Although commit e6c4efd87ab0 ("btrfs: Fix and enhance merge_extent_mapping() to insert best fitted extent map") fixed up the negetive em->len, it has introduced several regressions, several has been fixed by
commit 32be3a1ac6d0 ("btrfs: Fix the wrong condition judgment about subset extent map"), commit 8dff9c853410 ("Btrfs: deal with duplciates during extent_map insertion in btrfs_get_extent") and commit 8e2bd3b7fac9 ("Btrfs: deal with existing encompassing extent map in btrfs_get_extent()"). Unfortunately, there is one more regression which is caught recently by a user's workloads. While debugging the above issue, I found that all of these bugs are caused by some racy situations, which can be very tricky to reproduce, so I created several extent map specific test cases in btrfs's selftest framework. Patch 1-2 are fixing two bugs. Patch 3-4 are some preparatory work. Patch 3-5 are regression tests about the logic of handling EEXIST from adding extent map. Patch 8-10 are debugging wise, one is a direct tracepoint and the other is to enable kprobe on merge_extent_mapping. v2: - Improve commit log to provide more details about the bug. - Adjust bugfixes to the front so that we can merge them firstly. Liu Bo (10): Btrfs: fix incorrect block_len in merge_extent_mapping Btrfs: fix unexpected EEXIST from btrfs_get_extent Btrfs: add helper for em merge logic Btrfs: move extent map specific code to extent_map.c Btrfs: add extent map selftests Btrfs: extent map selftest: buffered write vs dio read Btrfs: extent map selftest: dio write vs dio read Btrfs: add WARN_ONCE to detect unexpected error from merge_extent_mapping Btrfs: add tracepoint for em's EEXIST case Btrfs: noinline merge_extent_mapping fs/btrfs/Makefile | 2 +- fs/btrfs/extent_map.c | 134 ++++++++++++++ fs/btrfs/extent_map.h | 2 + fs/btrfs/inode.c | 108 +----------- fs/btrfs/tests/btrfs-tests.c | 3 + fs/btrfs/tests/btrfs-tests.h | 1 + fs/btrfs/tests/extent-map-tests.c | 363 ++++++++++++++++++++++++++++++++++++++ include/trace/events/btrfs.h | 35 ++++ 8 files changed, 540 insertions(+), 108 deletions(-) create mode 100644 fs/btrfs/tests/extent-map-tests.c -- 2.9.4 -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html