From: Vitaly Fertman <vitaly_fertman@xxxxxxxxxxx> make sleep between reads twice in ext4_multi_mount_protect twice longer than between write and read, make the later one equal to the system check_interval Xyratex-Bug-Id: MRP-390 Reviewed-by: Andrew Perepechko <Andrew_Perepechko@xxxxxxxxxxx> --- lib/ext2fs/mmp.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/lib/ext2fs/mmp.c b/lib/ext2fs/mmp.c index 9a771de7..cb968adf 100644 --- a/lib/ext2fs/mmp.c +++ b/lib/ext2fs/mmp.c @@ -296,6 +296,13 @@ errcode_t ext2fs_mmp_start(ext2_filsys fs) if (mmp_check_interval < EXT4_MMP_MIN_CHECK_INTERVAL) mmp_check_interval = EXT4_MMP_MIN_CHECK_INTERVAL; + /* + * If check_interval in MMP block is larger, use that instead of + * check_interval from the superblock. + */ + if (mmp_s->mmp_check_interval > mmp_check_interval) + mmp_check_interval = mmp_s->mmp_check_interval; + seq = mmp_s->mmp_seq; if (seq == EXT4_MMP_SEQ_CLEAN) goto clean_seq; @@ -309,13 +316,6 @@ errcode_t ext2fs_mmp_start(ext2_filsys fs) goto mmp_error; } - /* - * If check_interval in MMP block is larger, use that instead of - * check_interval from the superblock. - */ - if (mmp_s->mmp_check_interval > mmp_check_interval) - mmp_check_interval = mmp_s->mmp_check_interval; - sleep(2 * mmp_check_interval + 1); retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, fs->mmp_buf); @@ -344,7 +344,10 @@ clean_seq: if (retval) goto mmp_error; - sleep(2 * mmp_check_interval + 1); + /* This sleep between write & read must be shorter than the previous + * sleep between 2 reads, so that the check above of a racing thread + * would never succeed between this write & read. */ + sleep(mmp_check_interval + 1); retval = ext2fs_mmp_read(fs, fs->super->s_mmp_block, fs->mmp_buf); if (retval) -- 2.14.3 (Apple Git-98)
