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xfs: introduce in-core global counter of allocbt blocks 

Introduce an in-core counter to track the sum of all allocbt blocks
used by the filesystem. This value is currently tracked per-ag via
the ->agf_btreeblks field in the AGF, which also happens to include
rmapbt blocks. A global, in-core count of allocbt blocks is required
to identify the subset of global ->m_fdblocks that consists of
unavailable blocks currently used for allocation btrees. To support
this calculation at block reservation time, construct a similar
global counter for allocbt blocks, populate it on first read of each
AGF and update it as allocbt blocks are used and released.

Signed-off-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Allison Henderson <allison.henderson@oracle.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
This commit is contained in:
Brian Foster 2021-04-28 15:05:50 -07:00 committed by Darrick J. Wong
parent 2675ad3890
commit 16eaab839a
3 changed files with 22 additions and 0 deletions
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14
fs/xfs/libxfs/xfs_alloc.c
View File

@ -3033,6 +3033,7 @@ xfs_alloc_read_agf(
struct xfs_agf *agf; /* ag freelist header */
struct xfs_perag *pag; /* per allocation group data */
int error;
int allocbt_blks;
trace_xfs_alloc_read_agf(mp, agno);
@ -3063,6 +3064,19 @@ xfs_alloc_read_agf(
pag->pagf_refcount_level = be32_to_cpu(agf->agf_refcount_level);
pag->pagf_init = 1;
pag->pagf_agflreset = xfs_agfl_needs_reset(mp, agf);
/*
* Update the in-core allocbt counter. Filter out the rmapbt
* subset of the btreeblks counter because the rmapbt is managed
* by perag reservation. Subtract one for the rmapbt root block
* because the rmap counter includes it while the btreeblks
* counter only tracks non-root blocks.
*/
allocbt_blks = pag->pagf_btreeblks;
if (xfs_sb_version_hasrmapbt(&mp->m_sb))
allocbt_blks -= be32_to_cpu(agf->agf_rmap_blocks) - 1;
if (allocbt_blks > 0)
atomic64_add(allocbt_blks, &mp->m_allocbt_blks);
}
#ifdef DEBUG
else if (!XFS_FORCED_SHUTDOWN(mp)) {

2
fs/xfs/libxfs/xfs_alloc_btree.c
View File

@ -71,6 +71,7 @@ xfs_allocbt_alloc_block(
return 0;
}
atomic64_inc(&cur->bc_mp->m_allocbt_blks);
xfs_extent_busy_reuse(cur->bc_mp, cur->bc_ag.agno, bno, 1, false);
new->s = cpu_to_be32(bno);
@ -94,6 +95,7 @@ xfs_allocbt_free_block(
if (error)
return error;
atomic64_dec(&cur->bc_mp->m_allocbt_blks);
xfs_extent_busy_insert(cur->bc_tp, be32_to_cpu(agf->agf_seqno), bno, 1,
XFS_EXTENT_BUSY_SKIP_DISCARD);
return 0;

6
fs/xfs/xfs_mount.h
View File

@ -170,6 +170,12 @@ typedef struct xfs_mount {
* extents or anything related to the rt device.
*/
struct percpu_counter m_delalloc_blks;
/*
* Global count of allocation btree blocks in use across all AGs. Only
* used when perag reservation is enabled. Helps prevent block
* reservation from attempting to reserve allocation btree blocks.
*/
atomic64_t m_allocbt_blks;
struct radix_tree_root m_perag_tree; /* per-ag accounting info */
spinlock_t m_perag_lock; /* lock for m_perag_tree */