kernel/git/stable/linux.git/fs/btrfs/delalloc-space.c, branch linux-6.6.y

btrfs: don't reserve space for checksums when writing to nocow files

2024-02-23T08:24:48+00:00

commit feefe1f49d26bad9d8997096e3a200280fa7b1c5 upstream. Currently when doing a write to a file we always reserve metadata space for inserting data checksums. However we don't need to do it if we have a nodatacow file (-o nodatacow mount option or chattr +C) or if checksums are disabled (-o nodatasum mount option), as in that case we are only adding unnecessary pressure to metadata reservations. For example on x86_64, with the default node size of 16K, a 4K buffered write into a nodatacow file is reserving 655360 bytes of metadata space, as it's accounting for checksums. After this change, which stops reserving space for checksums if we have a nodatacow file or checksums are disabled, we only need to reserve 393216 bytes of metadata. CC: stable@vger.kernel.org # 6.1+ Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: fix qgroup_free_reserved_data int overflow

2023-12-20T16:02:03+00:00

commit 9e65bfca24cf1d77e4a5c7a170db5867377b3fe7 upstream. The reserved data counter and input parameter is a u64, but we inadvertently accumulate it in an int. Overflowing that int results in freeing the wrong amount of data and breaking reserve accounting. Unfortunately, this overflow rot spreads from there, as the qgroup release/free functions rely on returning an int to take advantage of negative values for error codes. Therefore, the full fix is to return the "released" or "freed" amount by a u64 argument and to return 0 or negative error code via the return value. Most of the call sites simply ignore the return value, though some of them handle the error and count the returned bytes. Change all of them accordingly. CC: stable@vger.kernel.org # 6.1+ Reviewed-by: Qu Wenruo Signed-off-by: Boris Burkov Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: don't arbitrarily slow down delalloc if we're committing

2023-11-28T17:20:02+00:00

commit 11aeb97b45ad2e0040cbb2a589bc403152526345 upstream. We have a random schedule_timeout() if the current transaction is committing, which seems to be a holdover from the original delalloc reservation code. Remove this, we have the proper flushing stuff, we shouldn't be hoping for random timing things to make everything work. This just induces latency for no reason. CC: stable@vger.kernel.org # 5.4+ Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Greg Kroah-Hartman

btrfs: count extents before taking inode's spinlock when reserving metadata

2023-04-17T16:01:19+00:00

When reserving metadata space for delalloc (and direct IO too), at btrfs_delalloc_reserve_metadata(), there's no need to count the number of extents while holding the inode's spinlock, since that does not require access to any field of the inode. This section of code can be called concurrently, when we have direct IO writes against different file ranges that don't increase the inode's i_size, so it's beneficial to shorten the critical section by counting the number of extents before taking the inode's spinlock. Reviewed-by: Josef Bacik Signed-off-by: Filipe Manana Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: update function comments

2022-12-05T17:00:45+00:00

Update, reformat or reword function comments. This also removes the kdoc marker so we don't get reports when the function name is missing. Changes made: - remove kdoc markers - reformat the brief description to be a proper sentence - reword to imperative voice - align parameter list - fix typos Signed-off-by: David Sterba

btrfs: move BTRFS_FS_STATE* definitions and helpers to fs.h

2022-12-05T17:00:42+00:00

We're going to use fs.h to hold fs wide related helpers and definitions, move the FS_STATE enum and related helpers to fs.h, and then update all files that need these definitions to include fs.h. Reviewed-by: Johannes Thumshirn Reviewed-by: Anand Jain Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: move the printk helpers out of ctree.h

2022-12-05T17:00:41+00:00

We have a bunch of printk helpers that are in ctree.h. These have nothing to do with ctree.c, so move them into their own header. Subsequent patches will cleanup the printk helpers. Reviewed-by: Johannes Thumshirn Signed-off-by: Josef Bacik Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add the ability to use NO_FLUSH for data reservations

2022-09-29T15:08:28+00:00

In order to accommodate NOWAIT IOCB's we need to be able to do NO_FLUSH data reservations, so plumb this through the delalloc reservation system. Reviewed-by: Filipe Manana Signed-off-by: Josef Bacik Signed-off-by: Stefan Roesch Signed-off-by: David Sterba

btrfs: convert count_max_extents() to use fs_info->max_extent_size

2022-07-25T15:45:41+00:00

If count_max_extents() uses BTRFS_MAX_EXTENT_SIZE to calculate the number of extents needed, btrfs release the metadata reservation too much on its way to write out the data. Now that BTRFS_MAX_EXTENT_SIZE is replaced with fs_info->max_extent_size, convert count_max_extents() to use it instead, and fix the calculation of the metadata reservation. CC: stable@vger.kernel.org # 5.12+ Fixes: d8e3fb106f39 ("btrfs: zoned: use ZONE_APPEND write for zoned mode") Signed-off-by: Naohiro Aota Signed-off-by: David Sterba

btrfs: avoid blocking on space revervation when doing nowait dio writes

2022-05-16T15:03:10+00:00

When doing a NOWAIT direct IO write, if we can NOCOW then it means we can proceed with the non-blocking, NOWAIT path. However reserving the metadata space and qgroup meta space can often result in blocking - flushing delalloc, wait for ordered extents to complete, trigger transaction commits, etc, going against the semantics of a NOWAIT write. So make the NOWAIT write path to try to reserve all the metadata it needs without resulting in a blocking behaviour - if we get -ENOSPC or -EDQUOT then return -EAGAIN to make the caller fallback to a blocking direct IO write. This is part of a patchset comprised of the following patches: btrfs: avoid blocking on page locks with nowait dio on compressed range btrfs: avoid blocking nowait dio when locking file range btrfs: avoid double nocow check when doing nowait dio writes btrfs: stop allocating a path when checking if cross reference exists btrfs: free path at can_nocow_extent() before checking for checksum items btrfs: release path earlier at can_nocow_extent() btrfs: avoid blocking when allocating context for nowait dio read/write btrfs: avoid blocking on space revervation when doing nowait dio writes The following test was run before and after applying this patchset: $ cat io-uring-nodatacow-test.sh #!/bin/bash DEV=/dev/sdc MNT=/mnt/sdc MOUNT_OPTIONS="-o ssd -o nodatacow" MKFS_OPTIONS="-R free-space-tree -O no-holes" NUM_JOBS=4 FILE_SIZE=8G RUN_TIME=300 cat < /tmp/fio-job.ini [io_uring_rw] rw=randrw fsync=0 fallocate=posix group_reporting=1 direct=1 ioengine=io_uring iodepth=64 bssplit=4k/20:8k/20:16k/20:32k/10:64k/10:128k/5:256k/5:512k/5:1m/5 filesize=$FILE_SIZE runtime=$RUN_TIME time_based filename=foobar directory=$MNT numjobs=$NUM_JOBS thread EOF echo performance | \ tee /sys/devices/system/cpu/cpu*/cpufreq/scaling_governor umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV &> /dev/null mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT The test was run a 12 cores box with 64G of ram, using a non-debug kernel config (Debian's default config) and a spinning disk. Result before the patchset: READ: bw=407MiB/s (427MB/s), 407MiB/s-407MiB/s (427MB/s-427MB/s), io=119GiB (128GB), run=300175-300175msec WRITE: bw=407MiB/s (427MB/s), 407MiB/s-407MiB/s (427MB/s-427MB/s), io=119GiB (128GB), run=300175-300175msec Result after the patchset: READ: bw=436MiB/s (457MB/s), 436MiB/s-436MiB/s (457MB/s-457MB/s), io=128GiB (137GB), run=300044-300044msec WRITE: bw=435MiB/s (456MB/s), 435MiB/s-435MiB/s (456MB/s-456MB/s), io=128GiB (137GB), run=300044-300044msec That's about +7.2% throughput for reads and +6.9% for writes. Signed-off-by: Filipe Manana Signed-off-by: David Sterba