diff options
| author | Christoph Hellwig <hch@lst.de> | 2026-01-27 16:10:20 +0100 |
|---|---|---|
| committer | Carlos Maiolino <cem@kernel.org> | 2026-01-29 10:57:18 +0100 |
| commit | c17a1c03493bee4e7882ac79a52b8150cb464e56 (patch) | |
| tree | 033266e671f9fdf24daa6b04fa104a8a170ddd00 | |
| parent | 692243cac63195ba38512a86bdb47b9c3190716b (diff) | |
xfs: use a seprate member to track space availabe in the GC scatch buffer
When scratch_head wraps back to 0 and scratch_tail is also 0 because no
I/O has completed yet, the ring buffer could be mistaken for empty.
Fix this by introducing a separate scratch_available member in
struct xfs_zone_gc_data. This actually ends up simplifying the code as
well.
Reported-by: Chris Mason <clm@meta.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
| -rw-r--r-- | fs/xfs/xfs_zone_gc.c | 25 |
1 files changed, 9 insertions, 16 deletions
diff --git a/fs/xfs/xfs_zone_gc.c b/fs/xfs/xfs_zone_gc.c index dfa6653210c7..8c08e5519bff 100644 --- a/fs/xfs/xfs_zone_gc.c +++ b/fs/xfs/xfs_zone_gc.c @@ -131,10 +131,13 @@ struct xfs_zone_gc_data { /* * Scratchpad to buffer GC data, organized as a ring buffer over * discontiguous folios. scratch_head is where the buffer is filled, - * and scratch_tail tracks the buffer space freed. + * scratch_tail tracks the buffer space freed, and scratch_available + * counts the space available in the ring buffer between the head and + * the tail. */ struct folio *scratch_folios[XFS_GC_NR_BUFS]; unsigned int scratch_size; + unsigned int scratch_available; unsigned int scratch_head; unsigned int scratch_tail; @@ -212,6 +215,7 @@ xfs_zone_gc_data_alloc( goto out_free_scratch; } data->scratch_size = XFS_GC_BUF_SIZE * XFS_GC_NR_BUFS; + data->scratch_available = data->scratch_size; INIT_LIST_HEAD(&data->reading); INIT_LIST_HEAD(&data->writing); INIT_LIST_HEAD(&data->resetting); @@ -574,18 +578,6 @@ xfs_zone_gc_ensure_target( return oz; } -static unsigned int -xfs_zone_gc_scratch_available( - struct xfs_zone_gc_data *data) -{ - if (!data->scratch_tail) - return data->scratch_size - data->scratch_head; - - if (!data->scratch_head) - return data->scratch_tail; - return (data->scratch_size - data->scratch_head) + data->scratch_tail; -} - static bool xfs_zone_gc_space_available( struct xfs_zone_gc_data *data) @@ -596,7 +588,7 @@ xfs_zone_gc_space_available( if (!oz) return false; return oz->oz_allocated < rtg_blocks(oz->oz_rtg) && - xfs_zone_gc_scratch_available(data); + data->scratch_available; } static void @@ -625,8 +617,7 @@ xfs_zone_gc_alloc_blocks( if (!oz) return NULL; - *count_fsb = min(*count_fsb, - XFS_B_TO_FSB(mp, xfs_zone_gc_scratch_available(data))); + *count_fsb = min(*count_fsb, XFS_B_TO_FSB(mp, data->scratch_available)); /* * Directly allocate GC blocks from the reserved pool. @@ -730,6 +721,7 @@ xfs_zone_gc_start_chunk( bio->bi_end_io = xfs_zone_gc_end_io; xfs_zone_gc_add_data(chunk); data->scratch_head = (data->scratch_head + len) % data->scratch_size; + data->scratch_available -= len; WRITE_ONCE(chunk->state, XFS_GC_BIO_NEW); list_add_tail(&chunk->entry, &data->reading); @@ -862,6 +854,7 @@ xfs_zone_gc_finish_chunk( data->scratch_tail = (data->scratch_tail + chunk->len) % data->scratch_size; + data->scratch_available += chunk->len; /* * Cycle through the iolock and wait for direct I/O and layouts to |