linux-ext4 - Re: [PATCH 5/5] ext4: Improve scalability of ext4 orphan file handling

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Message-ID: <202108120223.efg5X7VY-lkp@intel.com>
Date:   Thu, 12 Aug 2021 02:19:33 +0800
From:   kernel test robot <lkp@...el.com>
To:     Jan Kara <jack@...e.cz>, Ted Tso <tytso@....edu>
Cc:     kbuild-all@...ts.01.org, linux-ext4@...r.kernel.org,
        Jan Kara <jack@...e.cz>, Lukas Czerner <lczerner@...hat.com>
Subject: Re: [PATCH 5/5] ext4: Improve scalability of ext4 orphan file
 handling

Hi Jan,

I love your patch! Perhaps something to improve:

[auto build test WARNING on ext4/dev]
[also build test WARNING on ext3/for_next linus/master v5.14-rc5 next-20210811]
[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]

url:    https://github.com/0day-ci/linux/commits/Jan-Kara/ext4-Speedup-orphan-file-handling/20210811-182113
base:   https://git.kernel.org/pub/scm/linux/kernel/git/tytso/ext4.git dev
config: parisc-randconfig-s032-20210810 (attached as .config)
compiler: hppa-linux-gcc (GCC) 10.3.0
reproduce:
        wget https://raw.githubusercontent.com/intel/lkp-tests/master/sbin/make.cross -O ~/bin/make.cross
        chmod +x ~/bin/make.cross
        # apt-get install sparse
        # sparse version: v0.6.3-348-gf0e6938b-dirty
        # https://github.com/0day-ci/linux/commit/77029a42c6e037181b218cbf10a93561e664fb9e
        git remote add linux-review https://github.com/0day-ci/linux
        git fetch --no-tags linux-review Jan-Kara/ext4-Speedup-orphan-file-handling/20210811-182113
        git checkout 77029a42c6e037181b218cbf10a93561e664fb9e
        # save the attached .config to linux build tree
        COMPILER_INSTALL_PATH=$HOME/0day COMPILER=gcc-10.3.0 make.cross C=1 CF='-fdiagnostic-prefix -D__CHECK_ENDIAN__' O=build_dir ARCH=parisc SHELL=/bin/bash fs/ext4/

If you fix the issue, kindly add following tag as appropriate
Reported-by: kernel test robot <lkp@...el.com>


sparse warnings: (new ones prefixed by >>)
>> fs/ext4/orphan.c:76:18: sparse: sparse: cast from restricted __le32
>> fs/ext4/orphan.c:76:18: sparse: sparse: cast from restricted __le32
>> fs/ext4/orphan.c:76:18: sparse: sparse: cast to restricted __le32

vim +76 fs/ext4/orphan.c

    10	
    11	static int ext4_orphan_file_add(handle_t *handle, struct inode *inode)
    12	{
    13		int i, j, start;
    14		struct ext4_orphan_info *oi = &EXT4_SB(inode->i_sb)->s_orphan_info;
    15		int ret = 0;
    16		bool found = false;
    17		__le32 *bdata;
    18		int inodes_per_ob = ext4_inodes_per_orphan_block(inode->i_sb);
    19		int looped = 0;
    20	
    21		/*
    22		 * Find block with free orphan entry. Use CPU number for a naive hash
    23		 * for a search start in the orphan file
    24		 */
    25		start = raw_smp_processor_id()*13 % oi->of_blocks;
    26		i = start;
    27		do {
    28			if (atomic_dec_if_positive(&oi->of_binfo[i].ob_free_entries)
    29			    >= 0) {
    30				found = true;
    31				break;
    32			}
    33			if (++i >= oi->of_blocks)
    34				i = 0;
    35		} while (i != start);
    36	
    37		if (!found) {
    38			/*
    39			 * For now we don't grow or shrink orphan file. We just use
    40			 * whatever was allocated at mke2fs time. The additional
    41			 * credits we would have to reserve for each orphan inode
    42			 * operation just don't seem worth it.
    43			 */
    44			return -ENOSPC;
    45		}
    46	
    47		ret = ext4_journal_get_write_access(handle, inode->i_sb,
    48					oi->of_binfo[i].ob_bh, EXT4_JTR_ORPHAN_FILE);
    49		if (ret)
    50			return ret;
    51	
    52		bdata = (__le32 *)(oi->of_binfo[i].ob_bh->b_data);
    53		/* Find empty slot in a block */
    54		j = 0;
    55		do {
    56			if (looped) {
    57				/*
    58				 * Did we walk through the block several times without
    59				 * finding free entry? It is theoretically possible
    60				 * if entries get constantly allocated and freed or
    61				 * if the block is corrupted. Avoid indefinite looping
    62				 * and bail. We'll use orphan list instead.
    63				 */
    64				if (looped > 3) {
    65					atomic_inc(&oi->of_binfo[i].ob_free_entries);
    66					return -ENOSPC;
    67				}
    68				cond_resched();
    69			}
    70			while (bdata[j]) {
    71				if (++j >= inodes_per_ob) {
    72					j = 0;
    73					looped++;
    74				}
    75			}
  > 76		} while (cmpxchg(&bdata[j], 0, cpu_to_le32(inode->i_ino)) != 0);
    77	
    78		EXT4_I(inode)->i_orphan_idx = i * inodes_per_ob + j;
    79		ext4_set_inode_state(inode, EXT4_STATE_ORPHAN_FILE);
    80	
    81		return ext4_handle_dirty_metadata(handle, NULL, oi->of_binfo[i].ob_bh);
    82	}
    83	

---
0-DAY CI Kernel Test Service, Intel Corporation
https://lists.01.org/hyperkitty/list/kbuild-all@lists.01.org

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