* Snapshot of root makes an undeletable folder
@ 2011-09-04 15:29 Jérôme Poulin
2011-09-04 21:05 ` Ilya Dryomov
0 siblings, 1 reply; 3+ messages in thread
From: Jérôme Poulin @ 2011-09-04 15:29 UTC (permalink / raw)
To: linux-btrfs
I recently converted a long-used ext4 filesystem after e2fsck to btrfs
using btrfs-convert, everything went fine and all my files are there.
I then decided to make the filesystem more managable so I made a
snapshot of the root and removed the rest of the root like:
Original listing:
ext2_saved folder1 folder2 folder3 folder4 lost+found
btrfs sub snap . music
rm -rf folder1 folder2 folder3 folder4 lost+found music/lost+found
So now I end up with only a music folder on root which I was able to
mount using subvol= to another folder and use the btrfs FS for other
subvolumes.
The next day I decided to remove the ext2_image snapshot and grow the
filesystem to accomodate for other files, this was still OK.
Then I though about my folder organization again and renamed music to
downloads, this is still OK and then create music in downloads, I was
told "music" already exists, however I can't neither see it, list it,
cd to it or remove it.
I then made a snapshot of downloads to music and now music is listed as:
ls: cannot access /mnt/btrfs/downloads/music: No such file or directory
d????????? ? ? ? ? ? music
btrfsck gives me:
root /mnt # btrfsck /dev/vgP4RAID5/btrfs
root 289 root dir 256 error
found 52167258112 bytes used err is 1
total csum bytes: 50868244
total tree bytes: 76210176
total fs tree bytes: 6860800
btree space waste bytes: 15322691
file data blocks allocated: 52091047936
referenced 52091047936
Btrfs v0.19-35-g1b444cd-dirty
There is also a OOPS associated to it:
[82291.652513] new size for /dev/mapper/vgP4RAID5-btrfs is 75161927680
[83636.560865] btrfs failed to delete reference to music, inode 263 parent 256
[83679.232134] ------------[ cut here ]------------
[83679.232142] WARNING: at fs/dcache.c:1350 d_set_d_op+0x8e/0xc0()
[83679.232144] Hardware name: P55-USB3
[83679.232145] Modules linked in: snd_seq_dummy snd_seq snd_seq_device
nvidia(P) squashfs xfs exportfs reiserfs ext3 jbd
snd_hda_codec_realtek usbhid snd_hda_intel snd_hda_codec hid usblp
snd_hwdep snd_pcm sg i2c_i801 intel_agp snd_timer snd evdev ppdev
parport_pc soundcore snd_page_alloc i2c_core r8169 intel_gtt parport
mii processor pcspkr iTCO_wdt iTCO_vendor_support button ipv6 sr_mod
sd_mod cdrom pata_acpi pata_jmicron ahci libahci libata uhci_hcd
xhci_hcd btrfs zlib_deflate crc32c libcrc32c ext4 mbcache jbd2 crc16
fuse usb_storage scsi_mod ehci_hcd usbcore raid456 async_raid6_recov
async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 md_mod
dm_snapshot dm_mod loop
[83679.232186] Pid: 14614, comm: ls Tainted: P 3.0.4-Ti #2
[83679.232187] Call Trace:
[83679.232193] [<ffffffff8105c7ef>] warn_slowpath_common+0x7f/0xc0
[83679.232195] [<ffffffff8105c84a>] warn_slowpath_null+0x1a/0x20
[83679.232196] [<ffffffff8116bdfe>] d_set_d_op+0x8e/0xc0
[83679.232199] [<ffffffff8117c50f>] simple_lookup+0x3f/0x60
[83679.232201] [<ffffffff811626f5>] d_alloc_and_lookup+0x45/0x90
[83679.232204] [<ffffffff8116f765>] ? d_lookup+0x35/0x60
[83679.232206] [<ffffffff81163f5e>] do_lookup+0x29e/0x310
[83679.232208] [<ffffffff81164bdc>] path_lookupat+0x11c/0x700
[83679.232210] [<ffffffff811651f1>] do_path_lookup+0x31/0xc0
[83679.232211] [<ffffffff81166db9>] user_path_at+0x59/0xa0
[83679.232214] [<ffffffff812b871b>] ? tty_ioctl+0x5cb/0xbc0
[83679.232217] [<ffffffff810398f0>] ? do_page_fault+0x1c0/0x4d0
[83679.232220] [<ffffffff8115c284>] vfs_fstatat+0x44/0x70
[83679.232224] [<ffffffff81072f0d>] ? do_sigaction+0x12d/0x1f0
[83679.232226] [<ffffffff8115c2eb>] vfs_stat+0x1b/0x20
[83679.232227] [<ffffffff8115c42a>] sys_newstat+0x1a/0x40
[83679.232229] [<ffffffff810732dd>] ? sys_rt_sigaction+0x8d/0xc0
[83679.232233] [<ffffffff813f4485>] ? page_fault+0x25/0x30
[83679.232267] [<ffffffff813f4a42>] system_call_fastpath+0x16/0x1b
[83679.232269] ---[ end trace 6bdc8b9bb849be1c ]---
[83679.232270] ------------[ cut here ]------------
[83679.232272] WARNING: at fs/dcache.c:1354 d_set_d_op+0xb1/0xc0()
[83679.232273] Hardware name: P55-USB3
[83679.232274] Modules linked in: snd_seq_dummy snd_seq snd_seq_device
nvidia(P) squashfs xfs exportfs reiserfs ext3 jbd
snd_hda_codec_realtek usbhid snd_hda_intel snd_hda_codec hid usblp
snd_hwdep snd_pcm sg i2c_i801 intel_agp snd_timer snd evdev ppdev
parport_pc soundcore snd_page_alloc i2c_core r8169 intel_gtt parport
mii processor pcspkr iTCO_wdt iTCO_vendor_support button ipv6 sr_mod
sd_mod cdrom pata_acpi pata_jmicron ahci libahci libata uhci_hcd
xhci_hcd btrfs zlib_deflate crc32c libcrc32c ext4 mbcache jbd2 crc16
fuse usb_storage scsi_mod ehci_hcd usbcore raid456 async_raid6_recov
async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 md_mod
dm_snapshot dm_mod loop
[83679.232309] Pid: 14614, comm: ls Tainted: P W 3.0.4-Ti #2
[83679.232310] Call Trace:
[83679.232313] [<ffffffff8105c7ef>] warn_slowpath_common+0x7f/0xc0
[83679.232316] [<ffffffff8105c84a>] warn_slowpath_null+0x1a/0x20
[83679.232318] [<ffffffff8116be21>] d_set_d_op+0xb1/0xc0
[83679.232321] [<ffffffff8117c50f>] simple_lookup+0x3f/0x60
[83679.232323] [<ffffffff811626f5>] d_alloc_and_lookup+0x45/0x90
[83679.232326] [<ffffffff8116f765>] ? d_lookup+0x35/0x60
[83679.232328] [<ffffffff81163f5e>] do_lookup+0x29e/0x310
[83679.232330] [<ffffffff81164bdc>] path_lookupat+0x11c/0x700
[83679.232333] [<ffffffff811651f1>] do_path_lookup+0x31/0xc0
[83679.232336] [<ffffffff81166db9>] user_path_at+0x59/0xa0
[83679.232338] [<ffffffff812b871b>] ? tty_ioctl+0x5cb/0xbc0
[83679.232341] [<ffffffff810398f0>] ? do_page_fault+0x1c0/0x4d0
[83679.232344] [<ffffffff8115c284>] vfs_fstatat+0x44/0x70
[83679.232346] [<ffffffff81072f0d>] ? do_sigaction+0x12d/0x1f0
[83679.232349] [<ffffffff8115c2eb>] vfs_stat+0x1b/0x20
[83679.232351] [<ffffffff8115c42a>] sys_newstat+0x1a/0x40
[83679.232354] [<ffffffff810732dd>] ? sys_rt_sigaction+0x8d/0xc0
[83679.232356] [<ffffffff813f4485>] ? page_fault+0x25/0x30
[83679.232359] [<ffffffff813f4a42>] system_call_fastpath+0x16/0x1b
[83679.232361] ---[ end trace 6bdc8b9bb849be1d ]---
[84677.658072] BTRFS: inode 263 still on the orphan list
[84678.463683] ------------[ cut here ]------------
[84678.463714] WARNING: at fs/btrfs/extent-tree.c:6891
btrfs_free_block_groups+0x226/0x310 [btrfs]()
[84678.463718] Hardware name: P55-USB3
[84678.463720] Modules linked in: snd_seq_dummy snd_seq snd_seq_device
nvidia(P) squashfs xfs exportfs reiserfs ext3 jbd
snd_hda_codec_realtek usbhid snd_hda_intel snd_hda_codec hid usblp
snd_hwdep snd_pcm sg i2c_i801 intel_agp snd_timer snd evdev ppdev
parport_pc soundcore snd_page_alloc i2c_core r8169 intel_gtt parport
mii processor pcspkr iTCO_wdt iTCO_vendor_support button ipv6 sr_mod
sd_mod cdrom pata_acpi pata_jmicron ahci libahci libata uhci_hcd
xhci_hcd btrfs zlib_deflate crc32c libcrc32c ext4 mbcache jbd2 crc16
fuse usb_storage scsi_mod ehci_hcd usbcore raid456 async_raid6_recov
async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 md_mod
dm_snapshot dm_mod loop
[84678.463782] Pid: 14783, comm: umount Tainted: P W 3.0.4-Ti #2
[84678.463785] Call Trace:
[84678.463795] [<ffffffff8105c7ef>] warn_slowpath_common+0x7f/0xc0
[84678.463802] [<ffffffff8105c84a>] warn_slowpath_null+0x1a/0x20
[84678.463809] [<ffffffffa01dde06>] btrfs_free_block_groups+0x226/0x310 [btrfs]
[84678.463816] [<ffffffffa01e938e>] close_ctree+0x1de/0x370 [btrfs]
[84678.463819] [<ffffffff81171821>] ? dispose_list+0x41/0x50
[84678.463821] [<ffffffff81172574>] ? evict_inodes+0x124/0x140
[84678.463825] [<ffffffffa01c34bd>] btrfs_put_super+0x1d/0x30 [btrfs]
[84678.463828] [<ffffffff811598a2>] generic_shutdown_super+0x72/0x100
[84678.463830] [<ffffffff811599c6>] kill_anon_super+0x16/0x60
[84678.463832] [<ffffffff81159cdc>] deactivate_locked_super+0x3c/0x90
[84678.463834] [<ffffffff8115a72e>] deactivate_super+0x4e/0x70
[84678.463836] [<ffffffff81175fb8>] mntput_no_expire+0x98/0xe0
[84678.463838] [<ffffffff81176c9c>] sys_umount+0x6c/0x380
[84678.463841] [<ffffffff813f4a42>] system_call_fastpath+0x16/0x1b
[84678.463842] ---[ end trace 6bdc8b9bb849be1e ]---
[84678.463844] space_info has 2883506176 free, is not full
[84678.463845] space_info total=17863540736, used=14979870720,
pinned=0, reserved=98304, may_use=0, readonly=65536
[84999.733748] device label music devid 1 transid 77 /dev/mapper/vgP4RAID5-btrfs
[84999.734781] btrfs: enabling disk space caching
So as a workaround I applied to my kernel 2 patches:
* Btrfs-reverse-enough-space-for-file-clone.patch (I hope this patch
is in 3.1, as it could cause DoS else.)
* 2-2-btrfs-allow-cross-subvolume-BTRFS_IOC_CLONE.patch
I snapshotted the btrfs volume using LVM to test, made a new
subvolume, cp -a --reflink=always the content of the downloads
subvolume except music, then deleted the other subvolume, and now
everything works, btrfsck is happy and no more problems.
I will keep working with the old subvolume until I get an answer in
case you need more informations.
I can also tell that this is half-reproducible using a new btrfs
filesystem and snapshotting the root, except that after the second
snapshot the folder won't appear as unlistable, however it is not
removable unless you delete the original subvolume.
^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Snapshot of root makes an undeletable folder
2011-09-04 15:29 Snapshot of root makes an undeletable folder Jérôme Poulin
@ 2011-09-04 21:05 ` Ilya Dryomov
2011-09-05 17:29 ` Jérôme Poulin
0 siblings, 1 reply; 3+ messages in thread
From: Ilya Dryomov @ 2011-09-04 21:05 UTC (permalink / raw)
To: Jérôme Poulin; +Cc: linux-btrfs
On Sun, Sep 04, 2011 at 11:29:43AM -0400, J=C3=A9r=C3=B4me Poulin wrote=
:
> I recently converted a long-used ext4 filesystem after e2fsck to btrf=
s
> using btrfs-convert, everything went fine and all my files are there.
> I then decided to make the filesystem more managable so I made a
> snapshot of the root and removed the rest of the root like:
>=20
> Original listing:
> ext2_saved folder1 folder2 folder3 folder4 lost+found
>=20
> btrfs sub snap . music
> rm -rf folder1 folder2 folder3 folder4 lost+found music/lost+found
>=20
> So now I end up with only a music folder on root which I was able to
> mount using subvol=3D to another folder and use the btrfs FS for othe=
r
> subvolumes.
>=20
> The next day I decided to remove the ext2_image snapshot and grow the
> filesystem to accomodate for other files, this was still OK.
>=20
> Then I though about my folder organization again and renamed music to
> downloads, this is still OK and then create music in downloads, I was
> told "music" already exists, however I can't neither see it, list it,
> cd to it or remove it.
This is because music directory actually exists. When you executed
btrfs sub snap . music=20
btrfs created music directory item in your default subvolume and *then*
took a snapshot of the default subvolume with that music directory item
already in it. Btrfs readdir skips references from the snapshot to
itself, so you can't see it. Even though you renamed your snapshot to
"downloads", snapshot's contents still don't allow you to create a
"music" directory in it.
The correct way to do what you want is to create a subvolume "music",
and move folders from default to music. Then you can snapshot your
newly created music subvolume in a clean way, rename it, etc.
> I then made a snapshot of downloads to music and now music is listed =
as:
> ls: cannot access /mnt/btrfs/downloads/music: No such file or directo=
ry
> d????????? ? ? ? ? ? music
What command and in what directory did you run to make a snapshot of
downloads to music ? I can't reproduce this off-hand.
> btrfsck gives me:
> root /mnt # btrfsck /dev/vgP4RAID5/btrfs
> root 289 root dir 256 error
> found 52167258112 bytes used err is 1
> total csum bytes: 50868244
> total tree bytes: 76210176
> total fs tree bytes: 6860800
> btree space waste bytes: 15322691
> file data blocks allocated: 52091047936
> referenced 52091047936
> Btrfs v0.19-35-g1b444cd-dirty
>=20
>=20
> There is also a OOPS associated to it:
> [82291.652513] new size for /dev/mapper/vgP4RAID5-btrfs is 7516192768=
0
> [83636.560865] btrfs failed to delete reference to music, inode 263 p=
arent 256
> [83679.232134] ------------[ cut here ]------------
> [83679.232142] WARNING: at fs/dcache.c:1350 d_set_d_op+0x8e/0xc0()
> [83679.232144] Hardware name: P55-USB3
> [83679.232145] Modules linked in: snd_seq_dummy snd_seq snd_seq_devic=
e
> nvidia(P) squashfs xfs exportfs reiserfs ext3 jbd
> snd_hda_codec_realtek usbhid snd_hda_intel snd_hda_codec hid usblp
> snd_hwdep snd_pcm sg i2c_i801 intel_agp snd_timer snd evdev ppdev
> parport_pc soundcore snd_page_alloc i2c_core r8169 intel_gtt parport
> mii processor pcspkr iTCO_wdt iTCO_vendor_support button ipv6 sr_mod
> sd_mod cdrom pata_acpi pata_jmicron ahci libahci libata uhci_hcd
> xhci_hcd btrfs zlib_deflate crc32c libcrc32c ext4 mbcache jbd2 crc16
> fuse usb_storage scsi_mod ehci_hcd usbcore raid456 async_raid6_recov
> async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 md_mod
> dm_snapshot dm_mod loop
> [83679.232186] Pid: 14614, comm: ls Tainted: P 3.0.4-Ti #2
> [83679.232187] Call Trace:
> [83679.232193] [<ffffffff8105c7ef>] warn_slowpath_common+0x7f/0xc0
> [83679.232195] [<ffffffff8105c84a>] warn_slowpath_null+0x1a/0x20
> [83679.232196] [<ffffffff8116bdfe>] d_set_d_op+0x8e/0xc0
> [83679.232199] [<ffffffff8117c50f>] simple_lookup+0x3f/0x60
> [83679.232201] [<ffffffff811626f5>] d_alloc_and_lookup+0x45/0x90
> [83679.232204] [<ffffffff8116f765>] ? d_lookup+0x35/0x60
> [83679.232206] [<ffffffff81163f5e>] do_lookup+0x29e/0x310
> [83679.232208] [<ffffffff81164bdc>] path_lookupat+0x11c/0x700
> [83679.232210] [<ffffffff811651f1>] do_path_lookup+0x31/0xc0
> [83679.232211] [<ffffffff81166db9>] user_path_at+0x59/0xa0
> [83679.232214] [<ffffffff812b871b>] ? tty_ioctl+0x5cb/0xbc0
> [83679.232217] [<ffffffff810398f0>] ? do_page_fault+0x1c0/0x4d0
> [83679.232220] [<ffffffff8115c284>] vfs_fstatat+0x44/0x70
> [83679.232224] [<ffffffff81072f0d>] ? do_sigaction+0x12d/0x1f0
> [83679.232226] [<ffffffff8115c2eb>] vfs_stat+0x1b/0x20
> [83679.232227] [<ffffffff8115c42a>] sys_newstat+0x1a/0x40
> [83679.232229] [<ffffffff810732dd>] ? sys_rt_sigaction+0x8d/0xc0
> [83679.232233] [<ffffffff813f4485>] ? page_fault+0x25/0x30
> [83679.232267] [<ffffffff813f4a42>] system_call_fastpath+0x16/0x1b
> [83679.232269] ---[ end trace 6bdc8b9bb849be1c ]---
> [83679.232270] ------------[ cut here ]------------
> [83679.232272] WARNING: at fs/dcache.c:1354 d_set_d_op+0xb1/0xc0()
> [83679.232273] Hardware name: P55-USB3
> [83679.232274] Modules linked in: snd_seq_dummy snd_seq snd_seq_devic=
e
> nvidia(P) squashfs xfs exportfs reiserfs ext3 jbd
> snd_hda_codec_realtek usbhid snd_hda_intel snd_hda_codec hid usblp
> snd_hwdep snd_pcm sg i2c_i801 intel_agp snd_timer snd evdev ppdev
> parport_pc soundcore snd_page_alloc i2c_core r8169 intel_gtt parport
> mii processor pcspkr iTCO_wdt iTCO_vendor_support button ipv6 sr_mod
> sd_mod cdrom pata_acpi pata_jmicron ahci libahci libata uhci_hcd
> xhci_hcd btrfs zlib_deflate crc32c libcrc32c ext4 mbcache jbd2 crc16
> fuse usb_storage scsi_mod ehci_hcd usbcore raid456 async_raid6_recov
> async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 md_mod
> dm_snapshot dm_mod loop
> [83679.232309] Pid: 14614, comm: ls Tainted: P W 3.0.4-Ti #2
> [83679.232310] Call Trace:
> [83679.232313] [<ffffffff8105c7ef>] warn_slowpath_common+0x7f/0xc0
> [83679.232316] [<ffffffff8105c84a>] warn_slowpath_null+0x1a/0x20
> [83679.232318] [<ffffffff8116be21>] d_set_d_op+0xb1/0xc0
> [83679.232321] [<ffffffff8117c50f>] simple_lookup+0x3f/0x60
> [83679.232323] [<ffffffff811626f5>] d_alloc_and_lookup+0x45/0x90
> [83679.232326] [<ffffffff8116f765>] ? d_lookup+0x35/0x60
> [83679.232328] [<ffffffff81163f5e>] do_lookup+0x29e/0x310
> [83679.232330] [<ffffffff81164bdc>] path_lookupat+0x11c/0x700
> [83679.232333] [<ffffffff811651f1>] do_path_lookup+0x31/0xc0
> [83679.232336] [<ffffffff81166db9>] user_path_at+0x59/0xa0
> [83679.232338] [<ffffffff812b871b>] ? tty_ioctl+0x5cb/0xbc0
> [83679.232341] [<ffffffff810398f0>] ? do_page_fault+0x1c0/0x4d0
> [83679.232344] [<ffffffff8115c284>] vfs_fstatat+0x44/0x70
> [83679.232346] [<ffffffff81072f0d>] ? do_sigaction+0x12d/0x1f0
> [83679.232349] [<ffffffff8115c2eb>] vfs_stat+0x1b/0x20
> [83679.232351] [<ffffffff8115c42a>] sys_newstat+0x1a/0x40
> [83679.232354] [<ffffffff810732dd>] ? sys_rt_sigaction+0x8d/0xc0
> [83679.232356] [<ffffffff813f4485>] ? page_fault+0x25/0x30
> [83679.232359] [<ffffffff813f4a42>] system_call_fastpath+0x16/0x1b
> [83679.232361] ---[ end trace 6bdc8b9bb849be1d ]---
> [84677.658072] BTRFS: inode 263 still on the orphan list
> [84678.463683] ------------[ cut here ]------------
> [84678.463714] WARNING: at fs/btrfs/extent-tree.c:6891
> btrfs_free_block_groups+0x226/0x310 [btrfs]()
> [84678.463718] Hardware name: P55-USB3
> [84678.463720] Modules linked in: snd_seq_dummy snd_seq snd_seq_devic=
e
> nvidia(P) squashfs xfs exportfs reiserfs ext3 jbd
> snd_hda_codec_realtek usbhid snd_hda_intel snd_hda_codec hid usblp
> snd_hwdep snd_pcm sg i2c_i801 intel_agp snd_timer snd evdev ppdev
> parport_pc soundcore snd_page_alloc i2c_core r8169 intel_gtt parport
> mii processor pcspkr iTCO_wdt iTCO_vendor_support button ipv6 sr_mod
> sd_mod cdrom pata_acpi pata_jmicron ahci libahci libata uhci_hcd
> xhci_hcd btrfs zlib_deflate crc32c libcrc32c ext4 mbcache jbd2 crc16
> fuse usb_storage scsi_mod ehci_hcd usbcore raid456 async_raid6_recov
> async_pq raid6_pq async_xor xor async_memcpy async_tx raid1 md_mod
> dm_snapshot dm_mod loop
> [84678.463782] Pid: 14783, comm: umount Tainted: P W 3.0.4-T=
i #2
> [84678.463785] Call Trace:
> [84678.463795] [<ffffffff8105c7ef>] warn_slowpath_common+0x7f/0xc0
> [84678.463802] [<ffffffff8105c84a>] warn_slowpath_null+0x1a/0x20
> [84678.463809] [<ffffffffa01dde06>] btrfs_free_block_groups+0x226/0x=
310 [btrfs]
> [84678.463816] [<ffffffffa01e938e>] close_ctree+0x1de/0x370 [btrfs]
> [84678.463819] [<ffffffff81171821>] ? dispose_list+0x41/0x50
> [84678.463821] [<ffffffff81172574>] ? evict_inodes+0x124/0x140
> [84678.463825] [<ffffffffa01c34bd>] btrfs_put_super+0x1d/0x30 [btrfs=
]
> [84678.463828] [<ffffffff811598a2>] generic_shutdown_super+0x72/0x10=
0
> [84678.463830] [<ffffffff811599c6>] kill_anon_super+0x16/0x60
> [84678.463832] [<ffffffff81159cdc>] deactivate_locked_super+0x3c/0x9=
0
> [84678.463834] [<ffffffff8115a72e>] deactivate_super+0x4e/0x70
> [84678.463836] [<ffffffff81175fb8>] mntput_no_expire+0x98/0xe0
> [84678.463838] [<ffffffff81176c9c>] sys_umount+0x6c/0x380
> [84678.463841] [<ffffffff813f4a42>] system_call_fastpath+0x16/0x1b
> [84678.463842] ---[ end trace 6bdc8b9bb849be1e ]---
> [84678.463844] space_info has 2883506176 free, is not full
> [84678.463845] space_info total=3D17863540736, used=3D14979870720,
> pinned=3D0, reserved=3D98304, may_use=3D0, readonly=3D65536
> [84999.733748] device label music devid 1 transid 77 /dev/mapper/vgP4=
RAID5-btrfs
> [84999.734781] btrfs: enabling disk space caching
>=20
>=20
> So as a workaround I applied to my kernel 2 patches:
> * Btrfs-reverse-enough-space-for-file-clone.patch (I hope this patc=
h
> is in 3.1, as it could cause DoS else.)
> * 2-2-btrfs-allow-cross-subvolume-BTRFS_IOC_CLONE.patch
>=20
> I snapshotted the btrfs volume using LVM to test, made a new
> subvolume, cp -a --reflink=3Dalways the content of the downloads
> subvolume except music, then deleted the other subvolume, and now
> everything works, btrfsck is happy and no more problems.
>=20
> I will keep working with the old subvolume until I get an answer in
> case you need more informations.
> I can also tell that this is half-reproducible using a new btrfs
> filesystem and snapshotting the root, except that after the second
> snapshot the folder won't appear as unlistable, however it is not
> removable unless you delete the original subvolume.
I'm not sure what do you mean by "it's not removable" part, but the par=
t
where after a second snapshot you can see the folder is expected
behaviour due to the fact that Btrfs allows subvolumes (and snapshots)
anywhere in the tree, but with only one access point (the dentry added
on creation). This is done to avoid various problems related to hard
links, and the rest of those points appear as empty directories with a
special inode number.
Thanks,
Ilya
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^ permalink raw reply [flat|nested] 3+ messages in thread
* Re: Snapshot of root makes an undeletable folder
2011-09-04 21:05 ` Ilya Dryomov
@ 2011-09-05 17:29 ` Jérôme Poulin
0 siblings, 0 replies; 3+ messages in thread
From: Jérôme Poulin @ 2011-09-05 17:29 UTC (permalink / raw)
To: Ilya Dryomov, linux-btrfs
On Sun, Sep 4, 2011 at 5:05 PM, Ilya Dryomov <idryomov@gmail.com> wrote=
:
> On Sun, Sep 04, 2011 at 11:29:43AM -0400, J=C3=A9r=C3=B4me Poulin wro=
te:
>> Then I though about my folder organization again and renamed music t=
o
>> downloads, this is still OK and then create music in downloads, I wa=
s
>> told "music" already exists, however I can't neither see it, list it=
,
>> cd to it or remove it.
>
> This is because music directory actually exists. =C2=A0When you execu=
ted
>
> btrfs sub snap . music
>
> btrfs created music directory item in your default subvolume and *the=
n*
> took a snapshot of the default subvolume with that music directory it=
em
> already in it. =C2=A0Btrfs readdir skips references from the snapshot=
to
> itself, so you can't see it. =C2=A0Even though you renamed your snaps=
hot to
> "downloads", snapshot's contents still don't allow you to create a
> "music" directory in it.
>
I understand that btrfs creates a snapshot containing the snapshot
directory however in my tests on a clean FS, as soon as I create a
second snapshot I am able to rmdir it.
> The correct way to do what you want is to create a subvolume "music",
> and move folders from default to music. =C2=A0Then you can snapshot y=
our
> newly created music subvolume in a clean way, rename it, etc.
>
This is where cp --reflink=3Dalways is useful as move copies the files
across subvolumes.
>> I then made a snapshot of downloads to music and now music is listed=
as:
>> ls: cannot access /mnt/btrfs/downloads/music: No such file or direct=
ory
>> d????????? ? ? =C2=A0 =C2=A0 =C2=A0? =C2=A0 =C2=A0 =C2=A0 =C2=A0 ? =C2=
=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0 =C2=A0? music
>
> What command and in what directory did you run to make a snapshot of
> downloads to music ? =C2=A0I can't reproduce this off-hand.
>
I wasn't able to reproduce this unreadable directory using a clean FS
or similar operations, this was just 'ls' trying to list the downloads
directory.
>> btrfsck gives me:
=2E..
>>
>> There is also a OOPS associated to it:
=2E..
>>
>>
>> So as a workaround I applied to my kernel 2 patches:
>> * Btrfs-reverse-enough-space-for-file-clone.patch
>> (I hope this patch is in 3.1, as it could cause DoS else.)
>> * 2-2-btrfs-allow-cross-subvolume-BTRFS_IOC_CLONE.patch
>>
Any idea why those patch aren't part of the main tree yet?
>> I snapshotted the btrfs volume using LVM to test, made a new
>> subvolume, cp -a --reflink=3Dalways the content of the downloads
>> subvolume except music, then deleted the other subvolume, and now
>> everything works, btrfsck is happy and no more problems.
>>
And will the filesystem be stable if I use this method? Or should I
re-make a new btrfs ?
>> I will keep working with the old subvolume until I get an answer in
>> case you need more informations.
Should I keep it?
>> I can also tell that this is half-reproducible using a new btrfs
>> filesystem and snapshotting the root, except that after the second
>> snapshot the folder won't appear as unlistable, however it is not
>> removable unless you delete the original subvolume.
>
> I'm not sure what do you mean by "it's not removable" part, but the p=
art
> where after a second snapshot you can see the folder is expected
> behaviour due to the fact that Btrfs allows subvolumes (and snapshots=
)
> anywhere in the tree, but with only one access point (the dentry adde=
d
> on creation). =C2=A0This is done to avoid various problems related to=
hard
> links, and the rest of those points appear as empty directories with =
a
> special inode number.
>
This is to be expected after what you explained.
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^ permalink raw reply [flat|nested] 3+ messages in thread
end of thread, other threads:[~2011-09-05 17:29 UTC | newest]
Thread overview: 3+ messages (download: mbox.gz follow: Atom feed
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2011-09-04 15:29 Snapshot of root makes an undeletable folder Jérôme Poulin
2011-09-04 21:05 ` Ilya Dryomov
2011-09-05 17:29 ` Jérôme Poulin
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