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2025-07-06btrfs: make the extent map shrinker run asynchronously as a work queue jobFilipe Manana
[ Upstream commit 1020443840569535f6025a855958f07ea3eebf71 ] Currently the extent map shrinker is run synchronously for kswapd tasks that end up calling the fs shrinker (fs/super.c:super_cache_scan()). This has some disadvantages and for some heavy workloads with memory pressure it can cause some delays and stalls that make a machine unresponsive for some periods. This happens because: 1) We can have several kswapd tasks on machines with multiple NUMA zones, and running the extent map shrinker concurrently can cause high contention on some spin locks, namely the spin locks that protect the radix tree that tracks roots, the per root xarray that tracks open inodes and the list of delayed iputs. This not only delays the shrinker but also causes high CPU consumption and makes the task running the shrinker monopolize a core, resulting in the symptoms of an unresponsive system. This was noted in previous commits such as commit ae1e766f623f ("btrfs: only run the extent map shrinker from kswapd tasks"); 2) The extent map shrinker's iteration over inodes can often be slow, even after changing the data structure that tracks open inodes for a root from a red black tree (up to kernel 6.10) to an xarray (kernel 6.10+). The transition to the xarray while it made things a bit faster, it's still somewhat slow - for example in a test scenario with 10000 inodes that have no extent maps loaded, the extent map shrinker took between 5ms to 8ms, using a release, non-debug kernel. Iterating over the extent maps of an inode can also be slow if have an inode with many thousands of extent maps, since we use a red black tree to track and search extent maps. So having the extent map shrinker run synchronously adds extra delay for other things a kswapd task does. So make the extent map shrinker run asynchronously as a job for the system unbounded workqueue, just like what we do for data and metadata space reclaim jobs. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2025-05-22btrfs: add back warning for mount option commit values exceeding 300Kyoji Ogasawara
commit 4ce2affc6ef9f84b4aebbf18bd5c57397b6024eb upstream. The Btrfs documentation states that if the commit value is greater than 300 a warning should be issued. The warning was accidentally lost in the new mount API update. Fixes: 6941823cc878 ("btrfs: remove old mount API code") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Kyoji Ogasawara <sawara04.o@gmail.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-04-25btrfs: correctly escape subvol in btrfs_show_options()Johannes Kimmel
commit dc08c58696f8555e4a802f1f23c894a330d80ab7 upstream. Currently, displaying the btrfs subvol mount option doesn't escape ','. This makes parsing /proc/self/mounts and /proc/self/mountinfo ambiguous for subvolume names that contain commas. The text after the comma could be mistaken for another option (think "subvol=foo,ro", where ro is actually part of the subvolumes name). Replace the manual escape characters list with a call to seq_show_option(). Thanks to Calvin Walton for suggesting this approach. Fixes: c8d3fe028f64 ("Btrfs: show subvol= and subvolid= in /proc/mounts") CC: stable@vger.kernel.org # 5.4+ Suggested-by: Calvin Walton <calvin.walton@kepstin.ca> Signed-off-by: Johannes Kimmel <kernel@bareminimum.eu> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2025-02-08btrfs: output the reason for open_ctree() failureQu Wenruo
commit d0f038104fa37380e2a725e669508e43d0c503e9 upstream. There is a recent ML report that mounting a large fs backed by hardware RAID56 controller (with one device missing) took too much time, and systemd seems to kill the mount attempt. In that case, the only error message is: BTRFS error (device sdj): open_ctree failed There is no reason on why the failure happened, making it very hard to understand the reason. At least output the error number (in the particular case it should be -EINTR) to provide some clue. Link: https://lore.kernel.org/linux-btrfs/9b9c4d2810abcca2f9f76e32220ed9a90febb235.camel@scientia.org/ Reported-by: Christoph Anton Mitterer <calestyo@scientia.org> Cc: stable@vger.kernel.org Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2024-12-14btrfs: fix mount failure due to remount racesQu Wenruo
[ Upstream commit 951a3f59d268fe1397aaeb9a96fcb1944890c4cb ] [BUG] The following reproducer can cause btrfs mount to fail: dev="/dev/test/scratch1" mnt1="/mnt/test" mnt2="/mnt/scratch" mkfs.btrfs -f $dev mount $dev $mnt1 btrfs subvolume create $mnt1/subvol1 btrfs subvolume create $mnt1/subvol2 umount $mnt1 mount $dev $mnt1 -o subvol=subvol1 while mount -o remount,ro $mnt1; do mount -o remount,rw $mnt1; done & bg=$! while mount $dev $mnt2 -o subvol=subvol2; do umount $mnt2; done kill $bg wait umount -R $mnt1 umount -R $mnt2 The script will fail with the following error: mount: /mnt/scratch: /dev/mapper/test-scratch1 already mounted on /mnt/test. dmesg(1) may have more information after failed mount system call. umount: /mnt/test: target is busy. umount: /mnt/scratch/: not mounted And there is no kernel error message. [CAUSE] During the btrfs mount, to support mounting different subvolumes with different RO/RW flags, we need to detect that and retry if needed: Retry with matching RO flags if the initial mount fail with -EBUSY. The problem is, during that retry we do not hold any super block lock (s_umount), this means there can be a remount process changing the RO flags of the original fs super block. If so, we can have an EBUSY error during retry. And this time we treat any failure as an error, without any retry and cause the above EBUSY mount failure. [FIX] The current retry behavior is racy because we do not have a super block thus no way to hold s_umount to prevent the race with remount. Solve the root problem by allowing fc->sb_flags to mismatch from the sb->s_flags at btrfs_get_tree_super(). Then at the re-entry point btrfs_get_tree_subvol(), manually check the fc->s_flags against sb->s_flags, if it's a RO->RW mismatch, then reconfigure with s_umount lock hold. Reported-by: Enno Gotthold <egotthold@suse.com> Reported-by: Fabian Vogt <fvogt@suse.com> [ Special thanks for the reproducer and early analysis pointing to btrfs. ] Fixes: f044b318675f ("btrfs: handle the ro->rw transition for mounting different subvolumes") Link: https://bugzilla.suse.com/show_bug.cgi?id=1231836 Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14btrfs: drop unused parameter data from btrfs_fill_super()David Sterba
[ Upstream commit 01c5db782e3ad1aea1d06a1765c710328c145f10 ] The only caller passes NULL, we can drop the parameter. This is since the new mount option parser done in 3bb17a25bcb09a ("btrfs: add get_tree callback for new mount API"). Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com> Stable-dep-of: 951a3f59d268 ("btrfs: fix mount failure due to remount races") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-12-14btrfs: drop unused parameter options from open_ctree()David Sterba
[ Upstream commit 87cbab86366e75dec52f787e0e0b17b2aea769ca ] Since the new mount option parser in commit ad21f15b0f79 ("btrfs: switch to the new mount API") we don't pass the options like that anymore. Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com> Stable-dep-of: 951a3f59d268 ("btrfs: fix mount failure due to remount races") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-11-07btrfs: fix per-subvolume RO/RW flags with new mount APIQu Wenruo
[BUG] With util-linux 2.40.2, the 'mount' utility is already utilizing the new mount API. e.g: # strace mount -o subvol=subv1,ro /dev/test/scratch1 /mnt/test/ ... fsconfig(3, FSCONFIG_SET_STRING, "source", "/dev/mapper/test-scratch1", 0) = 0 fsconfig(3, FSCONFIG_SET_STRING, "subvol", "subv1", 0) = 0 fsconfig(3, FSCONFIG_SET_FLAG, "ro", NULL, 0) = 0 fsconfig(3, FSCONFIG_CMD_CREATE, NULL, NULL, 0) = 0 fsmount(3, FSMOUNT_CLOEXEC, 0) = 4 mount_setattr(4, "", AT_EMPTY_PATH, {attr_set=MOUNT_ATTR_RDONLY, attr_clr=0, propagation=0 /* MS_??? */, userns_fd=0}, 32) = 0 move_mount(4, "", AT_FDCWD, "/mnt/test", MOVE_MOUNT_F_EMPTY_PATH) = 0 But this leads to a new problem, that per-subvolume RO/RW mount no longer works, if the initial mount is RO: # mount -o subvol=subv1,ro /dev/test/scratch1 /mnt/test # mount -o rw,subvol=subv2 /dev/test/scratch1 /mnt/scratch # mount | grep mnt /dev/mapper/test-scratch1 on /mnt/test type btrfs (ro,relatime,discard=async,space_cache=v2,subvolid=256,subvol=/subv1) /dev/mapper/test-scratch1 on /mnt/scratch type btrfs (ro,relatime,discard=async,space_cache=v2,subvolid=257,subvol=/subv2) # touch /mnt/scratch/foobar touch: cannot touch '/mnt/scratch/foobar': Read-only file system This is a common use cases on distros. [CAUSE] We have a workaround for remount to handle the RO->RW change, but if the mount is using the new mount API, we do not do that, and rely on the mount tool NOT to set the ro flag. But that's not how the mount tool is doing for the new API: fsconfig(3, FSCONFIG_SET_STRING, "source", "/dev/mapper/test-scratch1", 0) = 0 fsconfig(3, FSCONFIG_SET_STRING, "subvol", "subv1", 0) = 0 fsconfig(3, FSCONFIG_SET_FLAG, "ro", NULL, 0) = 0 <<<< Setting RO flag for super block fsconfig(3, FSCONFIG_CMD_CREATE, NULL, NULL, 0) = 0 fsmount(3, FSMOUNT_CLOEXEC, 0) = 4 mount_setattr(4, "", AT_EMPTY_PATH, {attr_set=MOUNT_ATTR_RDONLY, attr_clr=0, propagation=0 /* MS_??? */, userns_fd=0}, 32) = 0 move_mount(4, "", AT_FDCWD, "/mnt/test", MOVE_MOUNT_F_EMPTY_PATH) = 0 This means we will set the super block RO at the first mount. Later RW mount will not try to reconfigure the fs to RW because the mount tool is already using the new API. This totally breaks the per-subvolume RO/RW mount behavior. [FIX] Do not skip the reconfiguration even if using the new API. The old comments are just expecting any mount tool to properly skip the RO flag set even if we specify "ro", which is not the reality. Update the comments regarding the backward compatibility on the kernel level so it works with old and new mount utilities. CC: stable@vger.kernel.org # 6.8+ Fixes: f044b318675f ("btrfs: handle the ro->rw transition for mounting different subvolumes") Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-10-22btrfs: reject ro->rw reconfiguration if there are hard ro requirementsQu Wenruo
[BUG] Syzbot reports the following crash: BTRFS info (device loop0 state MCS): disabling free space tree BTRFS info (device loop0 state MCS): clearing compat-ro feature flag for FREE_SPACE_TREE (0x1) BTRFS info (device loop0 state MCS): clearing compat-ro feature flag for FREE_SPACE_TREE_VALID (0x2) Oops: general protection fault, probably for non-canonical address 0xdffffc0000000003: 0000 [#1] PREEMPT SMP KASAN NOPTI KASAN: null-ptr-deref in range [0x0000000000000018-0x000000000000001f] Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.3-debian-1.16.3-2~bpo12+1 04/01/2014 RIP: 0010:backup_super_roots fs/btrfs/disk-io.c:1691 [inline] RIP: 0010:write_all_supers+0x97a/0x40f0 fs/btrfs/disk-io.c:4041 Call Trace: <TASK> btrfs_commit_transaction+0x1eae/0x3740 fs/btrfs/transaction.c:2530 btrfs_delete_free_space_tree+0x383/0x730 fs/btrfs/free-space-tree.c:1312 btrfs_start_pre_rw_mount+0xf28/0x1300 fs/btrfs/disk-io.c:3012 btrfs_remount_rw fs/btrfs/super.c:1309 [inline] btrfs_reconfigure+0xae6/0x2d40 fs/btrfs/super.c:1534 btrfs_reconfigure_for_mount fs/btrfs/super.c:2020 [inline] btrfs_get_tree_subvol fs/btrfs/super.c:2079 [inline] btrfs_get_tree+0x918/0x1920 fs/btrfs/super.c:2115 vfs_get_tree+0x90/0x2b0 fs/super.c:1800 do_new_mount+0x2be/0xb40 fs/namespace.c:3472 do_mount fs/namespace.c:3812 [inline] __do_sys_mount fs/namespace.c:4020 [inline] __se_sys_mount+0x2d6/0x3c0 fs/namespace.c:3997 do_syscall_x64 arch/x86/entry/common.c:52 [inline] do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83 entry_SYSCALL_64_after_hwframe+0x77/0x7f [CAUSE] To support mounting different subvolume with different RO/RW flags for the new mount APIs, btrfs introduced two workaround to support this feature: - Skip mount option/feature checks if we are mounting a different subvolume - Reconfigure the fs to RW if the initial mount is RO Combining these two, we can have the following sequence: - Mount the fs ro,rescue=all,clear_cache,space_cache=v1 rescue=all will mark the fs as hard read-only, so no v2 cache clearing will happen. - Mount a subvolume rw of the same fs. We go into btrfs_get_tree_subvol(), but fc_mount() returns EBUSY because our new fc is RW, different from the original fs. Now we enter btrfs_reconfigure_for_mount(), which switches the RO flag first so that we can grab the existing fs_info. Then we reconfigure the fs to RW. - During reconfiguration, option/features check is skipped This means we will restart the v2 cache clearing, and convert back to v1 cache. This will trigger fs writes, and since the original fs has "rescue=all" option, it skips the csum tree read. And eventually causing NULL pointer dereference in super block writeback. [FIX] For reconfiguration caused by different subvolume RO/RW flags, ensure we always run btrfs_check_options() to ensure we have proper hard RO requirements met. In fact the function btrfs_check_options() doesn't really do many complex checks, but hard RO requirement and some feature dependency checks, thus there is no special reason not to do the check for mount reconfiguration. Reported-by: syzbot+56360f93efa90ff15870@syzkaller.appspotmail.com Link: https://lore.kernel.org/linux-btrfs/0000000000008c5d090621cb2770@google.com/ Fixes: f044b318675f ("btrfs: handle the ro->rw transition for mounting different subvolumes") CC: stable@vger.kernel.org # 6.8+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-10-22btrfs: clear force-compress on remount when compress mount option is givenFilipe Manana
After the migration to use fs context for processing mount options we had a slight change in the semantics for remounting a filesystem that was mounted with compress-force. Before we could clear compress-force by passing only "-o compress[=algo]" during a remount, but after that change that does not work anymore, force-compress is still present and one needs to pass "-o compress-force=no,compress[=algo]" to the mount command. Example, when running on a kernel 6.8+: $ mount -o compress-force=zlib:9 /dev/sdi /mnt/sdi $ mount | grep sdi /dev/sdi on /mnt/sdi type btrfs (rw,relatime,compress-force=zlib:9,discard=async,space_cache=v2,subvolid=5,subvol=/) $ mount -o remount,compress=zlib:5 /mnt/sdi $ mount | grep sdi /dev/sdi on /mnt/sdi type btrfs (rw,relatime,compress-force=zlib:5,discard=async,space_cache=v2,subvolid=5,subvol=/) On a 6.7 kernel (or older): $ mount -o compress-force=zlib:9 /dev/sdi /mnt/sdi $ mount | grep sdi /dev/sdi on /mnt/sdi type btrfs (rw,relatime,compress-force=zlib:9,discard=async,space_cache=v2,subvolid=5,subvol=/) $ mount -o remount,compress=zlib:5 /mnt/sdi $ mount | grep sdi /dev/sdi on /mnt/sdi type btrfs (rw,relatime,compress=zlib:5,discard=async,space_cache=v2,subvolid=5,subvol=/) So update btrfs_parse_param() to clear "compress-force" when "compress" is given, providing the same semantics as kernel 6.7 and older. Reported-by: Roman Mamedov <rm@romanrm.net> Link: https://lore.kernel.org/linux-btrfs/20241014182416.13d0f8b0@nvm/ CC: stable@vger.kernel.org # 6.8+ Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-08-16btrfs: only enable extent map shrinker for DEBUG buildsQu Wenruo
Although there are several patches improving the extent map shrinker, there are still reports of too frequent shrinker behavior, taking too much CPU for the kswapd process. So let's only enable extent shrinker for now, until we got more comprehensive understanding and a better solution. Link: https://lore.kernel.org/linux-btrfs/3df4acd616a07ef4d2dc6bad668701504b412ffc.camel@intelfx.name/ Link: https://lore.kernel.org/linux-btrfs/c30fd6b3-ca7a-4759-8a53-d42878bf84f7@gmail.com/ Fixes: 956a17d9d050 ("btrfs: add a shrinker for extent maps") CC: stable@vger.kernel.org # 6.10+ Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-08-13btrfs: only run the extent map shrinker from kswapd tasksFilipe Manana
Currently the extent map shrinker can be run by any task when attempting to allocate memory and there's enough memory pressure to trigger it. To avoid too much latency we stop iterating over extent maps and removing them once the task needs to reschedule. This logic was introduced in commit b3ebb9b7e92a ("btrfs: stop extent map shrinker if reschedule is needed"). While that solved high latency problems for some use cases, it's still not enough because with a too high number of tasks entering the extent map shrinker code, either due to memory allocations or because they are a kswapd task, we end up having a very high level of contention on some spin locks, namely: 1) The fs_info->fs_roots_radix_lock spin lock, which we need to find roots to iterate over their inodes; 2) The spin lock of the xarray used to track open inodes for a root (struct btrfs_root::inodes) - on 6.10 kernels and below, it used to be a red black tree and the spin lock was root->inode_lock; 3) The fs_info->delayed_iput_lock spin lock since the shrinker adds delayed iputs (calls btrfs_add_delayed_iput()). Instead of allowing the extent map shrinker to be run by any task, make it run only by kswapd tasks. This still solves the problem of running into OOM situations due to an unbounded extent map creation, which is simple to trigger by direct IO writes, as described in the changelog of commit 956a17d9d050 ("btrfs: add a shrinker for extent maps"), and by a similar case when doing buffered IO on files with a very large number of holes (keeping the file open and creating many holes, whose extent maps are only released when the file is closed). Reported-by: kzd <kzd@56709.net> Link: https://bugzilla.kernel.org/show_bug.cgi?id=219121 Reported-by: Octavia Togami <octavia.togami@gmail.com> Link: https://lore.kernel.org/linux-btrfs/CAHPNGSSt-a4ZZWrtJdVyYnJFscFjP9S7rMcvEMaNSpR556DdLA@mail.gmail.com/ Fixes: 956a17d9d050 ("btrfs: add a shrinker for extent maps") CC: stable@vger.kernel.org # 6.10+ Tested-by: kzd <kzd@56709.net> Tested-by: Octavia Togami <octavia.togami@gmail.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-08-01btrfs: emit a warning about space cache v1 being deprecatedJosef Bacik
We've been wanting to get rid of this for a while, add a message to indicate that this feature is going away and when so we can finally have a date when we're going to remove it. The output looks like this BTRFS warning (device nvme0n1): space cache v1 is being deprecated and will be removed in a future release, please use -o space_cache=v2 Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Neal Gompa <neal@gompa.dev> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-19btrfs: change BTRFS_MOUNT_* flags to 64bit typeQu Wenruo
Currently the BTRFS_MOUNT_* flags are already beyond 32 bits, this is going to cause compilation errors for some 32 bit systems, as their unsigned long is only 32 bits long, thus flag BTRFS_MOUNT_IGNORESUPERFLAGS overflows and can lead to errors. Fix the problem by: - Migrate all existing BTRFS_MOUNT_* flags to unsigned long long - Migrate all mount option related variables to unsigned long long * btrfs_fs_info::mount_opt * btrfs_fs_context::mount_opt * mount_opt parameter of btrfs_check_options() * old_opts parameter of btrfs_remount_begin() * old_opts parameter of btrfs_remount_cleanup() * mount_opt parameter of btrfs_check_mountopts_zoned() * mount_opt and opt parameters of check_ro_option() Fixes: 32e6216512b4 ("btrfs: introduce new "rescue=ignoresuperflags" mount option") Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: introduce new "rescue=ignoresuperflags" mount optionQu Wenruo
This new mount option allows the kernel to skip the super flags check, it's mostly to allow the kernel to do a rescue mount of an interrupted checksum conversion. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: introduce new "rescue=ignoremetacsums" mount optionQu Wenruo
Introduce "rescue=ignoremetacsums" to ignore metadata csums, all the other metadata sanity checks are still kept as is. This new mount option is mostly to allow the kernel to mount an interrupted checksum conversion (at the metadata csum overwrite stage). And since the main part of metadata sanity checks is inside tree-checker, we shouldn't lose much safety, and the new mount option is rescue mount option it requires full read-only mount. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: remove unused Opt enumsQu Wenruo
The following three Opt_* enums haven't been utilized since the port to new mount API: - Opt_ignorebadroots - Opt_ignoredatacsums - Opt_rescue_all All those enums are from the old day where we have dedicated mount options, nowadays they have been moved to "rescue=" mount option groups, and no more global tokens for them. So we can safely remove them now. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: move the direct IO code into its own fileFilipe Manana
The direct IO code is over a thousand lines and it's currently spread between file.c and inode.c, which makes it not easy to locate some parts of it sometimes. Also inode.c is about 11 thousand lines and file.c about 4 thousand lines, both too big. So move all the direct IO code into a dedicated file, so that it's easy to locate all its code and reduce the sizes of inode.c and file.c. This is a pure move of code without any other changes except export a a couple functions from inode.c (get_extent_allocation_hint() and create_io_em()) because they are used in inode.c and the new direct-io.c file, and a couple functions from file.c (btrfs_buffered_write() and btrfs_write_check()) because they are used both in file.c and in the new direct-io.c file. Reviewed-by: Boris Burkov <boris@bur.io> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: remove super block argument from btrfs_iget()Filipe Manana
It's pointless to pass a super block argument to btrfs_iget() because we always pass a root and from it we can get the super block through: root->fs_info->sb So remove the super block argument. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: constify pointer parameters where applicableDavid Sterba
We can add const to many parameters, this is for clarity and minor addition to safety. There are some minor effects, in the assembly code and .ko measured on release config. This patch does not cover all possible conversions. Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: add MODULE_DESCRIPTION()Jeff Johnson
Fix the 'make W=1' warning: WARNING: modpost: missing MODULE_DESCRIPTION() in fs/btrfs/btrfs.o Signed-off-by: Jeff Johnson <quic_jjohnson@quicinc.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: add and use helper to commit the current transactionFilipe Manana
We have several places that attach to the current transaction with btrfs_attach_transaction_barrier() and then commit the transaction if there is one. Add a helper and use it to deduplicate this pattern. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-07-11btrfs: simplify range parameters of btrfs_wait_ordered_roots()David Sterba
The range is specified only in two ways, we can simplify the case for the whole filesystem range as a NULL block group parameter. Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-21btrfs: re-introduce 'norecovery' mount optionQu Wenruo
Although 'norecovery' mount option was marked as deprecated for a long time and a warning message was printed during the deprecation window, it's still actively utilized by several projects that need a safer way to mount a btrfs without any writes. Furthermore this 'norecovery' mount option is supported by other major filesystems, which makes it less clear what's our motivation to remove it. Re-introduce the 'norecovery' mount option, and output a message to recommend 'rescue=nologreplay' option. Link: https://lore.kernel.org/linux-btrfs/ZkxZT0J-z0GYvfy8@gardel-login/#t Link: https://github.com/systemd/systemd/pull/32892 Link: https://bugzilla.suse.com/show_bug.cgi?id=1222429 Reported-by: Lennart Poettering <lennart@poettering.net> Reported-by: Jiri Slaby <jslaby@suse.com> Fixes: a1912f712188 ("btrfs: remove code for inode_cache and recovery mount options") CC: stable@vger.kernel.org # 6.8+ Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07btrfs: add tracepoints for extent map shrinker eventsFilipe Manana
Add some tracepoints for the extent map shrinker to help debug and analyse main events. These have proved useful during development of the shrinker. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07btrfs: add a shrinker for extent mapsFilipe Manana
Extent maps are used either to represent existing file extent items, or to represent new extents that are going to be written and the respective file extent items are created when the ordered extent completes. We currently don't have any limit for how many extent maps we can have, neither per inode nor globally. Most of the time this not too noticeable because extent maps are removed in the following situations: 1) When evicting an inode; 2) When releasing folios (pages) through the btrfs_release_folio() address space operation callback. However we won't release extent maps in the folio range if the folio is either dirty or under writeback or if the inode's i_size is less than or equals to 16M (see try_release_extent_mapping(). This 16M i_size constraint was added back in 2008 with commit 70dec8079d78 ("Btrfs: extent_io and extent_state optimizations"), but there's no explanation about why we have it or why the 16M value. This means that for buffered IO we can reach an OOM situation due to too many extent maps if either of the following happens: 1) There's a set of tasks constantly doing IO on many files with a size not larger than 16M, specially if they keep the files open for very long periods, therefore preventing inode eviction. This requires a really high number of such files, and having many non mergeable extent maps (due to random 4K writes for example) and a machine with very little memory; 2) There's a set tasks constantly doing random write IO (therefore creating many non mergeable extent maps) on files and keeping them open for long periods of time, so inode eviction doesn't happen and there's always a lot of dirty pages or pages under writeback, preventing btrfs_release_folio() from releasing the respective extent maps. This second case was actually reported in the thread pointed by the Link tag below, and it requires a very large file under heavy IO and a machine with very little amount of RAM, which is probably hard to happen in practice in a real world use case. However when using direct IO this is not so hard to happen, because the page cache is not used, and therefore btrfs_release_folio() is never called. Which means extent maps are dropped only when evicting the inode, and that means that if we have tasks that keep a file descriptor open and keep doing IO on a very large file (or files), we can exhaust memory due to an unbounded amount of extent maps. This is especially easy to happen if we have a huge file with millions of small extents and their extent maps are not mergeable (non contiguous offsets and disk locations). This was reported in that thread with the following fio test: $ cat test.sh #!/bin/bash DEV=/dev/sdj MNT=/mnt/sdj MOUNT_OPTIONS="-o ssd" MKFS_OPTIONS="" cat <<EOF > /tmp/fio-job.ini [global] name=fio-rand-write filename=$MNT/fio-rand-write rw=randwrite bs=4K direct=1 numjobs=16 fallocate=none time_based runtime=90000 [file1] size=300G ioengine=libaio iodepth=16 EOF umount $MNT &> /dev/null mkfs.btrfs -f $MKFS_OPTIONS $DEV mount $MOUNT_OPTIONS $DEV $MNT fio /tmp/fio-job.ini umount $MNT Monitoring the btrfs_extent_map slab while running the test with: $ watch -d -n 1 'cat /sys/kernel/slab/btrfs_extent_map/objects \ /sys/kernel/slab/btrfs_extent_map/total_objects' Shows the number of active and total extent maps skyrocketing to tens of millions, and on systems with a short amount of memory it's easy and quick to get into an OOM situation, as reported in that thread. So to avoid this issue add a shrinker that will remove extents maps, as long as they are not pinned, and takes proper care with any concurrent fsync to avoid missing extents (setting the full sync flag while in the middle of a fast fsync). This shrinker is triggered through the callbacks nr_cached_objects and free_cached_objects of struct super_operations. The shrinker will iterate over all roots and over all inodes of each root, and keeps track of the last scanned root and inode, so that the next time it runs, it starts from that root and from the next inode. This is similar to what xfs does for its inode reclaim (implements those callbacks, and cycles through inodes by starting from where it ended last time). Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Filipe Manana <fdmanana@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-05-07btrfs: change root->root_key.objectid to btrfs_root_id()Josef Bacik
A comment from Filipe on one of my previous cleanups brought my attention to a new helper we have for getting the root id of a root, which makes it easier to read in the code. The changes where made with the following Coccinelle semantic patch: // <smpl> @@ expression E,E1; @@ ( E->root_key.objectid = E1 | - E->root_key.objectid + btrfs_root_id(E) ) // </smpl> Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ minor style fixups ] Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04btrfs: factor out validation of btrfs_ioctl_vol_args::nameDavid Sterba
The validation of vol args name in several ioctls is not done properly. a terminating NUL is written to the end of the buffer unconditionally, assuming that this would be the last place in case the buffer is used completely. This does not communicate back the actual error (either an invalid or too long path). Factor out all such cases and use a helper to do the verification, simply look for NUL in the buffer. There's no expected practical change, the size of buffer is 4088, this is enough for most paths or names. Reviewed-by: Boris Burkov <boris@bur.io> Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04btrfs: remove unused included headersDavid Sterba
With help of neovim, LSP and clangd we can identify header files that are not actually needed to be included in the .c files. This is focused only on removal (with minor fixups), further cleanups are possible but will require doing the header files properly with forward declarations, minimized includes and include-what-you-use care. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-03-04btrfs: replace sb::s_blocksize by fs_info::sectorsizeDavid Sterba
The block size stored in the super block is used by subsystems outside of btrfs and it's a copy of fs_info::sectorsize. Unify that to always use our sectorsize, with the exception of mount where we first need to use fixed values (4K) until we read the super block and can set the sectorsize. Replace all uses, in most cases it's fewer pointer indirections. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-01-22Merge tag 'for-6.8-rc1-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: - zoned mode fixes: - fix slowdown when writing large file sequentially by looking up block groups with enough space faster - locking fixes when activating a zone - new mount API fixes: - preserve mount options for a ro/rw mount of the same subvolume - scrub fixes: - fix use-after-free in case the chunk length is not aligned to 64K, this does not happen normally but has been reported on images converted from ext4 - similar alignment check was missing with raid-stripe-tree - subvolume deletion fixes: - prevent calling ioctl on already deleted subvolume - properly track flag tracking a deleted subvolume - in subpage mode, fix decompression of an inline extent (zlib, lzo, zstd) - fix crash when starting writeback on a folio, after integration with recent MM changes this needs to be started conditionally - reject unknown flags in defrag ioctl - error handling, API fixes, minor warning fixes * tag 'for-6.8-rc1-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: scrub: limit RST scrub to chunk boundary btrfs: scrub: avoid use-after-free when chunk length is not 64K aligned btrfs: don't unconditionally call folio_start_writeback in subpage btrfs: use the original mount's mount options for the legacy reconfigure btrfs: don't warn if discard range is not aligned to sector btrfs: tree-checker: fix inline ref size in error messages btrfs: zstd: fix and simplify the inline extent decompression btrfs: lzo: fix and simplify the inline extent decompression btrfs: zlib: fix and simplify the inline extent decompression btrfs: defrag: reject unknown flags of btrfs_ioctl_defrag_range_args btrfs: avoid copying BTRFS_ROOT_SUBVOL_DEAD flag to snapshot of subvolume being deleted btrfs: don't abort filesystem when attempting to snapshot deleted subvolume btrfs: zoned: fix lock ordering in btrfs_zone_activate() btrfs: fix unbalanced unlock of mapping_tree_lock btrfs: ref-verify: free ref cache before clearing mount opt btrfs: fix kvcalloc() arguments order in btrfs_ioctl_send() btrfs: zoned: optimize hint byte for zoned allocator btrfs: zoned: factor out prepare_allocation_zoned()
2024-01-18btrfs: use the original mount's mount options for the legacy reconfigureJosef Bacik
btrfs/330, which tests our old trick to allow mount -o ro,subvol=/x /dev/sda1 /foo mount -o rw,subvol=/y /dev/sda1 /bar fails on the block group tree. This is because we aren't preserving the mount options for what is essentially a remount, and thus we're ending up without the FREE_SPACE_TREE mount option, which triggers our free space tree delete codepath. This isn't possible with the block group tree and thus it falls over. Fix this by making sure we copy the existing mount options for the existing fs mount over in this case. Fixes: f044b318675f ("btrfs: handle the ro->rw transition for mounting different subvolumes") Reviewed-by: Neal Gompa <neal@gompa.dev> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2024-01-10Merge tag 'for-6.8-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs updates from David Sterba: "There are no exciting changes for users, it's been mostly API conversions and some fixes or refactoring. The mount API conversion is a base for future improvements that would come with VFS. Metadata processing has been converted to folios, not yet enabling the large folios but it's one patch away once everything gets tested enough. Core changes: - convert extent buffers to folios: - direct API conversion where possible - performance can drop by a few percent on metadata heavy workloads, the folio sizes are not constant and the calculations add up in the item helpers - both regular and subpage modes - data cannot be converted yet, we need to port that to iomap and there are some other generic changes required - convert mount to the new API, should not be user visible: - options deprecated long time ago have been removed: inode_cache, recovery - the new logic that splits mount to two phases slightly changes timing of device scanning for multi-device filesystems - LSM options will now work (like for selinux) - convert delayed nodes radix tree to xarray, preserving the preload-like logic that still allows to allocate with GFP_NOFS - more validation of sysfs value of scrub_speed_max - refactor chunk map structure, reduce size and improve performance - extent map refactoring, smaller data structures, improved performance - reduce size of struct extent_io_tree, embedded in several structures - temporary pages used for compression are cached and attached to a shrinker, this may slightly improve performance - in zoned mode, remove redirty extent buffer tracking, zeros are written in case an out-of-order is detected and proper data are written to the actual write pointer - cleanups, refactoring, error message improvements, updated tests - verify and update branch name or tag - remove unwanted text" * tag 'for-6.8-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: (89 commits) btrfs: pass btrfs_io_geometry into btrfs_max_io_len btrfs: pass struct btrfs_io_geometry to set_io_stripe btrfs: open code set_io_stripe for RAID56 btrfs: change block mapping to switch/case in btrfs_map_block btrfs: factor out block mapping for single profiles btrfs: factor out block mapping for RAID5/6 btrfs: reduce scope of data_stripes in btrfs_map_block btrfs: factor out block mapping for RAID10 btrfs: factor out block mapping for DUP profiles btrfs: factor out RAID1 block mapping btrfs: factor out block-mapping for RAID0 btrfs: re-introduce struct btrfs_io_geometry btrfs: factor out helper for single device IO check btrfs: migrate btrfs_repair_io_failure() to folio interfaces btrfs: migrate eb_bitmap_offset() to folio interfaces btrfs: migrate various end io functions to folios btrfs: migrate subpage code to folio interfaces btrfs: migrate get_eb_page_index() and get_eb_offset_in_page() to folios btrfs: don't double put our subpage reference in alloc_extent_buffer btrfs: cleanup metadata page pointer usage ...
2024-01-08Merge tag 'vfs-6.8.super' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs Pull vfs super updates from Christian Brauner: "This contains the super work for this cycle including the long-awaited series by Jan to make it possible to prevent writing to mounted block devices: - Writing to mounted devices is dangerous and can lead to filesystem corruption as well as crashes. Furthermore syzbot comes with more and more involved examples how to corrupt block device under a mounted filesystem leading to kernel crashes and reports we can do nothing about. Add tracking of writers to each block device and a kernel cmdline argument which controls whether other writeable opens to block devices open with BLK_OPEN_RESTRICT_WRITES flag are allowed. Note that this effectively only prevents modification of the particular block device's page cache by other writers. The actual device content can still be modified by other means - e.g. by issuing direct scsi commands, by doing writes through devices lower in the storage stack (e.g. in case loop devices, DM, or MD are involved) etc. But blocking direct modifications of the block device page cache is enough to give filesystems a chance to perform data validation when loading data from the underlying storage and thus prevent kernel crashes. Syzbot can use this cmdline argument option to avoid uninteresting crashes. Also users whose userspace setup does not need writing to mounted block devices can set this option for hardening. We expect that this will be interesting to quite a few workloads. Btrfs is currently opted out of this because they still haven't merged patches we require for this to work from three kernel releases ago. - Reimplement block device freezing and thawing as holder operations on the block device. This allows us to extend block device freezing to all devices associated with a superblock and not just the main device. It also allows us to remove get_active_super() and thus another function that scans the global list of superblocks. Freezing via additional block devices only works if the filesystem chooses to use @fs_holder_ops for these additional devices as well. That currently only includes ext4 and xfs. Earlier releases switched get_tree_bdev() and mount_bdev() to use @fs_holder_ops. The remaining nilfs2 open-coded version of mount_bdev() has been converted to rely on @fs_holder_ops as well. So block device freezing for the main block device will continue to work as before. There should be no regressions in functionality. The only special case is btrfs where block device freezing for the main block device never worked because sb->s_bdev isn't set. Block device freezing for btrfs can be fixed once they can switch to @fs_holder_ops but that can happen whenever they're ready" * tag 'vfs-6.8.super' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: (27 commits) block: Fix a memory leak in bdev_open_by_dev() super: don't bother with WARN_ON_ONCE() super: massage wait event mechanism ext4: Block writes to journal device xfs: Block writes to log device fs: Block writes to mounted block devices btrfs: Do not restrict writes to btrfs devices block: Add config option to not allow writing to mounted devices block: Remove blkdev_get_by_*() functions bcachefs: Convert to bdev_open_by_path() fs: handle freezing from multiple devices fs: remove dead check nilfs2: simplify device handling fs: streamline thaw_super_locked ext4: simplify device handling xfs: simplify device handling fs: simplify setup_bdev_super() calls blkdev: comment fs_holder_ops porting: document block device freeze and thaw changes fs: remove unused helper ...
2023-12-15btrfs: remove code for inode_cache and recovery mount optionsJosef Bacik
We've deprecated these a while ago in 5.11, go ahead and remove the code for them. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: set clear_cache if we use usebackuprootJosef Bacik
We're currently setting this when we try to load the roots and we see that usebackuproot is set. Instead set this at mount option parsing time. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: move one shot mount option clearing to super.cJosef Bacik
There's no reason this has to happen in open_ctree, and in fact in the old mount API we had to call this from remount. Move this to super.c, unexport it, and call it from both mount and reconfigure. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: remove old mount API codeJosef Bacik
Now that we've switched to the new mount API, remove the old stuff. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: move the device specific mount options to super.cJosef Bacik
We add these mount options based on the fs_devices settings, which can be set once we've opened the fs_devices. Move these into their own helper and call it from get_tree_super. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: switch to the new mount APIJosef Bacik
Now that we have all of the parts in place to use the new mount API, switch our fs_type to use the new callbacks. There are a few things that have to be done at the same time because of the order of operations changes that come along with the new mount API. These must be done in the same patch otherwise things will go wrong. 1. Export and use btrfs_check_options in open_ctree(). This is because the options are done ahead of time, and we need to check them once we have the feature flags loaded. 2. Update the free space cache settings. Since we're coming in with the options already set we need to make sure we don't undo what the user has asked for. 3. Set our sb_flags at init_fs_context time, the fs_context stuff is trying to manage the sb_flagss itself, so move that into init_fs_context and out of the fill super part. Additionally I've marked the unused functions with __maybe_unused and will remove them in a future patch. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: handle the ro->rw transition for mounting different subvolumesJosef Bacik
This is a special case that we've carried around since 0723a0473fb4 ("btrfs: allow mounting btrfs subvolumes with different ro/rw options") where we'll under the covers flip the file system to RW if you're mixing and matching ro/rw options with different subvol mounts. The first mount is what the super gets setup as, so we'd handle this by remount the super as rw under the covers to facilitate this behavior. With the new mount API we can't really allow this, because user space has the ability to specify the super block settings, and the mount settings. So if the user explicitly sets the super block as read only, and then tried to mount a rw mount with the super block we'll reject this. However the old API was less descriptive and thus we allowed this kind of behavior. This patch preserves this behavior for the old API calls. This is inspired by Christians work [1], and includes his comment in btrfs_get_tree_super() explaining the history and how it all works in the old and new APIs. Link: https://lore.kernel.org/all/20230626-fs-btrfs-mount-api-v1-2-045e9735a00b@kernel.org/ Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: add get_tree callback for new mount APIJosef Bacik
This is the actual mounting callback for the new mount API. Implement this using our current fill super as a guideline, making the appropriate adjustments for the new mount API. Our old mount operation had two fs_types, one to handle the actual opening, and the one that we called to handle the actual opening and then did the subvol lookup for returning the actual root dentry. This is mirrored here, but simply with different behaviors for ->get_tree. We use the existence of ->s_fs_info to tell which part we're in. The initial call allocates the fs_info, then call mount_fc() with a duplicated fc to do the actual open_ctree part. Then we take that vfsmount and use it to look up our subvolume that we're mounting and return that as our s_root. This idea was taken from Christians attempt to convert us to the new mount API [1]. In btrfs_get_tree_super() the mount device is scanned and opened in one go under uuid_mutex we expect that all related devices have been already scanned, either by mount or from the outside. A device forget can be called on some of the devices as the whole context is not protected but it's an unlikely event, though it's a minor behaviour change. References: https://lore.kernel.org/all/20230626-fs-btrfs-mount-api-v1-2-045e9735a00b@kernel.org/ Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add note about device scanning ] Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: add reconfigure callback for fs_contextJosef Bacik
This is what is used to remount the file system with the new mount API. Because the mount options are parsed separately and one at a time I've added a helper to emit the mount options after the fact once the mount is configured, this matches the dmesg output for what happens with the old mount API. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: add fs context handling functionsJosef Bacik
We are going to use the fs context to hold the mount options, so allocate the btrfs_fs_context when we're asked to init the fs context, and free it in the free callback. Reviewed-by: Christian Brauner <brauner@kernel.org> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: add parse_param callback for the new mount APIJosef Bacik
The parse_param callback handles one parameter at a time, take our existing mount option parsing loop and adjust it to handle one parameter at a time, and tie it into the fs_context_operations. Create a btrfs_fs_context object that will store the various mount properties, we'll house this in fc->fs_private. This is necessary to separate because remounting will use ->reconfigure, and we'll get a new copy of the parsed parameters, so we can no longer directly mess with the fs_info in this stage. In the future we'll add this to the btrfs_fs_info and update the users to use the new context object instead. There's a change how the option device= is processed. Previously all mount options were parsed in one go under uuid_mutex and the devices opened. This prevented a concurrent scan to happen during mount. Now we could see a device scan happen (e.g. by udev) but this should not affect the end result, mount will either see the populated fs_devices or will scan the device by itself. Alternatively we could save all the device paths first and then process them in one go as before but this does not seem to be necessary. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add note about device scanning ] Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: add fs_parameter definitionsJosef Bacik
In order to convert to the new mount API we have to change how we do the mount option parsing. For now we're going to duplicate these helpers to make it easier to follow, and then remove the old code once everything is in place. This patch contains the re-definition of all of our mount options into the new fs_parameter_spec format. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: split out ro->rw and rw->ro helpers into their own functionsJosef Bacik
When we remount ro->rw or rw->ro we have some cleanup tasks that have to be managed. Split these out into their own function to make btrfs_remount smaller. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: move space cache settings into open_ctreeJosef Bacik
Currently we pre-load the space cache settings in btrfs_parse_options, however when we switch to the new mount API the mount option parsing will happen before we have the super block loaded. Add a helper to set the appropriate options based on the fs settings, this will allow us to have consistent free space cache settings. This also folds in the space cache related decisions we make for subpage sectorsize support, so all of this is done in one place. Since this was being called by parse options it looks like we're changing the behavior of remount, but in fact we aren't. The pre-loading of the free space cache settings is done because we want to handle the case of users not using any space_cache options, we'll derive the appropriate mount option based on the on disk state. On remount this wouldn't reset anything as we'll have cleared the v1 cache generation if we mounted -o nospace_cache. Similarly it's impossible to turn off the free space tree without specifically saying -o nospace_cache,clear_cache, which will delete the free space tree and clear the compat_ro option. Again in this case calling this code in remount wouldn't result in any change. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com>
2023-12-15btrfs: split out the mount option validation code into its own helperJosef Bacik
We're going to need to validate mount options after they're all parsed with the new mount API, split this code out into its own helper so we can use it when we swap over to the new mount API. Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ minor adjustments in the messages ] Signed-off-by: David Sterba <dsterba@suse.com>
2023-11-28Merge tag 'for-6.7-rc3-tag' of ↵Linus Torvalds
git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux Pull btrfs fixes from David Sterba: "A few fixes and message updates: - for simple quotas, handle the case when a snapshot is created and the target qgroup already exists - fix a warning when file descriptor given to send ioctl is not writable - fix off-by-one condition when checking chunk maps - free pages when page array allocation fails during compression read, other cases were handled - fix memory leak on error handling path in ref-verify debugging feature - copy missing struct member 'version' in 64/32bit compat send ioctl - tree-checker verifies inline backref ordering - print messages to syslog on first mount and last unmount - update error messages when reading chunk maps" * tag 'for-6.7-rc3-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: send: ensure send_fd is writable btrfs: free the allocated memory if btrfs_alloc_page_array() fails btrfs: fix 64bit compat send ioctl arguments not initializing version member btrfs: make error messages more clear when getting a chunk map btrfs: fix off-by-one when checking chunk map includes logical address btrfs: ref-verify: fix memory leaks in btrfs_ref_tree_mod() btrfs: add dmesg output for first mount and last unmount of a filesystem btrfs: do not abort transaction if there is already an existing qgroup btrfs: tree-checker: add type and sequence check for inline backrefs