6.15-stable review patch. If anyone has any objections, please let me know.
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From: Christoph Hellwig hch@lst.de
commit 5948705adbf1a7afcecfe9a13ff39221ef61e16b upstream.
Busy extent tracking is primarily used to ensure that freed blocks are not reused for data allocations before the transaction that deleted them has been committed to stable storage, and secondarily to drive online discard. None of the use cases applies to zoned RTGs, as the zoned allocator can't overwrite blocks before resetting the zone, which already flushes out all transactions touching the RTGs.
So the busy extent tracking is not needed for zoned RTGs, and also not called for zoned RTGs. But somehow the code to skip allocating and freeing the structure got lost during the zoned XFS upstreaming process. This not only causes these structures to unnecessarily allocated, but can also lead to memory leaks as the xg_busy_extents pointer in the xfs_group structure is overlayed with the pointer for the linked list of to be reset zones.
Stop allocating and freeing the structure to not pointlessly allocate memory which is then leaked when the zone is reset.
Fixes: 080d01c41d44 ("xfs: implement zoned garbage collection") Signed-off-by: Christoph Hellwig hch@lst.de Cc: stable@vger.kernel.org # v6.15 [cem: Fix type and add stable tag] Reviewed-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Carlos Maiolino cem@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- fs/xfs/libxfs/xfs_group.c | 14 +++++++++----- fs/xfs/xfs_extent_busy.h | 8 ++++++++ 2 files changed, 17 insertions(+), 5 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_group.c b/fs/xfs/libxfs/xfs_group.c index e9d76bcdc820..20ad7c309489 100644 --- a/fs/xfs/libxfs/xfs_group.c +++ b/fs/xfs/libxfs/xfs_group.c @@ -163,7 +163,8 @@ xfs_group_free(
xfs_defer_drain_free(&xg->xg_intents_drain); #ifdef __KERNEL__ - kfree(xg->xg_busy_extents); + if (xfs_group_has_extent_busy(xg->xg_mount, xg->xg_type)) + kfree(xg->xg_busy_extents); #endif
if (uninit) @@ -189,9 +190,11 @@ xfs_group_insert( xg->xg_type = type;
#ifdef __KERNEL__ - xg->xg_busy_extents = xfs_extent_busy_alloc(); - if (!xg->xg_busy_extents) - return -ENOMEM; + if (xfs_group_has_extent_busy(mp, type)) { + xg->xg_busy_extents = xfs_extent_busy_alloc(); + if (!xg->xg_busy_extents) + return -ENOMEM; + } spin_lock_init(&xg->xg_state_lock); xfs_hooks_init(&xg->xg_rmap_update_hooks); #endif @@ -210,7 +213,8 @@ xfs_group_insert( out_drain: xfs_defer_drain_free(&xg->xg_intents_drain); #ifdef __KERNEL__ - kfree(xg->xg_busy_extents); + if (xfs_group_has_extent_busy(xg->xg_mount, xg->xg_type)) + kfree(xg->xg_busy_extents); #endif return error; } diff --git a/fs/xfs/xfs_extent_busy.h b/fs/xfs/xfs_extent_busy.h index f069b04e8ea1..3e6e019b6146 100644 --- a/fs/xfs/xfs_extent_busy.h +++ b/fs/xfs/xfs_extent_busy.h @@ -68,4 +68,12 @@ static inline void xfs_extent_busy_sort(struct list_head *list) list_sort(NULL, list, xfs_extent_busy_ag_cmp); }
+/* + * Zoned RTGs don't need to track busy extents, as the actual block freeing only + * happens by a zone reset, which forces out all transactions that touched the + * to be reset zone first. + */ +#define xfs_group_has_extent_busy(mp, type) \ + ((type) == XG_TYPE_AG || !xfs_has_zoned((mp))) + #endif /* __XFS_EXTENT_BUSY_H__ */