kernel.git/fs/btrfs/super.c, branch linux-rolling-lts

btrfs: only enforce free space tree if v1 cache is required for bs < ps cases

2026-01-17T15:35:25Z

[ Upstream commit 30bcf4e824aa37d305502f52e1527c7b1eabef3d ] [BUG] Since the introduction of btrfs bs < ps support, v1 cache was never on the plan due to its hard coded PAGE_SIZE usage, and the future plan to properly deprecate it. However for bs < ps cases, even if 'nospace_cache,clear_cache' mount option is specified, it's never respected and free space tree is always enabled: mkfs.btrfs -f -O ^bgt,fst $dev mount $dev $mnt -o clear_cache,nospace_cache umount $mnt btrfs ins dump-super $dev ... compat_ro_flags 0x3 ( FREE_SPACE_TREE | FREE_SPACE_TREE_VALID ) ... This means a different behavior compared to bs >= ps cases. [CAUSE] The forcing usage of v2 space cache is done inside btrfs_set_free_space_cache_settings(), however it never checks if we're even using space cache but always enabling v2 cache. [FIX] Instead unconditionally enable v2 cache, only forcing v2 cache if the old v1 cache is required. Now v2 space cache can be properly disabled on bs < ps cases: mkfs.btrfs -f -O ^bgt,fst $dev mount $dev $mnt -o clear_cache,nospace_cache umount $mnt btrfs ins dump-super $dev ... compat_ro_flags 0x0 ... Fixes: 9f73f1aef98b ("btrfs: force v2 space cache usage for subpage mount") Reviewed-by: Filipe Manana Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba Signed-off-by: Sasha Levin

btrfs: directly free partially initialized fs_info in btrfs_check_leaked_roots()

2025-10-17T16:33:27Z

If fs_info->super_copy or fs_info->super_for_commit allocated failed in btrfs_get_tree_subvol(), then no need to call btrfs_free_fs_info(). Otherwise btrfs_check_leaked_roots() would access NULL pointer because fs_info->allocated_roots had not been initialised. syzkaller reported the following information: ------------[ cut here ]------------ BUG: unable to handle page fault for address: fffffffffffffbb0 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 64c9067 P4D 64c9067 PUD 64cb067 PMD 0 Oops: Oops: 0000 [#1] SMP KASAN PTI CPU: 0 UID: 0 PID: 1402 Comm: syz.1.35 Not tainted 6.15.8 #4 PREEMPT(lazy) Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), (...) RIP: 0010:arch_atomic_read arch/x86/include/asm/atomic.h:23 [inline] RIP: 0010:raw_atomic_read include/linux/atomic/atomic-arch-fallback.h:457 [inline] RIP: 0010:atomic_read include/linux/atomic/atomic-instrumented.h:33 [inline] RIP: 0010:refcount_read include/linux/refcount.h:170 [inline] RIP: 0010:btrfs_check_leaked_roots+0x18f/0x2c0 fs/btrfs/disk-io.c:1230 [...] Call Trace: btrfs_free_fs_info+0x310/0x410 fs/btrfs/disk-io.c:1280 btrfs_get_tree_subvol+0x592/0x6b0 fs/btrfs/super.c:2029 btrfs_get_tree+0x63/0x80 fs/btrfs/super.c:2097 vfs_get_tree+0x98/0x320 fs/super.c:1759 do_new_mount+0x357/0x660 fs/namespace.c:3899 path_mount+0x716/0x19c0 fs/namespace.c:4226 do_mount fs/namespace.c:4239 [inline] __do_sys_mount fs/namespace.c:4450 [inline] __se_sys_mount fs/namespace.c:4427 [inline] __x64_sys_mount+0x28c/0x310 fs/namespace.c:4427 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x92/0x180 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7f032eaffa8d [...] Fixes: 3bb17a25bcb0 ("btrfs: add get_tree callback for new mount API") CC: stable@vger.kernel.org # 6.12+ Reviewed-by: Daniel Vacek Reviewed-by: Qu Wenruo Signed-off-by: Dewei Meng Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: only set the device specific options after devices are opened

2025-10-13T20:29:53Z

[BUG] With v6.17-rc kernels, btrfs will always set 'ssd' mount option even if the block device is not a rotating one: # cat /sys/block/sdd/queue/rotational 1 # cat /etc/fstab: LABEL=DATA2 /data2 btrfs rw,relatime,space_cache=v2,subvolid=5,subvol=/,nofail,nosuid,nodev 0 0 # mount [...] /dev/sdd on /data2 type btrfs (rw,nosuid,nodev,relatime,ssd,space_cache=v2,subvolid=5,subvol=/) [CAUSE] The 'ssd' mount option is set by set_device_specific_options(), and it expects that if there is any rotating device in the btrfs, it will set fs_devices::rotating. However after commit bddf57a70781 ("btrfs: delay btrfs_open_devices() until super block is created"), the device opening is delayed until the super block is created. But the timing of set_device_specific_options() is still left as is, this makes the function be called without any device opened. Since no device is opened, thus fs_devices::rotating will never be set, making btrfs incorrectly set 'ssd' mount option. [FIX] Only call set_device_specific_options() after btrfs_open_devices(). Also only call set_device_specific_options() after a new mount, if we're mounting a mounted btrfs, there is no need to set the device specific mount options again. Reported-by: HAN Yuwei Link: https://lore.kernel.org/linux-btrfs/C8FF75669DFFC3C5+5f93bf8a-80a0-48a6-81bf-4ec890abc99a@bupt.moe/ Fixes: bddf57a70781 ("btrfs: delay btrfs_open_devices() until super block is created") CC: stable@vger.kernel.org # 6.17 Signed-off-by: Qu Wenruo Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: add unlikely annotations to branches leading to EUCLEAN

2025-09-23T06:49:26Z

The unlikely() annotation is a static prediction hint that compiler may use to reorder code out of hot path. We use it elsewhere (namely tree-checker.c) for error branches that almost never happen, where EUCLEAN (a corruption) is one of them. Reviewed-by: Filipe Manana Signed-off-by: David Sterba

btrfs: more trivial BTRFS_PATH_AUTO_FREE conversions

2025-09-23T06:49:26Z

Trivial pattern for the auto freeing with goto -> return conversions if possible. The following cases are considered trivial in this patch: 1. Cases where there are no operations between btrfs_free_path() and the function returns. 2. Cases where only simple cleanup operations (such as kfree(), kvfree(), clear_bit(), and fs_path_free()) are present between btrfs_free_path() and the function return. Signed-off-by: Sun YangKai Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: fix typos in comments and strings

2025-09-23T06:49:16Z

Annual typo fixing pass. Strangely codespell found only about 30% of what is in this patch, the rest was done manually using text spellchecker with a custom dictionary of acceptable terms. Reviewed-by: Neal Gompa Signed-off-by: David Sterba

btrfs: add mount option for ref_tracker

2025-09-22T08:54:32Z

The ref_tracker infrastructure aids debugging but is not enabled by default as it has a performance impact. Add mount option 'ref_tracker' so it can be selectively enabled on a filesystem. Currently it track references of 'delayed inodes'. Signed-off-by: Leo Martins Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: move ref-verify under CONFIG_BTRFS_DEBUG

2025-09-22T08:54:32Z

Remove CONFIG_BTRFS_FS_REF_VERIFY Kconfig and add it as part of CONFIG_BTRFS_DEBUG. This should not be impactful to the performance of debug. The struct btrfs_ref takes an additional u64, btrfs_fs_info takes an additional spinlock_t and rb_root. All of the ref_verify logic is still protected by a mount option. Signed-off-by: Leo Martins Reviewed-by: David Sterba Signed-off-by: David Sterba

btrfs: use PTR_ERR_OR_ZERO() to simplify code inbtrfs_control_ioctl()

2025-09-22T08:54:31Z

Use the standard error pointer macro to simplify the code. Reviewed-by: Daniel Vacek Signed-off-by: Xichao Zhao Reviewed-by: David Sterba Signed-off-by: David Sterba

Merge tag 'for-6.17-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux

2025-09-21T04:41:26Z

Pull a few more btrfs fixes from David Sterba: - in tree-checker, fix wrong size of check for inode ref item - in ref-verify, handle combination of mount options that allow partially damaged extent tree (reported by syzbot) - additional validation of compression mount option to catch invalid string as level * tag 'for-6.17-rc6-tag' of git://git.kernel.org/pub/scm/linux/kernel/git/kdave/linux: btrfs: reject invalid compression level btrfs: ref-verify: handle damaged extent root tree btrfs: tree-checker: fix the incorrect inode ref size check