ext4: add an option to control error handling on file data
If the journal doesn't abort when it gets an IO error in file data
blocks, the file data corruption will spread silently. Because
most of applications and commands do buffered writes without fsync(),
they don't notice the IO error. It's scary for mission critical
systems. On the other hand, if the journal aborts whenever it gets
an IO error in file data blocks, the system will easily become
inoperable. So this patch introduces a filesystem option to
determine whether it aborts the journal or just call printk() when
it gets an IO error in file data.
If you mount an ext4 fs with data_err=abort option, it aborts on file
data write error. If you mount it with data_err=ignore, it doesn't
abort, just call printk(). data_err=ignore is the default.
Here is the corresponding patch of the ext3 version:
http://kerneltrap.org/mailarchive/linux-kernel/2008/9/9/3239374
Signed-off-by: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h
index f46a513..6690a41 100644
--- a/fs/ext4/ext4.h
+++ b/fs/ext4/ext4.h
@@ -540,6 +540,8 @@
#define EXT4_MOUNT_JOURNAL_ASYNC_COMMIT 0x1000000 /* Journal Async Commit */
#define EXT4_MOUNT_I_VERSION 0x2000000 /* i_version support */
#define EXT4_MOUNT_DELALLOC 0x8000000 /* Delalloc support */
+#define EXT4_MOUNT_DATA_ERR_ABORT 0x10000000 /* Abort on file data write */
+
/* Compatibility, for having both ext2_fs.h and ext4_fs.h included at once */
#ifndef _LINUX_EXT2_FS_H
#define clear_opt(o, opt) o &= ~EXT4_MOUNT_##opt
diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 79bd398..014677b 100644
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -778,6 +778,9 @@
seq_printf(seq, ",inode_readahead_blks=%u",
sbi->s_inode_readahead_blks);
+ if (test_opt(sb, DATA_ERR_ABORT))
+ seq_puts(seq, ",data_err=abort");
+
ext4_show_quota_options(seq, sb);
return 0;
}
@@ -907,6 +910,7 @@
Opt_commit, Opt_journal_update, Opt_journal_inum, Opt_journal_dev,
Opt_journal_checksum, Opt_journal_async_commit,
Opt_abort, Opt_data_journal, Opt_data_ordered, Opt_data_writeback,
+ Opt_data_err_abort, Opt_data_err_ignore,
Opt_usrjquota, Opt_grpjquota, Opt_offusrjquota, Opt_offgrpjquota,
Opt_jqfmt_vfsold, Opt_jqfmt_vfsv0, Opt_quota, Opt_noquota,
Opt_ignore, Opt_barrier, Opt_err, Opt_resize, Opt_usrquota,
@@ -953,6 +957,8 @@
{Opt_data_journal, "data=journal"},
{Opt_data_ordered, "data=ordered"},
{Opt_data_writeback, "data=writeback"},
+ {Opt_data_err_abort, "data_err=abort"},
+ {Opt_data_err_ignore, "data_err=ignore"},
{Opt_offusrjquota, "usrjquota="},
{Opt_usrjquota, "usrjquota=%s"},
{Opt_offgrpjquota, "grpjquota="},
@@ -1187,6 +1193,12 @@
sbi->s_mount_opt |= data_opt;
}
break;
+ case Opt_data_err_abort:
+ set_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
+ break;
+ case Opt_data_err_ignore:
+ clear_opt(sbi->s_mount_opt, DATA_ERR_ABORT);
+ break;
#ifdef CONFIG_QUOTA
case Opt_usrjquota:
qtype = USRQUOTA;
@@ -2535,6 +2547,10 @@
journal->j_flags |= JBD2_BARRIER;
else
journal->j_flags &= ~JBD2_BARRIER;
+ if (test_opt(sb, DATA_ERR_ABORT))
+ journal->j_flags |= JBD2_ABORT_ON_SYNCDATA_ERR;
+ else
+ journal->j_flags &= ~JBD2_ABORT_ON_SYNCDATA_ERR;
spin_unlock(&journal->j_state_lock);
}