kernel/linux.git/fs/inode.c, branch v6.12.80

bcachefs: do not use PF_MEMALLOC_NORECLAIM

2024-10-09T19:47:18+00:00

Patch series "remove PF_MEMALLOC_NORECLAIM" v3. This patch (of 2): bch2_new_inode relies on PF_MEMALLOC_NORECLAIM to try to allocate a new inode to achieve GFP_NOWAIT semantic while holding locks. If this allocation fails it will drop locks and use GFP_NOFS allocation context. We would like to drop PF_MEMALLOC_NORECLAIM because it is really dangerous to use if the caller doesn't control the full call chain with this flag set. E.g. if any of the function down the chain needed GFP_NOFAIL request the PF_MEMALLOC_NORECLAIM would override this and cause unexpected failure. While this is not the case in this particular case using the scoped gfp semantic is not really needed bacause we can easily pus the allocation context down the chain without too much clutter. [akpm@linux-foundation.org: fix kerneldoc warnings] Link: https://lkml.kernel.org/r/20240926172940.167084-1-mhocko@kernel.org Link: https://lkml.kernel.org/r/20240926172940.167084-2-mhocko@kernel.org Signed-off-by: Michal Hocko Reviewed-by: Christoph Hellwig Reviewed-by: Dave Chinner Reviewed-by: Jan Kara # For vfs changes Cc: Al Viro Cc: Christian Brauner Cc: James Morris Cc: Kent Overstreet Cc: Paul Moore Cc: Serge E. Hallyn Cc: Yafang Shao Cc: Matthew Wilcox (Oracle) Cc: Vlastimil Babka Signed-off-by: Andrew Morton

Merge tag 'bcachefs-2024-09-21' of git://evilpiepirate.org/bcachefs

2024-09-23T17:05:41+00:00

Pull bcachefs updates from Kent Overstreet: - rcu_pending, btree key cache rework: this solves lock contenting in the key cache, eliminating the biggest source of the srcu lock hold time warnings, and drastically improving performance on some metadata heavy workloads - on multithreaded creates we're now 3-4x faster than xfs. - We're now using an rhashtable instead of the system inode hash table; this is another significant performance improvement on multithreaded metadata workloads, eliminating more lock contention. - for_each_btree_key_in_subvolume_upto(): new helper for iterating over keys within a specific subvolume, eliminating a lot of open coded "subvolume_get_snapshot()" and also fixing another source of srcu lock time warnings, by running each loop iteration in its own transaction (as the existing for_each_btree_key() does). - More work on btree_trans locking asserts; we now assert that we don't hold btree node locks when trans->locked is false, which is important because we don't use lockdep for tracking individual btree node locks. - Some cleanups and improvements in the bset.c btree node lookup code, from Alan. - Rework of btree node pinning, which we use in backpointers fsck. The old hacky implementation, where the shrinker just skipped over nodes in the pinned range, was causing OOMs; instead we now use another shrinker with a much higher seeks number for pinned nodes. - Rebalance now uses BCH_WRITE_ONLY_SPECIFIED_DEVS; this fixes an issue where rebalance would sometimes fall back to allocating from the full filesystem, which is not what we want when it's trying to move data to a specific target. - Use __GFP_ACCOUNT, GFP_RECLAIMABLE for btree node, key cache allocations. - Idmap mounts are now supported (Hongbo Li) - Rename whiteouts are now supported (Hongbo Li) - Erasure coding can now handle devices being marked as failed, or forcibly removed. We still need the evacuate path for erasure coding, but it's getting very close to ready for people to start using. * tag 'bcachefs-2024-09-21' of git://evilpiepirate.org/bcachefs: (99 commits) bcachefs: return err ptr instead of null in read sb clean bcachefs: Remove duplicated include in backpointers.c bcachefs: Don't drop devices with stripe pointers bcachefs: bch2_ec_stripe_head_get() now checks for change in rw devices bcachefs: bch_fs.rw_devs_change_count bcachefs: bch2_dev_remove_stripes() bcachefs: bch2_trigger_ptr() calculates sectors even when no device bcachefs: improve error messages in bch2_ec_read_extent() bcachefs: improve error message on too few devices for ec bcachefs: improve bch2_new_stripe_to_text() bcachefs: ec_stripe_head.nr_created bcachefs: bch_stripe.disk_label bcachefs: stripe_to_mem() bcachefs: EIO errcode cleanup bcachefs: Rework btree node pinning bcachefs: split up btree cache counters for live, freeable bcachefs: btree cache counters should be size_t bcachefs: Don't count "skipped access bit" as touched in btree cache scan bcachefs: Failed devices no longer require mounting in degraded mode bcachefs: bch2_dev_rcu_noerror() ...

inode: make __iget() a static inline

2024-09-09T13:41:47+00:00

bcachefs is switching to an rhashtable for vfs inodes instead of the standard inode.c hashtable, so we need this exported, or - a static inline makes more sense for a single atomic_inc(). Signed-off-by: Kent Overstreet

fs/inode: Prevent dump_mapping() accessing invalid dentry.d_name.name

2024-08-30T06:22:41+00:00

It's observed that a crash occurs during hot-remove a memory device, in which user is accessing the hugetlb. See calltrace as following: ------------[ cut here ]------------ WARNING: CPU: 1 PID: 14045 at arch/x86/mm/fault.c:1278 do_user_addr_fault+0x2a0/0x790 Modules linked in: kmem device_dax cxl_mem cxl_pmem cxl_port cxl_pci dax_hmem dax_pmem nd_pmem cxl_acpi nd_btt cxl_core crc32c_intel nvme virtiofs fuse nvme_core nfit libnvdimm dm_multipath scsi_dh_rdac scsi_dh_emc s mirror dm_region_hash dm_log dm_mod CPU: 1 PID: 14045 Comm: daxctl Not tainted 6.10.0-rc2-lizhijian+ #492 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:do_user_addr_fault+0x2a0/0x790 Code: 48 8b 00 a8 04 0f 84 b5 fe ff ff e9 1c ff ff ff 4c 89 e9 4c 89 e2 be 01 00 00 00 bf 02 00 00 00 e8 b5 ef 24 00 e9 42 fe ff ff <0f> 0b 48 83 c4 08 4c 89 ea 48 89 ee 4c 89 e7 5b 5d 41 5c 41 5d 41 RSP: 0000:ffffc90000a575f0 EFLAGS: 00010046 RAX: ffff88800c303600 RBX: 0000000000000000 RCX: 0000000000000000 RDX: 0000000000001000 RSI: ffffffff82504162 RDI: ffffffff824b2c36 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: ffffc90000a57658 R13: 0000000000001000 R14: ffff88800bc2e040 R15: 0000000000000000 FS: 00007f51cb57d880(0000) GS:ffff88807fd00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000001000 CR3: 00000000072e2004 CR4: 00000000001706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: ? __warn+0x8d/0x190 ? do_user_addr_fault+0x2a0/0x790 ? report_bug+0x1c3/0x1d0 ? handle_bug+0x3c/0x70 ? exc_invalid_op+0x14/0x70 ? asm_exc_invalid_op+0x16/0x20 ? do_user_addr_fault+0x2a0/0x790 ? exc_page_fault+0x31/0x200 exc_page_fault+0x68/0x200 <...snip...> BUG: unable to handle page fault for address: 0000000000001000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 800000000ad92067 P4D 800000000ad92067 PUD 7677067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI ---[ end trace 0000000000000000 ]--- BUG: unable to handle page fault for address: 0000000000001000 #PF: supervisor read access in kernel mode #PF: error_code(0x0000) - not-present page PGD 800000000ad92067 P4D 800000000ad92067 PUD 7677067 PMD 0 Oops: Oops: 0000 [#1] PREEMPT SMP PTI CPU: 1 PID: 14045 Comm: daxctl Kdump: loaded Tainted: G W 6.10.0-rc2-lizhijian+ #492 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 RIP: 0010:dentry_name+0x1f4/0x440 <...snip...> ? dentry_name+0x2fa/0x440 vsnprintf+0x1f3/0x4f0 vprintk_store+0x23a/0x540 vprintk_emit+0x6d/0x330 _printk+0x58/0x80 dump_mapping+0x10b/0x1a0 ? __pfx_free_object_rcu+0x10/0x10 __dump_page+0x26b/0x3e0 ? vprintk_emit+0xe0/0x330 ? _printk+0x58/0x80 ? dump_page+0x17/0x50 dump_page+0x17/0x50 do_migrate_range+0x2f7/0x7f0 ? do_migrate_range+0x42/0x7f0 ? offline_pages+0x2f4/0x8c0 offline_pages+0x60a/0x8c0 memory_subsys_offline+0x9f/0x1c0 ? lockdep_hardirqs_on+0x77/0x100 ? _raw_spin_unlock_irqrestore+0x38/0x60 device_offline+0xe3/0x110 state_store+0x6e/0xc0 kernfs_fop_write_iter+0x143/0x200 vfs_write+0x39f/0x560 ksys_write+0x65/0xf0 do_syscall_64+0x62/0x130 Previously, some sanity check have been done in dump_mapping() before the print facility parsing '%pd' though, it's still possible to run into an invalid dentry.d_name.name. Since dump_mapping() only needs to dump the filename only, retrieve it by itself in a safer way to prevent an unnecessary crash. Note that either retrieving the filename with '%pd' or strncpy_from_kernel_nofault(), the filename could be unreliable. Signed-off-by: Li Zhijian Link: https://lore.kernel.org/r/20240826055503.1522320-1-lizhijian@fujitsu.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

inode: port __I_LRU_ISOLATING to var event

2024-08-30T06:22:40+00:00

Port the __I_LRU_ISOLATING mechanism to use the new var event mechanism. Link: https://lore.kernel.org/r/20240823-work-i_state-v3-5-5cd5fd207a57@kernel.org Reviewed-by: Josef Bacik Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

inode: port __I_NEW to var event

2024-08-30T06:22:39+00:00

Port the __I_NEW mechanism to use the new var event mechanism. Link: https://lore.kernel.org/r/20240823-work-i_state-v3-4-5cd5fd207a57@kernel.org Reviewed-by: Josef Bacik Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

fs: add i_state helpers

2024-08-30T06:22:39+00:00

The i_state member is an unsigned long so that it can be used with the wait bit infrastructure which expects unsigned long. This wastes 4 bytes which we're unlikely to ever use. Switch to using the var event wait mechanism using the address of the bit. Thanks to Linus for the address idea. Link: https://lore.kernel.org/r/20240823-work-i_state-v3-1-5cd5fd207a57@kernel.org Reviewed-by: Josef Bacik Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

vfs: fix race between evice_inodes() and find_inode()&iput()

2024-08-30T06:22:39+00:00

Hi, all Recently I noticed a bug[1] in btrfs, after digged it into and I believe it'a race in vfs. Let's assume there's a inode (ie ino 261) with i_count 1 is called by iput(), and there's a concurrent thread calling generic_shutdown_super(). cpu0: cpu1: iput() // i_count is 1 ->spin_lock(inode) ->dec i_count to 0 ->iput_final() generic_shutdown_super() ->__inode_add_lru() ->evict_inodes() // cause some reason[2] ->if (atomic_read(inode->i_count)) continue; // return before // inode 261 passed the above check // list_lru_add_obj() // and then schedule out ->spin_unlock() // note here: the inode 261 // was still at sb list and hash list, // and I_FREEING|I_WILL_FREE was not been set btrfs_iget() // after some function calls ->find_inode() // found the above inode 261 ->spin_lock(inode) // check I_FREEING|I_WILL_FREE // and passed ->__iget() ->spin_unlock(inode) // schedule back ->spin_lock(inode) // check (I_NEW|I_FREEING|I_WILL_FREE) flags, // passed and set I_FREEING iput() ->spin_unlock(inode) ->spin_lock(inode) ->evict() // dec i_count to 0 ->iput_final() ->spin_unlock() ->evict() Now, we have two threads simultaneously evicting the same inode, which may trigger the BUG(inode->i_state & I_CLEAR) statement both within clear_inode() and iput(). To fix the bug, recheck the inode->i_count after holding i_lock. Because in the most scenarios, the first check is valid, and the overhead of spin_lock() can be reduced. If there is any misunderstanding, please let me know, thanks. [1]: https://lore.kernel.org/linux-btrfs/000000000000eabe1d0619c48986@google.com/ [2]: The reason might be 1. SB_ACTIVE was removed or 2. mapping_shrinkable() return false when I reproduced the bug. Reported-by: syzbot+67ba3c42bcbb4665d3ad@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=67ba3c42bcbb4665d3ad CC: stable@vger.kernel.org Fixes: 63997e98a3be ("split invalidate_inodes()") Signed-off-by: Julian Sun Link: https://lore.kernel.org/r/20240823130730.658881-1-sunjunchao2870@gmail.com Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

vfs: drop one lock trip in evict()

2024-08-30T06:22:38+00:00

Most commonly neither I_LRU_ISOLATING nor I_SYNC are set, but the stock kernel takes a back-to-back relock trip to check for them. It probably can be avoided altogether, but for now massage things back to just one lock acquire. Signed-off-by: Mateusz Guzik Link: https://lore.kernel.org/r/20240813143626.1573445-1-mjguzik@gmail.com Reviewed-by: Zhihao Cheng Reviewed-by: Jeff Layton Reviewed-by: Jan Kara Signed-off-by: Christian Brauner

inode: remove __I_DIO_WAKEUP

2024-08-30T06:22:37+00:00

Afaict, we can just rely on inode->i_dio_count for waiting instead of this awkward indirection through __I_DIO_WAKEUP. This survives LTP dio and xfstests dio tests. Link: https://lore.kernel.org/r/20240816-vfs-misc-dio-v1-1-80fe21a2c710@kernel.org Reviewed-by: Josef Bacik Reviewed-by: Jeff Layton Signed-off-by: Christian Brauner