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Qu Wenruo a3cf0e4342 btrfs: qgroup: free per-trans reserved space when a subvolume gets dropped
[BUG]
Sometime fsstress could lead to qgroup warning for case like
generic/013:

  BTRFS warning (device dm-3): qgroup 0/259 has unreleased space, type 1 rsv 81920
  ------------[ cut here ]------------
  WARNING: CPU: 9 PID: 24535 at fs/btrfs/disk-io.c:4142 close_ctree+0x1dc/0x323 [btrfs]
  Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 0.0.0 02/06/2015
  RIP: 0010:close_ctree+0x1dc/0x323 [btrfs]
  Call Trace:
   btrfs_put_super+0x15/0x17 [btrfs]
   generic_shutdown_super+0x72/0x110
   kill_anon_super+0x18/0x30
   btrfs_kill_super+0x17/0x30 [btrfs]
   deactivate_locked_super+0x3b/0xa0
   deactivate_super+0x40/0x50
   cleanup_mnt+0x135/0x190
   __cleanup_mnt+0x12/0x20
   task_work_run+0x64/0xb0
   __prepare_exit_to_usermode+0x1bc/0x1c0
   __syscall_return_slowpath+0x47/0x230
   do_syscall_64+0x64/0xb0
   entry_SYSCALL_64_after_hwframe+0x44/0xa9
  ---[ end trace 6c341cdf9b6cc3c1 ]---
  BTRFS error (device dm-3): qgroup reserved space leaked

While that subvolume 259 is no longer in that filesystem.

[CAUSE]
Normally per-trans qgroup reserved space is freed when a transaction is
committed, in commit_fs_roots().

However for completely dropped subvolume, that subvolume is completely
gone, thus is no longer in the fs_roots_radix, and its per-trans
reserved qgroup will never be freed.

Since the subvolume is already gone, leaked per-trans space won't cause
any trouble for end users.

[FIX]
Just call btrfs_qgroup_free_meta_all_pertrans() before a subvolume is
completely dropped.

Signed-off-by: Qu Wenruo <wqu@suse.com>
Signed-off-by: David Sterba <dsterba@suse.com>
2020-07-27 12:55:44 +02:00
Documentation Char/misc driver fixes for 5.8-rc7 2020-07-26 09:33:25 -07:00
LICENSES LICENSES: Rename other to deprecated 2019-05-03 06:34:32 -06:00
arch Merge branch 'parisc-5.8-2' of git://git.kernel.org/pub/scm/linux/kernel/git/deller/parisc-linux into master 2020-07-26 12:14:46 -07:00
block block-5.8-2020-07-10 2020-07-10 09:55:46 -07:00
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crypto keys: asymmetric: fix error return code in software_key_query() 2020-07-15 15:49:04 -07:00
drivers Char/misc driver fixes for 5.8-rc7 2020-07-26 09:33:25 -07:00
fs btrfs: qgroup: free per-trans reserved space when a subvolume gets dropped 2020-07-27 12:55:44 +02:00
include btrfs: add metadata_uuid to FS_INFO ioctl 2020-07-27 12:55:43 +02:00
init kbuild: fix CONFIG_CC_CAN_LINK(_STATIC) for cross-compilation with Clang 2020-07-02 00:57:45 +09:00
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kernel Fix a interaction/regression between uprobes based shared library tracing & GDB. 2020-07-25 13:55:38 -07:00
lib RISC-V Fixes for 5.8-rc5 (ideally) 2020-07-11 19:22:46 -07:00
mm khugepaged: fix null-pointer dereference due to race 2020-07-24 12:42:41 -07:00
net Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net into master 2020-07-25 11:50:59 -07:00
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scripts Kbuild fixes for v5.8 (3rd) 2020-07-26 13:46:57 -07:00
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tools Merge git://git.kernel.org/pub/scm/linux/kernel/git/netdev/net into master 2020-07-25 11:50:59 -07:00
usr bpfilter: match bit size of bpfilter_umh to that of the kernel 2020-05-17 18:52:01 +09:00
virt kvm: use more precise cast and do not drop __user 2020-07-02 05:39:31 -04:00
.clang-format block: add bio_for_each_bvec_all() 2020-05-25 11:25:24 +02:00
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MAINTAINERS Merge branch 'akpm' into master (patches from Andrew) 2020-07-24 14:24:35 -07:00
Makefile Linux 5.8-rc7 2020-07-26 14:14:06 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.