linux-toradex.git/fs/quota, branch v5.0

quota: Lock s_umount in exclusive mode for Q_XQUOTA{ON,OFF} quotactls.

2018-12-18T17:29:15+00:00

Commit 1fa5efe3622db58cb8c7b9a50665e9eb9a6c7e97 (ext4: Use generic helpers for quotaon
and quotaoff) made possible to call quotactl(Q_XQUOTAON/OFF) on ext4 filesystems
with sysfile quota support. This leads to calling dquot_enable/disable without s_umount
held in excl. mode, because quotactl_cmd_onoff checks only for Q_QUOTAON/OFF.

The following WARN_ON_ONCE triggers (in this case for dquot_enable, ext4, latest Linus' tree):

[  117.807056] EXT4-fs (dm-0): mounted filesystem with ordered data mode. Opts: quota,prjquota

[...]

[  155.036847] WARNING: CPU: 0 PID: 2343 at fs/quota/dquot.c:2469 dquot_enable+0x34/0xb9
[  155.036851] Modules linked in: quota_v2 quota_tree ipv6 af_packet joydev mousedev psmouse serio_raw pcspkr i2c_piix4 intel_agp intel_gtt e1000 ttm drm_kms_helper drm agpgart fb_sys_fops syscopyarea sysfillrect sysimgblt i2c_core input_leds kvm_intel kvm irqbypass qemu_fw_cfg floppy evdev parport_pc parport button crc32c_generic dm_mod ata_generic pata_acpi ata_piix libata loop ext4 crc16 mbcache jbd2 usb_storage usbcore sd_mod scsi_mod
[  155.036901] CPU: 0 PID: 2343 Comm: qctl Not tainted 4.20.0-rc6-00025-gf5d582777bcb #9
[  155.036903] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.10.2-1ubuntu1 04/01/2014
[  155.036911] RIP: 0010:dquot_enable+0x34/0xb9
[  155.036915] Code: 41 56 41 55 41 54 55 53 4c 8b 6f 28 74 02 0f 0b 4d 8d 7d 70 49 89 fc 89 cb 41 89 d6 89 f5 4c 89 ff e8 23 09 ea ff 85 c0 74 0a <0f> 0b 4c 89 ff e8 8b 09 ea ff 85 db 74 6a 41 8b b5 f8 00 00 00 0f
[  155.036918] RSP: 0018:ffffb09b00493e08 EFLAGS: 00010202
[  155.036922] RAX: 0000000000000001 RBX: 0000000000000008 RCX: 0000000000000008
[  155.036924] RDX: 0000000000000001 RSI: 0000000000000002 RDI: ffff9781b67cd870
[  155.036926] RBP: 0000000000000002 R08: 0000000000000000 R09: 61c8864680b583eb
[  155.036929] R10: ffffb09b00493e48 R11: ffffffffff7ce7d4 R12: ffff9781b7ee8d78
[  155.036932] R13: ffff9781b67cd800 R14: 0000000000000004 R15: ffff9781b67cd870
[  155.036936] FS:  00007fd813250b88(0000) GS:ffff9781ba000000(0000) knlGS:0000000000000000
[  155.036939] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  155.036942] CR2: 00007fd812ff61d6 CR3: 000000007c882000 CR4: 00000000000006b0
[  155.036951] DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
[  155.036953] DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
[  155.036955] Call Trace:
[  155.037004]  dquot_quota_enable+0x8b/0xd0
[  155.037011]  kernel_quotactl+0x628/0x74e
[  155.037027]  ? do_mprotect_pkey+0x2a6/0x2cd
[  155.037034]  __x64_sys_quotactl+0x1a/0x1d
[  155.037041]  do_syscall_64+0x55/0xe4
[  155.037078]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[  155.037105] RIP: 0033:0x7fd812fe1198
[  155.037109] Code: 02 77 0d 48 89 c1 48 c1 e9 3f 75 04 48 8b 04 24 48 83 c4 50 5b c3 48 83 ec 08 49 89 ca 48 63 d2 48 63 ff b8 b3 00 00 00 0f 05 <48> 89 c7 e8 c1 eb ff ff 5a c3 48 63 ff b8 bb 00 00 00 0f 05 48 89
[  155.037112] RSP: 002b:00007ffe8cd7b050 EFLAGS: 00000206 ORIG_RAX: 00000000000000b3
[  155.037116] RAX: ffffffffffffffda RBX: 00007ffe8cd7b148 RCX: 00007fd812fe1198
[  155.037119] RDX: 0000000000000000 RSI: 00007ffe8cd7cea9 RDI: 0000000000580102
[  155.037121] RBP: 00007ffe8cd7b0f0 R08: 000055fc8eba8a9d R09: 0000000000000000
[  155.037124] R10: 00007ffe8cd7b074 R11: 0000000000000206 R12: 00007ffe8cd7b168
[  155.037126] R13: 000055fc8eba8897 R14: 0000000000000000 R15: 0000000000000000
[  155.037131] ---[ end trace 210f864257175c51 ]---

and then the syscall proceeds without s_umount locking.

This patch locks the superblock ->s_umount sem. in exclusive mode for all Q_XQUOTAON/OFF
quotactls too in addition to Q_QUOTAON/OFF.

AFAICT, other than ext4, only xfs and ocfs2 are affected by this change.
The VFS will now call in xfs_quota_* functions with s_umount held, which wasn't the case
before. This looks good to me but I can not say for sure. Ext4 and ocfs2 where already
beeing called with s_umount exclusive via quota_quotaon/off which is basically the same.

Signed-off-by: Javier Barrio 
Signed-off-by: Jan Kara

fs/quota: Fix spectre gadget in do_quotactl

2018-08-22T16:17:48+00:00

'type' is user-controlled, so sanitize it after the bounds check to
avoid using it in speculative execution. This covers the following
potential gadgets detected with the help of smatch:

* fs/ext4/super.c:5741 ext4_quota_read() warn: potential spectre issue
  'sb_dqopt(sb)->files' [r]
* fs/ext4/super.c:5778 ext4_quota_write() warn: potential spectre issue
  'sb_dqopt(sb)->files' [r]
* fs/f2fs/super.c:1552 f2fs_quota_read() warn: potential spectre issue
  'sb_dqopt(sb)->files' [r]
* fs/f2fs/super.c:1608 f2fs_quota_write() warn: potential spectre issue
  'sb_dqopt(sb)->files' [r]
* fs/quota/dquot.c:412 mark_info_dirty() warn: potential spectre issue
  'sb_dqopt(sb)->info' [w]
* fs/quota/dquot.c:933 dqinit_needed() warn: potential spectre issue
  'dquots' [r]
* fs/quota/dquot.c:2112 dquot_commit_info() warn: potential spectre
  issue 'dqopt->ops' [r]
* fs/quota/dquot.c:2362 vfs_load_quota_inode() warn: potential spectre
  issue 'dqopt->files' [w] (local cap)
* fs/quota/dquot.c:2369 vfs_load_quota_inode() warn: potential spectre
  issue 'dqopt->ops' [w] (local cap)
* fs/quota/dquot.c:2370 vfs_load_quota_inode() warn: potential spectre
  issue 'dqopt->info' [w] (local cap)
* fs/quota/quota.c:110 quota_getfmt() warn: potential spectre issue
  'sb_dqopt(sb)->info' [r]
* fs/quota/quota_v2.c:84 v2_check_quota_file() warn: potential spectre
  issue 'quota_magics' [w]
* fs/quota/quota_v2.c:85 v2_check_quota_file() warn: potential spectre
  issue 'quota_versions' [w]
* fs/quota/quota_v2.c:96 v2_read_file_info() warn: potential spectre
  issue 'dqopt->info' [r]
* fs/quota/quota_v2.c:172 v2_write_file_info() warn: potential spectre
  issue 'dqopt->info' [r]

Additionally, a quick inspection indicates there are array accesses with
'type' in quota_on() and quota_off() functions which are also addressed
by this.

Cc: Josh Poimboeuf 
Cc: stable@vger.kernel.org
Signed-off-by: Jeremy Cline 
Signed-off-by: Jan Kara

fs/quota: Replace XQM_MAXQUOTAS usage with MAXQUOTAS

2018-08-22T16:17:29+00:00

XQM_MAXQUOTAS and MAXQUOTAS are, it appears, equivalent. Replace all
usage of XQM_MAXQUOTAS and remove it along with the unused XQM_*QUOTA
definitions.

Signed-off-by: Jeremy Cline 
Signed-off-by: Jan Kara

quota: Cleanup list iteration in dqcache_shrink_scan()

2018-06-20T09:04:26+00:00

Use list_first_entry() and list_empty() instead of opencoded variants.

Reviewed-by: Matthew Wilcox 
Signed-off-by: Jan Kara

quota: reclaim least recently used dquots

2018-06-20T09:04:26+00:00

The dquots in the free_dquots list are not reclaimed in LRU way.
put_dquot_last() puts entries to the tail and dqcache_shrink_scan()
frees from the tail. Free unreferenced dquots in LRU order because it
seems more reasonable than freeing most recently used.

Signed-off-by: Greg Thelen 
Signed-off-by: Shakeel Butt 
Signed-off-by: Jan Kara

fs: quota: Replace GFP_ATOMIC with GFP_KERNEL in dquot_init

2018-04-09T15:48:54+00:00

dquot_init() is never called in atomic context.
This function is only set as a parameter of fs_initcall().

Despite never getting called from atomic context,
dquot_init() calls __get_free_pages() with GFP_ATOMIC,
which waits busily for allocation.
GFP_ATOMIC is not necessary and can be replaced with GFP_KERNEL,
to avoid busy waiting and improve the possibility of sucessful allocation.

This is found by a static analysis tool named DCNS written by myself.
And I also manually check it.

Signed-off-by: Jia-Ju Bai 
Signed-off-by: Jan Kara

fs/quota: use COMPAT_SYSCALL_DEFINE for sys32_quotactl()

2018-04-02T18:15:47+00:00

While sys32_quotactl() is only needed on x86, it can use the recommended
COMPAT_SYSCALL_DEFINEx() machinery for its setup.

Acked-by: Jan Kara 
Cc: Christoph Hellwig 
Signed-off-by: Dominik Brodowski

fs/quota: add kernel_quotactl() helper; remove in-kernel call to syscall

2018-04-02T18:15:46+00:00

Using the fs-internal kernel_quotactl() helper allows us to get rid of
the fs-internal call to the sys_quotactl() syscall.

This patch is part of a series which removes in-kernel calls to syscalls.
On this basis, the syscall entry path can be streamlined. For details, see
http://lkml.kernel.org/r/20180325162527.GA17492@light.dominikbrodowski.net

Acked-by: Jan Kara 
Signed-off-by: Dominik Brodowski

quota: Check for register_shrinker() failure.

2017-11-29T15:46:48+00:00

register_shrinker() might return -ENOMEM error since Linux 3.12.
Call panic() as with other failure checks in this function if
register_shrinker() failed.

Fixes: 1d3d4437eae1 ("vmscan: per-node deferred work")
Signed-off-by: Tetsuo Handa 
Cc: Jan Kara 
Cc: Michal Hocko 
Reviewed-by: Michal Hocko 
Signed-off-by: Jan Kara

quota: propagate error from __dquot_initialize

2017-11-28T15:08:08+00:00

In commit 6184fc0b8dd7 ("quota: Propagate error from ->acquire_dquot()"),
we have propagated error from __dquot_initialize to caller, but we forgot
to handle such error in add_dquot_ref(), so, currently, during quota
accounting information initialization flow, if we failed for some of
inodes, we just ignore such error, and do account for others, which is
not a good implementation.

In this patch, we choose to let user be aware of such error, so after
turning on quota successfully, we can make sure all inodes disk usage
can be accounted, which will be more reasonable.

Suggested-by: Jan Kara 
Signed-off-by: Chao Yu 
Signed-off-by: Jan Kara