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8cd44dd1d1
When btrfs makes a block group read-only, it adds all free regions in the
block group to space_info->bytes_readonly. That free space excludes
reserved and pinned regions. OTOH, when btrfs makes the block group
read-write again, it moves all the unused regions into the block group's
zone_unusable. That unused region includes reserved and pinned regions.
As a result, it counts too much zone_unusable bytes.
Fortunately (or unfortunately), having erroneous zone_unusable does not
affect the calculation of space_info->bytes_readonly, because free
space (num_bytes in btrfs_dec_block_group_ro) calculation is done based on
the erroneous zone_unusable and it reduces the num_bytes just to cancel the
error.
This behavior can be easily discovered by adding a WARN_ON to check e.g,
"bg->pinned > 0" in btrfs_dec_block_group_ro(), and running fstests test
case like btrfs/282.
Fix it by properly considering pinned and reserved in
btrfs_dec_block_group_ro(). Also, add a WARN_ON and introduce
btrfs_space_info_update_bytes_zone_unusable() to catch a similar mistake.
Fixes:
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||
|---|---|---|
| .. | ||
| events | ||
| misc | ||
| stages | ||
| bpf_probe.h | ||
| define_custom_trace.h | ||
| define_trace.h | ||
| perf.h | ||
| syscall.h | ||
| trace_custom_events.h | ||
| trace_events.h | ||