[03/16] xfs: finobt AG reserves don't consider last AG can be a runt
diff mbox series

Message ID 20181107063127.3902-4-david@fromorbit.com
State Accepted
Headers show
Series
  • xfs: Block size > PAGE_SIZE support
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Commit Message

Dave Chinner Nov. 7, 2018, 6:31 a.m. UTC
From: Dave Chinner <dchinner@redhat.com>

The last AG may be very small comapred to all other AGs, and hence
AG reservations based on the superblock AG size may actually consume
more space than the AG actually has. This results on assert failures
like:

XFS: Assertion failed: xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved + xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <= pag->pagf_freeblks + pag->pagf_flcount, file: fs/xfs/libxfs/xfs_ag_resv.c, line: 319
[   48.932891]  xfs_ag_resv_init+0x1bd/0x1d0
[   48.933853]  xfs_fs_reserve_ag_blocks+0x37/0xb0
[   48.934939]  xfs_mountfs+0x5b3/0x920
[   48.935804]  xfs_fs_fill_super+0x462/0x640
[   48.936784]  ? xfs_test_remount_options+0x60/0x60
[   48.937908]  mount_bdev+0x178/0x1b0
[   48.938751]  mount_fs+0x36/0x170
[   48.939533]  vfs_kern_mount.part.43+0x54/0x130
[   48.940596]  do_mount+0x20e/0xcb0
[   48.941396]  ? memdup_user+0x3e/0x70
[   48.942249]  ksys_mount+0xba/0xd0
[   48.943046]  __x64_sys_mount+0x21/0x30
[   48.943953]  do_syscall_64+0x54/0x170
[   48.944835]  entry_SYSCALL_64_after_hwframe+0x49/0xbe

Hence we need to ensure the finobt per-ag space reservations take
into account the size of the last AG rather than treat it like all
the other full size AGs.

Note that both refcountbt and rmapbt already take the size of the AG
into account via reading the AGF length directly.

Signed-off-by: Dave Chinner <dchinner@redhat.com>
---
 fs/xfs/libxfs/xfs_ialloc_btree.c | 17 +++++++++++++----
 1 file changed, 13 insertions(+), 4 deletions(-)

Comments

Darrick J. Wong Nov. 7, 2018, 4:55 p.m. UTC | #1
On Wed, Nov 07, 2018 at 05:31:14PM +1100, Dave Chinner wrote:
> From: Dave Chinner <dchinner@redhat.com>
> 
> The last AG may be very small comapred to all other AGs, and hence
> AG reservations based on the superblock AG size may actually consume
> more space than the AG actually has. This results on assert failures
> like:
> 
> XFS: Assertion failed: xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved + xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <= pag->pagf_freeblks + pag->pagf_flcount, file: fs/xfs/libxfs/xfs_ag_resv.c, line: 319
> [   48.932891]  xfs_ag_resv_init+0x1bd/0x1d0
> [   48.933853]  xfs_fs_reserve_ag_blocks+0x37/0xb0
> [   48.934939]  xfs_mountfs+0x5b3/0x920
> [   48.935804]  xfs_fs_fill_super+0x462/0x640
> [   48.936784]  ? xfs_test_remount_options+0x60/0x60
> [   48.937908]  mount_bdev+0x178/0x1b0
> [   48.938751]  mount_fs+0x36/0x170
> [   48.939533]  vfs_kern_mount.part.43+0x54/0x130
> [   48.940596]  do_mount+0x20e/0xcb0
> [   48.941396]  ? memdup_user+0x3e/0x70
> [   48.942249]  ksys_mount+0xba/0xd0
> [   48.943046]  __x64_sys_mount+0x21/0x30
> [   48.943953]  do_syscall_64+0x54/0x170
> [   48.944835]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> 
> Hence we need to ensure the finobt per-ag space reservations take
> into account the size of the last AG rather than treat it like all
> the other full size AGs.
> 
> Note that both refcountbt and rmapbt already take the size of the AG
> into account via reading the AGF length directly.
> 
> Signed-off-by: Dave Chinner <dchinner@redhat.com>
> ---
>  fs/xfs/libxfs/xfs_ialloc_btree.c | 17 +++++++++++++----
>  1 file changed, 13 insertions(+), 4 deletions(-)
> 
> diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
> index 86c50208a143..62014780d5e4 100644
> --- a/fs/xfs/libxfs/xfs_ialloc_btree.c
> +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
> @@ -538,15 +538,24 @@ xfs_inobt_rec_check_count(
>  
>  static xfs_extlen_t
>  xfs_inobt_max_size(
> -	struct xfs_mount	*mp)
> +	struct xfs_mount	*mp,
> +	xfs_agnumber_t		agno)
>  {
> +	uint32_t		agblocks = mp->m_sb.sb_agblocks;
> +
>  	/* Bail out if we're uninitialized, which can happen in mkfs. */
>  	if (mp->m_inobt_mxr[0] == 0)
>  		return 0;
>  
> +	/* last AG can be a runt */
> +	if (agno == mp->m_sb.sb_agcount - 1) {
> +		div_u64_rem(mp->m_sb.sb_dblocks, mp->m_sb.sb_agblocks,
> +				&agblocks);
> +	}

Why not: agblocks = xfs_ag_block_count(mp, agno); ?

--D

> +
>  	return xfs_btree_calc_size(mp->m_inobt_mnr,
> -		(uint64_t)mp->m_sb.sb_agblocks * mp->m_sb.sb_inopblock /
> -				XFS_INODES_PER_CHUNK);
> +				(uint64_t)agblocks * mp->m_sb.sb_inopblock /
> +					XFS_INODES_PER_CHUNK);
>  }
>  
>  static int
> @@ -594,7 +603,7 @@ xfs_finobt_calc_reserves(
>  	if (error)
>  		return error;
>  
> -	*ask += xfs_inobt_max_size(mp);
> +	*ask += xfs_inobt_max_size(mp, agno);
>  	*used += tree_len;
>  	return 0;
>  }
> -- 
> 2.19.1
>
Dave Chinner Nov. 9, 2018, 12:21 a.m. UTC | #2
On Wed, Nov 07, 2018 at 08:55:08AM -0800, Darrick J. Wong wrote:
> On Wed, Nov 07, 2018 at 05:31:14PM +1100, Dave Chinner wrote:
> > From: Dave Chinner <dchinner@redhat.com>
> > 
> > The last AG may be very small comapred to all other AGs, and hence
> > AG reservations based on the superblock AG size may actually consume
> > more space than the AG actually has. This results on assert failures
> > like:
> > 
> > XFS: Assertion failed: xfs_perag_resv(pag, XFS_AG_RESV_METADATA)->ar_reserved + xfs_perag_resv(pag, XFS_AG_RESV_RMAPBT)->ar_reserved <= pag->pagf_freeblks + pag->pagf_flcount, file: fs/xfs/libxfs/xfs_ag_resv.c, line: 319
> > [   48.932891]  xfs_ag_resv_init+0x1bd/0x1d0
> > [   48.933853]  xfs_fs_reserve_ag_blocks+0x37/0xb0
> > [   48.934939]  xfs_mountfs+0x5b3/0x920
> > [   48.935804]  xfs_fs_fill_super+0x462/0x640
> > [   48.936784]  ? xfs_test_remount_options+0x60/0x60
> > [   48.937908]  mount_bdev+0x178/0x1b0
> > [   48.938751]  mount_fs+0x36/0x170
> > [   48.939533]  vfs_kern_mount.part.43+0x54/0x130
> > [   48.940596]  do_mount+0x20e/0xcb0
> > [   48.941396]  ? memdup_user+0x3e/0x70
> > [   48.942249]  ksys_mount+0xba/0xd0
> > [   48.943046]  __x64_sys_mount+0x21/0x30
> > [   48.943953]  do_syscall_64+0x54/0x170
> > [   48.944835]  entry_SYSCALL_64_after_hwframe+0x49/0xbe
> > 
> > Hence we need to ensure the finobt per-ag space reservations take
> > into account the size of the last AG rather than treat it like all
> > the other full size AGs.
> > 
> > Note that both refcountbt and rmapbt already take the size of the AG
> > into account via reading the AGF length directly.
> > 
> > Signed-off-by: Dave Chinner <dchinner@redhat.com>
> > ---
> >  fs/xfs/libxfs/xfs_ialloc_btree.c | 17 +++++++++++++----
> >  1 file changed, 13 insertions(+), 4 deletions(-)
> > 
> > diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
> > index 86c50208a143..62014780d5e4 100644
> > --- a/fs/xfs/libxfs/xfs_ialloc_btree.c
> > +++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
> > @@ -538,15 +538,24 @@ xfs_inobt_rec_check_count(
> >  
> >  static xfs_extlen_t
> >  xfs_inobt_max_size(
> > -	struct xfs_mount	*mp)
> > +	struct xfs_mount	*mp,
> > +	xfs_agnumber_t		agno)
> >  {
> > +	uint32_t		agblocks = mp->m_sb.sb_agblocks;
> > +
> >  	/* Bail out if we're uninitialized, which can happen in mkfs. */
> >  	if (mp->m_inobt_mxr[0] == 0)
> >  		return 0;
> >  
> > +	/* last AG can be a runt */
> > +	if (agno == mp->m_sb.sb_agcount - 1) {
> > +		div_u64_rem(mp->m_sb.sb_dblocks, mp->m_sb.sb_agblocks,
> > +				&agblocks);
> > +	}
> 
> Why not: agblocks = xfs_ag_block_count(mp, agno); ?
> 

forgot about that function :)

Will fix.

Cheers,

Dave.

Patch
diff mbox series

diff --git a/fs/xfs/libxfs/xfs_ialloc_btree.c b/fs/xfs/libxfs/xfs_ialloc_btree.c
index 86c50208a143..62014780d5e4 100644
--- a/fs/xfs/libxfs/xfs_ialloc_btree.c
+++ b/fs/xfs/libxfs/xfs_ialloc_btree.c
@@ -538,15 +538,24 @@  xfs_inobt_rec_check_count(
 
 static xfs_extlen_t
 xfs_inobt_max_size(
-	struct xfs_mount	*mp)
+	struct xfs_mount	*mp,
+	xfs_agnumber_t		agno)
 {
+	uint32_t		agblocks = mp->m_sb.sb_agblocks;
+
 	/* Bail out if we're uninitialized, which can happen in mkfs. */
 	if (mp->m_inobt_mxr[0] == 0)
 		return 0;
 
+	/* last AG can be a runt */
+	if (agno == mp->m_sb.sb_agcount - 1) {
+		div_u64_rem(mp->m_sb.sb_dblocks, mp->m_sb.sb_agblocks,
+				&agblocks);
+	}
+
 	return xfs_btree_calc_size(mp->m_inobt_mnr,
-		(uint64_t)mp->m_sb.sb_agblocks * mp->m_sb.sb_inopblock /
-				XFS_INODES_PER_CHUNK);
+				(uint64_t)agblocks * mp->m_sb.sb_inopblock /
+					XFS_INODES_PER_CHUNK);
 }
 
 static int
@@ -594,7 +603,7 @@  xfs_finobt_calc_reserves(
 	if (error)
 		return error;
 
-	*ask += xfs_inobt_max_size(mp);
+	*ask += xfs_inobt_max_size(mp, agno);
 	*used += tree_len;
 	return 0;
 }