kernel/linux.git/fs/ext4/balloc.c, branch v6.1

ext4: use ext4_debug() instead of jbd_debug()

2022-08-03T03:52:19+00:00

We use jbd_debug() in some places in ext4. It seems a bit strange to use jbd2 debugging output function for ext4 code. Also these days ext4_debug() uses dynamic printk so each debug message can be enabled / disabled on its own so the time when it made some sense to have these combined (to allow easier common selecting of messages to report) has passed. Just convert all jbd_debug() uses in ext4 to ext4_debug(). Signed-off-by: Jan Kara Reviewed-by: Lukas Czerner Link: https://lore.kernel.org/r/20220608112355.4397-1-jack@suse.cz Signed-off-by: Theodore Ts'o

ext4: fix kernel doc warnings

2022-03-15T21:45:36+00:00

Signed-off-by: Theodore Ts'o

ext4: flush background discard kwork when retry allocation

2021-08-31T03:35:53+00:00

The background discard kwork tries to mark blocks used and issue discard. This can make filesystem suffer from NOSPC error, xfstest generic/371 can fail due to it. Fix it by flushing discard kwork in ext4_should_retry_alloc. At the same time, give up discard at the moment. Signed-off-by: Wang Jianchao Link: https://lore.kernel.org/r/20210830075246.12516-6-jianchao.wan9@gmail.com Signed-off-by: Theodore Ts'o

ext4: fix trailing whitespace

2021-04-10T03:24:52+00:00

Made suggested modifications from checkpatch in reference to ERROR: trailing whitespace Signed-off-by: Jack Qiu Reviewed-by: Ritesh Harjani Link: https://lore.kernel.org/r/20210409042035.15516-1-jack.qiu@huawei.com Signed-off-by: Theodore Ts'o

ext4: shrink race window in ext4_should_retry_alloc()

2021-03-06T16:56:10+00:00

When generic/371 is run on kvm-xfstests using 5.10 and 5.11 kernels, it fails at significant rates on the two test scenarios that disable delayed allocation (ext3conv and data_journal) and force actual block allocation for the fallocate and pwrite functions in the test. The failure rate on 5.10 for both ext3conv and data_journal on one test system typically runs about 85%. On 5.11, the failure rate on ext3conv sometimes drops to as low as 1% while the rate on data_journal increases to nearly 100%. The observed failures are largely due to ext4_should_retry_alloc() cutting off block allocation retries when s_mb_free_pending (used to indicate that a transaction in progress will free blocks) is 0. However, free space is usually available when this occurs during runs of generic/371. It appears that a thread attempting to allocate blocks is just missing transaction commits in other threads that increase the free cluster count and reset s_mb_free_pending while the allocating thread isn't running. Explicitly testing for free space availability avoids this race. The current code uses a post-increment operator in the conditional expression that determines whether the retry limit has been exceeded. This means that the conditional expression uses the value of the retry counter before it's increased, resulting in an extra retry cycle. The current code actually retries twice before hitting its retry limit rather than once. Increasing the retry limit to 3 from the current actual maximum retry count of 2 in combination with the change described above reduces the observed failure rate to less that 0.1% on both ext3conv and data_journal with what should be limited impact on users sensitive to the overhead caused by retries. A per filesystem percpu counter exported via sysfs is added to allow users or developers to track the number of times the retry limit is exceeded without resorting to debugging methods. This should provide some insight into worst case retry behavior. Signed-off-by: Eric Whitney Link: https://lore.kernel.org/r/20210218151132.19678-1-enwlinux@gmail.com Signed-off-by: Theodore Ts'o

ext4: use ASSERT() to replace J_ASSERT()

2020-12-03T14:36:57+00:00

There are currently multiple forms of assertion, such as J_ASSERT(). J_ASEERT() is provided for the jbd module, which is a public module. Maybe we should use custom ASSERT() like other file systems, such as xfs, which would be better. Signed-off-by: Chunguang Xu Reviewed-by: Andreas Dilger Link: https://lore.kernel.org/r/1604764698-4269-1-git-send-email-brookxu@tencent.com Signed-off-by: Theodore Ts'o

ext4: fast commit recovery path

2020-10-22T03:22:38+00:00

This patch adds fast commit recovery path support for Ext4 file system. We add several helper functions that are similar in spirit to e2fsprogs journal recovery path handlers. Example of such functions include - a simple block allocator, idempotent block bitmap update function etc. Using these routines and the fast commit log in the fast commit area, the recovery path (ext4_fc_replay()) performs fast commit log recovery. Reported-by: kernel test robot Signed-off-by: Harshad Shirwadkar Link: https://lore.kernel.org/r/20201015203802.3597742-8-harshadshirwadkar@gmail.com Signed-off-by: Theodore Ts'o

ext4: use common helpers in all places reading metadata buffers

2020-10-18T14:37:14+00:00

Revome all open codes that read metadata buffers, switch to use ext4_read_bh_*() common helpers. Signed-off-by: zhangyi (F) Suggested-by: Jan Kara Link: https://lore.kernel.org/r/20200924073337.861472-4-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o

ext4: clear buffer verified flag if read meta block from disk

2020-10-18T14:37:13+00:00

The metadata buffer is no longer trusted after we read it from disk again because it is not uptodate for some reasons (e.g. failed to write back). Otherwise we may get below memory corruption problem in ext4_ext_split()->memset() if we read stale data from the newly allocated extent block on disk which has been failed to async write out but miss verify again since the verified bit has already been set on the buffer. [ 29.774674] BUG: unable to handle kernel paging request at ffff88841949d000 ... [ 29.783317] Oops: 0002 [#2] SMP [ 29.784219] R10: 00000000000f4240 R11: 0000000000002e28 R12: ffff88842fa1c800 [ 29.784627] CPU: 1 PID: 126 Comm: kworker/u4:3 Tainted: G D W [ 29.785546] R13: ffffffff9cddcc20 R14: ffffffff9cddd420 R15: ffff88842fa1c2f8 [ 29.786679] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),BIOS ?-20190727_0738364 [ 29.787588] FS: 0000000000000000(0000) GS:ffff88842fa00000(0000) knlGS:0000000000000000 [ 29.789288] Workqueue: writeback wb_workfn [ 29.790319] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [ 29.790321] (flush-8:0) [ 29.790844] CR2: 0000000000000008 CR3: 00000004234f2000 CR4: 00000000000006f0 [ 29.791924] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 [ 29.792839] RIP: 0010:__memset+0x24/0x30 [ 29.793739] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 [ 29.794256] Code: 90 90 90 90 90 90 0f 1f 44 00 00 49 89 f9 48 89 d1 83 e2 07 48 c1 e9 033 [ 29.795161] Kernel panic - not syncing: Fatal exception in interrupt ... [ 29.808149] Call Trace: [ 29.808475] ext4_ext_insert_extent+0x102e/0x1be0 [ 29.809085] ext4_ext_map_blocks+0xa89/0x1bb0 [ 29.809652] ext4_map_blocks+0x290/0x8a0 [ 29.809085] ext4_ext_map_blocks+0xa89/0x1bb0 [ 29.809652] ext4_map_blocks+0x290/0x8a0 [ 29.810161] ext4_writepages+0xc85/0x17c0 ... Fix this by clearing buffer's verified bit if we read meta block from disk again. Signed-off-by: zhangyi (F) Cc: stable@vger.kernel.org Link: https://lore.kernel.org/r/20200924073337.861472-2-yi.zhang@huawei.com Signed-off-by: Theodore Ts'o

ext4: indicate via a block bitmap read is prefetched via a tracepoint

2020-08-07T18:12:35+00:00

Modify the ext4_read_block_bitmap_load tracepoint so that it tells us whether a block bitmap is being prefetched. Signed-off-by: Theodore Ts'o Reviewed-by: Artem Blagodarenko