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xfs: try any AG when allocating the first btree block when reflinking

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When a reflink operation causes the bmap code to allocate a btree block
we're currently doing single-AG allocations due to having ->firstblock
set and then try any higher AG due a little reflink quirk we've put in
when adding the reflink code.  But given that we do not have a minleft
reservation of any kind in this AG we can still not have any space in
the same or higher AG even if the file system has enough free space.
To fix this use a XFS_ALLOCTYPE_FIRST_AG allocation in this fall back
path instead.

[And yes, we need to redo this properly instead of piling hacks over
 hacks.  I'm working on that, but it's not going to be a small series.
 In the meantime this fixes the customer reported issue]

Also add a warning for failing allocations to make it easier to debug.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
This commit is contained in:
Christoph Hellwig 2017-03-08 10:38:53 -08:00 committed by Darrick J. Wong
parent f65e6fad29
commit 2fcc319d24
2 changed files with 10 additions and 6 deletions
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10
fs/xfs/libxfs/xfs_bmap.c
View File

@ -763,8 +763,8 @@ xfs_bmap_extents_to_btree(
args.type = XFS_ALLOCTYPE_START_BNO;
args.fsbno = XFS_INO_TO_FSB(mp, ip->i_ino);
} else if (dfops->dop_low) {
try_another_ag:
args.type = XFS_ALLOCTYPE_START_BNO;
try_another_ag:
args.fsbno = *firstblock;
} else {
args.type = XFS_ALLOCTYPE_NEAR_BNO;
@ -790,13 +790,17 @@ try_another_ag:
if (xfs_sb_version_hasreflink(&cur->bc_mp->m_sb) &&
args.fsbno == NULLFSBLOCK &&
args.type == XFS_ALLOCTYPE_NEAR_BNO) {
dfops->dop_low = true;
args.type = XFS_ALLOCTYPE_FIRST_AG;
goto try_another_ag;
}
if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
xfs_iroot_realloc(ip, -1, whichfork);
xfs_btree_del_cursor(cur, XFS_BTREE_ERROR);
return -ENOSPC;
}
/*
* Allocation can't fail, the space was reserved.
*/
ASSERT(args.fsbno != NULLFSBLOCK);
ASSERT(*firstblock == NULLFSBLOCK ||
args.agno >= XFS_FSB_TO_AGNO(mp, *firstblock));
*firstblock = cur->bc_private.b.firstblock = args.fsbno;

6
fs/xfs/libxfs/xfs_bmap_btree.c
View File

@ -447,8 +447,8 @@ xfs_bmbt_alloc_block(
if (args.fsbno == NULLFSBLOCK) {
args.fsbno = be64_to_cpu(start->l);
try_another_ag:
args.type = XFS_ALLOCTYPE_START_BNO;
try_another_ag:
/*
* Make sure there is sufficient room left in the AG to
* complete a full tree split for an extent insert. If
@ -488,8 +488,8 @@ try_another_ag:
if (xfs_sb_version_hasreflink(&cur->bc_mp->m_sb) &&
args.fsbno == NULLFSBLOCK &&
args.type == XFS_ALLOCTYPE_NEAR_BNO) {
cur->bc_private.b.dfops->dop_low = true;
args.fsbno = cur->bc_private.b.firstblock;
args.type = XFS_ALLOCTYPE_FIRST_AG;
goto try_another_ag;
}
@ -506,7 +506,7 @@ try_another_ag:
goto error0;
cur->bc_private.b.dfops->dop_low = true;
}
if (args.fsbno == NULLFSBLOCK) {
if (WARN_ON_ONCE(args.fsbno == NULLFSBLOCK)) {
XFS_BTREE_TRACE_CURSOR(cur, XBT_EXIT);
*stat = 0;
return 0;