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authorLinus Torvalds <torvalds@linux-foundation.org>2023-06-02 17:25:22 -0400
committerLinus Torvalds <torvalds@linux-foundation.org>2023-06-02 17:25:22 -0400
commit6d7d0603ca7c397a07efc88e314e38b4242a3a8d (patch)
treedb8072825fd71da64117fbf9cf056af65dcf061d
parente0178b546d24f42a85f4d4da080fb801e0d49107 (diff)
parent3582e74599d376bc18cae123045cd295360d885b (diff)
downloadiio-6d7d0603ca7c397a07efc88e314e38b4242a3a8d.tar.gz
Merge tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4
Pull ext4 fix from Ted Ts'o: "Fix an ext4 regression which landed during the 6.4 merge window" * tag 'ext4_for_linus_stable' of git://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4: Revert "ext4: remove ac->ac_found > sbi->s_mb_min_to_scan dead check in ext4_mb_check_limits"
-rw-r--r--fs/ext4/mballoc.c16
1 files changed, 15 insertions, 1 deletions
diff --git a/fs/ext4/mballoc.c b/fs/ext4/mballoc.c
index 7b2e36d103cb10..20f67a260df504 100644
--- a/fs/ext4/mballoc.c
+++ b/fs/ext4/mballoc.c
@@ -2062,7 +2062,7 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
if (bex->fe_len < gex->fe_len)
return;
- if (finish_group)
+ if (finish_group || ac->ac_found > sbi->s_mb_min_to_scan)
ext4_mb_use_best_found(ac, e4b);
}
@@ -2074,6 +2074,20 @@ static void ext4_mb_check_limits(struct ext4_allocation_context *ac,
* in the context. Later, the best found extent will be used, if
* mballoc can't find good enough extent.
*
+ * The algorithm used is roughly as follows:
+ *
+ * * If free extent found is exactly as big as goal, then
+ * stop the scan and use it immediately
+ *
+ * * If free extent found is smaller than goal, then keep retrying
+ * upto a max of sbi->s_mb_max_to_scan times (default 200). After
+ * that stop scanning and use whatever we have.
+ *
+ * * If free extent found is bigger than goal, then keep retrying
+ * upto a max of sbi->s_mb_min_to_scan times (default 10) before
+ * stopping the scan and using the extent.
+ *
+ *
* FIXME: real allocation policy is to be designed yet!
*/
static void ext4_mb_measure_extent(struct ext4_allocation_context *ac,