xfs: improve handling of busy extents in the low-level allocator (ebf55872) · Commits · 戴 / test

fs/xfs/libxfs/xfs_alloc.c

+49 −44

Original line number	Diff line number	Diff line
		@@ -221,20 +221,22 @@ xfs_alloc_get_rec(
		* Compute aligned version of the found extent.
		* Takes alignment and min length into account.
		*/
		STATIC void
		STATIC bool
		xfs_alloc_compute_aligned(
		xfs_alloc_arg_t args, / allocation argument structure */
		xfs_agblock_t foundbno, /* starting block in found extent */
		xfs_extlen_t foundlen, /* length in found extent */
		xfs_agblock_t resbno, / result block number */
		xfs_extlen_t reslen) / result length */
		xfs_extlen_t reslen, / result length */
		unsigned *busy_gen)
		{
		xfs_agblock_t bno;
		xfs_extlen_t len;
		xfs_agblock_t bno = foundbno;
		xfs_extlen_t len = foundlen;
		xfs_extlen_t diff;
		bool busy;

		/* Trim busy sections out of found extent */
		xfs_extent_busy_trim(args, foundbno, foundlen, &bno, &len);
		busy = xfs_extent_busy_trim(args, &bno, &len, busy_gen);

		/*
		* If we have a largish extent that happens to start before min_agbno,
		@@ -259,6 +261,8 @@ xfs_alloc_compute_aligned(
		*resbno = bno;
		*reslen = len;
		}

		return busy;
		}

		/*
		@@ -737,10 +741,11 @@ xfs_alloc_ag_vextent_exact(
		int error;
		xfs_agblock_t fbno; /* start block of found extent */
		xfs_extlen_t flen; /* length of found extent */
		xfs_agblock_t tbno; /* start block of trimmed extent */
		xfs_extlen_t tlen; /* length of trimmed extent */
		xfs_agblock_t tend; /* end block of trimmed extent */
		xfs_agblock_t tbno; /* start block of busy extent */
		xfs_extlen_t tlen; /* length of busy extent */
		xfs_agblock_t tend; /* end block of busy extent */
		int i; /* success/failure of operation */
		unsigned busy_gen;

		ASSERT(args->alignment == 1);

		@@ -773,7 +778,9 @@ xfs_alloc_ag_vextent_exact(
		/*
		* Check for overlapping busy extents.
		*/
		xfs_extent_busy_trim(args, fbno, flen, &tbno, &tlen);
		tbno = fbno;
		tlen = flen;
		xfs_extent_busy_trim(args, &tbno, &tlen, &busy_gen);

		/*
		* Give up if the start of the extent is busy, or the freespace isn't
		@@ -853,6 +860,7 @@ xfs_alloc_find_best_extent(
		xfs_agblock_t sdiff;
		int error;
		int i;
		unsigned busy_gen;

		/* The good extent is perfect, no need to search. */
		if (!gdiff)
		@@ -866,7 +874,8 @@ xfs_alloc_find_best_extent(
		if (error)
		goto error0;
		XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
		xfs_alloc_compute_aligned(args, sbno, slen, sbnoa, slena);
		xfs_alloc_compute_aligned(args, sbno, slen,
		sbnoa, slena, &busy_gen);

		/*
		* The good extent is closer than this one.
		@@ -955,7 +964,8 @@ xfs_alloc_ag_vextent_near(
		xfs_extlen_t ltlena; /* aligned ... */
		xfs_agblock_t ltnew; /* useful start bno of left side */
		xfs_extlen_t rlen; /* length of returned extent */
		int forced = 0;
		bool busy;
		unsigned busy_gen;
		#ifdef DEBUG
		/*
		* Randomly don't execute the first algorithm.
		@@ -982,6 +992,7 @@ restart:
		ltlen = 0;
		gtlena = 0;
		ltlena = 0;
		busy = false;

		/*
		* Get a cursor for the by-size btree.
		@@ -1064,8 +1075,8 @@ restart:
		if ((error = xfs_alloc_get_rec(cnt_cur, &ltbno, &ltlen, &i)))
		goto error0;
		XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
		xfs_alloc_compute_aligned(args, ltbno, ltlen,
		&ltbnoa, &ltlena);
		busy = xfs_alloc_compute_aligned(args, ltbno, ltlen,
		&ltbnoa, &ltlena, &busy_gen);
		if (ltlena < args->minlen)
		continue;
		if (ltbnoa < args->min_agbno \|\| ltbnoa > args->max_agbno)
		@@ -1183,8 +1194,8 @@ restart:
		if ((error = xfs_alloc_get_rec(bno_cur_lt, &ltbno, &ltlen, &i)))
		goto error0;
		XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
		xfs_alloc_compute_aligned(args, ltbno, ltlen,
		&ltbnoa, &ltlena);
		busy \|= xfs_alloc_compute_aligned(args, ltbno, ltlen,
		&ltbnoa, &ltlena, &busy_gen);
		if (ltlena >= args->minlen && ltbnoa >= args->min_agbno)
		break;
		if ((error = xfs_btree_decrement(bno_cur_lt, 0, &i)))
		@@ -1199,8 +1210,8 @@ restart:
		if ((error = xfs_alloc_get_rec(bno_cur_gt, &gtbno, &gtlen, &i)))
		goto error0;
		XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
		xfs_alloc_compute_aligned(args, gtbno, gtlen,
		&gtbnoa, &gtlena);
		busy \|= xfs_alloc_compute_aligned(args, gtbno, gtlen,
		&gtbnoa, &gtlena, &busy_gen);
		if (gtlena >= args->minlen && gtbnoa <= args->max_agbno)
		break;
		if ((error = xfs_btree_increment(bno_cur_gt, 0, &i)))
		@@ -1261,9 +1272,9 @@ restart:
		if (bno_cur_lt == NULL && bno_cur_gt == NULL) {
		xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);

		if (!forced++) {
		if (busy) {
		trace_xfs_alloc_near_busy(args);
		xfs_log_force(args->mp, XFS_LOG_SYNC);
		xfs_extent_busy_flush(args->mp, args->pag, busy_gen);
		goto restart;
		}
		trace_xfs_alloc_size_neither(args);
		@@ -1344,7 +1355,8 @@ xfs_alloc_ag_vextent_size(
		int i; /* temp status variable */
		xfs_agblock_t rbno; /* returned block number */
		xfs_extlen_t rlen; /* length of returned extent */
		int forced = 0;
		bool busy;
		unsigned busy_gen;

		restart:
		/*
		@@ -1353,6 +1365,7 @@ restart:
		cnt_cur = xfs_allocbt_init_cursor(args->mp, args->tp, args->agbp,
		args->agno, XFS_BTNUM_CNT);
		bno_cur = NULL;
		busy = false;

		/*
		* Look for an entry >= maxlen+alignment-1 blocks.
		@@ -1362,14 +1375,13 @@ restart:
		goto error0;

		/*
		* If none or we have busy extents that we cannot allocate from, then
		* we have to settle for a smaller extent. In the case that there are
		* no large extents, this will return the last entry in the tree unless
		* the tree is empty. In the case that there are only busy large
		* extents, this will return the largest small extent unless there
		* If none then we have to settle for a smaller extent. In the case that
		* there are no large extents, this will return the last entry in the
		* tree unless the tree is empty. In the case that there are only busy
		* large extents, this will return the largest small extent unless there
		* are no smaller extents available.
		*/
		if (!i \|\| forced > 1) {
		if (!i) {
		error = xfs_alloc_ag_vextent_small(args, cnt_cur,
		&fbno, &flen, &i);
		if (error)
		@@ -1380,13 +1392,11 @@ restart:
		return 0;
		}
		ASSERT(i == 1);
		xfs_alloc_compute_aligned(args, fbno, flen, &rbno, &rlen);
		busy = xfs_alloc_compute_aligned(args, fbno, flen, &rbno,
		&rlen, &busy_gen);
		} else {
		/*
		* Search for a non-busy extent that is large enough.
		* If we are at low space, don't check, or if we fall of
		* the end of the btree, turn off the busy check and
		* restart.
		*/
		for (;;) {
		error = xfs_alloc_get_rec(cnt_cur, &fbno, &flen, &i);
		@@ -1394,8 +1404,8 @@ restart:
		goto error0;
		XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);

		xfs_alloc_compute_aligned(args, fbno, flen,
		&rbno, &rlen);
		busy = xfs_alloc_compute_aligned(args, fbno, flen,
		&rbno, &rlen, &busy_gen);

		if (rlen >= args->maxlen)
		break;
		@@ -1407,18 +1417,13 @@ restart:
		/*
		* Our only valid extents must have been busy.
		* Make it unbusy by forcing the log out and
		* retrying. If we've been here before, forcing
		* the log isn't making the extents available,
		* which means they have probably been freed in
		* this transaction. In that case, we have to
		* give up on them and we'll attempt a minlen
		* allocation the next time around.
		* retrying.
		*/
		xfs_btree_del_cursor(cnt_cur,
		XFS_BTREE_NOERROR);
		trace_xfs_alloc_size_busy(args);
		if (!forced++)
		xfs_log_force(args->mp, XFS_LOG_SYNC);
		xfs_extent_busy_flush(args->mp,
		args->pag, busy_gen);
		goto restart;
		}
		}
		@@ -1454,8 +1459,8 @@ restart:
		XFS_WANT_CORRUPTED_GOTO(args->mp, i == 1, error0);
		if (flen < bestrlen)
		break;
		xfs_alloc_compute_aligned(args, fbno, flen,
		&rbno, &rlen);
		busy = xfs_alloc_compute_aligned(args, fbno, flen,
		&rbno, &rlen, &busy_gen);
		rlen = XFS_EXTLEN_MIN(args->maxlen, rlen);
		XFS_WANT_CORRUPTED_GOTO(args->mp, rlen == 0 \|\|
		(rlen <= flen && rbno + rlen <= fbno + flen),
		@@ -1484,10 +1489,10 @@ restart:
		*/
		args->len = rlen;
		if (rlen < args->minlen) {
		if (!forced++) {
		if (busy) {
		xfs_btree_del_cursor(cnt_cur, XFS_BTREE_NOERROR);
		trace_xfs_alloc_size_busy(args);
		xfs_log_force(args->mp, XFS_LOG_SYNC);
		xfs_extent_busy_flush(args->mp, args->pag, busy_gen);
		goto restart;
		}
		goto out_nominleft;

fs/xfs/xfs_extent_busy.c

+98 −27

Original line number	Diff line number	Diff line
		@@ -334,25 +334,31 @@ restart:
		* subset of the extent that is not busy. If *rlen is smaller than
		* args->minlen no suitable extent could be found, and the higher level
		* code needs to force out the log and retry the allocation.
		*
		* Return the current busy generation for the AG if the extent is busy. This
		* value can be used to wait for at least one of the currently busy extents
		* to be cleared. Note that the busy list is not guaranteed to be empty after
		* the gen is woken. The state of a specific extent must always be confirmed
		* with another call to xfs_extent_busy_trim() before it can be used.
		*/
		void
		bool
		xfs_extent_busy_trim(
		struct xfs_alloc_arg *args,
		xfs_agblock_t bno,
		xfs_extlen_t len,
		xfs_agblock_t *rbno,
		xfs_extlen_t *rlen)
		xfs_agblock_t *bno,
		xfs_extlen_t *len,
		unsigned *busy_gen)
		{
		xfs_agblock_t fbno;
		xfs_extlen_t flen;
		struct rb_node *rbp;
		bool ret = false;

		ASSERT(len > 0);

		spin_lock(&args->pag->pagb_lock);
		restart:
		fbno = bno;
		flen = len;
		fbno = *bno;
		flen = *len;
		rbp = args->pag->pagb_tree.rb_node;
		while (rbp && flen >= args->minlen) {
		struct xfs_extent_busy *busyp =
		@@ -504,24 +510,25 @@ restart:

		flen = fend - fbno;
		}
		spin_unlock(&args->pag->pagb_lock);
		out:

		if (fbno != bno \|\| flen != len) {
		trace_xfs_extent_busy_trim(args->mp, args->agno, bno, len,
		if (fbno != bno \|\| flen != len) {
		trace_xfs_extent_busy_trim(args->mp, args->agno, bno, len,
		fbno, flen);
		*bno = fbno;
		*len = flen;
		*busy_gen = args->pag->pagb_gen;
		ret = true;
		}
		*rbno = fbno;
		*rlen = flen;
		return;
		spin_unlock(&args->pag->pagb_lock);
		return ret;
		fail:
		/*
		* Return a zero extent length as failure indications. All callers
		* re-check if the trimmed extent satisfies the minlen requirement.
		*/
		spin_unlock(&args->pag->pagb_lock);
		trace_xfs_extent_busy_trim(args->mp, args->agno, bno, len, fbno, 0);
		*rbno = fbno;
		*rlen = 0;
		flen = 0;
		goto out;
		}

		STATIC void
		@@ -540,6 +547,21 @@ xfs_extent_busy_clear_one(
		kmem_free(busyp);
		}

		static void
		xfs_extent_busy_put_pag(
		struct xfs_perag *pag,
		bool wakeup)
		__releases(pag->pagb_lock)
		{
		if (wakeup) {
		pag->pagb_gen++;
		wake_up_all(&pag->pagb_wait);
		}

		spin_unlock(&pag->pagb_lock);
		xfs_perag_put(pag);
		}

		/*
		* Remove all extents on the passed in list from the busy extents tree.
		* If do_discard is set skip extents that need to be discarded, and mark
		@@ -554,27 +576,76 @@ xfs_extent_busy_clear(
		struct xfs_extent_busy busyp, n;
		struct xfs_perag *pag = NULL;
		xfs_agnumber_t agno = NULLAGNUMBER;
		bool wakeup = false;

		list_for_each_entry_safe(busyp, n, list, list) {
		if (busyp->agno != agno) {
		if (pag) {
		spin_unlock(&pag->pagb_lock);
		xfs_perag_put(pag);
		}
		pag = xfs_perag_get(mp, busyp->agno);
		spin_lock(&pag->pagb_lock);
		if (pag)
		xfs_extent_busy_put_pag(pag, wakeup);
		agno = busyp->agno;
		pag = xfs_perag_get(mp, agno);
		spin_lock(&pag->pagb_lock);
		wakeup = false;
		}

		if (do_discard && busyp->length &&
		!(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD))
		!(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD)) {
		busyp->flags = XFS_EXTENT_BUSY_DISCARDED;
		else
		} else {
		xfs_extent_busy_clear_one(mp, pag, busyp);
		wakeup = true;
		}
		}

		if (pag) {
		spin_unlock(&pag->pagb_lock);
		if (pag)
		xfs_extent_busy_put_pag(pag, wakeup);
		}

		/*
		* Flush out all busy extents for this AG.
		*/
		void
		xfs_extent_busy_flush(
		struct xfs_mount *mp,
		struct xfs_perag *pag,
		unsigned busy_gen)
		{
		DEFINE_WAIT (wait);
		int log_flushed = 0, error;

		trace_xfs_log_force(mp, 0, _THIS_IP_);
		error = _xfs_log_force(mp, XFS_LOG_SYNC, &log_flushed);
		if (error)
		return;

		do {
		prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
		if (busy_gen != READ_ONCE(pag->pagb_gen))
		break;
		schedule();
		} while (1);

		finish_wait(&pag->pagb_wait, &wait);
		}

		void
		xfs_extent_busy_wait_all(
		struct xfs_mount *mp)
		{
		DEFINE_WAIT (wait);
		xfs_agnumber_t agno;

		for (agno = 0; agno < mp->m_sb.sb_agcount; agno++) {
		struct xfs_perag *pag = xfs_perag_get(mp, agno);

		do {
		prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
		if (RB_EMPTY_ROOT(&pag->pagb_tree))
		break;
		schedule();
		} while (1);
		finish_wait(&pag->pagb_wait, &wait);

		xfs_perag_put(pag);
		}
		}

fs/xfs/xfs_extent_busy.h

+9 −2

Original line number	Diff line number	Diff line
		@@ -58,9 +58,16 @@ void
		xfs_extent_busy_reuse(struct xfs_mount *mp, xfs_agnumber_t agno,
		xfs_agblock_t fbno, xfs_extlen_t flen, bool userdata);

		bool
		xfs_extent_busy_trim(struct xfs_alloc_arg args, xfs_agblock_t bno,
		xfs_extlen_t len, unsigned busy_gen);

		void
		xfs_extent_busy_flush(struct xfs_mount mp, struct xfs_perag pag,
		unsigned busy_gen);

		void
		xfs_extent_busy_trim(struct xfs_alloc_arg *args, xfs_agblock_t bno,
		xfs_extlen_t len, xfs_agblock_t rbno, xfs_extlen_t rlen);
		xfs_extent_busy_wait_all(struct xfs_mount *mp);

		int
		xfs_extent_busy_ag_cmp(void priv, struct list_head a, struct list_head *b);

fs/xfs/xfs_mount.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -45,6 +45,7 @@
		#include "xfs_rmap_btree.h"
		#include "xfs_refcount_btree.h"
		#include "xfs_reflink.h"
		#include "xfs_extent_busy.h"


		static DEFINE_MUTEX(xfs_uuid_table_mutex);
		@@ -213,6 +214,7 @@ xfs_initialize_perag(
		INIT_RADIX_TREE(&pag->pag_ici_root, GFP_ATOMIC);
		if (xfs_buf_hash_init(pag))
		goto out_free_pag;
		init_waitqueue_head(&pag->pagb_wait);

		if (radix_tree_preload(GFP_NOFS))
		goto out_hash_destroy;
		@@ -1078,6 +1080,12 @@ xfs_unmountfs(
		*/
		xfs_log_force(mp, XFS_LOG_SYNC);

		/*
		* Wait for all busy extents to be freed, including completion of
		* any discard operation.
		*/
		xfs_extent_busy_wait_all(mp);

		/*
		* We now need to tell the world we are unmounting. This will allow
		* us to detect that the filesystem is going away and we should error

fs/xfs/xfs_mount.h

+2 −0

Original line number	Diff line number	Diff line
		@@ -384,6 +384,8 @@ typedef struct xfs_perag {
		xfs_agino_t pagl_rightrec;
		spinlock_t pagb_lock; /* lock for pagb_tree */
		struct rb_root pagb_tree; /* ordered tree of busy extents */
		unsigned int pagb_gen; /* generation count for pagb_tree */
		wait_queue_head_t pagb_wait; /* woken when pagb_gen changes */

		atomic_t pagf_fstrms; /* # of filestreams active in this AG */

Admin message