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(+)
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;
}
--
2.43.5Hi 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: arc-randconfig-001-20241122 (https://download.01.org/0day-ci/archive/20241122/202411221326.eoWoxSKf-lkp@intel.com/config)
compiler: arc-elf-gcc (GCC) 13.2.0
reproduce (this is a W=1 build): (https://download.01.org/0day-ci/archive/20241122/202411221326.eoWoxSKf-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/202411221326.eoWoxSKf-lkp@intel.com/
All errors (new ones prefixed by >>):
fs/ext4/super.c: In function 'ext4_acquire_dquot':
>> fs/ext4/super.c:6912:13: error: 'freeze_protected' undeclared (first use in this function); did you mean 'freeze_processes'?
6912 | if (freeze_protected)
| ^~~~~~~~~~~~~~~~
| freeze_processes
fs/ext4/super.c:6912:13: note: each undeclared identifier is reported only once for each function it appears in
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
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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
--
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki
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