From: Filipe Manana Date: Thu, 17 Apr 2025 15:44:34 +0000 (+0100) Subject: btrfs: avoid repeated extent state processing when converting extent bits X-Git-Tag: block-6.16-20250606~42^2~66 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=eeb808422f9be2ca8ba30c0ef1d68f04c7654d87;p=linux-block.git btrfs: avoid repeated extent state processing when converting extent bits When converting bits for an extent range, if we find an extent state with its start offset greater than current start offset, we insert a new extent state to cover the gap, with its end offset computed and stored in the @this_end local variable, and after the insertion we update the current start offset to @this_end + 1. However if the insert_state() call resulted in an extent state merge then the end offset of the merged extent may be greater than @this_end and if that's the case, since we jump to the 'search_again' label, we'll do a full tree search that will leave us in the same extent state - this is harmless but wastes time by doing a pointless tree search and extent state processing. So improve on this by updating the current start offset to the end offset of the inserted state plus 1. This also removes the use of the @this_end variable and directly set the value in the prealloc extent state to avoid any confusion and misuse in the future. Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba --- diff --git a/fs/btrfs/extent-io-tree.c b/fs/btrfs/extent-io-tree.c index d8d65a6a6cb1..14383f92c381 100644 --- a/fs/btrfs/extent-io-tree.c +++ b/fs/btrfs/extent-io-tree.c @@ -1428,14 +1428,8 @@ hit_next: * extent we found. */ if (state->start > start) { - u64 this_end; struct extent_state *inserted_state; - if (end < last_start) - this_end = end; - else - this_end = last_start - 1; - prealloc = alloc_extent_state_atomic(prealloc); if (!prealloc) { ret = -ENOMEM; @@ -1447,7 +1441,11 @@ hit_next: * extent. */ prealloc->start = start; - prealloc->end = this_end; + if (end < last_start) + prealloc->end = end; + else + prealloc->end = last_start - 1; + inserted_state = insert_state(tree, prealloc, bits, NULL); if (IS_ERR(inserted_state)) { ret = PTR_ERR(inserted_state); @@ -1457,7 +1455,7 @@ hit_next: cache_state(inserted_state, cached_state); if (inserted_state == prealloc) prealloc = NULL; - start = this_end + 1; + start = inserted_state->end + 1; goto search_again; } /*