diff options
| author | Christoph Hellwig <hch@lst.de> | 2025-10-23 17:17:03 +0200 |
|---|---|---|
| committer | Carlos Maiolino <cem@kernel.org> | 2025-10-31 12:06:03 +0100 |
| commit | 0db22d7ee462c42c1284e98d47840932792c1adb (patch) | |
| tree | fe37b798ef67300c30521a5a69e1172b532ba675 /fs/xfs/xfs_zone_alloc.c | |
| parent | 83bac569c762651ac6dff9a86f54ecc13d911f7d (diff) | |
xfs: document another racy GC case in xfs_zoned_map_extent
Besides blocks being invalidated, there is another case when the original
mapping could have changed between querying the rmap for GC and calling
xfs_zoned_map_extent. Document it there as it took us quite some time
to figure out what is going on while developing the multiple-GC
protection fix.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Hans Holmberg <hans.holmberg@wdc.com>
Reviewed-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>
Reviewed-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Carlos Maiolino <cem@kernel.org>
Diffstat (limited to 'fs/xfs/xfs_zone_alloc.c')
| -rw-r--r-- | fs/xfs/xfs_zone_alloc.c | 8 |
1 files changed, 8 insertions, 0 deletions
diff --git a/fs/xfs/xfs_zone_alloc.c b/fs/xfs/xfs_zone_alloc.c index 23cdab4515bb..040402240807 100644 --- a/fs/xfs/xfs_zone_alloc.c +++ b/fs/xfs/xfs_zone_alloc.c @@ -246,6 +246,14 @@ xfs_zoned_map_extent( * If a data write raced with this GC write, keep the existing data in * the data fork, mark our newly written GC extent as reclaimable, then * move on to the next extent. + * + * Note that this can also happen when racing with operations that do + * not actually invalidate the data, but just move it to a different + * inode (XFS_IOC_EXCHANGE_RANGE), or to a different offset inside the + * inode (FALLOC_FL_COLLAPSE_RANGE / FALLOC_FL_INSERT_RANGE). If the + * data was just moved around, GC fails to free the zone, but the zone + * becomes a GC candidate again as soon as all previous GC I/O has + * finished and these blocks will be moved out eventually. */ if (old_startblock != NULLFSBLOCK && old_startblock != data.br_startblock) |