diff mbox series

[v2,2/2] ext4: protect ext4_release_dquot against freezing

Message ID 20241121123855.645335-3-ojaswin@linux.ibm.com (mailing list archive)
State New
Headers show
Series Fix generic/390 failure due to quota release after freeze | expand

Commit Message

Ojaswin Mujoo Nov. 21, 2024, 12:38 p.m. UTC
Protect ext4_release_dquot against freezing so that we
don't try to start a transaction when FS is frozen, leading
to warnings.

Further, avoid taking the freeze protection if a transaction
is already running so that we don't need end up in a deadlock
as described in

  46e294efc355 ext4: fix deadlock with fs freezing and EA inodes

Suggested-by: Jan Kara <jack@suse.cz>
Signed-off-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
---
 fs/ext4/super.c | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

Comments

kernel test robot Nov. 22, 2024, 5:25 a.m. UTC | #1
Hi Ojaswin,

kernel test robot noticed the following build errors:

[auto build test ERROR on tytso-ext4/dev]
[also build test ERROR on brauner-vfs/vfs.all jack-fs/for_next linus/master v6.12 next-20241121]
[If your patch is applied to the wrong git tree, kindly drop us a note.
And when submitting patch, we suggest to use '--base' as documented in
https://git-scm.com/docs/git-format-patch#_base_tree_information]

url:    https://github.com/intel-lab-lkp/linux/commits/Ojaswin-Mujoo/quota-flush-quota_release_work-upon-quota-writeback/20241121-204331
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
patch link:    https://lore.kernel.org/r/20241121123855.645335-3-ojaswin%40linux.ibm.com
patch subject: [PATCH v2 2/2] ext4: protect ext4_release_dquot against freezing
config: i386-buildonly-randconfig-004-20241122 (https://download.01.org/0day-ci/archive/20241122/202411221352.NvzmPEy3-lkp@intel.com/config)
compiler: clang version 19.1.3 (https://github.com/llvm/llvm-project ab51eccf88f5321e7c60591c5546b254b6afab99)
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241122/202411221352.NvzmPEy3-lkp@intel.com/reproduce)

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202411221352.NvzmPEy3-lkp@intel.com/

All errors (new ones prefixed by >>):

   In file included from fs/ext4/super.c:27:
   In file included from include/linux/blkdev.h:9:
   In file included from include/linux/blk_types.h:10:
   In file included from include/linux/bvec.h:10:
   In file included from include/linux/highmem.h:8:
   In file included from include/linux/cacheflush.h:5:
   In file included from arch/x86/include/asm/cacheflush.h:5:
   In file included from include/linux/mm.h:2213:
   include/linux/vmstat.h:518:36: warning: arithmetic between different enumeration types ('enum node_stat_item' and 'enum lru_list') [-Wenum-enum-conversion]
     518 |         return node_stat_name(NR_LRU_BASE + lru) + 3; // skip "nr_"
         |                               ~~~~~~~~~~~ ^ ~~~
>> fs/ext4/super.c:6912:6: error: use of undeclared identifier 'freeze_protected'; did you mean 'freeze_processes'?
    6912 |         if (freeze_protected)
         |             ^~~~~~~~~~~~~~~~
         |             freeze_processes
   include/linux/freezer.h:46:12: note: 'freeze_processes' declared here
      46 | extern int freeze_processes(void);
         |            ^
   1 warning and 1 error generated.


vim +6912 fs/ext4/super.c

  6893	
  6894	static int ext4_acquire_dquot(struct dquot *dquot)
  6895	{
  6896		int ret, err;
  6897		handle_t *handle;
  6898	
  6899		handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
  6900					    EXT4_QUOTA_INIT_BLOCKS(dquot->dq_sb));
  6901		if (IS_ERR(handle))
  6902			return PTR_ERR(handle);
  6903		ret = dquot_acquire(dquot);
  6904		if (ret < 0)
  6905			ext4_error_err(dquot->dq_sb, -ret,
  6906				      "Failed to acquire dquot type %d",
  6907				      dquot->dq_id.type);
  6908		err = ext4_journal_stop(handle);
  6909		if (!ret)
  6910			ret = err;
  6911	
> 6912		if (freeze_protected)
  6913			sb_end_intwrite(dquot->dq_sb);
  6914	
  6915		return ret;
  6916	}
  6917
diff mbox series

Patch

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 16a4ce704460..f7437a592359 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -6887,12 +6887,25 @@  static int ext4_release_dquot(struct dquot *dquot)
 {
 	int ret, err;
 	handle_t *handle;
+	bool freeze_protected = false;
+
+	/*
+	 * Trying to sb_start_intwrite() in a running transaction
+	 * can result in a deadlock. Further, running transactions
+	 * are already protected from freezing.
+	 */
+	if (!ext4_journal_current_handle()) {
+		sb_start_intwrite(dquot->dq_sb);
+		freeze_protected = true;
+	}
 
 	handle = ext4_journal_start(dquot_to_inode(dquot), EXT4_HT_QUOTA,
 				    EXT4_QUOTA_DEL_BLOCKS(dquot->dq_sb));
 	if (IS_ERR(handle)) {
 		/* Release dquot anyway to avoid endless cycle in dqput() */
 		dquot_release(dquot);
+		if (freeze_protected)
+			sb_end_intwrite(dquot->dq_sb);
 		return PTR_ERR(handle);
 	}
 	ret = dquot_release(dquot);
@@ -6903,6 +6916,10 @@  static int ext4_release_dquot(struct dquot *dquot)
 	err = ext4_journal_stop(handle);
 	if (!ret)
 		ret = err;
+
+	if (freeze_protected)
+		sb_end_intwrite(dquot->dq_sb);
+
 	return ret;
 }