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2020-12-02btrfs: don't access possibly stale fs_info data for printing duplicate deviceJohannes Thumshirn1-1/+7
commit 0697d9a610998b8bdee6b2390836cb2391d8fd1a upstream. Syzbot reported a possible use-after-free when printing a duplicate device warning device_list_add(). At this point it can happen that a btrfs_device::fs_info is not correctly setup yet, so we're accessing stale data, when printing the warning message using the btrfs_printk() wrappers. ================================================================== BUG: KASAN: use-after-free in btrfs_printk+0x3eb/0x435 fs/btrfs/super.c:245 Read of size 8 at addr ffff8880878e06a8 by task syz-executor225/7068 CPU: 1 PID: 7068 Comm: syz-executor225 Not tainted 5.9.0-rc5-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1d6/0x29e lib/dump_stack.c:118 print_address_description+0x66/0x620 mm/kasan/report.c:383 __kasan_report mm/kasan/report.c:513 [inline] kasan_report+0x132/0x1d0 mm/kasan/report.c:530 btrfs_printk+0x3eb/0x435 fs/btrfs/super.c:245 device_list_add+0x1a88/0x1d60 fs/btrfs/volumes.c:943 btrfs_scan_one_device+0x196/0x490 fs/btrfs/volumes.c:1359 btrfs_mount_root+0x48f/0xb60 fs/btrfs/super.c:1634 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 fc_mount fs/namespace.c:978 [inline] vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x179d/0x29e0 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount+0x126/0x180 fs/namespace.c:3390 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x44840a RSP: 002b:00007ffedfffd608 EFLAGS: 00000293 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007ffedfffd670 RCX: 000000000044840a RDX: 0000000020000000 RSI: 0000000020000100 RDI: 00007ffedfffd630 RBP: 00007ffedfffd630 R08: 00007ffedfffd670 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000001a R13: 0000000000000004 R14: 0000000000000003 R15: 0000000000000003 Allocated by task 6945: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track mm/kasan/common.c:56 [inline] __kasan_kmalloc+0x100/0x130 mm/kasan/common.c:461 kmalloc_node include/linux/slab.h:577 [inline] kvmalloc_node+0x81/0x110 mm/util.c:574 kvmalloc include/linux/mm.h:757 [inline] kvzalloc include/linux/mm.h:765 [inline] btrfs_mount_root+0xd0/0xb60 fs/btrfs/super.c:1613 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 fc_mount fs/namespace.c:978 [inline] vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x179d/0x29e0 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount+0x126/0x180 fs/namespace.c:3390 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Freed by task 6945: kasan_save_stack mm/kasan/common.c:48 [inline] kasan_set_track+0x3d/0x70 mm/kasan/common.c:56 kasan_set_free_info+0x17/0x30 mm/kasan/generic.c:355 __kasan_slab_free+0xdd/0x110 mm/kasan/common.c:422 __cache_free mm/slab.c:3418 [inline] kfree+0x113/0x200 mm/slab.c:3756 deactivate_locked_super+0xa7/0xf0 fs/super.c:335 btrfs_mount_root+0x72b/0xb60 fs/btrfs/super.c:1678 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 fc_mount fs/namespace.c:978 [inline] vfs_kern_mount+0xc9/0x160 fs/namespace.c:1008 btrfs_mount+0x33c/0xae0 fs/btrfs/super.c:1732 legacy_get_tree+0xea/0x180 fs/fs_context.c:592 vfs_get_tree+0x88/0x270 fs/super.c:1547 do_new_mount fs/namespace.c:2875 [inline] path_mount+0x179d/0x29e0 fs/namespace.c:3192 do_mount fs/namespace.c:3205 [inline] __do_sys_mount fs/namespace.c:3413 [inline] __se_sys_mount+0x126/0x180 fs/namespace.c:3390 do_syscall_64+0x31/0x70 arch/x86/entry/common.c:46 entry_SYSCALL_64_after_hwframe+0x44/0xa9 The buggy address belongs to the object at ffff8880878e0000 which belongs to the cache kmalloc-16k of size 16384 The buggy address is located 1704 bytes inside of 16384-byte region [ffff8880878e0000, ffff8880878e4000) The buggy address belongs to the page: page:0000000060704f30 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x878e0 head:0000000060704f30 order:3 compound_mapcount:0 compound_pincount:0 flags: 0xfffe0000010200(slab|head) raw: 00fffe0000010200 ffffea00028e9a08 ffffea00021e3608 ffff8880aa440b00 raw: 0000000000000000 ffff8880878e0000 0000000100000001 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8880878e0580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880878e0600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb >ffff8880878e0680: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8880878e0700: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8880878e0780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ================================================================== The syzkaller reproducer for this use-after-free crafts a filesystem image and loop mounts it twice in a loop. The mount will fail as the crafted image has an invalid chunk tree. When this happens btrfs_mount_root() will call deactivate_locked_super(), which then cleans up fs_info and fs_info::sb. If a second thread now adds the same block-device to the filesystem, it will get detected as a duplicate device and device_list_add() will reject the duplicate and print a warning. But as the fs_info pointer passed in is non-NULL this will result in a use-after-free. Instead of printing possibly uninitialized or already freed memory in btrfs_printk(), explicitly pass in a NULL fs_info so the printing of the device name will be skipped altogether. There was a slightly different approach discussed in https://lore.kernel.org/linux-btrfs/20200114060920.4527-1-anand.jain@oracle.com/t/#u Link: https://lore.kernel.org/linux-btrfs/000000000000c9e14b05afcc41ba@google.com Reported-by: syzbot+582e66e5edf36a22c7b0@syzkaller.appspotmail.com CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Nikolay Borisov <nborisov@suse.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Johannes Thumshirn <johannes.thumshirn@wdc.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>
2020-11-18btrfs: dev-replace: fail mount if we don't have replace item with target deviceAnand Jain1-19/+7
commit cf89af146b7e62af55470cf5f3ec3c56ec144a5e upstream. If there is a device BTRFS_DEV_REPLACE_DEVID without the device replace item, then it means the filesystem is inconsistent state. This is either corruption or a crafted image. Fail the mount as this needs a closer look what is actually wrong. As of now if BTRFS_DEV_REPLACE_DEVID is present without the replace item, in __btrfs_free_extra_devids() we determine that there is an extra device, and free those extra devices but continue to mount the device. However, we were wrong in keeping tack of the rw_devices so the syzbot testcase failed: WARNING: CPU: 1 PID: 3612 at fs/btrfs/volumes.c:1166 close_fs_devices.part.0+0x607/0x800 fs/btrfs/volumes.c:1166 Kernel panic - not syncing: panic_on_warn set ... CPU: 1 PID: 3612 Comm: syz-executor.2 Not tainted 5.9.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x198/0x1fd lib/dump_stack.c:118 panic+0x347/0x7c0 kernel/panic.c:231 __warn.cold+0x20/0x46 kernel/panic.c:600 report_bug+0x1bd/0x210 lib/bug.c:198 handle_bug+0x38/0x90 arch/x86/kernel/traps.c:234 exc_invalid_op+0x14/0x40 arch/x86/kernel/traps.c:254 asm_exc_invalid_op+0x12/0x20 arch/x86/include/asm/idtentry.h:536 RIP: 0010:close_fs_devices.part.0+0x607/0x800 fs/btrfs/volumes.c:1166 RSP: 0018:ffffc900091777e0 EFLAGS: 00010246 RAX: 0000000000040000 RBX: ffffffffffffffff RCX: ffffc9000c8b7000 RDX: 0000000000040000 RSI: ffffffff83097f47 RDI: 0000000000000007 RBP: dffffc0000000000 R08: 0000000000000001 R09: ffff8880988a187f R10: 0000000000000000 R11: 0000000000000001 R12: ffff88809593a130 R13: ffff88809593a1ec R14: ffff8880988a1908 R15: ffff88809593a050 close_fs_devices fs/btrfs/volumes.c:1193 [inline] btrfs_close_devices+0x95/0x1f0 fs/btrfs/volumes.c:1179 open_ctree+0x4984/0x4a2d fs/btrfs/disk-io.c:3434 btrfs_fill_super fs/btrfs/super.c:1316 [inline] btrfs_mount_root.cold+0x14/0x165 fs/btrfs/super.c:1672 The fix here is, when we determine that there isn't a replace item then fail the mount if there is a replace target device (devid 0). CC: stable@vger.kernel.org # 4.19+ Reported-by: syzbot+4cfe71a4da060be47502@syzkaller.appspotmail.com Signed-off-by: Anand Jain <anand.jain@oracle.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>
2020-11-18btrfs: sysfs: init devices outside of the chunk_mutexJosef Bacik1-3/+4
[ Upstream commit ca10845a56856fff4de3804c85e6424d0f6d0cde ] While running btrfs/061, btrfs/073, btrfs/078, or btrfs/178 we hit the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc3+ #4 Not tainted ------------------------------------------------------ kswapd0/100 is trying to acquire lock: ffff96ecc22ef4a0 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330 but task is already holding lock: ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #3 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire+0x65/0x80 slab_pre_alloc_hook.constprop.0+0x20/0x200 kmem_cache_alloc+0x37/0x270 alloc_inode+0x82/0xb0 iget_locked+0x10d/0x2c0 kernfs_get_inode+0x1b/0x130 kernfs_get_tree+0x136/0x240 sysfs_get_tree+0x16/0x40 vfs_get_tree+0x28/0xc0 path_mount+0x434/0xc00 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (kernfs_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 kernfs_add_one+0x23/0x150 kernfs_create_link+0x63/0xa0 sysfs_do_create_link_sd+0x5e/0xd0 btrfs_sysfs_add_devices_dir+0x81/0x130 btrfs_init_new_device+0x67f/0x1250 btrfs_ioctl+0x1ef/0x2e20 __x64_sys_ioctl+0x83/0xb0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 btrfs_chunk_alloc+0x125/0x3a0 find_free_extent+0xdf6/0x1210 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb0/0x310 alloc_tree_block_no_bg_flush+0x4a/0x60 __btrfs_cow_block+0x11a/0x530 btrfs_cow_block+0x104/0x220 btrfs_search_slot+0x52e/0x9d0 btrfs_insert_empty_items+0x64/0xb0 btrfs_insert_delayed_items+0x90/0x4f0 btrfs_commit_inode_delayed_items+0x93/0x140 btrfs_log_inode+0x5de/0x2020 btrfs_log_inode_parent+0x429/0xc90 btrfs_log_new_name+0x95/0x9b btrfs_rename2+0xbb9/0x1800 vfs_rename+0x64f/0x9f0 do_renameat2+0x320/0x4e0 __x64_sys_rename+0x1f/0x30 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: __lock_acquire+0x119c/0x1fc0 lock_acquire+0xa7/0x3d0 __mutex_lock+0x7e/0x7e0 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 kthread+0x138/0x160 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> kernfs_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(kernfs_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/100: #0: ffffffff8dd74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffff8dd65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290 #2: ffff96ed2ade30e0 (&type->s_umount_key#36){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0 stack backtrace: CPU: 0 PID: 100 Comm: kswapd0 Not tainted 5.9.0-rc3+ #4 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x8b/0xb8 check_noncircular+0x12d/0x150 __lock_acquire+0x119c/0x1fc0 lock_acquire+0xa7/0x3d0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 __mutex_lock+0x7e/0x7e0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? lock_acquire+0xa7/0x3d0 ? find_held_lock+0x2b/0x80 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 ? _raw_spin_unlock_irqrestore+0x41/0x50 ? add_wait_queue_exclusive+0x70/0x70 ? balance_pgdat+0x670/0x670 kthread+0x138/0x160 ? kthread_create_worker_on_cpu+0x40/0x40 ret_from_fork+0x1f/0x30 This happens because we are holding the chunk_mutex at the time of adding in a new device. However we only need to hold the device_list_mutex, as we're going to iterate over the fs_devices devices. Move the sysfs init stuff outside of the chunk_mutex to get rid of this lockdep splat. CC: stable@vger.kernel.org # 4.4.x: f3cd2c58110dad14e: btrfs: sysfs, rename device_link add/remove functions CC: stable@vger.kernel.org # 4.4.x Reported-by: David Sterba <dsterba@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-11-10btrfs: tree-checker: Verify dev itemQu Wenruo1-9/+0
commit ab4ba2e133463c702b37242560d7fabedd2dc750 upstream. [BUG] For fuzzed image whose DEV_ITEM has invalid total_bytes as 0, then kernel will just panic: BUG: unable to handle kernel NULL pointer dereference at 0000000000000098 #PF error: [normal kernel read fault] PGD 800000022b2bd067 P4D 800000022b2bd067 PUD 22b2bc067 PMD 0 Oops: 0000 [#1] SMP PTI CPU: 0 PID: 1106 Comm: mount Not tainted 5.0.0-rc8+ #9 RIP: 0010:btrfs_verify_dev_extents+0x2a5/0x5a0 Call Trace: open_ctree+0x160d/0x2149 btrfs_mount_root+0x5b2/0x680 [CAUSE] If device extent verification finds a deivce with 0 total_bytes, then it assumes it's a seed dummy, then search for seed devices. But in this case, there is no seed device at all, causing NULL pointer. [FIX] Since this is caused by fuzzed image, let's go the tree-check way, just add a new verification for device item. Reported-by: Yoon Jungyeon <jungyeon@gatech.edu> Link: https://bugzilla.kernel.org/show_bug.cgi?id=202691 Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-10btrfs: tree-checker: Check chunk item at tree block read timeQu Wenruo1-3/+9
commit 075cb3c78fe7976c9f29ca1fa23f9728634ecefc upstream. Since we have btrfs_check_chunk_valid() in tree-checker, let's do chunk item verification in tree-checker too. Since the tree-checker is run at endio time, if one chunk leaf fails chunk verification, we can still retry the other copy, making btrfs more robust to fuzzed image as we may still get a good chunk item. Also since we have done chunk verification in tree block read time, skip the btrfs_check_chunk_valid() call in read_one_chunk() if we're reading chunk items from leaf. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> 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: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-10btrfs: Move btrfs_check_chunk_valid() to tree-check.[ch] and export itQu Wenruo1-93/+1
commit 82fc28fbedbb59642f05215db3b0ef4eb91aa31d upstream. By function, chunk item verification is more suitable to be done inside tree-checker. So move btrfs_check_chunk_valid() to tree-checker.c and export it. And since it's now moved to tree-checker, also add a better comment for what this function is doing. Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de> Signed-off-by: Qu Wenruo <wqu@suse.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> [bwh: Cherry-picked for 4.19 to ease backporting later fixes] Signed-off-by: Ben Hutchings <ben.hutchings@codethink.co.uk> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-11-05btrfs: improve device scanning messagesAnand Jain1-6/+8
commit 79dae17d8d44b2d15779e332180080af45df5352 upstream. Systems booting without the initramfs seems to scan an unusual kind of device path (/dev/root). And at a later time, the device is updated to the correct path. We generally print the process name and PID of the process scanning the device but we don't capture the same information if the device path is rescanned with a different pathname. The current message is too long, so drop the unnecessary UUID and add process name and PID. While at this also update the duplicate device warning to include the process name and PID so the messages are consistent CC: stable@vger.kernel.org # 4.19+ Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=89721 Signed-off-by: Anand Jain <anand.jain@oracle.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>
2020-09-17btrfs: fix lockdep splat in add_missing_devJosef Bacik1-0/+10
commit fccc0007b8dc952c6bc0805cdf842eb8ea06a639 upstream. Nikolay reported a lockdep splat in generic/476 that I could reproduce with btrfs/187. ====================================================== WARNING: possible circular locking dependency detected 5.9.0-rc2+ #1 Tainted: G W ------------------------------------------------------ kswapd0/100 is trying to acquire lock: ffff9e8ef38b6268 (&delayed_node->mutex){+.+.}-{3:3}, at: __btrfs_release_delayed_node.part.0+0x3f/0x330 but task is already holding lock: ffffffffa9d74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #2 (fs_reclaim){+.+.}-{0:0}: fs_reclaim_acquire+0x65/0x80 slab_pre_alloc_hook.constprop.0+0x20/0x200 kmem_cache_alloc_trace+0x3a/0x1a0 btrfs_alloc_device+0x43/0x210 add_missing_dev+0x20/0x90 read_one_chunk+0x301/0x430 btrfs_read_sys_array+0x17b/0x1b0 open_ctree+0xa62/0x1896 btrfs_mount_root.cold+0x12/0xea legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x10d/0x379 legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 path_mount+0x434/0xc00 __x64_sys_mount+0xe3/0x120 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->chunk_mutex){+.+.}-{3:3}: __mutex_lock+0x7e/0x7e0 btrfs_chunk_alloc+0x125/0x3a0 find_free_extent+0xdf6/0x1210 btrfs_reserve_extent+0xb3/0x1b0 btrfs_alloc_tree_block+0xb0/0x310 alloc_tree_block_no_bg_flush+0x4a/0x60 __btrfs_cow_block+0x11a/0x530 btrfs_cow_block+0x104/0x220 btrfs_search_slot+0x52e/0x9d0 btrfs_lookup_inode+0x2a/0x8f __btrfs_update_delayed_inode+0x80/0x240 btrfs_commit_inode_delayed_inode+0x119/0x120 btrfs_evict_inode+0x357/0x500 evict+0xcf/0x1f0 vfs_rmdir.part.0+0x149/0x160 do_rmdir+0x136/0x1a0 do_syscall_64+0x33/0x40 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&delayed_node->mutex){+.+.}-{3:3}: __lock_acquire+0x1184/0x1fa0 lock_acquire+0xa4/0x3d0 __mutex_lock+0x7e/0x7e0 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 kthread+0x138/0x160 ret_from_fork+0x1f/0x30 other info that might help us debug this: Chain exists of: &delayed_node->mutex --> &fs_info->chunk_mutex --> fs_reclaim Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(fs_reclaim); lock(&fs_info->chunk_mutex); lock(fs_reclaim); lock(&delayed_node->mutex); *** DEADLOCK *** 3 locks held by kswapd0/100: #0: ffffffffa9d74700 (fs_reclaim){+.+.}-{0:0}, at: __fs_reclaim_acquire+0x5/0x30 #1: ffffffffa9d65c50 (shrinker_rwsem){++++}-{3:3}, at: shrink_slab+0x115/0x290 #2: ffff9e8e9da260e0 (&type->s_umount_key#48){++++}-{3:3}, at: super_cache_scan+0x38/0x1e0 stack backtrace: CPU: 1 PID: 100 Comm: kswapd0 Tainted: G W 5.9.0-rc2+ #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.13.0-2.fc32 04/01/2014 Call Trace: dump_stack+0x92/0xc8 check_noncircular+0x12d/0x150 __lock_acquire+0x1184/0x1fa0 lock_acquire+0xa4/0x3d0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 __mutex_lock+0x7e/0x7e0 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? __btrfs_release_delayed_node.part.0+0x3f/0x330 ? lock_acquire+0xa4/0x3d0 ? btrfs_evict_inode+0x11e/0x500 ? find_held_lock+0x2b/0x80 __btrfs_release_delayed_node.part.0+0x3f/0x330 btrfs_evict_inode+0x24c/0x500 evict+0xcf/0x1f0 dispose_list+0x48/0x70 prune_icache_sb+0x44/0x50 super_cache_scan+0x161/0x1e0 do_shrink_slab+0x178/0x3c0 shrink_slab+0x17c/0x290 shrink_node+0x2b2/0x6d0 balance_pgdat+0x30a/0x670 kswapd+0x213/0x4c0 ? _raw_spin_unlock_irqrestore+0x46/0x60 ? add_wait_queue_exclusive+0x70/0x70 ? balance_pgdat+0x670/0x670 kthread+0x138/0x160 ? kthread_create_worker_on_cpu+0x40/0x40 ret_from_fork+0x1f/0x30 This is because we are holding the chunk_mutex when we call btrfs_alloc_device, which does a GFP_KERNEL allocation. We don't want to switch that to a GFP_NOFS lock because this is the only place where it matters. So instead use memalloc_nofs_save() around the allocation in order to avoid the lockdep splat. Reported-by: Nikolay Borisov <nborisov@suse.com> CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Josef Bacik <josef@toxicpanda.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>
2020-09-09btrfs: drop path before adding new uuid tree entryJosef Bacik1-1/+2
commit 9771a5cf937129307d9f58922d60484d58ababe7 upstream. With the conversion of the tree locks to rwsem I got the following lockdep splat: ====================================================== WARNING: possible circular locking dependency detected 5.8.0-rc7-00167-g0d7ba0c5b375-dirty #925 Not tainted ------------------------------------------------------ btrfs-uuid/7955 is trying to acquire lock: ffff88bfbafec0f8 (btrfs-root-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 but task is already holding lock: ffff88bfbafef2a8 (btrfs-uuid-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #1 (btrfs-uuid-00){++++}-{3:3}: down_read_nested+0x3e/0x140 __btrfs_tree_read_lock+0x39/0x180 __btrfs_read_lock_root_node+0x3a/0x50 btrfs_search_slot+0x4bd/0x990 btrfs_uuid_tree_add+0x89/0x2d0 btrfs_uuid_scan_kthread+0x330/0x390 kthread+0x133/0x150 ret_from_fork+0x1f/0x30 -> #0 (btrfs-root-00){++++}-{3:3}: __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 down_read_nested+0x3e/0x140 __btrfs_tree_read_lock+0x39/0x180 __btrfs_read_lock_root_node+0x3a/0x50 btrfs_search_slot+0x4bd/0x990 btrfs_find_root+0x45/0x1b0 btrfs_read_tree_root+0x61/0x100 btrfs_get_root_ref.part.50+0x143/0x630 btrfs_uuid_tree_iterate+0x207/0x314 btrfs_uuid_rescan_kthread+0x12/0x50 kthread+0x133/0x150 ret_from_fork+0x1f/0x30 other info that might help us debug this: Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(btrfs-uuid-00); lock(btrfs-root-00); lock(btrfs-uuid-00); lock(btrfs-root-00); *** DEADLOCK *** 1 lock held by btrfs-uuid/7955: #0: ffff88bfbafef2a8 (btrfs-uuid-00){++++}-{3:3}, at: __btrfs_tree_read_lock+0x39/0x180 stack backtrace: CPU: 73 PID: 7955 Comm: btrfs-uuid Kdump: loaded Not tainted 5.8.0-rc7-00167-g0d7ba0c5b375-dirty #925 Hardware name: Quanta Tioga Pass Single Side 01-0030993006/Tioga Pass Single Side, BIOS F08_3A18 12/20/2018 Call Trace: dump_stack+0x78/0xa0 check_noncircular+0x165/0x180 __lock_acquire+0x1272/0x2310 lock_acquire+0x9e/0x360 ? __btrfs_tree_read_lock+0x39/0x180 ? btrfs_root_node+0x1c/0x1d0 down_read_nested+0x3e/0x140 ? __btrfs_tree_read_lock+0x39/0x180 __btrfs_tree_read_lock+0x39/0x180 __btrfs_read_lock_root_node+0x3a/0x50 btrfs_search_slot+0x4bd/0x990 btrfs_find_root+0x45/0x1b0 btrfs_read_tree_root+0x61/0x100 btrfs_get_root_ref.part.50+0x143/0x630 btrfs_uuid_tree_iterate+0x207/0x314 ? btree_readpage+0x20/0x20 btrfs_uuid_rescan_kthread+0x12/0x50 kthread+0x133/0x150 ? kthread_create_on_node+0x60/0x60 ret_from_fork+0x1f/0x30 This problem exists because we have two different rescan threads, btrfs_uuid_scan_kthread which creates the uuid tree, and btrfs_uuid_tree_iterate that goes through and updates or deletes any out of date roots. The problem is they both do things in different order. btrfs_uuid_scan_kthread() reads the tree_root, and then inserts entries into the uuid_root. btrfs_uuid_tree_iterate() scans the uuid_root, but then does a btrfs_get_fs_root() which can read from the tree_root. It's actually easy enough to not be holding the path in btrfs_uuid_scan_kthread() when we add a uuid entry, as we already drop it further down and re-start the search when we loop. So simply move the path release before we add our entry to the uuid tree. This also fixes a problem where we're holding a path open after we do btrfs_end_transaction(), which has it's own problems. CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Josef Bacik <josef@toxicpanda.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>
2020-08-21btrfs: open device without device_list_mutexJosef Bacik1-3/+18
commit 18c850fdc5a801bad4977b0f1723761d42267e45 upstream. There's long existed a lockdep splat because we open our bdev's under the ->device_list_mutex at mount time, which acquires the bd_mutex. Usually this goes unnoticed, but if you do loopback devices at all suddenly the bd_mutex comes with a whole host of other dependencies, which results in the splat when you mount a btrfs file system. ====================================================== WARNING: possible circular locking dependency detected 5.8.0-0.rc3.1.fc33.x86_64+debug #1 Not tainted ------------------------------------------------------ systemd-journal/509 is trying to acquire lock: ffff970831f84db0 (&fs_info->reloc_mutex){+.+.}-{3:3}, at: btrfs_record_root_in_trans+0x44/0x70 [btrfs] but task is already holding lock: ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (sb_pagefaults){.+.+}-{0:0}: __sb_start_write+0x13e/0x220 btrfs_page_mkwrite+0x59/0x560 [btrfs] do_page_mkwrite+0x4f/0x130 do_wp_page+0x3b0/0x4f0 handle_mm_fault+0xf47/0x1850 do_user_addr_fault+0x1fc/0x4b0 exc_page_fault+0x88/0x300 asm_exc_page_fault+0x1e/0x30 -> #5 (&mm->mmap_lock#2){++++}-{3:3}: __might_fault+0x60/0x80 _copy_from_user+0x20/0xb0 get_sg_io_hdr+0x9a/0xb0 scsi_cmd_ioctl+0x1ea/0x2f0 cdrom_ioctl+0x3c/0x12b4 sr_block_ioctl+0xa4/0xd0 block_ioctl+0x3f/0x50 ksys_ioctl+0x82/0xc0 __x64_sys_ioctl+0x16/0x20 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #4 (&cd->lock){+.+.}-{3:3}: __mutex_lock+0x7b/0x820 sr_block_open+0xa2/0x180 __blkdev_get+0xdd/0x550 blkdev_get+0x38/0x150 do_dentry_open+0x16b/0x3e0 path_openat+0x3c9/0xa00 do_filp_open+0x75/0x100 do_sys_openat2+0x8a/0x140 __x64_sys_openat+0x46/0x70 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #3 (&bdev->bd_mutex){+.+.}-{3:3}: __mutex_lock+0x7b/0x820 __blkdev_get+0x6a/0x550 blkdev_get+0x85/0x150 blkdev_get_by_path+0x2c/0x70 btrfs_get_bdev_and_sb+0x1b/0xb0 [btrfs] open_fs_devices+0x88/0x240 [btrfs] btrfs_open_devices+0x92/0xa0 [btrfs] btrfs_mount_root+0x250/0x490 [btrfs] legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 vfs_kern_mount.part.0+0x71/0xb0 btrfs_mount+0x119/0x380 [btrfs] legacy_get_tree+0x30/0x50 vfs_get_tree+0x28/0xc0 do_mount+0x8c6/0xca0 __x64_sys_mount+0x8e/0xd0 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #2 (&fs_devs->device_list_mutex){+.+.}-{3:3}: __mutex_lock+0x7b/0x820 btrfs_run_dev_stats+0x36/0x420 [btrfs] commit_cowonly_roots+0x91/0x2d0 [btrfs] btrfs_commit_transaction+0x4e6/0x9f0 [btrfs] btrfs_sync_file+0x38a/0x480 [btrfs] __x64_sys_fdatasync+0x47/0x80 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #1 (&fs_info->tree_log_mutex){+.+.}-{3:3}: __mutex_lock+0x7b/0x820 btrfs_commit_transaction+0x48e/0x9f0 [btrfs] btrfs_sync_file+0x38a/0x480 [btrfs] __x64_sys_fdatasync+0x47/0x80 do_syscall_64+0x52/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xa9 -> #0 (&fs_info->reloc_mutex){+.+.}-{3:3}: __lock_acquire+0x1241/0x20c0 lock_acquire+0xb0/0x400 __mutex_lock+0x7b/0x820 btrfs_record_root_in_trans+0x44/0x70 [btrfs] start_transaction+0xd2/0x500 [btrfs] btrfs_dirty_inode+0x44/0xd0 [btrfs] file_update_time+0xc6/0x120 btrfs_page_mkwrite+0xda/0x560 [btrfs] do_page_mkwrite+0x4f/0x130 do_wp_page+0x3b0/0x4f0 handle_mm_fault+0xf47/0x1850 do_user_addr_fault+0x1fc/0x4b0 exc_page_fault+0x88/0x300 asm_exc_page_fault+0x1e/0x30 other info that might help us debug this: Chain exists of: &fs_info->reloc_mutex --> &mm->mmap_lock#2 --> sb_pagefaults Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(sb_pagefaults); lock(&mm->mmap_lock#2); lock(sb_pagefaults); lock(&fs_info->reloc_mutex); *** DEADLOCK *** 3 locks held by systemd-journal/509: #0: ffff97083bdec8b8 (&mm->mmap_lock#2){++++}-{3:3}, at: do_user_addr_fault+0x12e/0x4b0 #1: ffff97083144d598 (sb_pagefaults){.+.+}-{0:0}, at: btrfs_page_mkwrite+0x59/0x560 [btrfs] #2: ffff97083144d6a8 (sb_internal){.+.+}-{0:0}, at: start_transaction+0x3f8/0x500 [btrfs] stack backtrace: CPU: 0 PID: 509 Comm: systemd-journal Not tainted 5.8.0-0.rc3.1.fc33.x86_64+debug #1 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015 Call Trace: dump_stack+0x92/0xc8 check_noncircular+0x134/0x150 __lock_acquire+0x1241/0x20c0 lock_acquire+0xb0/0x400 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs] ? lock_acquire+0xb0/0x400 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs] __mutex_lock+0x7b/0x820 ? btrfs_record_root_in_trans+0x44/0x70 [btrfs] ? kvm_sched_clock_read+0x14/0x30 ? sched_clock+0x5/0x10 ? sched_clock_cpu+0xc/0xb0 btrfs_record_root_in_trans+0x44/0x70 [btrfs] start_transaction+0xd2/0x500 [btrfs] btrfs_dirty_inode+0x44/0xd0 [btrfs] file_update_time+0xc6/0x120 btrfs_page_mkwrite+0xda/0x560 [btrfs] ? sched_clock+0x5/0x10 do_page_mkwrite+0x4f/0x130 do_wp_page+0x3b0/0x4f0 handle_mm_fault+0xf47/0x1850 do_user_addr_fault+0x1fc/0x4b0 exc_page_fault+0x88/0x300 ? asm_exc_page_fault+0x8/0x30 asm_exc_page_fault+0x1e/0x30 RIP: 0033:0x7fa3972fdbfe Code: Bad RIP value. Fix this by not holding the ->device_list_mutex at this point. The device_list_mutex exists to protect us from modifying the device list while the file system is running. However it can also be modified by doing a scan on a device. But this action is specifically protected by the uuid_mutex, which we are holding here. We cannot race with opening at this point because we have the ->s_mount lock held during the mount. Not having the ->device_list_mutex here is perfectly safe as we're not going to change the devices at this point. CC: stable@vger.kernel.org # 4.19+ Signed-off-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: David Sterba <dsterba@suse.com> [ add some comments ] Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-07-29btrfs: fix mount failure caused by race with umountBoris Burkov1-0/+8
commit 48cfa61b58a1fee0bc49eef04f8ccf31493b7cdd upstream. It is possible to cause a btrfs mount to fail by racing it with a slow umount. The crux of the sequence is generic_shutdown_super not yet calling sop->put_super before btrfs_mount_root calls btrfs_open_devices. If that occurs, btrfs_open_devices will decide the opened counter is non-zero, increment it, and skip resetting fs_devices->total_rw_bytes to 0. From here, mount will call sget which will result in grab_super trying to take the super block umount semaphore. That semaphore will be held by the slow umount, so mount will block. Before up-ing the semaphore, umount will delete the super block, resulting in mount's sget reliably allocating a new one, which causes the mount path to dutifully fill it out, and increment total_rw_bytes a second time, which causes the mount to fail, as we see double the expected bytes. Here is the sequence laid out in greater detail: CPU0 CPU1 down_write sb->s_umount btrfs_kill_super kill_anon_super(sb) generic_shutdown_super(sb); shrink_dcache_for_umount(sb); sync_filesystem(sb); evict_inodes(sb); // SLOW btrfs_mount_root btrfs_scan_one_device fs_devices = device->fs_devices fs_info->fs_devices = fs_devices // fs_devices-opened makes this a no-op btrfs_open_devices(fs_devices, mode, fs_type) s = sget(fs_type, test, set, flags, fs_info); find sb in s_instances grab_super(sb); down_write(&s->s_umount); // blocks sop->put_super(sb) // sb->fs_devices->opened == 2; no-op spin_lock(&sb_lock); hlist_del_init(&sb->s_instances); spin_unlock(&sb_lock); up_write(&sb->s_umount); return 0; retry lookup don't find sb in s_instances (deleted by CPU0) s = alloc_super return s; btrfs_fill_super(s, fs_devices, data) open_ctree // fs_devices total_rw_bytes improperly set! btrfs_read_chunk_tree read_one_dev // increment total_rw_bytes again!! super_total_bytes < fs_devices->total_rw_bytes // ERROR!!! To fix this, we clear total_rw_bytes from within btrfs_read_chunk_tree before the calls to read_one_dev, while holding the sb umount semaphore and the uuid mutex. To reproduce, it is sufficient to dirty a decent number of inodes, then quickly umount and mount. for i in $(seq 0 500) do dd if=/dev/zero of="/mnt/foo/$i" bs=1M count=1 done umount /mnt/foo& mount /mnt/foo does the trick for me. CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Boris Burkov <boris@bur.io> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-06-22btrfs: include non-missing as a qualifier for the latest_bdevAnand Jain1-0/+2
commit 998a0671961f66e9fad4990ed75f80ba3088c2f1 upstream. btrfs_free_extra_devids() updates fs_devices::latest_bdev to point to the bdev with greatest device::generation number. For a typical-missing device the generation number is zero so fs_devices::latest_bdev will never point to it. But if the missing device is due to alienation [1], then device::generation is not zero and if it is greater or equal to the rest of device generations in the list, then fs_devices::latest_bdev ends up pointing to the missing device and reports the error like [2]. [1] We maintain devices of a fsid (as in fs_device::fsid) in the fs_devices::devices list, a device is considered as an alien device if its fsid does not match with the fs_device::fsid Consider a working filesystem with raid1: $ mkfs.btrfs -f -d raid1 -m raid1 /dev/sda /dev/sdb $ mount /dev/sda /mnt-raid1 $ umount /mnt-raid1 While mnt-raid1 was unmounted the user force-adds one of its devices to another btrfs filesystem: $ mkfs.btrfs -f /dev/sdc $ mount /dev/sdc /mnt-single $ btrfs dev add -f /dev/sda /mnt-single Now the original mnt-raid1 fails to mount in degraded mode, because fs_devices::latest_bdev is pointing to the alien device. $ mount -o degraded /dev/sdb /mnt-raid1 [2] mount: wrong fs type, bad option, bad superblock on /dev/sdb, missing codepage or helper program, or other error In some cases useful info is found in syslog - try dmesg | tail or so. kernel: BTRFS warning (device sdb): devid 1 uuid 072a0192-675b-4d5a-8640-a5cf2b2c704d is missing kernel: BTRFS error (device sdb): failed to read devices kernel: BTRFS error (device sdb): open_ctree failed Fix the root cause by checking if the device is not missing before it can be considered for the fs_devices::latest_bdev. CC: stable@vger.kernel.org # 4.19+ Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.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>
2020-06-22btrfs: merge btrfs_find_device and find_deviceAnand Jain1-42/+42
commit 09ba3bc9dd150457c506e4661380a6183af651c1 upstream. Both btrfs_find_device() and find_device() does the same thing except that the latter does not take the seed device onto account in the device scanning context. We can merge them. Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> [4.19.y backport notes: Vikash : - To apply this patch, a portion of commit e4319cd9cace was used to change the first argument of function "btrfs_find_device" from "struct btrfs_fs_info" to "struct btrfs_fs_devices". Signed-off-by: Vikash Bansal <bvikas@vmware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-02-24btrfs: device stats, log when stats are zeroedAnand Jain1-0/+2
[ Upstream commit a69976bc69308aa475d0ba3b8b3efd1d013c0460 ] We had a report indicating that some read errors aren't reported by the device stats in the userland. It is important to have the errors reported in the device stat as user land scripts might depend on it to take the reasonable corrective actions. But to debug these issue we need to be really sure that request to reset the device stat did not come from the userland itself. So log an info message when device error reset happens. For example: BTRFS info (device sdc): device stats zeroed by btrfs(9223) Reported-by: philip@philip-seeger.de Link: https://www.spinics.net/lists/linux-btrfs/msg96528.html Reviewed-by: Josef Bacik <josef@toxicpanda.com> Signed-off-by: Anand Jain <anand.jain@oracle.com> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-05btrfs: fix ncopies raid_attr for RAID56Hans van Kranenburg1-2/+2
[ Upstream commit da612e31aee51bd13231c78a47c714b543bd3ad8 ] RAID5 and RAID6 profile store one copy of the data, not 2 or 3. These values are not yet used anywhere so there's no change. Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Hans van Kranenburg <hans.van.kranenburg@mendix.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-12-05btrfs: Check for missing device before bio submission in btrfs_map_bioNikolay Borisov1-7/+2
[ Upstream commit fc8a168aa9ab1680c2bd52bf9db7c994e0f2524f ] Before btrfs_map_bio submits all stripe bios it does a number of checks to ensure the device for every stripe is present. However, it doesn't do a DEV_STATE_MISSING check, instead this is relegated to the lower level btrfs_schedule_bio (in the async submission case, sync submission doesn't check DEV_STATE_MISSING at all). Additionally btrfs_schedule_bios does the duplicate device->bdev check which has already been performed in btrfs_map_bio. This patch moves the DEV_STATE_MISSING check in btrfs_map_bio and removes the duplicate device->bdev check. Doing so ensures that no bio cloning/submission happens for both async/sync requests in the face of missing device. This makes the async io submission path slightly shorter in terms of instruction count. No functional changes. Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Anand Jain <anand.jain@oracle.com> Signed-off-by: Nikolay Borisov <nborisov@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>
2019-09-16btrfs: Use real device structure to verify dev extentQu Wenruo1-0/+12
[ Upstream commit 1b3922a8bc74231f9a767d1be6d9a061a4d4eeab ] [BUG] Linux v5.0-rc1 will fail fstests/btrfs/163 with the following kernel message: BTRFS error (device dm-6): dev extent devid 1 physical offset 13631488 len 8388608 is beyond device boundary 0 BTRFS error (device dm-6): failed to verify dev extents against chunks: -117 BTRFS error (device dm-6): open_ctree failed [CAUSE] Commit cf90d884b347 ("btrfs: Introduce mount time chunk <-> dev extent mapping check") introduced strict check on dev extents. We use btrfs_find_device() with dev uuid and fs uuid set to NULL, and only dependent on @devid to find the real device. For seed devices, we call clone_fs_devices() in open_seed_devices() to allow us search seed devices directly. However clone_fs_devices() just populates devices with devid and dev uuid, without populating other essential members, like disk_total_bytes. This makes any device returned by btrfs_find_device(fs_info, devid, NULL, NULL) is just a dummy, with 0 disk_total_bytes, and any dev extents on the seed device will not pass the device boundary check. [FIX] This patch will try to verify the device returned by btrfs_find_device() and if it's a dummy then re-search in seed devices. Fixes: cf90d884b347 ("btrfs: Introduce mount time chunk <-> dev extent mapping check") CC: stable@vger.kernel.org # 4.19+ Reported-by: Filipe Manana <fdmanana@suse.com> Signed-off-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-09-16btrfs: volumes: Make sure no dev extent is beyond device boundaryQu Wenruo1-0/+17
[ Upstream commit 05a37c48604c19b50873fd9663f9140c150469d1 ] Add extra dev extent end check against device boundary. 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>
2019-08-06btrfs: fix minimum number of chunk errors for DUPDavid Sterba1-2/+1
[ Upstream commit 0ee5f8ae082e1f675a2fb6db601c31ac9958a134 ] The list of profiles in btrfs_chunk_max_errors lists DUP as a profile DUP able to tolerate 1 device missing. Though this profile is special with 2 copies, it still needs the device, unlike the others. Looking at the history of changes, thre's no clear reason why DUP is there, functions were refactored and blocks of code merged to one helper. d20983b40e828 Btrfs: fix writing data into the seed filesystem - factor code to a helper de11cc12df173 Btrfs: don't pre-allocate btrfs bio - unrelated change, DUP still in the list with max errors 1 a236aed14ccb0 Btrfs: Deal with failed writes in mirrored configurations - introduced the max errors, leaves DUP and RAID1 in the same group Reviewed-by: Qu Wenruo <wqu@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2019-07-10btrfs: Ensure replaced device doesn't have pending chunk allocationNikolay Borisov1-0/+2
commit debd1c065d2037919a7da67baf55cc683fee09f0 upstream. Recent FITRIM work, namely bbbf7243d62d ("btrfs: combine device update operations during transaction commit") combined the way certain operations are recoded in a transaction. As a result an ASSERT was added in dev_replace_finish to ensure the new code works correctly. Unfortunately I got reports that it's possible to trigger the assert, meaning that during a device replace it's possible to have an unfinished chunk allocation on the source device. This is supposed to be prevented by the fact that a transaction is committed before finishing the replace oepration and alter acquiring the chunk mutex. This is not sufficient since by the time the transaction is committed and the chunk mutex acquired it's possible to allocate a chunk depending on the workload being executed on the replaced device. This bug has been present ever since device replace was introduced but there was never code which checks for it. The correct way to fix is to ensure that there is no pending device modification operation when the chunk mutex is acquire and if there is repeat transaction commit. Unfortunately it's not possible to just exclude the source device from btrfs_fs_devices::dev_alloc_list since this causes ENOSPC to be hit in transaction commit. Fixing that in another way would need to add special cases to handle the last writes and forbid new ones. The looped transaction fix is more obvious, and can be easily backported. The runtime of dev-replace is long so there's no noticeable delay caused by that. Reported-by: David Sterba <dsterba@suse.com> Fixes: 391cd9df81ac ("Btrfs: fix unprotected alloc list insertion during the finishing procedure of replace") CC: stable@vger.kernel.org # 4.4+ Signed-off-by: Nikolay Borisov <nborisov@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>
2019-04-03btrfs: don't report readahead errors and don't update statisticsDavid Sterba1-1/+1
commit 0cc068e6ee59c1fffbfa977d8bf868b7551d80ac upstream. As readahead is an optimization, all errors are usually filtered out, but still properly handled when the real read call is done. The commit 5e9d398240b2 ("btrfs: readpages() should submit IO as read-ahead") added REQ_RAHEAD to readpages() because that's only used for readahead (despite what one would expect from the callback name). This causes a flood of messages and inflated read error stats, so skip reporting in case it's readahead. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=202403 Reported-by: LimeTech <tomm@lime-technology.com> Fixes: 5e9d398240b2 ("btrfs: readpages() should submit IO as read-ahead") CC: stable@vger.kernel.org # 4.19+ Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-03-23btrfs: ensure that a DUP or RAID1 block group has exactly two stripesJohannes Thumshirn1-2/+2
commit 349ae63f40638a28c6fce52e8447c2d14b84cc0c upstream. We recently had a customer issue with a corrupted filesystem. When trying to mount this image btrfs panicked with a division by zero in calc_stripe_length(). The corrupt chunk had a 'num_stripes' value of 1. calc_stripe_length() takes this value and divides it by the number of copies the RAID profile is expected to have to calculate the amount of data stripes. As a DUP profile is expected to have 2 copies this division resulted in 1/2 = 0. Later then the 'data_stripes' variable is used as a divisor in the stripe length calculation which results in a division by 0 and thus a kernel panic. When encountering a filesystem with a DUP block group and a 'num_stripes' value unequal to 2, refuse mounting as the image is corrupted and will lead to unexpected behaviour. Code inspection showed a RAID1 block group has the same issues. Fixes: e06cd3dd7cea ("Btrfs: add validadtion checks for chunk loading") CC: stable@vger.kernel.org # 4.4+ Reviewed-by: Qu Wenruo <wqu@suse.com> Reviewed-by: Nikolay Borisov <nborisov@suse.com> Signed-off-by: Johannes Thumshirn <jthumshirn@suse.de> Reviewed-by: David Sterba <dsterba@suse.com> Signed-off-by: David Sterba <dsterba@suse.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-02-12btrfs: harden agaist duplicate fsid on scanned devicesAnand Jain1-0/+29