LCOV - code coverage report
Current view: top level - fs/xfs - xfs_extent_busy.c (source / functions) Hit Total Coverage
Test: fstests of 6.5.0-rc4-xfsx @ Mon Jul 31 20:08:34 PDT 2023 Lines: 195 220 88.6 %
Date: 2023-07-31 20:08:34 Functions: 12 12 100.0 %

          Line data    Source code
       1             : // SPDX-License-Identifier: GPL-2.0
       2             : /*
       3             :  * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc.
       4             :  * Copyright (c) 2010 David Chinner.
       5             :  * Copyright (c) 2011 Christoph Hellwig.
       6             :  * All Rights Reserved.
       7             :  */
       8             : #include "xfs.h"
       9             : #include "xfs_fs.h"
      10             : #include "xfs_format.h"
      11             : #include "xfs_log_format.h"
      12             : #include "xfs_shared.h"
      13             : #include "xfs_trans_resv.h"
      14             : #include "xfs_mount.h"
      15             : #include "xfs_alloc.h"
      16             : #include "xfs_extent_busy.h"
      17             : #include "xfs_trace.h"
      18             : #include "xfs_trans.h"
      19             : #include "xfs_log.h"
      20             : #include "xfs_ag.h"
      21             : 
      22             : void
      23   105841020 : xfs_extent_busy_insert(
      24             :         struct xfs_trans        *tp,
      25             :         struct xfs_perag        *pag,
      26             :         xfs_agblock_t           bno,
      27             :         xfs_extlen_t            len,
      28             :         unsigned int            flags)
      29             : {
      30   105841020 :         struct xfs_extent_busy  *new;
      31   105841020 :         struct xfs_extent_busy  *busyp;
      32   105841020 :         struct rb_node          **rbp;
      33   105841020 :         struct rb_node          *parent = NULL;
      34             : 
      35   105841020 :         new = kmem_zalloc(sizeof(struct xfs_extent_busy), 0);
      36   105827517 :         new->agno = pag->pag_agno;
      37   105827517 :         new->bno = bno;
      38   105827517 :         new->length = len;
      39   105827517 :         INIT_LIST_HEAD(&new->list);
      40   105827517 :         new->flags = flags;
      41             : 
      42             :         /* trace before insert to be able to see failed inserts */
      43   105827517 :         trace_xfs_extent_busy(tp->t_mountp, pag->pag_agno, bno, len);
      44             : 
      45   105825016 :         spin_lock(&pag->pagb_lock);
      46   105850360 :         rbp = &pag->pagb_tree.rb_node;
      47  1063758062 :         while (*rbp) {
      48   957903232 :                 parent = *rbp;
      49   957903232 :                 busyp = rb_entry(parent, struct xfs_extent_busy, rb_node);
      50             : 
      51   957903232 :                 if (new->bno < busyp->bno) {
      52   224643926 :                         rbp = &(*rbp)->rb_left;
      53   224643926 :                         ASSERT(new->bno + new->length <= busyp->bno);
      54   733259306 :                 } else if (new->bno > busyp->bno) {
      55   733259306 :                         rbp = &(*rbp)->rb_right;
      56   733259306 :                         ASSERT(bno >= busyp->bno + busyp->length);
      57             :                 } else {
      58           0 :                         ASSERT(0);
      59             :                 }
      60             :         }
      61             : 
      62   105854830 :         rb_link_node(&new->rb_node, parent, rbp);
      63   105854830 :         rb_insert_color(&new->rb_node, &pag->pagb_tree);
      64             : 
      65   105850256 :         list_add(&new->list, &tp->t_busy);
      66   105847035 :         spin_unlock(&pag->pagb_lock);
      67   105856021 : }
      68             : 
      69             : /*
      70             :  * Search for a busy extent within the range of the extent we are about to
      71             :  * allocate.  You need to be holding the busy extent tree lock when calling
      72             :  * xfs_extent_busy_search(). This function returns 0 for no overlapping busy
      73             :  * extent, -1 for an overlapping but not exact busy extent, and 1 for an exact
      74             :  * match. This is done so that a non-zero return indicates an overlap that
      75             :  * will require a synchronous transaction, but it can still be
      76             :  * used to distinguish between a partial or exact match.
      77             :  */
      78             : int
      79    98885538 : xfs_extent_busy_search(
      80             :         struct xfs_mount        *mp,
      81             :         struct xfs_perag        *pag,
      82             :         xfs_agblock_t           bno,
      83             :         xfs_extlen_t            len)
      84             : {
      85    98885538 :         struct rb_node          *rbp;
      86    98885538 :         struct xfs_extent_busy  *busyp;
      87    98885538 :         int                     match = 0;
      88             : 
      89             :         /* find closest start bno overlap */
      90    98885538 :         spin_lock(&pag->pagb_lock);
      91    98885137 :         rbp = pag->pagb_tree.rb_node;
      92   422180751 :         while (rbp) {
      93   323295795 :                 busyp = rb_entry(rbp, struct xfs_extent_busy, rb_node);
      94   323295795 :                 if (bno < busyp->bno) {
      95             :                         /* may overlap, but exact start block is lower */
      96   131893247 :                         if (bno + len > busyp->bno)
      97         187 :                                 match = -1;
      98   131893247 :                         rbp = rbp->rb_left;
      99   191402548 :                 } else if (bno > busyp->bno) {
     100             :                         /* may overlap, but exact start block is higher */
     101   191402367 :                         if (bno < busyp->bno + busyp->length)
     102           0 :                                 match = -1;
     103   191402367 :                         rbp = rbp->rb_right;
     104             :                 } else {
     105             :                         /* bno matches busyp, length determines exact match */
     106         181 :                         match = (busyp->length == len) ? 1 : -1;
     107             :                         break;
     108             :                 }
     109             :         }
     110    98885137 :         spin_unlock(&pag->pagb_lock);
     111    98890862 :         return match;
     112             : }
     113             : 
     114             : /*
     115             :  * The found free extent [fbno, fend] overlaps part or all of the given busy
     116             :  * extent.  If the overlap covers the beginning, the end, or all of the busy
     117             :  * extent, the overlapping portion can be made unbusy and used for the
     118             :  * allocation.  We can't split a busy extent because we can't modify a
     119             :  * transaction/CIL context busy list, but we can update an entry's block
     120             :  * number or length.
     121             :  *
     122             :  * Returns true if the extent can safely be reused, or false if the search
     123             :  * needs to be restarted.
     124             :  */
     125             : STATIC bool
     126        9377 : xfs_extent_busy_update_extent(
     127             :         struct xfs_mount        *mp,
     128             :         struct xfs_perag        *pag,
     129             :         struct xfs_extent_busy  *busyp,
     130             :         xfs_agblock_t           fbno,
     131             :         xfs_extlen_t            flen,
     132             :         bool                    userdata) __releases(&pag->pagb_lock)
     133             :                                           __acquires(&pag->pagb_lock)
     134             : {
     135        9377 :         xfs_agblock_t           fend = fbno + flen;
     136        9377 :         xfs_agblock_t           bbno = busyp->bno;
     137        9377 :         xfs_agblock_t           bend = bbno + busyp->length;
     138             : 
     139             :         /*
     140             :          * This extent is currently being discarded.  Give the thread
     141             :          * performing the discard a chance to mark the extent unbusy
     142             :          * and retry.
     143             :          */
     144        9377 :         if (busyp->flags & XFS_EXTENT_BUSY_DISCARDED) {
     145           0 :                 spin_unlock(&pag->pagb_lock);
     146           0 :                 delay(1);
     147           0 :                 spin_lock(&pag->pagb_lock);
     148           0 :                 return false;
     149             :         }
     150             : 
     151             :         /*
     152             :          * If there is a busy extent overlapping a user allocation, we have
     153             :          * no choice but to force the log and retry the search.
     154             :          *
     155             :          * Fortunately this does not happen during normal operation, but
     156             :          * only if the filesystem is very low on space and has to dip into
     157             :          * the AGFL for normal allocations.
     158             :          */
     159        9377 :         if (userdata)
     160           0 :                 goto out_force_log;
     161             : 
     162        9377 :         if (bbno < fbno && bend > fend) {
     163             :                 /*
     164             :                  * Case 1:
     165             :                  *    bbno           bend
     166             :                  *    +BBBBBBBBBBBBBBBBB+
     167             :                  *        +---------+
     168             :                  *        fbno   fend
     169             :                  */
     170             : 
     171             :                 /*
     172             :                  * We would have to split the busy extent to be able to track
     173             :                  * it correct, which we cannot do because we would have to
     174             :                  * modify the list of busy extents attached to the transaction
     175             :                  * or CIL context, which is immutable.
     176             :                  *
     177             :                  * Force out the log to clear the busy extent and retry the
     178             :                  * search.
     179             :                  */
     180           0 :                 goto out_force_log;
     181        9377 :         } else if (bbno >= fbno && bend <= fend) {
     182             :                 /*
     183             :                  * Case 2:
     184             :                  *    bbno           bend
     185             :                  *    +BBBBBBBBBBBBBBBBB+
     186             :                  *    +-----------------+
     187             :                  *    fbno           fend
     188             :                  *
     189             :                  * Case 3:
     190             :                  *    bbno           bend
     191             :                  *    +BBBBBBBBBBBBBBBBB+
     192             :                  *    +--------------------------+
     193             :                  *    fbno                    fend
     194             :                  *
     195             :                  * Case 4:
     196             :                  *             bbno           bend
     197             :                  *             +BBBBBBBBBBBBBBBBB+
     198             :                  *    +--------------------------+
     199             :                  *    fbno                    fend
     200             :                  *
     201             :                  * Case 5:
     202             :                  *             bbno           bend
     203             :                  *             +BBBBBBBBBBBBBBBBB+
     204             :                  *    +-----------------------------------+
     205             :                  *    fbno                             fend
     206             :                  *
     207             :                  */
     208             : 
     209             :                 /*
     210             :                  * The busy extent is fully covered by the extent we are
     211             :                  * allocating, and can simply be removed from the rbtree.
     212             :                  * However we cannot remove it from the immutable list
     213             :                  * tracking busy extents in the transaction or CIL context,
     214             :                  * so set the length to zero to mark it invalid.
     215             :                  *
     216             :                  * We also need to restart the busy extent search from the
     217             :                  * tree root, because erasing the node can rearrange the
     218             :                  * tree topology.
     219             :                  */
     220        9377 :                 rb_erase(&busyp->rb_node, &pag->pagb_tree);
     221        9377 :                 busyp->length = 0;
     222        9377 :                 return false;
     223           0 :         } else if (fend < bend) {
     224             :                 /*
     225             :                  * Case 6:
     226             :                  *              bbno           bend
     227             :                  *             +BBBBBBBBBBBBBBBBB+
     228             :                  *             +---------+
     229             :                  *             fbno   fend
     230             :                  *
     231             :                  * Case 7:
     232             :                  *             bbno           bend
     233             :                  *             +BBBBBBBBBBBBBBBBB+
     234             :                  *    +------------------+
     235             :                  *    fbno            fend
     236             :                  *
     237             :                  */
     238           0 :                 busyp->bno = fend;
     239           0 :                 busyp->length = bend - fend;
     240           0 :         } else if (bbno < fbno) {
     241             :                 /*
     242             :                  * Case 8:
     243             :                  *    bbno           bend
     244             :                  *    +BBBBBBBBBBBBBBBBB+
     245             :                  *        +-------------+
     246             :                  *        fbno       fend
     247             :                  *
     248             :                  * Case 9:
     249             :                  *    bbno           bend
     250             :                  *    +BBBBBBBBBBBBBBBBB+
     251             :                  *        +----------------------+
     252             :                  *        fbno                fend
     253             :                  */
     254           0 :                 busyp->length = fbno - busyp->bno;
     255             :         } else {
     256           0 :                 ASSERT(0);
     257             :         }
     258             : 
     259           0 :         trace_xfs_extent_busy_reuse(mp, pag->pag_agno, fbno, flen);
     260           0 :         return true;
     261             : 
     262           0 : out_force_log:
     263           0 :         spin_unlock(&pag->pagb_lock);
     264           0 :         xfs_log_force(mp, XFS_LOG_SYNC);
     265           0 :         trace_xfs_extent_busy_force(mp, pag->pag_agno, fbno, flen);
     266           0 :         spin_lock(&pag->pagb_lock);
     267           0 :         return false;
     268             : }
     269             : 
     270             : 
     271             : /*
     272             :  * For a given extent [fbno, flen], make sure we can reuse it safely.
     273             :  */
     274             : void
     275      981898 : xfs_extent_busy_reuse(
     276             :         struct xfs_mount        *mp,
     277             :         struct xfs_perag        *pag,
     278             :         xfs_agblock_t           fbno,
     279             :         xfs_extlen_t            flen,
     280             :         bool                    userdata)
     281             : {
     282      981898 :         struct rb_node          *rbp;
     283             : 
     284      981898 :         ASSERT(flen > 0);
     285      981898 :         spin_lock(&pag->pagb_lock);
     286      991275 : restart:
     287      991275 :         rbp = pag->pagb_tree.rb_node;
     288     5574471 :         while (rbp) {
     289     4592573 :                 struct xfs_extent_busy *busyp =
     290     4592573 :                         rb_entry(rbp, struct xfs_extent_busy, rb_node);
     291     4592573 :                 xfs_agblock_t   bbno = busyp->bno;
     292     4592573 :                 xfs_agblock_t   bend = bbno + busyp->length;
     293             : 
     294     4592573 :                 if (fbno + flen <= bbno) {
     295     1827766 :                         rbp = rbp->rb_left;
     296     1827766 :                         continue;
     297     2764807 :                 } else if (fbno >= bend) {
     298     2755430 :                         rbp = rbp->rb_right;
     299     2755430 :                         continue;
     300             :                 }
     301             : 
     302        9377 :                 if (!xfs_extent_busy_update_extent(mp, pag, busyp, fbno, flen,
     303             :                                                   userdata))
     304        9377 :                         goto restart;
     305             :         }
     306      981898 :         spin_unlock(&pag->pagb_lock);
     307      981898 : }
     308             : 
     309             : /*
     310             :  * For a given extent [fbno, flen], search the busy extent list to find a
     311             :  * subset of the extent that is not busy.  If *rlen is smaller than
     312             :  * args->minlen no suitable extent could be found, and the higher level
     313             :  * code needs to force out the log and retry the allocation.
     314             :  *
     315             :  * Return the current busy generation for the AG if the extent is busy. This
     316             :  * value can be used to wait for at least one of the currently busy extents
     317             :  * to be cleared. Note that the busy list is not guaranteed to be empty after
     318             :  * the gen is woken. The state of a specific extent must always be confirmed
     319             :  * with another call to xfs_extent_busy_trim() before it can be used.
     320             :  */
     321             : bool
     322  6130180963 : xfs_extent_busy_trim(
     323             :         struct xfs_alloc_arg    *args,
     324             :         xfs_agblock_t           *bno,
     325             :         xfs_extlen_t            *len,
     326             :         unsigned                *busy_gen)
     327             : {
     328  6130180963 :         xfs_agblock_t           fbno;
     329  6130180963 :         xfs_extlen_t            flen;
     330  6130180963 :         struct rb_node          *rbp;
     331  6130180963 :         bool                    ret = false;
     332             : 
     333  6130180963 :         ASSERT(*len > 0);
     334             : 
     335  6130180963 :         spin_lock(&args->pag->pagb_lock);
     336  6128771443 :         fbno = *bno;
     337  6128771443 :         flen = *len;
     338  6128771443 :         rbp = args->pag->pagb_tree.rb_node;
     339 54990449601 :         while (rbp && flen >= args->minlen) {
     340 52204986629 :                 struct xfs_extent_busy *busyp =
     341 52204986629 :                         rb_entry(rbp, struct xfs_extent_busy, rb_node);
     342 52204986629 :                 xfs_agblock_t   fend = fbno + flen;
     343 52204986629 :                 xfs_agblock_t   bbno = busyp->bno;
     344 52204986629 :                 xfs_agblock_t   bend = bbno + busyp->length;
     345             : 
     346 52204986629 :                 if (fend <= bbno) {
     347 22332821461 :                         rbp = rbp->rb_left;
     348 22332821461 :                         continue;
     349 29872165168 :                 } else if (fbno >= bend) {
     350 25442346917 :                         rbp = rbp->rb_right;
     351 25442346917 :                         continue;
     352             :                 }
     353             : 
     354  4429818251 :                 if (bbno <= fbno) {
     355             :                         /* start overlap */
     356             : 
     357             :                         /*
     358             :                          * Case 1:
     359             :                          *    bbno           bend
     360             :                          *    +BBBBBBBBBBBBBBBBB+
     361             :                          *        +---------+
     362             :                          *        fbno   fend
     363             :                          *
     364             :                          * Case 2:
     365             :                          *    bbno           bend
     366             :                          *    +BBBBBBBBBBBBBBBBB+
     367             :                          *    +-------------+
     368             :                          *    fbno       fend
     369             :                          *
     370             :                          * Case 3:
     371             :                          *    bbno           bend
     372             :                          *    +BBBBBBBBBBBBBBBBB+
     373             :                          *        +-------------+
     374             :                          *        fbno       fend
     375             :                          *
     376             :                          * Case 4:
     377             :                          *    bbno           bend
     378             :                          *    +BBBBBBBBBBBBBBBBB+
     379             :                          *    +-----------------+
     380             :                          *    fbno           fend
     381             :                          *
     382             :                          * No unbusy region in extent, return failure.
     383             :                          */
     384  3712407661 :                         if (fend <= bend)
     385  3331643009 :                                 goto fail;
     386             : 
     387             :                         /*
     388             :                          * Case 5:
     389             :                          *    bbno           bend
     390             :                          *    +BBBBBBBBBBBBBBBBB+
     391             :                          *        +----------------------+
     392             :                          *        fbno                fend
     393             :                          *
     394             :                          * Case 6:
     395             :                          *    bbno           bend
     396             :                          *    +BBBBBBBBBBBBBBBBB+
     397             :                          *    +--------------------------+
     398             :                          *    fbno                    fend
     399             :                          *
     400             :                          * Needs to be trimmed to:
     401             :                          *                       +-------+
     402             :                          *                       fbno fend
     403             :                          */
     404             :                         fbno = bend;
     405   717410590 :                 } else if (bend >= fend) {
     406             :                         /* end overlap */
     407             : 
     408             :                         /*
     409             :                          * Case 7:
     410             :                          *             bbno           bend
     411             :                          *             +BBBBBBBBBBBBBBBBB+
     412             :                          *    +------------------+
     413             :                          *    fbno            fend
     414             :                          *
     415             :                          * Case 8:
     416             :                          *             bbno           bend
     417             :                          *             +BBBBBBBBBBBBBBBBB+
     418             :                          *    +--------------------------+
     419             :                          *    fbno                    fend
     420             :                          *
     421             :                          * Needs to be trimmed to:
     422             :                          *    +-------+
     423             :                          *    fbno fend
     424             :                          */
     425             :                         fend = bbno;
     426             :                 } else {
     427             :                         /* middle overlap */
     428             : 
     429             :                         /*
     430             :                          * Case 9:
     431             :                          *             bbno           bend
     432             :                          *             +BBBBBBBBBBBBBBBBB+
     433             :                          *    +-----------------------------------+
     434             :                          *    fbno                             fend
     435             :                          *
     436             :                          * Can be trimmed to:
     437             :                          *    +-------+        OR         +-------+
     438             :                          *    fbno fend                   fbno fend
     439             :                          *
     440             :                          * Backward allocation leads to significant
     441             :                          * fragmentation of directories, which degrades
     442             :                          * directory performance, therefore we always want to
     443             :                          * choose the option that produces forward allocation
     444             :                          * patterns.
     445             :                          * Preferring the lower bno extent will make the next
     446             :                          * request use "fend" as the start of the next
     447             :                          * allocation;  if the segment is no longer busy at
     448             :                          * that point, we'll get a contiguous allocation, but
     449             :                          * even if it is still busy, we will get a forward
     450             :                          * allocation.
     451             :                          * We try to avoid choosing the segment at "bend",
     452             :                          * because that can lead to the next allocation
     453             :                          * taking the segment at "fbno", which would be a
     454             :                          * backward allocation.  We only use the segment at
     455             :                          * "fbno" if it is much larger than the current
     456             :                          * requested size, because in that case there's a
     457             :                          * good chance subsequent allocations will be
     458             :                          * contiguous.
     459             :                          */
     460   434652977 :                         if (bbno - fbno >= args->maxlen) {
     461             :                                 /* left candidate fits perfect */
     462             :                                 fend = bbno;
     463    13154771 :                         } else if (fend - bend >= args->maxlen * 4) {
     464             :                                 /* right candidate has enough free space */
     465             :                                 fbno = bend;
     466    11701163 :                         } else if (bbno - fbno >= args->minlen) {
     467             :                                 /* left candidate fits minimum requirement */
     468             :                                 fend = bbno;
     469             :                         } else {
     470    11665462 :                                 goto fail;
     471             :                         }
     472             :                 }
     473             : 
     474  1086509780 :                 flen = fend - fbno;
     475             :         }
     476  2785462972 : out:
     477             : 
     478  6128771443 :         if (fbno != *bno || flen != *len) {
     479  3530589343 :                 trace_xfs_extent_busy_trim(args->mp, args->agno, *bno, *len,
     480             :                                           fbno, flen);
     481  3527048913 :                 *bno = fbno;
     482  3527048913 :                 *len = flen;
     483  3527048913 :                 *busy_gen = args->pag->pagb_gen;
     484  3527048913 :                 ret = true;
     485             :         }
     486  6125231013 :         spin_unlock(&args->pag->pagb_lock);
     487  6134107824 :         return ret;
     488  3343308471 : fail:
     489             :         /*
     490             :          * Return a zero extent length as failure indications.  All callers
     491             :          * re-check if the trimmed extent satisfies the minlen requirement.
     492             :          */
     493  3343308471 :         flen = 0;
     494  3343308471 :         goto out;
     495             : }
     496             : 
     497             : STATIC void
     498   105868172 : xfs_extent_busy_clear_one(
     499             :         struct xfs_mount        *mp,
     500             :         struct xfs_perag        *pag,
     501             :         struct xfs_extent_busy  *busyp)
     502             : {
     503   105868172 :         if (busyp->length) {
     504   105858795 :                 trace_xfs_extent_busy_clear(mp, busyp->agno, busyp->bno,
     505             :                                                 busyp->length);
     506   105858795 :                 rb_erase(&busyp->rb_node, &pag->pagb_tree);
     507             :         }
     508             : 
     509   105868172 :         list_del_init(&busyp->list);
     510   105868172 :         kmem_free(busyp);
     511   105868172 : }
     512             : 
     513             : static void
     514     8338870 : xfs_extent_busy_put_pag(
     515             :         struct xfs_perag        *pag,
     516             :         bool                    wakeup)
     517             :                 __releases(pag->pagb_lock)
     518             : {
     519     8338870 :         if (wakeup) {
     520     8338744 :                 pag->pagb_gen++;
     521     8338744 :                 wake_up_all(&pag->pagb_wait);
     522             :         }
     523             : 
     524     8338870 :         spin_unlock(&pag->pagb_lock);
     525     8338870 :         xfs_perag_put(pag);
     526     8338870 : }
     527             : 
     528             : /*
     529             :  * Remove all extents on the passed in list from the busy extents tree.
     530             :  * If do_discard is set skip extents that need to be discarded, and mark
     531             :  * these as undergoing a discard operation instead.
     532             :  */
     533             : void
     534  5465817457 : xfs_extent_busy_clear(
     535             :         struct xfs_mount        *mp,
     536             :         struct list_head        *list,
     537             :         bool                    do_discard)
     538             : {
     539  5465817457 :         struct xfs_extent_busy  *busyp, *n;
     540  5465817457 :         struct xfs_perag        *pag = NULL;
     541  5465817457 :         xfs_agnumber_t          agno = NULLAGNUMBER;
     542  5465817457 :         bool                    wakeup = false;
     543             : 
     544  5570621612 :         list_for_each_entry_safe(busyp, n, list, list) {
     545   105868904 :                 if (busyp->agno != agno) {
     546     8338870 :                         if (pag)
     547     4363186 :                                 xfs_extent_busy_put_pag(pag, wakeup);
     548     8338870 :                         agno = busyp->agno;
     549     8338870 :                         pag = xfs_perag_get(mp, agno);
     550     8338870 :                         spin_lock(&pag->pagb_lock);
     551     8338870 :                         wakeup = false;
     552             :                 }
     553             : 
     554   105868904 :                 if (do_discard && busyp->length &&
     555         748 :                     !(busyp->flags & XFS_EXTENT_BUSY_SKIP_DISCARD)) {
     556         732 :                         busyp->flags = XFS_EXTENT_BUSY_DISCARDED;
     557             :                 } else {
     558   105868172 :                         xfs_extent_busy_clear_one(mp, pag, busyp);
     559   105868172 :                         wakeup = true;
     560             :                 }
     561             :         }
     562             : 
     563  5464752708 :         if (pag)
     564     3975684 :                 xfs_extent_busy_put_pag(pag, wakeup);
     565  5464752708 : }
     566             : 
     567             : /*
     568             :  * Flush out all busy extents for this AG.
     569             :  *
     570             :  * If the current transaction is holding busy extents, the caller may not want
     571             :  * to wait for committed busy extents to resolve. If we are being told just to
     572             :  * try a flush or progress has been made since we last skipped a busy extent,
     573             :  * return immediately to allow the caller to try again.
     574             :  *
     575             :  * If we are freeing extents, we might actually be holding the only free extents
     576             :  * in the transaction busy list and the log force won't resolve that situation.
     577             :  * In this case, we must return -EAGAIN to avoid a deadlock by informing the
     578             :  * caller it needs to commit the busy extents it holds before retrying the
     579             :  * extent free operation.
     580             :  */
     581             : int
     582      216806 : xfs_extent_busy_flush(
     583             :         struct xfs_trans        *tp,
     584             :         struct xfs_perag        *pag,
     585             :         unsigned                busy_gen,
     586             :         uint32_t                alloc_flags)
     587             : {
     588      216806 :         DEFINE_WAIT             (wait);
     589      216806 :         int                     error;
     590             : 
     591      216806 :         error = xfs_log_force(tp->t_mountp, XFS_LOG_SYNC);
     592      216928 :         if (error)
     593             :                 return error;
     594             : 
     595             :         /* Avoid deadlocks on uncommitted busy extents. */
     596      216924 :         if (!list_empty(&tp->t_busy)) {
     597          13 :                 if (alloc_flags & XFS_ALLOC_FLAG_TRYFLUSH)
     598             :                         return 0;
     599             : 
     600           0 :                 if (busy_gen != READ_ONCE(pag->pagb_gen))
     601             :                         return 0;
     602             : 
     603           0 :                 if (alloc_flags & XFS_ALLOC_FLAG_FREEING)
     604             :                         return -EAGAIN;
     605             :         }
     606             : 
     607             :         /* Wait for committed busy extents to resolve. */
     608      216913 :         do {
     609      216912 :                 prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
     610      216891 :                 if  (busy_gen != READ_ONCE(pag->pagb_gen))
     611             :                         break;
     612           1 :                 schedule();
     613             :         } while (1);
     614             : 
     615      216890 :         finish_wait(&pag->pagb_wait, &wait);
     616      216890 :         return 0;
     617             : }
     618             : 
     619             : void
     620       66825 : xfs_extent_busy_wait_all(
     621             :         struct xfs_mount        *mp)
     622             : {
     623       66825 :         struct xfs_perag        *pag;
     624       66825 :         DEFINE_WAIT             (wait);
     625       66825 :         xfs_agnumber_t          agno;
     626             : 
     627      595314 :         for_each_perag(mp, agno, pag) {
     628      528489 :                 do {
     629      528489 :                         prepare_to_wait(&pag->pagb_wait, &wait, TASK_KILLABLE);
     630      528489 :                         if  (RB_EMPTY_ROOT(&pag->pagb_tree))
     631             :                                 break;
     632           0 :                         schedule();
     633             :                 } while (1);
     634      528489 :                 finish_wait(&pag->pagb_wait, &wait);
     635             :         }
     636       66825 : }
     637             : 
     638             : /*
     639             :  * Callback for list_sort to sort busy extents by the AG they reside in.
     640             :  */
     641             : int
     642   653061480 : xfs_extent_busy_ag_cmp(
     643             :         void                    *priv,
     644             :         const struct list_head  *l1,
     645             :         const struct list_head  *l2)
     646             : {
     647   653061480 :         struct xfs_extent_busy  *b1 =
     648   653061480 :                 container_of(l1, struct xfs_extent_busy, list);
     649   653061480 :         struct xfs_extent_busy  *b2 =
     650   653061480 :                 container_of(l2, struct xfs_extent_busy, list);
     651   653061480 :         s32 diff;
     652             : 
     653   653061480 :         diff = b1->agno - b2->agno;
     654   653061480 :         if (!diff)
     655   568157619 :                 diff = b1->bno - b2->bno;
     656   653061480 :         return diff;
     657             : }
     658             : 
     659             : /* Are there any busy extents in this AG? */
     660             : bool
     661      285215 : xfs_extent_busy_list_empty(
     662             :         struct xfs_perag        *pag)
     663             : {
     664      285215 :         bool                    res;
     665             : 
     666      285215 :         spin_lock(&pag->pagb_lock);
     667      285422 :         res = RB_EMPTY_ROOT(&pag->pagb_tree);
     668      285422 :         spin_unlock(&pag->pagb_lock);
     669      285310 :         return res;
     670             : }

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