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2024-12-14quota: flush quota_release_work upon quota writebackOjaswin Mujoo1-0/+2
[ Upstream commit ac6f420291b3fee1113f21d612fa88b628afab5b ] One of the paths quota writeback is called from is: freeze_super() sync_filesystem() ext4_sync_fs() dquot_writeback_dquots() Since we currently don't always flush the quota_release_work queue in this path, we can end up with the following race: 1. dquot are added to releasing_dquots list during regular operations. 2. FS Freeze starts, however, this does not flush the quota_release_work queue. 3. Freeze completes. 4. Kernel eventually tries to flush the workqueue while FS is frozen which hits a WARN_ON since transaction gets started during frozen state: ext4_journal_check_start+0x28/0x110 [ext4] (unreliable) __ext4_journal_start_sb+0x64/0x1c0 [ext4] ext4_release_dquot+0x90/0x1d0 [ext4] quota_release_workfn+0x43c/0x4d0 Which is the following line: WARN_ON(sb->s_writers.frozen == SB_FREEZE_COMPLETE); Which ultimately results in generic/390 failing due to dmesg noise. This was detected on powerpc machine 15 cores. To avoid this, make sure to flush the workqueue during dquot_writeback_dquots() so we dont have any pending workitems after freeze. Reported-by: Disha Goel <disgoel@linux.ibm.com> CC: stable@vger.kernel.org Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Reviewed-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com> Signed-off-by: Jan Kara <jack@suse.cz> Link: https://patch.msgid.link/20241121123855.645335-2-ojaswin@linux.ibm.com Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-09-04quota: Remove BUG_ON from dqget()Jan Kara1-3/+2
[ Upstream commit 249f374eb9b6b969c64212dd860cc1439674c4a8 ] dqget() checks whether dquot->dq_sb is set when returning it using BUG_ON. Firstly this doesn't work as an invalidation check for quite some time (we release dquot with dq_sb set these days), secondly using BUG_ON is quite harsh. Use WARN_ON_ONCE and check whether dquot is still hashed instead. Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26quota: Fix rcu annotations of inode dquot pointersJan Kara1-27/+39
[ Upstream commit 179b8c97ebf63429589f5afeba59a181fe70603e ] Dquot pointers in i_dquot array in the inode are protected by dquot_srcu. Annotate the array pointers with __rcu, perform the locked dereferences with srcu_dereference_check() instead of plain reads, and set the array elements with rcu_assign_pointer(). Fixes: b9ba6f94b238 ("quota: remove dqptr_sem") Reported-by: kernel test robot <lkp@intel.com> Closes: https://lore.kernel.org/oe-kbuild-all/202402061900.rTuYDlo6-lkp@intel.com/ Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26quota: Fix potential NULL pointer dereferenceWang Jianjian1-41/+57
[ Upstream commit d0aa72604fbd80c8aabb46eda00535ed35570f1f ] Below race may cause NULL pointer dereference P1 P2 dquot_free_inode quota_off drop_dquot_ref remove_dquot_ref dquots = i_dquot(inode) dquots = i_dquot(inode) srcu_read_lock dquots[cnt]) != NULL (1) dquots[type] = NULL (2) spin_lock(&dquots[cnt]->dq_dqb_lock) (3) .... If dquot_free_inode(or other routines) checks inode's quota pointers (1) before quota_off sets it to NULL(2) and use it (3) after that, NULL pointer dereference will be triggered. So let's fix it by using a temporary pointer to avoid this issue. Signed-off-by: Wang Jianjian <wangjianjian3@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20240202081852.2514092-1-wangjianjian3@huawei.com> Stable-dep-of: 179b8c97ebf6 ("quota: Fix rcu annotations of inode dquot pointers") Signed-off-by: Sasha Levin <sashal@kernel.org>
2024-03-26quota: simplify drop_dquot_ref()Baokun Li1-61/+9
[ Upstream commit 7bce48f0fec602b3b6c335963b26d9eefa417788 ] As Honza said, remove_inode_dquot_ref() currently does not release the last dquot reference but instead adds the dquot to tofree_head list. This is because dqput() can sleep while dropping of the last dquot reference (writing back the dquot and calling ->release_dquot()) and that must not happen under dq_list_lock. Now that dqput() queues the final dquot cleanup into a workqueue, remove_inode_dquot_ref() can call dqput() unconditionally and we can significantly simplify it. Here we open code the simplified code of remove_inode_dquot_ref() into remove_dquot_ref() and remove the function put_dquot_list() which is no longer used. Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230630110822.3881712-6-libaokun1@huawei.com> Stable-dep-of: 179b8c97ebf6 ("quota: Fix rcu annotations of inode dquot pointers") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-11-28quota: explicitly forbid quota files from being encryptedEric Biggers1-0/+14
commit d3cc1b0be258191d6360c82ea158c2972f8d3991 upstream. Since commit d7e7b9af104c ("fscrypt: stop using keyrings subsystem for fscrypt_master_key"), xfstest generic/270 causes a WARNING when run on f2fs with test_dummy_encryption in the mount options: $ kvm-xfstests -c f2fs/encrypt generic/270 [...] WARNING: CPU: 1 PID: 2453 at fs/crypto/keyring.c:240 fscrypt_destroy_keyring+0x1f5/0x260 The cause of the WARNING is that not all encrypted inodes have been evicted before fscrypt_destroy_keyring() is called, which violates an assumption. This happens because the test uses an external quota file, which gets automatically encrypted due to test_dummy_encryption. Encryption of quota files has never really been supported. On ext4, ext4_quota_read() does not decrypt the data, so encrypted quota files are always considered invalid on ext4. On f2fs, f2fs_quota_read() uses the pagecache, so trying to use an encrypted quota file gets farther, resulting in the issue described above being possible. But this was never intended to be possible, and there is no use case for it. Therefore, make the quota support layer explicitly reject using IS_ENCRYPTED inodes when quotaon is attempted. Cc: stable@vger.kernel.org Signed-off-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230905003227.326998-1-ebiggers@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-10-25quota: Fix slow quotaoffJan Kara1-27/+39
commit 869b6ea1609f655a43251bf41757aa44e5350a8f upstream. Eric has reported that commit dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") heavily increases runtime of generic/270 xfstest for ext4 in nojournal mode. The reason for this is that ext4 in nojournal mode leaves dquots dirty until the last dqput() and thus the cleanup done in quota_release_workfn() has to write them all. Due to the way quota_release_workfn() is written this results in synchronize_srcu() call for each dirty dquot which makes the dquot cleanup when turning quotas off extremely slow. To be able to avoid synchronize_srcu() for each dirty dquot we need to rework how we track dquots to be cleaned up. Instead of keeping the last dquot reference while it is on releasing_dquots list, we drop it right away and mark the dquot with new DQ_RELEASING_B bit instead. This way we can we can remove dquot from releasing_dquots list when new reference to it is acquired and thus there's no need to call synchronize_srcu() each time we drop dq_list_lock. References: https://lore.kernel.org/all/ZRytn6CxFK2oECUt@debian-BULLSEYE-live-builder-AMD64 Reported-by: Eric Whitney <enwlinux@gmail.com> Fixes: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") CC: stable@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2023-09-19quota: fix dqput() to follow the guarantees dquot_srcu should provideBaokun Li1-18/+78
[ Upstream commit dabc8b20756601b9e1cc85a81d47d3f98ed4d13a ] The dquot_mark_dquot_dirty() using dquot references from the inode should be protected by dquot_srcu. quota_off code takes care to call synchronize_srcu(&dquot_srcu) to not drop dquot references while they are used by other users. But dquot_transfer() breaks this assumption. We call dquot_transfer() to drop the last reference of dquot and add it to free_dquots, but there may still be other users using the dquot at this time, as shown in the function graph below: cpu1 cpu2 _________________|_________________ wb_do_writeback CHOWN(1) ... ext4_da_update_reserve_space dquot_claim_block ... dquot_mark_dquot_dirty // try to dirty old quota test_bit(DQ_ACTIVE_B, &dquot->dq_flags) // still ACTIVE if (test_bit(DQ_MOD_B, &dquot->dq_flags)) // test no dirty, wait dq_list_lock ... dquot_transfer __dquot_transfer dqput_all(transfer_from) // rls old dquot dqput // last dqput dquot_release clear_bit(DQ_ACTIVE_B, &dquot->dq_flags) atomic_dec(&dquot->dq_count) put_dquot_last(dquot) list_add_tail(&dquot->dq_free, &free_dquots) // add the dquot to free_dquots if (!test_and_set_bit(DQ_MOD_B, &dquot->dq_flags)) add dqi_dirty_list // add released dquot to dirty_list This can cause various issues, such as dquot being destroyed by dqcache_shrink_scan() after being added to free_dquots, which can trigger a UAF in dquot_mark_dquot_dirty(); or after dquot is added to free_dquots and then to dirty_list, it is added to free_dquots again after dquot_writeback_dquots() is executed, which causes the free_dquots list to be corrupted and triggers a UAF when dqcache_shrink_scan() is called for freeing dquot twice. As Honza said, we need to fix dquot_transfer() to follow the guarantees dquot_srcu should provide. But calling synchronize_srcu() directly from dquot_transfer() is too expensive (and mostly unnecessary). So we add dquot whose last reference should be dropped to the new global dquot list releasing_dquots, and then queue work item which would call synchronize_srcu() and after that perform the final cleanup of all the dquots on releasing_dquots. Fixes: 4580b30ea887 ("quota: Do not dirty bad dquots") Suggested-by: Jan Kara <jack@suse.cz> Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230630110822.3881712-5-libaokun1@huawei.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-19quota: add new helper dquot_active()Baokun Li1-9/+14
[ Upstream commit 33bcfafc48cb186bc4bbcea247feaa396594229e ] Add new helper function dquot_active() to make the code more concise. Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230630110822.3881712-4-libaokun1@huawei.com> Stable-dep-of: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-19quota: rename dquot_active() to inode_quota_active()Baokun Li1-10/+10
[ Upstream commit 4b9bdfa16535de8f49bf954aeed0f525ee2fc322 ] Now we have a helper function dquot_dirty() to determine if dquot has DQ_MOD_B bit. dquot_active() can easily be misunderstood as a helper function to determine if dquot has DQ_ACTIVE_B bit. So we avoid this by renaming it to inode_quota_active() and later on we will add the helper function dquot_active() to determine if dquot has DQ_ACTIVE_B bit. Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230630110822.3881712-3-libaokun1@huawei.com> Stable-dep-of: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-09-19quota: factor out dquot_write_dquot()Baokun Li1-23/+16
[ Upstream commit 024128477809f8073d870307c8157b8826ebfd08 ] Refactor out dquot_write_dquot() to reduce duplicate code. Signed-off-by: Baokun Li <libaokun1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230630110822.3881712-2-libaokun1@huawei.com> Stable-dep-of: dabc8b207566 ("quota: fix dqput() to follow the guarantees dquot_srcu should provide") Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-26quota: fix warning in dqgrab()Ye Bin1-1/+1
[ Upstream commit d6a95db3c7ad160bc16b89e36449705309b52bcb ] There's issue as follows when do fault injection: WARNING: CPU: 1 PID: 14870 at include/linux/quotaops.h:51 dquot_disable+0x13b7/0x18c0 Modules linked in: CPU: 1 PID: 14870 Comm: fsconfig Not tainted 6.3.0-next-20230505-00006-g5107a9c821af-dirty #541 RIP: 0010:dquot_disable+0x13b7/0x18c0 RSP: 0018:ffffc9000acc79e0 EFLAGS: 00010246 RAX: 0000000000000000 RBX: 0000000000000000 RCX: ffff88825e41b980 RDX: 0000000000000000 RSI: ffff88825e41b980 RDI: 0000000000000002 RBP: ffff888179f68000 R08: ffffffff82087ca7 R09: 0000000000000000 R10: 0000000000000001 R11: ffffed102f3ed026 R12: ffff888179f68130 R13: ffff888179f68110 R14: dffffc0000000000 R15: ffff888179f68118 FS: 00007f450a073740(0000) GS:ffff88882fc00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007ffe96f2efd8 CR3: 000000025c8ad000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> dquot_load_quota_sb+0xd53/0x1060 dquot_resume+0x172/0x230 ext4_reconfigure+0x1dc6/0x27b0 reconfigure_super+0x515/0xa90 __x64_sys_fsconfig+0xb19/0xd20 do_syscall_64+0x39/0xb0 entry_SYSCALL_64_after_hwframe+0x63/0xcd Above issue may happens as follows: ProcessA ProcessB ProcessC sys_fsconfig vfs_fsconfig_locked reconfigure_super ext4_remount dquot_suspend -> suspend all type quota sys_fsconfig vfs_fsconfig_locked reconfigure_super ext4_remount dquot_resume ret = dquot_load_quota_sb add_dquot_ref do_open -> open file O_RDWR vfs_open do_dentry_open get_write_access atomic_inc_unless_negative(&inode->i_writecount) ext4_file_open dquot_file_open dquot_initialize __dquot_initialize dqget atomic_inc(&dquot->dq_count); __dquot_initialize __dquot_initialize dqget if (!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) ext4_acquire_dquot -> Return error DQ_ACTIVE_B flag isn't set dquot_disable invalidate_dquots if (atomic_read(&dquot->dq_count)) dqgrab WARN_ON_ONCE(!test_bit(DQ_ACTIVE_B, &dquot->dq_flags)) -> Trigger warning In the above scenario, 'dquot->dq_flags' has no DQ_ACTIVE_B is normal when dqgrab(). To solve above issue just replace the dqgrab() use in invalidate_dquots() with atomic_inc(&dquot->dq_count). Signed-off-by: Ye Bin <yebin10@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230605140731.2427629-3-yebin10@huawei.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-08-26quota: Properly disable quotas when add_dquot_ref() failsJan Kara1-1/+2
[ Upstream commit 6a4e3363792e30177cc3965697e34ddcea8b900b ] When add_dquot_ref() fails (usually due to IO error or ENOMEM), we want to disable quotas we are trying to enable. However dquot_disable() call was passed just the flags we are enabling so in case flags == DQUOT_USAGE_ENABLED dquot_disable() call will just fail with EINVAL instead of properly disabling quotas. Fix the problem by always passing DQUOT_LIMITS_ENABLED | DQUOT_USAGE_ENABLED to dquot_disable() in this case. Reported-and-tested-by: Ye Bin <yebin10@huawei.com> Reported-by: syzbot+e633c79ceaecbf479854@syzkaller.appspotmail.com Signed-off-by: Jan Kara <jack@suse.cz> Message-Id: <20230605140731.2427629-2-yebin10@huawei.com> Signed-off-by: Sasha Levin <sashal@kernel.org>
2023-01-14ext4: fix bug_on in __es_tree_search caused by bad quota inodeBaokun Li1-0/+2
commit d323877484765aaacbb2769b06e355c2041ed115 upstream. We got a issue as fllows: ================================================================== kernel BUG at fs/ext4/extents_status.c:202! invalid opcode: 0000 [#1] PREEMPT SMP CPU: 1 PID: 810 Comm: mount Not tainted 6.1.0-rc1-next-g9631525255e3 #352 RIP: 0010:__es_tree_search.isra.0+0xb8/0xe0 RSP: 0018:ffffc90001227900 EFLAGS: 00010202 RAX: 0000000000000000 RBX: 0000000077512a0f RCX: 0000000000000000 RDX: 0000000000000002 RSI: 0000000000002a10 RDI: ffff8881004cd0c8 RBP: ffff888177512ac8 R08: 47ffffffffffffff R09: 0000000000000001 R10: 0000000000000001 R11: 00000000000679af R12: 0000000000002a10 R13: ffff888177512d88 R14: 0000000077512a10 R15: 0000000000000000 FS: 00007f4bd76dbc40(0000)GS:ffff88842fd00000(0000)knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00005653bf993cf8 CR3: 000000017bfdf000 CR4: 00000000000006e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: <TASK> ext4_es_cache_extent+0xe2/0x210 ext4_cache_extents+0xd2/0x110 ext4_find_extent+0x5d5/0x8c0 ext4_ext_map_blocks+0x9c/0x1d30 ext4_map_blocks+0x431/0xa50 ext4_getblk+0x82/0x340 ext4_bread+0x14/0x110 ext4_quota_read+0xf0/0x180 v2_read_header+0x24/0x90 v2_check_quota_file+0x2f/0xa0 dquot_load_quota_sb+0x26c/0x760 dquot_load_quota_inode+0xa5/0x190 ext4_enable_quotas+0x14c/0x300 __ext4_fill_super+0x31cc/0x32c0 ext4_fill_super+0x115/0x2d0 get_tree_bdev+0x1d2/0x360 ext4_get_tree+0x19/0x30 vfs_get_tree+0x26/0xe0 path_mount+0x81d/0xfc0 do_mount+0x8d/0xc0 __x64_sys_mount+0xc0/0x160 do_syscall_64+0x35/0x80 entry_SYSCALL_64_after_hwframe+0x63/0xcd </TASK> ================================================================== Above issue may happen as follows: ------------------------------------- ext4_fill_super ext4_orphan_cleanup ext4_enable_quotas ext4_quota_enable ext4_iget --> get error inode <5> ext4_ext_check_inode --> Wrong imode makes it escape inspection make_bad_inode(inode) --> EXT4_BOOT_LOADER_INO set imode dquot_load_quota_inode vfs_setup_quota_inode --> check pass dquot_load_quota_sb v2_check_quota_file v2_read_header ext4_quota_read ext4_bread ext4_getblk ext4_map_blocks ext4_ext_map_blocks ext4_find_extent ext4_cache_extents ext4_es_cache_extent __es_tree_search.isra.0 ext4_es_end --> Wrong extents trigger BUG_ON In the above issue, s_usr_quota_inum is set to 5, but inode<5> contains incorrect imode and disordered extents. Because 5 is EXT4_BOOT_LOADER_INO, the ext4_ext_check_inode check in the ext4_iget function can be bypassed, finally, the extents that are not checked trigger the BUG_ON in the __es_tree_search function. To solve this issue, check whether the inode is bad_inode in vfs_setup_quota_inode(). Signed-off-by: Baokun Li <libaokun1@huawei.com> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Reviewed-by: Jason Yan <yanaijie@huawei.com> Reviewed-by: Jan Kara <jack@suse.cz> Link: https://lore.kernel.org/r/20221026042310.3839669-2-libaokun1@huawei.com Signed-off-by: Theodore Ts'o <tytso@mit.edu> Cc: stable@kernel.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-10-26quota: Check next/prev free block number after reading from quota fileZhihao Cheng1-0/+38
commit 6c8ea8b8cd4722efd419f91ca46a2dc81b7d89a3 upstream. Following process: Init: v2_read_file_info: <3> dqi_free_blk 0 dqi_free_entry 5 dqi_blks 6 Step 1. chown bin f_a -> dquot_acquire -> v2_write_dquot: qtree_write_dquot do_insert_tree find_free_dqentry get_free_dqblk write_blk(info->dqi_blocks) // info->dqi_blocks = 6, failure. The content in physical block (corresponding to blk 6) is random. Step 2. chown root f_a -> dquot_transfer -> dqput_all -> dqput -> ext4_release_dquot -> v2_release_dquot -> qtree_delete_dquot: dquot_release remove_tree free_dqentry put_free_dqblk(6) info->dqi_free_blk = blk // info->dqi_free_blk = 6 Step 3. drop cache (buffer head for block 6 is released) Step 4. chown bin f_b -> dquot_acquire -> commit_dqblk -> v2_write_dquot: qtree_write_dquot do_insert_tree find_free_dqentry get_free_dqblk dh = (struct qt_disk_dqdbheader *)buf blk = info->dqi_free_blk // 6 ret = read_blk(info, blk, buf) // The content of buf is random info->dqi_free_blk = le32_to_cpu(dh->dqdh_next_free) // random blk Step 5. chown bin f_c -> notify_change -> ext4_setattr -> dquot_transfer: dquot = dqget -> acquire_dquot -> ext4_acquire_dquot -> dquot_acquire -> commit_dqblk -> v2_write_dquot -> dq_insert_tree: do_insert_tree find_free_dqentry get_free_dqblk blk = info->dqi_free_blk // If blk < 0 and blk is not an error code, it will be returned as dquot transfer_to[USRQUOTA] = dquot // A random negative value __dquot_transfer(transfer_to) dquot_add_inodes(transfer_to[cnt]) spin_lock(&dquot->dq_dqb_lock) // page fault , which will lead to kernel page fault: Quota error (device sda): qtree_write_dquot: Error -8000 occurred while creating quota BUG: unable to handle page fault for address: ffffffffffffe120 #PF: supervisor write access in kernel mode #PF: error_code(0x0002) - not-present page Oops: 0002 [#1] PREEMPT SMP CPU: 0 PID: 5974 Comm: chown Not tainted 6.0.0-rc1-00004 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996) RIP: 0010:_raw_spin_lock+0x3a/0x90 Call Trace: dquot_add_inodes+0x28/0x270 __dquot_transfer+0x377/0x840 dquot_transfer+0xde/0x540 ext4_setattr+0x405/0x14d0 notify_change+0x68e/0x9f0 chown_common+0x300/0x430 __x64_sys_fchownat+0x29/0x40 In order to avoid accessing invalid quota memory address, this patch adds block number checking of next/prev free block read from quota file. Fetch a reproducer in [Link]. Link: https://bugzilla.kernel.org/show_bug.cgi?id=216372 Fixes: 1da177e4c3f4152 ("Linux-2.6.12-rc2") CC: stable@vger.kernel.org Link: https://lore.kernel.org/r/20220923134555.2623931-2-chengzhihao1@huawei.com Signed-off-by: Zhihao Cheng <chengzhihao1@huawei.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-06-22quota: Prevent memory allocation recursion while holding dq_lockMatthew Wilcox (Oracle)1-0/+10
[ Upstream commit 537e11cdc7a6b3ce94fa25ed41306193df9677b7 ] As described in commit 02117b8ae9c0 ("f2fs: Set GF_NOFS in read_cache_page_gfp while doing f2fs_quota_read"), we must not enter filesystem reclaim while holding the dq_lock. Prevent this more generally by using memalloc_nofs_save() while holding the lock. Link: https://lore.kernel.org/r/20220605143815.2330891-2-willy@infradead.org Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org>
2022-02-23quota: make dquot_quota_sync return errors from ->sync_fsDarrick J. Wong1-3/+8
[ Upstream commit dd5532a4994bfda0386eb2286ec00758cee08444 ] Strangely, dquot_quota_sync ignores the return code from the ->sync_fs call, which means that quotacalls like Q_SYNC never see the error. This doesn't seem right, so fix that. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Jan Kara <jack@suse.cz> Reviewed-by: Christoph Hellwig <hch@lst.de> Acked-by: Christian Brauner <brauner@kernel.org> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-11-18quota: correct error number in free_dqentry()Zhang Yi1-0/+1
commit d0e36a62bd4c60c09acc40e06ba4831a4d0bc75b upstream. Fix the error path in free_dqentry(), pass out the error number if the block to free is not correct. Fixes: 1ccd14b9c271 ("quota: Split off quota tree handling into a separate file") Link: https://lore.kernel.org/r/20211008093821.1001186-3-yi.zhang@huawei.com Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Cc: stable@kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-11-18quota: check block number when reading the block in quota fileZhang Yi1-0/+14
commit 9bf3d20331295b1ecb81f4ed9ef358c51699a050 upstream. The block number in the quota tree on disk should be smaller than the v2_disk_dqinfo.dqi_blocks. If the quota file was corrupted, we may be allocating an 'allocated' block and that would lead to a loop in a tree, which will probably trigger oops later. This patch adds a check for the block number in the quota tree to prevent such potential issue. Link: https://lore.kernel.org/r/20211008093821.1001186-2-yi.zhang@huawei.com Signed-off-by: Zhang Yi <yi.zhang@huawei.com> Cc: stable@kernel.org Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2021-03-04quota: Fix memory leak when handling corrupted quota fileJan Kara1-3/+8
[ Upstream commit a4db1072e1a3bd7a8d9c356e1902b13ac5deb8ef ] When checking corrupted quota file we can bail out and leak allocated info structure. Properly free info structure on error return. Reported-by: syzbot+77779c9b52ab78154b08@syzkaller.appspotmail.com Fixes: 11c514a99bb9 ("quota: Sanity-check quota file headers on load") Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org>
2021-01-06quota: Don't overflow quota file offsetsJan Kara1-4/+4
[ Upstream commit 10f04d40a9fa29785206c619f80d8beedb778837 ] The on-disk quota format supports quota files with upto 2^32 blocks. Be careful when computing quota file offsets in the quota files from block numbers as they can overflow 32-bit types. Since quota files larger than 4GB would require ~26 millions of quota users, this is mostly a theoretical concern now but better be careful, fuzzers would find the problem sooner or later anyway... Reviewed-by: Andreas Dilger <adilger@dilger.ca> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-12-26fs: quota: fix array-index-out-of-bounds bug by passing correct argument to ↵Anant Thazhemadam1-1/+1
vfs_cleanup_quota_inode() commit e51d68e76d604c6d5d1eb13ae1d6da7f6c8c0dfc upstream. When dquot_resume() was last updated, the argument that got passed to vfs_cleanup_quota_inode was incorrectly set. If type = -1 and dquot_load_quota_sb() returns a negative value, then vfs_cleanup_quota_inode() gets called with -1 passed as an argument, and this leads to an array-index-out-of-bounds bug. Fix this issue by correctly passing the arguments. Fixes: ae45f07d47cc ("quota: Simplify dquot_resume()") Link: https://lore.kernel.org/r/20201208194338.7064-1-anant.thazhemadam@gmail.com Reported-by: syzbot+2643e825238d7aabb37f@syzkaller.appspotmail.com Tested-by: syzbot+2643e825238d7aabb37f@syzkaller.appspotmail.com CC: stable@vger.kernel.org Signed-off-by: Anant Thazhemadam <anant.thazhemadam@gmail.com> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-12-26quota: Sanity-check quota file headers on loadJan Kara1-0/+19
commit 11c514a99bb960941535134f0587102855e8ddee upstream. Perform basic sanity checks of quota headers to avoid kernel crashes on corrupted quota files. CC: stable@vger.kernel.org Reported-by: syzbot+f816042a7ae2225f25ba@syzkaller.appspotmail.com Reviewed-by: Andreas Dilger <adilger@dilger.ca> Signed-off-by: Jan Kara <jack@suse.cz> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-10-15Merge tag 'fs_for_v5.10-rc1' of ↵Linus Torvalds2-6/+37
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull UDF, reiserfs, ext2, quota fixes from Jan Kara: - a couple of UDF fixes for issues found by syzbot fuzzing - a couple of reiserfs fixes for issues found by syzbot fuzzing - some minor ext2 cleanups - quota patches to support grace times beyond year 2038 for XFS quota APIs * tag 'fs_for_v5.10-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: reiserfs: Fix oops during mount udf: Limit sparing table size udf: Remove pointless union in udf_inode_info udf: Avoid accessing uninitialized data on failed inode read quota: clear padding in v2r1_mem2diskdqb() reiserfs: Initialize inode keys properly udf: Fix memory leak when mounting udf: Remove redundant initialization of variable ret reiserfs: only call unlock_new_inode() if I_NEW ext2: Fix some kernel-doc warnings in balloc.c quota: Expand comment describing d_itimer quota: widen timestamps for the fs_disk_quota structure reiserfs: Fix memory leak in reiserfs_parse_options() udf: Use kvzalloc() in udf_sb_alloc_bitmap() ext2: remove duplicate include
2020-10-12Merge branch 'work.quota-compat' of ↵Linus Torvalds5-140/+93
git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs Pull compat quotactl cleanups from Al Viro: "More Christoph's compat cleanups: quotactl(2)" * 'work.quota-compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: quota: simplify the quotactl compat handling compat: add a compat_need_64bit_alignment_fixup() helper compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h>
2020-09-25quota: clear padding in v2r1_mem2diskdqb()Eric Dumazet1-0/+1
Freshly allocated memory contains garbage, better make sure to init all struct v2r1_disk_dqblk fields to avoid KMSAN report: BUG: KMSAN: uninit-value in qtree_entry_unused+0x137/0x1b0 fs/quota/quota_tree.c:218 CPU: 0 PID: 23373 Comm: syz-executor.1 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+0x21c/0x280 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:219 qtree_entry_unused+0x137/0x1b0 fs/quota/quota_tree.c:218 v2r1_mem2diskdqb+0x43d/0x710 fs/quota/quota_v2.c:285 qtree_write_dquot+0x226/0x870 fs/quota/quota_tree.c:394 v2_write_dquot+0x1ad/0x280 fs/quota/quota_v2.c:333 dquot_commit+0x4af/0x600 fs/quota/dquot.c:482 ext4_write_dquot fs/ext4/super.c:5934 [inline] ext4_mark_dquot_dirty+0x4d8/0x6a0 fs/ext4/super.c:5985 mark_dquot_dirty fs/quota/dquot.c:347 [inline] mark_all_dquot_dirty fs/quota/dquot.c:385 [inline] dquot_alloc_inode+0xc05/0x12b0 fs/quota/dquot.c:1755 __ext4_new_inode+0x8204/0x9d70 fs/ext4/ialloc.c:1155 ext4_tmpfile+0x41a/0x850 fs/ext4/namei.c:2686 vfs_tmpfile+0x2a2/0x570 fs/namei.c:3283 do_tmpfile fs/namei.c:3316 [inline] path_openat+0x4035/0x6a90 fs/namei.c:3359 do_filp_open+0x2b8/0x710 fs/namei.c:3395 do_sys_openat2+0xa88/0x1140 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_compat_sys_openat fs/open.c:1242 [inline] __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240 __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline] __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c RIP: 0023:0xf7ff4549 Code: b8 01 10 06 03 74 b4 01 10 07 03 74 b0 01 10 08 03 74 d8 01 00 00 00 00 00 00 00 00 00 00 00 00 00 51 52 55 89 e5 0f 34 cd 80 <5d> 5a 59 c3 90 90 90 90 eb 0d 90 90 90 90 90 90 90 90 90 90 90 90 RSP: 002b:00000000f55cd0cc EFLAGS: 00000296 ORIG_RAX: 0000000000000127 RAX: ffffffffffffffda RBX: 00000000ffffff9c RCX: 0000000020000000 RDX: 0000000000410481 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000 Uninit was created at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:143 [inline] kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:126 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80 slab_alloc_node mm/slub.c:2907 [inline] slab_alloc mm/slub.c:2916 [inline] __kmalloc+0x2bb/0x4b0 mm/slub.c:3982 kmalloc include/linux/slab.h:559 [inline] getdqbuf+0x56/0x150 fs/quota/quota_tree.c:52 qtree_write_dquot+0xf2/0x870 fs/quota/quota_tree.c:378 v2_write_dquot+0x1ad/0x280 fs/quota/quota_v2.c:333 dquot_commit+0x4af/0x600 fs/quota/dquot.c:482 ext4_write_dquot fs/ext4/super.c:5934 [inline] ext4_mark_dquot_dirty+0x4d8/0x6a0 fs/ext4/super.c:5985 mark_dquot_dirty fs/quota/dquot.c:347 [inline] mark_all_dquot_dirty fs/quota/dquot.c:385 [inline] dquot_alloc_inode+0xc05/0x12b0 fs/quota/dquot.c:1755 __ext4_new_inode+0x8204/0x9d70 fs/ext4/ialloc.c:1155 ext4_tmpfile+0x41a/0x850 fs/ext4/namei.c:2686 vfs_tmpfile+0x2a2/0x570 fs/namei.c:3283 do_tmpfile fs/namei.c:3316 [inline] path_openat+0x4035/0x6a90 fs/namei.c:3359 do_filp_open+0x2b8/0x710 fs/namei.c:3395 do_sys_openat2+0xa88/0x1140 fs/open.c:1168 do_sys_open fs/open.c:1184 [inline] __do_compat_sys_openat fs/open.c:1242 [inline] __se_compat_sys_openat+0x2a4/0x310 fs/open.c:1240 __ia32_compat_sys_openat+0x56/0x70 fs/open.c:1240 do_syscall_32_irqs_on arch/x86/entry/common.c:80 [inline] __do_fast_syscall_32+0x129/0x180 arch/x86/entry/common.c:139 do_fast_syscall_32+0x6a/0xc0 arch/x86/entry/common.c:162 do_SYSENTER_32+0x73/0x90 arch/x86/entry/common.c:205 entry_SYSENTER_compat_after_hwframe+0x4d/0x5c Fixes: 498c60153ebb ("quota: Implement quota format with 64-bit space and inode limits") Link: https://lore.kernel.org/r/20200924183619.4176790-1-edumazet@google.com Signed-off-by: Eric Dumazet <edumazet@google.com> Cc: Jan Kara <jack@suse.com> Signed-off-by: Jan Kara <jack@suse.cz>
2020-09-17quota: simplify the quotactl compat handlingChristoph Hellwig5-140/+93
Fold the misaligned u64 workarounds into the main quotactl flow instead of implementing a separate compat syscall handler. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-09-10quota: widen timestamps for the fs_disk_quota structureDarrick J. Wong1-6/+36
Soon, XFS will support quota grace period expiration timestamps beyond the year 2038, widen the timestamp fields to handle the extra time bits. Internally, XFS now stores unsigned 34-bit quantities, so the extra 8 bits here should work fine. (Note that XFS is the only user of this structure.) Link: https://lore.kernel.org/r/20200909163413.GJ7955@magnolia Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jan Kara <jack@suse.cz>
2020-08-23treewide: Use fallthrough pseudo-keywordGustavo A. R. Silva1-1/+1
Replace the existing /* fall through */ comments and its variants with the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary fall-through markings when it is the case. [1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through Signed-off-by: Gustavo A. R. Silva <gustavoars@kernel.org>
2020-08-06Merge tag 'for_v5.9-rc1' of ↵Linus Torvalds1-1/+1
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull ext2, udf, reiserfs, quota cleanups and minor fixes from Jan Kara: "A few ext2 fixups and then several (mostly comment and documentation) cleanups in ext2, udf, reiserfs, and quota" * tag 'for_v5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: reiserfs: delete duplicated words udf: osta_udf.h: delete a duplicated word reiserfs: reiserfs.h: delete a duplicated word ext2: ext2.h: fix duplicated word + typos udf: Replace HTTP links with HTTPS ones quota: Fixup http links in quota doc Replace HTTP links with HTTPS ones: DISKQUOTA ext2: initialize quota info in ext2_xattr_set() ext2: fix some incorrect comments in inode.c ext2: remove nocheck option ext2: fix missing percpu_counter_inc ext2: ext2_find_entry() return -ENOENT if no entry found ext2: propagate errors up to ext2_find_entry()'s callers ext2: fix improper assignment for e_value_offs
2020-07-09Replace HTTP links with HTTPS ones: DISKQUOTAAlexander A. Klimov1-1/+1
Rationale: Reduces attack surface on kernel devs opening the links for MITM as HTTPS traffic is much harder to manipulate. Deterministic algorithm: For each file: If not .svg: For each line: If doesn't contain `\bxmlns\b`: For each link, `\bhttp://[^# \t\r\n]*(?:\w|/)`: If neither `\bgnu\.org/license`, nor `\bmozilla\.org/MPL\b`: If both the HTTP and HTTPS versions return 200 OK and serve the same content: Replace HTTP with HTTPS. Link: https://lore.kernel.org/r/20200708171905.15396-1-grandmaster@al2klimov.de Signed-off-by: Alexander A. Klimov <grandmaster@al2klimov.de> Signed-off-by: Jan Kara <jack@suse.cz>
2020-06-24block: move block-related definitions out of fs.hChristoph Hellwig1-0/+1
Move most of the block related definition out of fs.h into more suitable headers. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2020-04-27sysctl: pass kernel pointers to ->proc_handlerChristoph Hellwig1-1/+1
Instead of having all the sysctl handlers deal with user pointers, which is rather hairy in terms of the BPF interaction, copy the input to and from userspace in common code. This also means that the strings are always NUL-terminated by the common code, making the API a little bit safer. As most handler just pass through the data to one of the common handlers a lot of the changes are mechnical. Signed-off-by: Christoph Hellwig <hch@lst.de> Acked-by: Andrey Ignatov <rdna@fb.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2020-01-30Merge tag 'for_v5.6-rc1' of ↵Linus Torvalds2-4/+4
git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs Pull UDF, quota, reiserfs, ext2 fixes and cleanups from Jan Kara: "A few assorted fixes and cleanups for udf, quota, reiserfs, and ext2" * tag 'for_v5.6-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/jack/linux-fs: fs/reiserfs: remove unused macros fs/quota: remove unused macro udf: Clarify meaning of f_files in udf_statfs udf: Allow writing to 'Rewritable' partitions udf: Disallow R/W mode for disk with Metadata partition udf: Fix meaning of ENTITYID_FLAGS_* macros to be really bitwise-or flags udf: Fix free space reporting for metadata and virtual partitions udf: Update header files to UDF 2.60 udf: Move OSTA Identifier Suffix macros from ecma_167.h to osta_udf.h udf: Fix spelling in EXT_NEXT_EXTENT_ALLOCDESCS ext2: Adjust indentation in ext2_fill_super quota: avoid time_t in v1_disk_dqblk definition reiserfs: Fix spurious unlock in reiserfs_fill_super() error handling reiserfs: Fix memory leak of journal device string ext2: set proper errno in error case of ext2_fill_super()
2020-01-21fs/quota: remove unused macroAlex Shi1-2/+0
__QUOTA_V2_PARANOIA macro is never used. better to remove it. Link: https://lore.kernel.org/r/1579602334-57039-1-git-send-email-alex.shi@linux.alibaba.com Signed-off-by: Alex Shi <alex.shi@linux.alibaba.com> Cc: Jan Kara <jack@suse.com> Cc: linux-kernel@vger.kernel.org Signed-off-by: Jan Kara <jack@suse.cz>
2019-12-18fs: avoid softlockups in s_inodes iteratorsEric Sandeen1-0/+1
Anything that walks all inodes on sb->s_inodes list without rescheduling risks softlockups. Previous efforts were made in 2 functions, see: c27d82f fs/drop_caches.c: avoid softlockups in drop_pagecache_sb() ac05fbb inode: don't softlockup when evicting inodes but there hasn't been an audit of all walkers, so do that now. This also consistently moves the cond_resched() calls to the bottom of each loop in cases where it already exists. One loop remains: remove_dquot_ref(), because I'm not quite sure how to deal with that one w/o taking the i_lock. Signed-off-by: Eric Sandeen <sandeen@redhat.com> Reviewed-by: Jan Kara <jack@suse.cz> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-12-16quota: avoid time_t in v1_disk_dqblk definitionArnd Bergmann1-2/+4
The time_t type is part of the user interface and not always the same, with the move to 64-bit timestamps and the difference between architectures. Make the quota format definition independent of this type and use a basic type of the same length. Make it unsigned in the process to keep the v1 format working until year 2106 instead of 2038 on 32-bit architectures. Hopefully, everybody has already moved to a newer format long ago (v2 was introduced with linux-2.4), but it's hard to be sure. Link: https://lore.kernel.org/r/20191213205221.3787308-6-arnd@arndb.de Signed-off-by: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Jan Kara <jack@suse.cz>
2019-12-06Merge branch 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfsLinus Torvalds1-7/+1
Pull vfs d_inode/d_flags memory ordering fixes from Al Viro: "Fallout from tree-wide audit for ->d_inode/->d_flags barriers use. Basically, the problem is that negative pinned dentries require careful treatment - unless ->d_lock is locked or parent is held at least shared, another thread can make them positive right under us. Most of the uses turned out to be safe - the main surprises as far as filesystems are concerned were - race in dget_parent() fastpath, that might end up with the caller observing the returned dentry _negative_, due to insufficient barriers. It is positive in memory, but we could end up seeing the wrong value of ->d_inode in CPU cache. Fixed. - manual checks that result of lookup_one_len_unlocked() is positive (and rejection of negatives). Again, insufficient barriers (we might end up with inconsistent observed values of ->d_inode and ->d_flags). Fixed by switching to a new primitive that does the checks itself and returns ERR_PTR(-ENOENT) instead of a negative dentry. That way we get rid of boilerplate converting negatives into ERR_PTR(-ENOENT) in the callers and have a single place to deal with the barrier-related mess - inside fs/namei.c rather than in every caller out there. The guts of pathname resolution *do* need to be careful - the race found by Ritesh is real, as well as several similar races. Fortunately, it turns out that we can take care of that with fairly local changes in there. The tree-wide audit had not been fun, and I hate the idea of repeating it. I think the right approach would be to annotate the places where we are _not_ guaranteed ->d_inode/->d_flags stability and have sparse catch regressions. But I'm still not sure what would be the least invasive way of doing that and it's clearly the next cycle fodder" * 'fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: fs/namei.c: fix missing barriers when checking positivity fix dget_parent() fastpath race new helper: lookup_positive_unlocked() fs/namei.c: pull positivity check into follow_managed()
2019-11-15new helper: lookup_positive_unlocked()Al Viro1-6/+1
Most of the callers of lookup_one_len_unlocked() treat negatives are ERR_PTR(-ENOENT). Provide a helper that would do just that. Note that a pinned positive dentry remains positive - it's ->d_inode is stable, etc.; a pinned _negative_ dentry can become positive at any point as long as you are not holding its parent at least shared. So using lookup_one_len_unlocked() needs to be careful; lookup_positive_unlocked() is safer and that's what the callers end up open-coding anyway. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2019-11-11fs/quota: handle overflows of sysctl fs.quota.* and report as unsigned longKonstantin Khlebnikov1-12/+17
Quota statistics counted as 64-bit per-cpu counter. Reading sums per-cpu fractions as signed 64-bit int, filters negative values and then reports lower half as signed 32-bit int. Result may looks like: fs.quota.allocated_dquots = 22327 fs.quota.cache_hits = -489852115 fs.quota.drops = -487288718 fs.quota.free_dquots = 22083 fs.quota.lookups = -486883485 fs.quota.reads = 22327 fs.quota.syncs = 335064 fs.quota.writes = 3088689 Values bigger than 2^31-1 reported as negative. All counters except "allocated_dquots" and "free_dquots" are monotonic, thus they should be reported as is without filtering negative values. Kernel doesn't have generic helper for 64-bit sysctl yet, let's use at least unsigned lo