw-r--r-- | fs/xfs/xfs_log_cil.c | 93 | ||||
-rw-r--r-- | fs/xfs/xfs_log_priv.h | 5 |
6 files changed, 311 insertions, 117 deletions
diff --git a/fs/xfs/xfs_discard.c b/fs/xfs/xfs_discard.c index afc4c78b9eed..d5787991bb5b 100644 --- a/fs/xfs/xfs_discard.c +++ b/fs/xfs/xfs_discard.c @@ -1,6 +1,6 @@ // SPDX-License-Identifier: GPL-2.0 /* - * Copyright (C) 2010 Red Hat, Inc. + * Copyright (C) 2010, 2023 Red Hat, Inc. * All Rights Reserved. */ #include "xfs.h" @@ -19,21 +19,147 @@ #include "xfs_log.h" #include "xfs_ag.h" -STATIC int -xfs_trim_extents( +/* + * Notes on an efficient, low latency fstrim algorithm + * + * We need to walk the filesystem free space and issue discards on the free + * space that meet the search criteria (size and location). We cannot issue + * discards on extents that might be in use, or are so recently in use they are + * still marked as busy. To serialise against extent state changes whilst we are + * gathering extents to trim, we must hold the AGF lock to lock out other + * allocations and extent free operations that might change extent state. + * + * However, we cannot just hold the AGF for the entire AG free space walk whilst + * we issue discards on each free space that is found. Storage devices can have + * extremely slow discard implementations (e.g. ceph RBD) and so walking a + * couple of million free extents and issuing synchronous discards on each + * extent can take a *long* time. Whilst we are doing this walk, nothing else + * can access the AGF, and we can stall transactions and hence the log whilst + * modifications wait for the AGF lock to be released. This can lead hung tasks + * kicking the hung task timer and rebooting the system. This is bad. + * + * Hence we need to take a leaf from the bulkstat playbook. It takes the AGI + * lock, gathers a range of inode cluster buffers that are allocated, drops the + * AGI lock and then reads all the inode cluster buffers and processes them. It + * loops doing this, using a cursor to keep track of where it is up to in the AG + * for each iteration to restart the INOBT lookup from. + * + * We can't do this exactly with free space - once we drop the AGF lock, the + * state of the free extent is out of our control and we cannot run a discard + * safely on it in this situation. Unless, of course, we've marked the free + * extent as busy and undergoing a discard operation whilst we held the AGF + * locked. + * + * This is exactly how online discard works - free extents are marked busy when + * they are freed, and once the extent free has been committed to the journal, + * the busy extent record is marked as "undergoing discard" and the discard is + * then issued on the free extent. Once the discard completes, the busy extent + * record is removed and the extent is able to be allocated again. + * + * In the context of fstrim, if we find a free extent we need to discard, we + * don't have to discard it immediately. All we need to do it record that free + * extent as being busy and under discard, and all the allocation routines will + * now avoid trying to allocate it. Hence if we mark the extent as busy under + * the AGF lock, we can safely discard it without holding the AGF lock because + * nothing will attempt to allocate that free space until the discard completes. + * + * This also allows us to issue discards asynchronously like we do with online + * discard, and so for fast devices fstrim will run much faster as we can have + * multiple discard operations in flight at once, as well as pipeline the free + * extent search so that it overlaps in flight discard IO. + */ + +struct workqueue_struct *xfs_discard_wq; + +static void +xfs_discard_endio_work( + struct work_struct *work) +{ + struct xfs_busy_extents *extents = + container_of(work, struct xfs_busy_extents, endio_work); + + xfs_extent_busy_clear(extents->mount, &extents->extent_list, false); + kmem_free(extents->owner); +} + +/* + * Queue up the actual completion to a thread to avoid IRQ-safe locking for + * pagb_lock. + */ +static void +xfs_discard_endio( + struct bio *bio) +{ + struct xfs_busy_extents *extents = bio->bi_private; + + INIT_WORK(&extents->endio_work, xfs_discard_endio_work); + queue_work(xfs_discard_wq, &extents->endio_work); + bio_put(bio); +} + +/* + * Walk the discard list and issue discards on all the busy extents in the + * list. We plug and chain the bios so that we only need a single completion + * call to clear all the busy extents once the discards are complete. + */ +int +xfs_discard_extents( + struct xfs_mount *mp, + struct xfs_busy_extents *extents) +{ + struct xfs_extent_busy *busyp; + struct bio *bio = NULL; + struct blk_plug plug; + int error = 0; + + blk_start_plug(&plug); + list_for_each_entry(busyp, &extents->extent_list, list) { + trace_xfs_discard_extent(mp, busyp->agno, busyp->bno, + busyp->length); + + error = __blkdev_issue_discard(mp->m_ddev_targp->bt_bdev, + XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno), + XFS_FSB_TO_BB(mp, busyp->length), + GFP_NOFS, &bio); + if (error && error != -EOPNOTSUPP) { + xfs_info(mp, + "discard failed for extent [0x%llx,%u], error %d", + (unsigned long long)busyp->bno, + busyp->length, + error); + break; + } + } + + if (bio) { + bio->bi_private = extents; + bio->bi_end_io = xfs_discard_endio; + submit_bio(bio); + } else { + xfs_discard_endio_work(&extents->endio_work); + } + blk_finish_plug(&plug); + + return error; +} + + +static int +xfs_trim_gather_extents( struct xfs_perag *pag, xfs_daddr_t start, xfs_daddr_t end, xfs_daddr_t minlen, + struct xfs_alloc_rec_incore *tcur, + struct xfs_busy_extents *extents, uint64_t *blocks_trimmed) { struct xfs_mount *mp = pag->pag_mount; - struct block_device *bdev = mp->m_ddev_targp->bt_bdev; struct xfs_btree_cur *cur; struct xfs_buf *agbp; - struct xfs_agf *agf; int error; int i; + int batch = 100; /* * Force out the log. This means any transactions that might have freed @@ -45,20 +171,28 @@ xfs_trim_extents( error = xfs_alloc_read_agf(pag, NULL, 0, &agbp); if (error) return error; - agf = agbp->b_addr; cur = xfs_allocbt_init_cursor(mp, NULL, agbp, pag, XFS_BTNUM_CNT); /* - * Look up the longest btree in the AGF and start with it. + * Look up the extent length requested in the AGF and start with it. */ - error = xfs_alloc_lookup_ge(cur, 0, be32_to_cpu(agf->agf_longest), &i); + if (tcur->ar_startblock == NULLAGBLOCK) + error = xfs_alloc_lookup_ge(cur, 0, tcur->ar_blockcount, &i); + else + error = xfs_alloc_lookup_le(cur, tcur->ar_startblock, + tcur->ar_blockcount, &i); if (error) goto out_del_cursor; + if (i == 0) { + /* nothing of that length left in the AG, we are done */ + tcur->ar_blockcount = 0; + goto out_del_cursor; + } /* * Loop until we are done with all extents that are large - * enough to be worth discarding. + * enough to be worth discarding or we hit batch limits. */ while (i) { xfs_agblock_t fbno; @@ -73,7 +207,16 @@ xfs_trim_extents( error = -EFSCORRUPTED; break; } - ASSERT(flen <= be32_to_cpu(agf->agf_longest)); + + if (--batch <= 0) { + /* + * Update the cursor to point at this extent so we + * restart the next batch from this extent. + */ + tcur->ar_startblock = fbno; + tcur->ar_blockcount = flen; + break; + } /* * use daddr format for all range/len calculations as that is @@ -88,6 +231,7 @@ xfs_trim_extents( */ if (dlen < minlen) { trace_xfs_discard_toosmall(mp, pag->pag_agno, fbno, flen); + tcur->ar_blockcount = 0; break; } @@ -110,29 +254,103 @@ xfs_trim_extents( goto next_extent; } - trace_xfs_discard_extent(mp, pag->pag_agno, fbno, flen); - error = blkdev_issue_discard(bdev, dbno, dlen, GFP_NOFS); - if (error) - break; + xfs_extent_busy_insert_discard(pag, fbno, flen, + &extents->extent_list); *blocks_trimmed += flen; - next_extent: error = xfs_btree_decrement(cur, 0, &i); if (error) break; - if (fatal_signal_pending(current)) { - error = -ERESTARTSYS; - break; - } + /* + * If there's no more records in the tree, we are done. Set the + * cursor block count to 0 to indicate to the caller that there + * is no more extents to search. + */ + if (i == 0) + tcur->ar_blockcount = 0; } + /* + * If there was an error, release all the gathered busy extents because + * we aren't going to issue a discard on them any more. + */ + if (error) + xfs_extent_busy_clear(mp, &extents->extent_list, false); out_del_cursor: xfs_btree_del_cursor(cur, error); xfs_buf_relse(agbp); return error; } +static bool +xfs_trim_should_stop(void) +{ + return fatal_signal_pending(current) || freezing(current); +} + +/* + * Iterate the free list gathering extents and discarding them. We need a cursor + * for the repeated iteration of gather/discard loop, so use the longest extent + * we found in the last batch as the key to start the next. + */ +static int +xfs_trim_extents( + struct xfs_perag *pag, + xfs_daddr_t start, + xfs_daddr_t end, + xfs_daddr_t minlen, + uint64_t *blocks_trimmed) +{ + struct xfs_alloc_rec_incore tcur = { + .ar_blockcount = pag->pagf_longest, + .ar_startblock = NULLAGBLOCK, + }; + int error = 0; + + do { + struct xfs_busy_extents *extents; + + extents = kzalloc(sizeof(*extents), GFP_KERNEL); + if (!extents) { + error = -ENOMEM; + break; + } + + extents->mount = pag->pag_mount; + extents->owner = extents; + INIT_LIST_HEAD(&extents->extent_list); + + error = xfs_trim_gather_extents(pag, start, end, minlen, + &tcur, extents, blocks_trimmed); + if (error) { + kfree(extents); + break; + } + + /* + * We hand the extent list to the discard function here so the + * discarded extents can be removed from the busy extent list. + * This allows the discards to run asynchronously with gathering + * the next round of extents to discard. + * + * However, we must ensure that we do not reference the extent + * list after this function call, as it may have been freed by + * the time control returns to us. + */ + error = xfs_discard_extents(pag->pag_mount, extents); + if (error) + break; + + if (xfs_trim_should_stop()) + break; + + } while (tcur.ar_blockcount != 0); + + return error; + +} + /* * trim a range of the filesystem. * @@ -195,12 +413,12 @@ xfs_ioc_trim( for_each_perag_range(mp, agno, xfs_daddr_to_agno(mp, end), pag) { error = xfs_trim_extents(pag, start, end, minlen, &blocks_trimmed); - if (error) { + if (error) last_error = error; - if (error == -ERESTARTSYS) { - xfs_perag_rele(pag); - break; - } + + if (xfs_trim_should_stop()) { + xfs_perag_rele(pag); + break; } } diff --git a/fs/xfs/xfs_discard.h b/fs/xfs/xfs_discard.h index de92d9cc958f..2b1a85223a56 100644 --- a/fs/xfs/xfs_discard.h +++ b/fs/xfs/xfs_discard.h @@ -3,8 +3,10 @@ #define XFS_DISCARD_H 1 struct fstrim_range; -struct list_head; +struct xfs_mount; +struct xfs_busy_extents; -extern int xfs_ioc_trim(struct xfs_mount *, struct fstrim_range __user *); +int xfs_discard_extents(struct xfs_mount *mp, struct xfs_busy_extents *busy); +int xfs_ioc_trim(struct xfs_mount *mp, struct fstrim_range __user *fstrim); #endif /* XFS_DISCARD_H */ diff --git a/fs/xfs/xfs_extent_busy.c b/fs/xfs/xfs_extent_busy.c index 7c2fdc71e42d..746814815b1d 100644 --- a/fs/xfs/xfs_extent_busy.c +++ b/fs/xfs/xfs_extent_busy.c @@ -19,13 +19,13 @@ #include "xfs_log.h" #include "xfs_ag.h" -void -xfs_extent_busy_insert( - struct xfs_trans *tp, +static void +xfs_extent_busy_insert_list( struct xfs_perag *pag, xfs_agblock_t bno, xfs_extlen_t len, - unsigned int flags) + unsigned int flags, + struct list_head *busy_list) { struct xfs_extent_busy *new; struct xfs_extent_busy *busyp; @@ -40,7 +40,7 @@ xfs_extent_busy_insert( new->flags = flags; /* trace before insert to be able to see failed inserts */ - trace_xfs_extent_busy(tp->t_mountp, pag->pag_agno, bno, len); + trace_xfs_extent_busy(pag->pag_mount, pag->pag_agno, bno, len); spin_lock(&pag->pagb_lock); rbp = &pag->pagb_tree.rb_node; @@ -62,10 +62,32 @@ xfs_extent_busy_insert( rb_link_node(&new->rb_node, parent, rbp); rb_insert_color(&new->rb_node, &pag->pagb_tree); - list_add(&new->list, &tp->t_busy); + list_add(&new->list, busy_list); spin_unlock(&pag->pagb_lock); } +void +xfs_extent_busy_insert( + struct xfs_trans *tp, + struct xfs_perag *pag, + xfs_agblock_t bno, + xfs_extlen_t len, + unsigned int flags) +{ + xfs_extent_busy_insert_list(pag, bno, len, flags, &tp->t_busy); +} + +void +xfs_extent_busy_insert_discard( + struct xfs_perag *pag, + xfs_agblock_t bno, + xfs_extlen_t len, + struct list_head *busy_list) +{ + xfs_extent_busy_insert_list(pag, bno, len, XFS_EXTENT_BUSY_DISCARDED, + busy_list); +} + /* * Search for a busy extent within the range of the extent we are about to * allocate. You need to be holding the busy extent tree lock when calling diff --git a/fs/xfs/xfs_extent_busy.h b/fs/xfs/xfs_extent_busy.h index c37bf87e6781..0639aab336f3 100644 --- a/fs/xfs/xfs_extent_busy.h +++ b/fs/xfs/xfs_extent_busy.h @@ -16,9 +16,6 @@ struct xfs_alloc_arg; /* * Busy block/extent entry. Indexed by a rbtree in perag to mark blocks that * have been freed but whose transactions aren't committed to disk yet. - * - * Note that we use the transaction ID to record the transaction, not the - * transaction structure itself. See xfs_extent_busy_insert() for details. */ struct xfs_extent_busy { struct rb_node rb_node; /* ag by-bno indexed search tree */ @@ -31,11 +28,32 @@ struct xfs_extent_busy { #define XFS_EXTENT_BUSY_SKIP_DISCARD 0x02 /* do not discard */ }; +/* + * List used to track groups of related busy extents all the way through + * to discard completion. + */ +struct xfs_busy_extents { + struct xfs_mount *mount; + struct list_head extent_list; + struct work_struct endio_work; + + /* + * Owner is the object containing the struct xfs_busy_extents to free + * once the busy extents have been processed. If only the + * xfs_busy_extents object needs freeing, then point this at itself. + */ + void *owner; +}; + void xfs_extent_busy_insert(struct xfs_trans *tp, struct xfs_perag *pag, xfs_agblock_t bno, xfs_extlen_t len, unsigned int flags); void +xfs_extent_busy_insert_discard(struct xfs_perag *pag, xfs_agblock_t bno, + xfs_extlen_t len, struct list_head *busy_list); + +void xfs_extent_busy_clear(struct xfs_mount *mp, struct list_head *list, bool do_discard); diff --git a/fs/xfs/xfs_log_cil.c b/fs/xfs/xfs_log_cil.c index ebc70aaa299c..67a99d94701e 100644 --- a/fs/xfs/xfs_log_cil.c +++ b/fs/xfs/xfs_log_cil.c @@ -16,8 +16,7 @@ #include "xfs_log.h" #include "xfs_log_priv.h" #include "xfs_trace.h" - -struct workqueue_struct *xfs_discard_wq; +#include "xfs_discard.h" /* * Allocate a new ticket. Failing to get a new ticket makes it really hard to @@ -103,7 +102,7 @@ xlog_cil_ctx_alloc(void) ctx = kmem_zalloc(sizeof(*ctx), KM_NOFS); INIT_LIST_HEAD(&ctx->committing); - INIT_LIST_HEAD(&ctx->busy_extents); + INIT_LIST_HEAD(&ctx->busy_extents.extent_list); INIT_LIST_HEAD(&ctx->log_items); INIT_LIST_HEAD(&ctx->lv_chain); INIT_WORK(&ctx->push_work, xlog_cil_push_work); @@ -132,7 +131,7 @@ xlog_cil_push_pcp_aggregate( if (!list_empty(&cilpcp->busy_extents)) { list_splice_init(&cilpcp->busy_extents, - &ctx->busy_extents); + &ctx->busy_extents.extent_list); } if (!list_empty(&cilpcp->log_items)) list_splice_init(&cilpcp->log_items, &ctx->log_items); @@ -708,76 +707,6 @@ xlog_cil_free_logvec( } } -static void -xlog_discard_endio_work( - struct work_struct *work) -{ - struct xfs_cil_ctx *ctx = - container_of(work, struct xfs_cil_ctx, discard_endio_work); - struct xfs_mount *mp = ctx->cil->xc_log->l_mp; - - xfs_extent_busy_clear(mp, &ctx->busy_extents, false); - kmem_free(ctx); -} - -/* - * Queue up the actual completion to a thread to avoid IRQ-safe locking for - * pagb_lock. Note that we need a unbounded workqueue, otherwise we might - * get the execution delayed up to 30 seconds for weird reasons. - */ -static void -xlog_discard_endio( - struct bio *bio) -{ - struct xfs_cil_ctx *ctx = bio->bi_private; - - INIT_WORK(&ctx->discard_endio_work, xlog_discard_endio_work); - queue_work(xfs_discard_wq, &ctx->discard_endio_work); - bio_put(bio); -} - -static void -xlog_discard_busy_extents( - struct xfs_mount *mp, - struct xfs_cil_ctx *ctx) -{ - struct list_head *list = &ctx->busy_extents; - struct xfs_extent_busy *busyp; - struct bio *bio = NULL; - struct blk_plug plug; - int error = 0; - - ASSERT(xfs_has_discard(mp)); - - blk_start_plug(&plug); - list_for_each_entry(busyp, list, list) { - trace_xfs_discard_extent(mp, busyp->agno, busyp->bno, - busyp->length); - - error = __blkdev_issue_discard(mp->m_ddev_targp->bt_bdev, - XFS_AGB_TO_DADDR(mp, busyp->agno, busyp->bno), - XFS_FSB_TO_BB(mp, busyp->length), - GFP_NOFS, &bio); - if (error && error != -EOPNOTSUPP) { - xfs_info(mp, - "discard failed for extent [0x%llx,%u], error %d", - (unsigned long long)busyp->bno, - busyp->length, - error); - break; - } - } - - if (bio) { - bio->bi_private = ctx; - bio->bi_end_io = xlog_discard_endio; - submit_bio(bio); - } else { - xlog_discard_endio_work(&ctx->discard_endio_work); - } - blk_finish_plug(&plug); -} - /* * Mark all items committed and clear busy extents. We free the log vector * chains in a separate pass so that we unpin the log items as quickly as @@ -807,8 +736,8 @@ xlog_cil_committed( xfs_trans_committed_bulk(ctx->cil->xc_log->l_ailp, &ctx->lv_chain, ctx->start_lsn, abort); - xfs_extent_busy_sort(&ctx->busy_extents); - xfs_extent_busy_clear(mp, &ctx->busy_extents, + xfs_extent_busy_sort(&ctx->busy_extents.extent_list); + xfs_extent_busy_clear(mp, &ctx->busy_extents.extent_list, xfs_has_discard(mp) && !abort); spin_lock(&ctx->cil->xc_push_lock); @@ -817,10 +746,14 @@ xlog_cil_committed( xlog_cil_free_logvec(&ctx->lv_chain); - if (!list_empty(&ctx->busy_extents)) - xlog_discard_busy_extents(mp, ctx); - else - kmem_free(ctx); + if (!list_empty(&ctx->busy_extents.extent_list)) { + ctx->busy_extents.mount = mp; + ctx->busy_extents.owner = ctx; + xfs_discard_extents(mp, &ctx->busy_extents); + return; + } + + kmem_free(ctx); } void diff --git a/fs/xfs/xfs_log_priv.h b/fs/xfs/xfs_log_priv.h index af87648331d5..fa3ad1d7b31c 100644 --- a/fs/xfs/xfs_log_priv.h +++ b/fs/xfs/xfs_log_priv.h @@ -6,6 +6,8 @@ #ifndef __XFS_LOG_PRIV_H__ #define __XFS_LOG_PRIV_H__ +#include "xfs_extent_busy.h" /* for struct xfs_busy_extents */ + struct xfs_buf; struct xlog; struct xlog_ticket; @@ -223,12 +225,11 @@ struct xfs_cil_ctx { struct xlog_in_core *commit_iclog; struct xlog_ticket *ticket; /* chkpt ticket */ atomic_t space_used; /* aggregate size of regions */ - struct list_head busy_extents; /* busy extents in chkpt */ + struct xfs_busy_extents busy_extents; struct list_head log_items; /* log items in chkpt */ struct list_head lv_chain; /* logvecs being pushed */ struct list_head iclog_entry; struct list_head committing; /* ctx committing list */ - struct work_struct discard_endio_work; struct work_struct push_work; atomic_t order_id; |