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Dirtiable inode bdi default != sb bdi btrfs

DISCUSSION Cesar Eduardo Barros 8 participants 21 messages Sep 23, 2010 – Sep 30, 2010

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Cesar Eduardo Barros

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#0 lore raw

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.

[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8
Call Trace:
 [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
 [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
 [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
 [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
 [<ffffffff81127168>] touch_atime+0x107/0x12a
 [<ffffffff81122384>] ? filldir+0x0/0xd0
 [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
 [<ffffffff8112270b>] sys_getdents+0x81/0xd1
 [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
---[ end trace 8907b335812c497b ]---
------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Tainted: G        W   2.6.36-rc5+ #8
Call Trace:
 [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
 [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
 [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
 [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
 [<ffffffff81127168>] touch_atime+0x107/0x12a
 [<ffffffff81122384>] ? filldir+0x0/0xd0
 [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
 [<ffffffff8112270b>] sys_getdents+0x81/0xd1
 [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
---[ end trace 8907b335812c497c ]---

[...]

These are only the first two; they keep happening, with several different processes (it is not only find), but always btrfs (I have / and /home on btrfs and /boot on ext4). In case it makes any difference, /dev seems to be on devtmpfs, and everything uses relatime.

There is also the following one which is not on vfs_readdir:

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1104, comm: mkdir Tainted: G        W   2.6.36-rc5+ #8
Call Trace:
 [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
 [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
 [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
 [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
 [<ffffffffa01408c6>] btrfs_setattr+0x210/0x23a [btrfs]
 [<ffffffff8112865e>] notify_change+0x1a2/0x29d
 [<ffffffff81113794>] sys_fchmod+0xac/0xfd
 [<ffffffff811188e2>] ? sys_newfstat+0x2e/0x39
 [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
---[ end trace 8907b335812c498d ]---
Signature · 3 lines
Cesar Eduardo Barros
[email protected]
[email protected]
#1 lore raw

(Cc [email protected])

Quoted 23 lines · On Wed, 22 Sep 2010 21:54:30 -0300 Cesar Eduardo Barros <[email protected]>…

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.

[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Quoted 10 lines
Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b

Thanks. 692ebd17c2905313fff3c504c249c6a0faad16ec had a cc:stable in the changelog. I'd suggest it not be merged into -stable until this regression is sorted out!

Quoted 34 lines

...

These are only the first two; they keep happening, with several different processes (it is not only find), but always btrfs (I have / and /home on btrfs and /boot on ext4). In case it makes any difference, /dev seems to be on devtmpfs, and everything uses relatime.

There is also the following one which is not on vfs_readdir:

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1104, comm: mkdir Tainted: G W 2.6.36-rc5+ #8

Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffffa01408c6>] btrfs_setattr+0x210/0x23a [btrfs]
  [<ffffffff8112865e>] notify_change+0x1a2/0x29d
  [<ffffffff81113794>] sys_fchmod+0xac/0xfd
  [<ffffffff811188e2>] ? sys_newfstat+0x2e/0x39
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
#2 lore raw
Quoted 10 lines · Andrew Morton

(Cc [email protected])

Quoted 4 lines · On Wed, 22 Sep 2010 21:54:30 -0300 Cesar Eduardo Barros <[email protected]>…

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.

The problem is that btrfs isn't setting the inode bdi on the directory inode. I'm digging now to see if this code is right for blockdevice/special inodes as well.

-chris

#3 lore raw
In reply to Andrew Morton
Quoted 40 lines · Andrew Morton

(Cc [email protected])

Quoted 23 lines · On Wed, 22 Sep 2010 21:54:30 -0300 Cesar Eduardo Barros <[email protected]>…

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.

[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Quoted 10 lines
Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
Quoted 3 lines

Thanks. 692ebd17c2905313fff3c504c249c6a0faad16ec had a cc:stable in the changelog. I'd suggest it not be merged into -stable until this regression is sorted out!

It was just added, I'm discussing this with Chris on irc as I type this. But yes, lets not replace a regression with a new regression :-). So Greg, please hold off on these for a little while.

Signature · 1 line
Jens Axboe
#4 lore raw
Quoted 41 lines · Jens Axboe
Quoted 40 lines · Andrew Morton

(Cc [email protected])

Quoted 33 lines · On Wed, 22 Sep 2010 21:54:30 -0300 Cesar Eduardo Barros <[email protected]>…

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.

[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
Quoted 7 lines
Quoted 3 lines

Thanks. 692ebd17c2905313fff3c504c249c6a0faad16ec had a cc:stable in the changelog. I'd suggest it not be merged into -stable until this regression is sorted out!

It was just added, I'm discussing this with Chris on irc as I type this. But yes, lets not replace a regression with a new regression :-). So Greg, please hold off on these for a little while.

Ok, so which ones should I take out of the -stable tree? Just this one:

	692ebd17c2905313fff3c504c249c6a0faad16ec

or it and something else?

thanks,

greg k-h

#5 lore raw
Quoted 46 lines · Greg KH
Quoted 45 lines · Jens Axboe
Quoted 43 lines · Andrew Morton

(Cc [email protected])

Quoted 23 lines · On Wed, 22 Sep 2010 21:54:30 -0300 Cesar Eduardo Barros <[email protected]>…

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.

[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Quoted 10 lines
Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b

Thanks. 692ebd17c2905313fff3c504c249c6a0faad16ec had a cc:stable in the changelog. I'd suggest it not be merged into -stable until this regression is sorted out!

Quoted 7 lines
Quoted 3 lines

It was just added, I'm discussing this with Chris on irc as I type this. But yes, lets not replace a regression with a new regression :-). So Greg, please hold off on these for a little while.

Ok, so which ones should I take out of the -stable tree? Just this one:

	692ebd17c2905313fff3c504c249c6a0faad16ec

or it and something else?

You can keep 1/2, just hold off on the one labeled:

bdi: Fix warnings in __mark_inode_dirty for /dev/zero and friends

for now. I'm off to Japan in the morning, perhaps Jan can comment if he's available.

Signature · 1 line
Jens Axboe
#6 lore raw
Quoted 55 lines · Jens Axboe
Quoted 46 lines · Greg KH
Quoted 45 lines · Jens Axboe
Quoted 43 lines · Andrew Morton

(Cc [email protected])

Quoted 23 lines · On Wed, 22 Sep 2010 21:54:30 -0300 Cesar Eduardo Barros <[email protected]>…

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.

[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Quoted 10 lines
Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b

Thanks. 692ebd17c2905313fff3c504c249c6a0faad16ec had a cc:stable in the changelog. I'd suggest it not be merged into -stable until this regression is sorted out!

Quoted 7 lines
Quoted 3 lines

It was just added, I'm discussing this with Chris on irc as I type this. But yes, lets not replace a regression with a new regression :-). So Greg, please hold off on these for a little while.

Ok, so which ones should I take out of the -stable tree? Just this one:

	692ebd17c2905313fff3c504c249c6a0faad16ec

or it and something else?

Quoted 6 lines

You can keep 1/2, just hold off on the one labeled:

bdi: Fix warnings in __mark_inode_dirty for /dev/zero and friends

for now. I'm off to Japan in the morning, perhaps Jan can comment if he's available.

Ok, now dropped, thanks.

greg k-h

reviewer
#7 lore raw
In reply to Andrew Morton

[Added CCs for similar ecryptfs warning]

Quoted 24 lines · Andrew Morton
Quoted 24 lines

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.
[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
Quoted 8 lines
Quoted 8 lines
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b

Thanks for the report. These bdi pointers are a mess. As Chris pointed
out, btrfs forgets to properly initialize inode->i_mapping.backing_dev_info for directories and special inodes and thus these were previously attached to default_backing_dev_info which probably isn't what Chris would like to see.
I've also got a similar report for ecryptfs which also does not
initialize inode->i_mapping.backing_dev_info although it sets sb->s_bdi and thus again its inodes get filed to default_backing_dev_info lists. Quick search seems to reveal that other filesystems using handcrafted bdi's get it wrong as well and thus their inodes end up in the default_backing_dev_info lists which is generally undesirable (this was happening already before my patch, my code just started complaining about that).
That suggests that we should probably handle such cases in a more generic
way by changing the code in inode_init_always(). The patch below makes at least btrfs happy for me... Could you maybe test it? Thanks.

Honza

Signature · 3 lines
Jan Kara <[email protected]>
SUSE Labs, CR
---
Quoted 1 line

From 29f60c2b08ff9637a10439d1513805835ddcc746 Mon Sep 17 00:00:00 2001

From: Jan Kara <[email protected]>
Date: Mon, 27 Sep 2010 23:56:48 +0200
Subject: [PATCH] bdi: Initialize inode->i_mapping.backing_dev_info to sb->s_bdi

Currently, we initialize inode->i_mapping.backing_dev_info to the bdi of device sb->s_bdev points to. However there is quite a big number of filesystems that do not set sb->s_bdev (because they do not have one) but do set sb->s_bdi. These filesystems would generally benefit from setting inode->i_mapping.backing_dev_info to their s_bdi because otherwise their inodes would point to default_backing_dev_info and thus dirty inode tracking would happen there. So change inode initialization code to use sb->s_bdi if it is available.

Signed-off-by Jan Kara <[email protected]>
---
 fs/inode.c |   22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)
fs/inode.c +14 -8
index 8646433..e415be4 100644
@@ -172,15 +172,21 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	mapping->writeback_index = 0;
 
 	/*
-	 * If the block_device provides a backing_dev_info for client
-	 * inodes then use that.  Otherwise the inode share the bdev's
-	 * backing_dev_info.
+	 * If the filesystem provides a backing_dev_info for client inodes
+	 * then use that. Otherwise inodes share default_backing_dev_info.
 	 */
-	if (sb->s_bdev) {
-		struct backing_dev_info *bdi;
-
-		bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
-		mapping->backing_dev_info = bdi;
+	if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) {
+		/*
+		 * Catch cases where filesystem might be bitten by using s_bdi
+		 * instead of sb->s_bdev. Can be removed in 2.6.38.
+		 */
+		if (sb->s_bdev) {
+			struct backing_dev_info *bdi =
+			  sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
+			WARN(bdi != sb->s_bdi, "s_bdev bdi %s != s_bdi %s\n",
+			     bdi->name, sb->s_bdi->name);
+		}
+		mapping->backing_dev_info = sb->s_bdi;
 	}
 	inode->i_private = NULL;
 	inode->i_mapping = mapping;
Signature · 1 line
1.6.4.2
#8 lore raw
Quoted 34 lines · Jan Kara

[Added CCs for similar ecryptfs warning]

Quoted 24 lines · Andrew Morton
Quoted 24 lines

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.
[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
Quoted 8 lines
Quoted 8 lines
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
Quoted 5 lines

Thanks for the report. These bdi pointers are a mess. As Chris pointed
out, btrfs forgets to properly initialize inode->i_mapping.backing_dev_info for directories and special inodes and thus these were previously attached to default_backing_dev_info which probably isn't what Chris would like to see.

There's no actual writeback for these, so it works fine for btrfs either way.

Quoted 10 lines

I've also got a similar report for ecryptfs which also does not
initialize inode->i_mapping.backing_dev_info although it sets sb->s_bdi and thus again its inodes get filed to default_backing_dev_info lists. Quick search seems to reveal that other filesystems using handcrafted bdi's get it wrong as well and thus their inodes end up in the default_backing_dev_info lists which is generally undesirable (this was happening already before my patch, my code just started complaining about that).
That suggests that we should probably handle such cases in a more generic
way by changing the code in inode_init_always(). The patch below makes at least btrfs happy for me... Could you maybe test it? Thanks.

Christoph had a slightly different plan for this, I've cc'd him and kept the patch below for comment.

-chris

Quoted 63 lines

Honza

Signature · 22 lines
Jan Kara <[email protected]>
SUSE Labs, CR
---

From 29f60c2b08ff9637a10439d1513805835ddcc746 Mon Sep 17 00:00:00 2001
From: Jan Kara <[email protected]>
Date: Mon, 27 Sep 2010 23:56:48 +0200
Subject: [PATCH] bdi: Initialize inode->i_mapping.backing_dev_info to sb->s_bdi

Currently, we initialize inode->i_mapping.backing_dev_info to the bdi of device
sb->s_bdev points to. However there is quite a big number of filesystems that
do not set sb->s_bdev (because they do not have one) but do set sb->s_bdi.
These filesystems would generally benefit from setting
inode->i_mapping.backing_dev_info to their s_bdi because otherwise their inodes
would point to default_backing_dev_info and thus dirty inode tracking would
happen there. So change inode initialization code to use sb->s_bdi if it
is available.

Signed-off-by: Jan Kara <[email protected]>
---
 fs/inode.c |   22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)
fs/inode.c +14 -8
index 8646433..e415be4 100644
@@ -172,15 +172,21 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	mapping->writeback_index = 0;
 
 	/*
-	 * If the block_device provides a backing_dev_info for client
-	 * inodes then use that.  Otherwise the inode share the bdev's
-	 * backing_dev_info.
+	 * If the filesystem provides a backing_dev_info for client inodes
+	 * then use that. Otherwise inodes share default_backing_dev_info.
 	 */
-	if (sb->s_bdev) {
-		struct backing_dev_info *bdi;
-
-		bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
-		mapping->backing_dev_info = bdi;
+	if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) {
+		/*
+		 * Catch cases where filesystem might be bitten by using s_bdi
+		 * instead of sb->s_bdev. Can be removed in 2.6.38.
+		 */
+		if (sb->s_bdev) {
+			struct backing_dev_info *bdi =
+			  sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
+			WARN(bdi != sb->s_bdi, "s_bdev bdi %s != s_bdi %s\n",
+			     bdi->name, sb->s_bdi->name);
+		}
+		mapping->backing_dev_info = sb->s_bdi;
 	}
 	inode->i_private = NULL;
 	inode->i_mapping = mapping;
Signature · 1 line
1.6.4.2
reviewer
#9 lore raw
Quoted 35 lines · Chris Mason
Quoted 34 lines · Jan Kara

[Added CCs for similar ecryptfs warning]

Quoted 32 lines · Andrew Morton
Quoted 32 lines

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.
[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
Quoted 8 lines
Quoted 5 lines

Thanks for the report. These bdi pointers are a mess. As Chris pointed
out, btrfs forgets to properly initialize inode->i_mapping.backing_dev_info for directories and special inodes and thus these were previously attached to default_backing_dev_info which probably isn't what Chris would like to see.

There's no actual writeback for these, so it works fine for btrfs either way.

Ah, OK. I see you do all the writing already at inode dirtying time so
you don't really care what happens after the dirtying for inodes without page cache. So it's really just a cosmetic issue for btrfs.

Quoted 11 lines
Quoted 10 lines

I've also got a similar report for ecryptfs which also does not
initialize inode->i_mapping.backing_dev_info although it sets sb->s_bdi and thus again its inodes get filed to default_backing_dev_info lists. Quick search seems to reveal that other filesystems using handcrafted bdi's get it wrong as well and thus their inodes end up in the default_backing_dev_info lists which is generally undesirable (this was happening already before my patch, my code just started complaining about that).
That suggests that we should probably handle such cases in a more generic
way by changing the code in inode_init_always(). The patch below makes at least btrfs happy for me... Could you maybe test it? Thanks.

Quoted 2 lines

Christoph had a slightly different plan for this, I've cc'd him and kept the patch below for comment.

OK, thanks.

Honza

Quoted 58 lines
Quoted 58 lines

---

From 29f60c2b08ff9637a10439d1513805835ddcc746 Mon Sep 17 00:00:00 2001
From: Jan Kara <[email protected]>
Date: Mon, 27 Sep 2010 23:56:48 +0200
Subject: [PATCH] bdi: Initialize inode->i_mapping.backing_dev_info to sb->s_bdi

Currently, we initialize inode->i_mapping.backing_dev_info to the bdi of device sb->s_bdev points to. However there is quite a big number of filesystems that do not set sb->s_bdev (because they do not have one) but do set sb->s_bdi. These filesystems would generally benefit from setting inode->i_mapping.backing_dev_info to their s_bdi because otherwise their inodes would point to default_backing_dev_info and thus dirty inode tracking would happen there. So change inode initialization code to use sb->s_bdi if it is available.

Signed-off-by Jan Kara <[email protected]>
---
 fs/inode.c |   22 ++++++++++++++--------
 1 files changed, 14 insertions(+), 8 deletions(-)
fs/inode.c +14 -8
index 8646433..e415be4 100644
@@ -172,15 +172,21 @@ int inode_init_always(struct super_block *sb, struct inode *inode)
 	mapping->writeback_index = 0;
 
 	/*
-	 * If the block_device provides a backing_dev_info for client
-	 * inodes then use that.  Otherwise the inode share the bdev's
-	 * backing_dev_info.
+	 * If the filesystem provides a backing_dev_info for client inodes
+	 * then use that. Otherwise inodes share default_backing_dev_info.
 	 */
-	if (sb->s_bdev) {
-		struct backing_dev_info *bdi;
-
-		bdi = sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
-		mapping->backing_dev_info = bdi;
+	if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) {
+		/*
+		 * Catch cases where filesystem might be bitten by using s_bdi
+		 * instead of sb->s_bdev. Can be removed in 2.6.38.
+		 */
+		if (sb->s_bdev) {
+			struct backing_dev_info *bdi =
+			  sb->s_bdev->bd_inode->i_mapping->backing_dev_info;
+			WARN(bdi != sb->s_bdi, "s_bdev bdi %s != s_bdi %s\n",
+			     bdi->name, sb->s_bdi->name);
+		}
+		mapping->backing_dev_info = sb->s_bdi;
 	}
 	inode->i_private = NULL;
 	inode->i_mapping = mapping;
Signature · 1 line
1.6.4.2
Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR
#10 lore raw
In reply to Chris Mason
Quoted 4 lines · Chris Mason
Quoted 3 lines · Jan Kara

[Added CCs for similar ecryptfs warning]

Quoted 1 line · Andrew Morton
Quoted 1 line

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it di=

d not=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not=

have=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduce=

s the=20

Quoted 3 lines
Quoted 3 lines
Quoted 3 lines
Quoted 3 lines

warning.
[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22=

342=20

Quoted 8 lines
Quoted 8 lines
Quoted 8 lines
Quoted 8 lines

/dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default !=3D sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb=20

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_in=

tel=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_=

seq=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 bt=

usb=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_la=

ptop snd=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page=

_alloc=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes=

_x86_64=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_help=

er drm=20

Quoted 1 line
Quoted 1 line
Quoted 1 line
Quoted 1 line

i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_sc=

an]

Quoted 11 lines
Quoted 11 lines
Quoted 11 lines
Quoted 11 lines

Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
Quoted 1 line
Quoted 1 line

Thanks for the report. These bdi pointers are a mess. As Chris po=

inted

Quoted 1 line
Quoted 1 line

out, btrfs forgets to properly initialize inode->i_mapping.backing_=

dev_info

Quoted 1 line
Quoted 1 line

for directories and special inodes and thus these were previously a=

ttached

Quoted 1 line
Quoted 1 line

to default_backing_dev_info which probably isn't what Chris would l=

ike to

Quoted 3 lines
Quoted 1 line

see.

=20
There's no actual writeback for these, so it works fine for btrfs eit=

her

Quoted 1 line

way.

Side note: every time inode is marked as dirty, we wake up a bdi thread or the default bdi thread. So if we have inodes which do not need write-back, we should never mark them as dirty.

--=20
Best Regards,
Artem Bityutskiy (=D0=90=D1=80=D1=82=D1=91=D0=BC =D0=91=D0=B8=D1=82=D1=8E= =D1=86=D0=BA=D0=B8=D0=B9)

reviewer
#11 lore raw
Quoted 42 lines · Artem Bityutskiy
Quoted 41 lines · Chris Mason
Quoted 39 lines · Jan Kara

[Added CCs for similar ecryptfs warning]

Quoted 24 lines · Andrew Morton
Quoted 24 lines

This started appearing for me on v2.6.36-rc5-49-gc79bd89; it did not happen on v2.6.36-rc5-33-g1ce1e41, probably because it does not have commit 692ebd17c2905313fff3c504c249c6a0faad16ec which introduces the warning.
[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default != sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hda_intel iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev snd_seq snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl32 btusb cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi dell_laptop snd pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_page_alloc rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd aes_x86_64 aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_helper drm i2c_algo_bit i2c_core video output [last unloaded: scsi_wait_scan]
Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
Quoted 8 lines
Quoted 8 lines
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b

Thanks for the report. These bdi pointers are a mess. As Chris pointed
out, btrfs forgets to properly initialize inode->i_mapping.backing_dev_info for directories and special inodes and thus these were previously attached to default_backing_dev_info which probably isn't what Chris would like to see.

Quoted 6 lines
Quoted 2 lines

There's no actual writeback for these, so it works fine for btrfs either way.

Side note: every time inode is marked as dirty, we wake up a bdi thread or the default bdi thread. So if we have inodes which do not need write-back, we should never mark them as dirty.

Are you sure? I think we wake up the thread only when it's the first
dirty inode for the bdi...
And a side side note ;): It's harder not to dirty the inode than it seems.
E.g. btrfs (or similarly ext3) add the new inode data to the journal already at inode dirty time but still they need to track that the transaction carrying the inode is still uncommitted. Thus the inode *is* dirty in some sense. Only it does not need any writeout to happen...

Honza

Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR
#12 lore raw
Quoted 6 lines · Jan Kara
Quoted 5 lines · Artem Bityutskiy
Quoted 4 lines · Chris Mason
Quoted 3 lines · Jan Kara

[Added CCs for similar ecryptfs warning]

Quoted 1 line · Andrew Morton
Quoted 1 line

This started appearing for me on v2.6.36-rc5-49-gc79bd89; i=

t did not=20

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happen on v2.6.36-rc5-33-g1ce1e41, probably because it does=

not have=20

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commit 692ebd17c2905313fff3c504c249c6a0faad16ec which intro=

duces the=20

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warning.
[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transi=

d 22342=20

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/dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010
Dirtiable inode bdi default !=3D sb bdi btrfs
Modules linked in: ipv6 kvm_intel kvm uinput arc4 ecb=20

snd_hda_codec_intelhdmi snd_hda_codec_realtek iwlagn snd_hd=

a_intel=20

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iwlcore snd_hda_codec uvcvideo snd_hwdep mac80211 videodev =

snd_seq=20

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snd_seq_device v4l1_compat snd_pcm atl1c v4l2_compat_ioctl3=

2 btusb=20

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cfg80211 snd_timer i2c_i801 bluetooth iTCO_wdt dell_wmi del=

l_laptop snd=20

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pcspkr wmi dcdbas shpchp iTCO_vendor_support soundcore snd_=

page_alloc=20

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rfkill joydev microcode btrfs zlib_deflate libcrc32c cryptd=

aes_x86_64=20

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aes_generic xts gf128mul dm_crypt usb_storage i915 drm_kms_=

helper drm=20

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i2c_algo_bit i2c_core video output [last unloaded: scsi_wai=

t_scan]

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Pid: 1073, comm: find Not tainted 2.6.36-rc5+ #8

Call Trace:
  [<ffffffff8104d0e4>] warn_slowpath_common+0x85/0x9d
  [<ffffffff8104d19f>] warn_slowpath_fmt+0x46/0x48
  [<ffffffff811308b7>] inode_to_bdi+0x62/0x6d
  [<ffffffff81131b48>] __mark_inode_dirty+0xd0/0x177
  [<ffffffff81127168>] touch_atime+0x107/0x12a
  [<ffffffff81122384>] ? filldir+0x0/0xd0
  [<ffffffff8112259b>] vfs_readdir+0x8d/0xb4
  [<ffffffff8112270b>] sys_getdents+0x81/0xd1
  [<ffffffff81009c72>] system_call_fastpath+0x16/0x1b
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Thanks for the report. These bdi pointers are a mess. As Chri=

s pointed

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out, btrfs forgets to properly initialize inode->i_mapping.back=

ing_dev_info

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for directories and special inodes and thus these were previous=

ly attached

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to default_backing_dev_info which probably isn't what Chris wou=

ld like to

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see.

=20
There's no actual writeback for these, so it works fine for btrfs=

either

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way.

=20
Side note: every time inode is marked as dirty, we wake up a bdi th=

read

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or the default bdi thread. So if we have inodes which do not need write-back, we should never mark them as dirty.

Are you sure? I think we wake up the thread only when it's the firs=

t

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dirty inode for the bdi...

Err, right. If no one ever marks it as clean then we won't wake-up the thread. But I thought that marking it as dirty even once is bad because this causes bdi thread creation, which consumes resources.

Sorry for my ignorance, I did not really follow the conversation, I jus= t
remember that when I looked at bdi stuff, I noticed that during boot th= e
kernel created many bdi threads which were never used then. They eventually exited. But I thought that creating useless bdi threads it about concuming resources and slowing down the boot.

As I remember, the reason was touch_atime() for some of the threads.

But really, I did not dig this, I just noticed this conversation and wanted to let you know about the issue I noticed this summer.

--=20
Best Regards,
Artem Bityutskiy (=D0=90=D1=80=D1=82=D1=91=D0=BC =D0=91=D0=B8=D1=82=D1=8E= =D1=86=D0=BA=D0=B8=D0=B9)

--
To unsubscribe from this list: send the line "unsubscribe linux-btrfs" = in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html

#13 lore raw
In reply to Chris Mason

Here is the patch that I already proposed a while ago. I've tested xfstests on btrfs and xfstests to make sure the btrfs issue is fixed, and I've also tested the original dirtying of device files issue and I/O operations on block device files to test the special case in the patch.

---
From: Christoph Hellwig <[email protected]>
Subject: [PATCH] writeback: always use sb->s_bdi for writeback purposes

We currently use struct backing_dev_info for various different purposes. Originally it was introduced to describe a backing device which includes an unplug and congestion function and various bits of readahead information and VM-relevant flags. We're also using for tracking dirty inodes for writeback.

To make writeback properly find all inodes we need to only access the per-filesystem backing_device pointed to by the superblock in ->s_bdi inside the writeback code, and not the instances pointeded to by inode->i_mapping->backing_dev which can be overriden by special devices or might not be set at all by some filesystems.

Long term we should split out the writeback-relevant bits of struct backing_device_info (which includes more than the current bdi_writeback) and only point to it from the superblock while leaving the traditional backing device as a separate structure that can be overriden by devices.

The one exception for now is the block device filesystem which really wants different writeback contexts for it's different (internal) inodes to handle the writeout more efficiently. For now we do this with a hack in fs-writeback.c because we're so late in the cycle, but in the future I plan to replace this with a superblock method that allows for multiple writeback contexts per filesystem.

Signed-off-by Christoph Hellwig <[email protected]>
fs/fs-writeback.c +3 -15
Index: linux-2.6/fs/fs-writeback.c
===================================================================
@@ -72,22 +72,10 @@ int writeback_in_progress(struct backing
 static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
-	struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
 
-	/*
-	 * For inodes on standard filesystems, we use superblock's bdi. For
-	 * inodes on virtual filesystems, we want to use inode mapping's bdi
-	 * because they can possibly point to something useful (think about
-	 * block_dev filesystem).
-	 */
-	if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) {
-		/* Some device inodes could play dirty tricks. Catch them... */
-		WARN(bdi != sb->s_bdi && bdi_cap_writeback_dirty(bdi),
-			"Dirtiable inode bdi %s != sb bdi %s\n",
-			bdi->name, sb->s_bdi->name);
-		return sb->s_bdi;
-	}
-	return bdi;
+	if (strcmp(sb->s_type->name, "bdev") == 0)
+		return inode->i_mapping->backing_dev_info;
+	return sb->s_bdi;
 }
 
 static void bdi_queue_work(struct backing_dev_info *bdi,
reviewer
#14 lore raw
Quoted 4 lines · Christoph Hellwig

---
From: Christoph Hellwig <[email protected]>
Subject: [PATCH] writeback: always use sb->s_bdi for writeback purposes

...

Quoted 6 lines

The one exception for now is the block device filesystem which really wants different writeback contexts for it's different (internal) inodes to handle the writeout more efficiently. For now we do this with a hack in fs-writeback.c because we're so late in the cycle, but in the future I plan to replace this with a superblock method that allows for multiple writeback contexts per filesystem.

Another exception I know about is mtd_inodefs filesystem
(drivers/mtd/mtdchar.c).

Quoted 19 lines
Signed-off-by Christoph Hellwig <[email protected]>

Index: linux-2.6/fs/fs-writeback.c
===================================================================

fs/fs-writeback.c +0 -8
@@ -72,22 +72,10 @@ int writeback_in_progress(struct backing
 static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
-	struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
 
-	/*
-	 * For inodes on standard filesystems, we use superblock's bdi. For
-	 * inodes on virtual filesystems, we want to use inode mapping's bdi
-	 * because they can possibly point to something useful (think about
-	 * block_dev filesystem).
-	 */
-	if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) {

fs/fs-writeback.c int writeback_in_progress(struct backing · line 78

Quoted 10 lines
fs/fs-writeback.c +3 -7
-		/* Some device inodes could play dirty tricks. Catch them... */
-		WARN(bdi != sb->s_bdi && bdi_cap_writeback_dirty(bdi),
-			"Dirtiable inode bdi %s != sb bdi %s\n",
-			bdi->name, sb->s_bdi->name);
-		return sb->s_bdi;
-	}
-	return bdi;
+	if (strcmp(sb->s_type->name, "bdev") == 0)
+		return inode->i_mapping->backing_dev_info;
+	return sb->s_bdi;

So at least here you'd need also add a similar exception for
"mtd_inodefs". Because of these exeptions I've chosen the (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) check rather than your exception based check. All in all I don't care much what ends up in the kernel as it's just a temporary solution...
Also I've added the warning to catch situations where inodes would get
filed to a different backing device after the patch. So far the reported warnings were harmless but still I'm more comfortable when it's there because otherwise we can so easily miss some device-driver-invented filesystem like mtd_inodefs which would break silently after the change...

Honza

Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR
#15 lore raw
Quoted 6 lines · Jan Kara
Quoted 4 lines · Christoph Hellwig

---
From: Christoph Hellwig <[email protected]>
Subject: [PATCH] writeback: always use sb->s_bdi for writeback purposes

...

Quoted 8 lines
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The one exception for now is the block device filesystem which really wants different writeback contexts for it's different (internal) inodes to handle the writeout more efficiently. For now we do this with a hack in fs-writeback.c because we're so late in the cycle, but in the future I plan to replace this with a superblock method that allows for multiple writeback contexts per filesystem.

Another exception I know about is mtd_inodefs filesystem
(drivers/mtd/mtdchar.c).

No, it's not. MTD only has three different backing_dev_info instances which have different flags in the mapping-relevant portion of the backing_dev.

Quoted 2 lines

So at least here you'd need also add a similar exception for
"mtd_inodefs".

No. For one thing we don't need any exception for correctnes alone - even the block device variant would work fine with the default case. But for mtd specificly we don't need an exception for performance either given that there are no per-device bdis in mtd.

reviewer
#16 lore raw
Quoted 13 lines · Christoph Hellwig
Quoted 12 lines · Jan Kara
Quoted 4 lines · Christoph Hellwig

---
From: Christoph Hellwig <[email protected]>
Subject: [PATCH] writeback: always use sb->s_bdi for writeback purposes

...

Quoted 6 lines

The one exception for now is the block device filesystem which really wants different writeback contexts for it's different (internal) inodes to handle the writeout more efficiently. For now we do this with a hack in fs-writeback.c because we're so late in the cycle, but in the future I plan to replace this with a superblock method that allows for multiple writeback contexts per filesystem.

Quoted 6 lines
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Another exception I know about is mtd_inodefs filesystem
(drivers/mtd/mtdchar.c).

No, it's not. MTD only has three different backing_dev_info instances which have different flags in the mapping-relevant portion of the backing_dev.

In the end I agree I was probably wrong but it's not that simple ;)

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So at least here you'd need also add a similar exception for
"mtd_inodefs".

No. For one thing we don't need any exception for correctnes alone - even the block device variant would work fine with the default case.

Here I don't agree. If you don't have some kind of exception, sb->s_bdi for both "block" and "mtd_inodefs" filesystems points to noop_backing_dev_info and you get no writeback for that one. So it isn't just a performance issue but also a correctness one.

Regarding mtd_inodefs I now looked in more detail what MTD actually does and it seems to me that MTD device inodes do not seem to carry any cached state that flusher threads could write back. So returning noop_backing_dev_info might be the right thing for them after all... (added David Woodhouse and MTD list to CC so that they can shout if it's not the case). Coming to this conclusion, I'm happy with your patch going in as is...
Honza

Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR
#17 lore raw
Quoted 6 lines · Jan Kara
Quoted 2 lines

No. For one thing we don't need any exception for correctnes alone - even the block device variant would work fine with the default case.

Here I don't agree. If you don't have some kind of exception, sb->s_bdi for both "block" and "mtd_inodefs" filesystems points to noop_backing_dev_info and you get no writeback for that one. So it isn't just a performance issue but also a correctness one.

Indeed - for internal filesystems that require writeback the change causes trouble if they haven't registered a s_bdi. But for all user visible filesystems that doesn't happen as we require s_bdi for sync or even unmounts to work.

#18 lore raw
In reply to Chris Mason

Here is the patch that I already proposed a while ago. I've tested xfstests on btrfs and xfstests to make sure the btrfs issue is fixed, and I've also tested the original dirtying of device files issue and I/O operations on block device files to test the special case in the patch.

---
From: Christoph Hellwig <[email protected]>
Subject: [PATCH] writeback: always use sb->s_bdi for writeback purposes

We currently use struct backing_dev_info for various different purposes. Originally it was introduced to describe a backing device which includes an unplug and congestion function and various bits of readahead information and VM-relevant flags. We're also using for tracking dirty inodes for writeback.

To make writeback properly find all inodes we need to only access the per-filesystem backing_device pointed to by the superblock in ->s_bdi inside the writeback code, and not the instances pointeded to by inode->i_mapping->backing_dev which can be overriden by special devices or might not be set at all by some filesystems.

Long term we should split out the writeback-relevant bits of struct backing_device_info (which includes more than the current bdi_writeback) and only point to it from the superblock while leaving the traditional backing device as a separate structure that can be overriden by devices.

The one exception for now is the block device filesystem which really wants different writeback contexts for it's different (internal) inodes to handle the writeout more efficiently. For now we do this with a hack in fs-writeback.c because we're so late in the cycle, but in the future I plan to replace this with a superblock method that allows for multiple writeback contexts per filesystem.

Signed-off-by Christoph Hellwig <[email protected]>
fs/fs-writeback.c +3 -15
Index: linux-2.6/fs/fs-writeback.c
===================================================================
@@ -72,22 +72,10 @@ int writeback_in_progress(struct backing
 static inline struct backing_dev_info *inode_to_bdi(struct inode *inode)
 {
 	struct super_block *sb = inode->i_sb;
-	struct backing_dev_info *bdi = inode->i_mapping->backing_dev_info;
 
-	/*
-	 * For inodes on standard filesystems, we use superblock's bdi. For
-	 * inodes on virtual filesystems, we want to use inode mapping's bdi
-	 * because they can possibly point to something useful (think about
-	 * block_dev filesystem).
-	 */
-	if (sb->s_bdi && sb->s_bdi != &noop_backing_dev_info) {
-		/* Some device inodes could play dirty tricks. Catch them... */
-		WARN(bdi != sb->s_bdi && bdi_cap_writeback_dirty(bdi),
-			"Dirtiable inode bdi %s != sb bdi %s\n",
-			bdi->name, sb->s_bdi->name);
-		return sb->s_bdi;
-	}
-	return bdi;
+	if (strcmp(sb->s_type->name, "bdev") == 0)
+		return inode->i_mapping->backing_dev_info;
+	return sb->s_bdi;
 }
 
 static void bdi_queue_work(struct backing_dev_info *bdi,
author Tested-by
#19 lore raw
In reply to Jan Kara

Em 27-09-2010 19:25, Jan Kara escreveu:

Quoted 10 lines

[Added CCs for similar ecryptfs warning]

Quoted 8 lines · Andrew Morton
Quoted 8 lines

[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010

Dirtiable inode bdi default != sb bdi btrfs

Quoted 3 lines

That suggests that we should probably handle such cases in a more generic
way by changing the code in inode_init_always(). The patch below makes at least btrfs happy for me... Could you maybe test it? Thanks.

Applied on top of v2.6.36-rc5-151-g32163f4, running it right now. The warning messages no longer happen, and everything seems to be working fine.

Tested-by Cesar Eduardo Barros <[email protected]>
Signature · 3 lines
Cesar Eduardo Barros
[email protected]
[email protected]
reviewer
#20 lore raw
Quoted 15 lines · Cesar Eduardo Barros

Em 27-09-2010 19:25, Jan Kara escreveu:

Quoted 10 lines

[Added CCs for similar ecryptfs warning]

Quoted 8 lines · Andrew Morton
Quoted 8 lines

[...]
device fsid 44d595920ddedfa-3ece6b56e80f689e devid 1 transid 22342 /dev/mapper/vg_cesarbinspiro-lv_home
SELinux: initialized (dev dm-3, type btrfs), uses xattr

------------[ cut here ]------------
WARNING: at fs/fs-writeback.c:87 inode_to_bdi+0x62/0x6d()
Hardware name: Inspiron N4010

Dirtiable inode bdi default != sb bdi btrfs

Quoted 3 lines

That suggests that we should probably handle such cases in a more generic
way by changing the code in inode_init_always(). The patch below makes at least btrfs happy for me... Could you maybe test it? Thanks.

Quoted 5 lines

Applied on top of v2.6.36-rc5-151-g32163f4, running it right now. The warning messages no longer happen, and everything seems to be working fine.

Tested-by Cesar Eduardo Barros <[email protected]>

Great, thanks for testing.

Honza

Signature · 2 lines
Jan Kara <[email protected]>
SUSE Labs, CR