ocfs2: add errors=continue
OCFS2 is often used in high-availaibility systems. However, ocfs2
converts the filesystem to read-only at the drop of the hat. This may
not be necessary, since turning the filesystem read-only would affect
other running processes as well, decreasing availability.
This attempt is to add errors=continue, which would return the EIO to
the calling process and terminate furhter processing so that the
filesystem is not corrupted further. However, the filesystem is not
converted to read-only.
As a future plan, I intend to create a small utility or extend
fsck.ocfs2 to fix small errors such as in the inode. The input to the
utility such as the inode can come from the kernel logs so we don't have
to schedule a downtime for fixing small-enough errors.
The patch changes the ocfs2_error to return an error. The error
returned depends on the mount option set. If none is set, the default
is to turn the filesystem read-only.
Perhaps errors=continue is not the best option name. Historically it is
used for making an attempt to progress in the current process itself.
Should we call it errors=eio? or errors=killproc? Suggestions/Comments
welcome.
Sources are available at:
https://github.com/goldwynr/linux/tree/error-cont
Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
Signed-off-by: Mark Fasheh <mfasheh@suse.de>
Cc: Joel Becker <jlbec@evilplan.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/fs/ocfs2/ocfs2.h b/fs/ocfs2/ocfs2.h
index 690ddc6..7a01262 100644
--- a/fs/ocfs2/ocfs2.h
+++ b/fs/ocfs2/ocfs2.h
@@ -286,6 +286,8 @@
OCFS2_MOUNT_HB_GLOBAL = 1 << 14, /* Global heartbeat */
OCFS2_MOUNT_JOURNAL_ASYNC_COMMIT = 1 << 15, /* Journal Async Commit */
+ OCFS2_MOUNT_ERRORS_CONT = 1 << 16, /* Return EIO to the calling process on error */
+ OCFS2_MOUNT_ERRORS_ROFS = 1 << 17, /* Change filesystem to read-only on error */
};
#define OCFS2_OSB_SOFT_RO 0x0001
diff --git a/fs/ocfs2/super.c b/fs/ocfs2/super.c
index 4474ef2..e79058e 100644
--- a/fs/ocfs2/super.c
+++ b/fs/ocfs2/super.c
@@ -192,6 +192,7 @@
Opt_resv_level,
Opt_dir_resv_level,
Opt_journal_async_commit,
+ Opt_err_cont,
Opt_err,
};
@@ -224,6 +225,7 @@
{Opt_resv_level, "resv_level=%u"},
{Opt_dir_resv_level, "dir_resv_level=%u"},
{Opt_journal_async_commit, "journal_async_commit"},
+ {Opt_err_cont, "errors=continue"},
{Opt_err, NULL}
};
@@ -1330,10 +1332,19 @@
mopt->mount_opt |= OCFS2_MOUNT_NOINTR;
break;
case Opt_err_panic:
+ mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_CONT;
+ mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_ROFS;
mopt->mount_opt |= OCFS2_MOUNT_ERRORS_PANIC;
break;
case Opt_err_ro:
+ mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_CONT;
mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_PANIC;
+ mopt->mount_opt |= OCFS2_MOUNT_ERRORS_ROFS;
+ break;
+ case Opt_err_cont:
+ mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_ROFS;
+ mopt->mount_opt &= ~OCFS2_MOUNT_ERRORS_PANIC;
+ mopt->mount_opt |= OCFS2_MOUNT_ERRORS_CONT;
break;
case Opt_data_ordered:
mopt->mount_opt &= ~OCFS2_MOUNT_DATA_WRITEBACK;
@@ -1530,6 +1541,8 @@
if (opts & OCFS2_MOUNT_ERRORS_PANIC)
seq_printf(s, ",errors=panic");
+ else if (opts & OCFS2_MOUNT_ERRORS_CONT)
+ seq_printf(s, ",errors=continue");
else
seq_printf(s, ",errors=remount-ro");
@@ -2539,31 +2552,43 @@
memset(osb, 0, sizeof(struct ocfs2_super));
}
-/* Put OCFS2 into a readonly state, or (if the user specifies it),
- * panic(). We do not support continue-on-error operation. */
-static void ocfs2_handle_error(struct super_block *sb)
+/* Depending on the mount option passed, perform one of the following:
+ * Put OCFS2 into a readonly state (default)
+ * Return EIO so that only the process errs
+ * Fix the error as if fsck.ocfs2 -y
+ * panic
+ */
+static int ocfs2_handle_error(struct super_block *sb)
{
struct ocfs2_super *osb = OCFS2_SB(sb);
-
- if (osb->s_mount_opt & OCFS2_MOUNT_ERRORS_PANIC)
- panic("OCFS2: (device %s): panic forced after error\n",
- sb->s_id);
+ int rv = 0;
ocfs2_set_osb_flag(osb, OCFS2_OSB_ERROR_FS);
+ pr_crit("On-disk corruption discovered. "
+ "Please run fsck.ocfs2 once the filesystem is unmounted.\n");
- if (sb->s_flags & MS_RDONLY &&
- (ocfs2_is_soft_readonly(osb) ||
- ocfs2_is_hard_readonly(osb)))
- return;
+ if (osb->s_mount_opt & OCFS2_MOUNT_ERRORS_PANIC) {
+ panic("OCFS2: (device %s): panic forced after error\n",
+ sb->s_id);
+ } else if (osb->s_mount_opt & OCFS2_MOUNT_ERRORS_CONT) {
+ pr_crit("OCFS2: Returning error to the calling process.\n");
+ rv = -EIO;
+ } else { /* default option */
+ rv = -EROFS;
+ if (sb->s_flags & MS_RDONLY &&
+ (ocfs2_is_soft_readonly(osb) ||
+ ocfs2_is_hard_readonly(osb)))
+ return rv;
- printk(KERN_CRIT "File system is now read-only due to the potential "
- "of on-disk corruption. Please run fsck.ocfs2 once the file "
- "system is unmounted.\n");
- sb->s_flags |= MS_RDONLY;
- ocfs2_set_ro_flag(osb, 0);
+ pr_crit("OCFS2: File system is now read-only.\n");
+ sb->s_flags |= MS_RDONLY;
+ ocfs2_set_ro_flag(osb, 0);
+ }
+
+ return rv;
}
-void __ocfs2_error(struct super_block *sb, const char *function,
+int __ocfs2_error(struct super_block *sb, const char *function,
const char *fmt, ...)
{
struct va_format vaf;
@@ -2580,7 +2605,7 @@
va_end(args);
- ocfs2_handle_error(sb);
+ return ocfs2_handle_error(sb);
}
/* Handle critical errors. This is intentionally more drastic than
diff --git a/fs/ocfs2/super.h b/fs/ocfs2/super.h
index 74ff74c..c1c87d9 100644
--- a/fs/ocfs2/super.h
+++ b/fs/ocfs2/super.h
@@ -32,7 +32,7 @@
int node_num);
__printf(3, 4)
-void __ocfs2_error(struct super_block *sb, const char *function,
+int __ocfs2_error(struct super_block *sb, const char *function,
const char *fmt, ...);
#define ocfs2_error(sb, fmt, args...) __ocfs2_error(sb, __PRETTY_FUNCTION__, fmt, ##args)