xfs: expose errortag knobs via sysfs

Creates a /sys/fs/xfs/$dev/errortag/ directory to control the errortag
values directly.  This enables us to control the randomness values,
rather than having to accept the defaults.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Brian Foster <bfoster@redhat.com>
Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com>

3 files changed, 157 insertions, 1 deletions

diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c
index 52f75bc1abac..e2278af6aed1 100644
--- a/fs/xfs/xfs_error.c
+++ b/fs/xfs/xfs_error.c
@@ -22,6 +22,7 @@
 #include "xfs_trans_resv.h"
 #include "xfs_mount.h"
 #include "xfs_error.h"
+#include "xfs_sysfs.h"
 
 #ifdef DEBUG
 
@@ -56,6 +57,145 @@ static unsigned int xfs_errortag_random_default[] = {
         XFS_RANDOM_AG_RESV_CRITICAL,
 };
 
+struct xfs_errortag_attr {
+        struct attribute        attr;
+        unsigned int            tag;
+};
+
+static inline struct xfs_errortag_attr *
+to_attr(struct attribute *attr)
+{
+        return container_of(attr, struct xfs_errortag_attr, attr);
+}
+
+static inline struct xfs_mount *
+to_mp(struct kobject *kobject)
+{
+        struct xfs_kobj *kobj = to_kobj(kobject);
+
+        return container_of(kobj, struct xfs_mount, m_errortag_kobj);
+}
+
+STATIC ssize_t
+xfs_errortag_attr_store(
+        struct kobject          *kobject,
+        struct attribute        *attr,
+        const char              *buf,
+        size_t                  count)
+{
+        struct xfs_mount        *mp = to_mp(kobject);
+        struct xfs_errortag_attr *xfs_attr = to_attr(attr);
+        int                     ret;
+        unsigned int            val;
+
+        if (strcmp(buf, "default") == 0) {
+                val = xfs_errortag_random_default[xfs_attr->tag];
+        } else {
+                ret = kstrtouint(buf, 0, &val);
+                if (ret)
+                        return ret;
+        }
+
+        ret = xfs_errortag_set(mp, xfs_attr->tag, val);
+        if (ret)
+                return ret;
+        return count;
+}
+
+STATIC ssize_t
+xfs_errortag_attr_show(
+        struct kobject          *kobject,
+        struct attribute        *attr,
+        char                    *buf)
+{
+        struct xfs_mount        *mp = to_mp(kobject);
+        struct xfs_errortag_attr *xfs_attr = to_attr(attr);
+
+        return snprintf(buf, PAGE_SIZE, "%u\n",
+                        xfs_errortag_get(mp, xfs_attr->tag));
+}
+
+static const struct sysfs_ops xfs_errortag_sysfs_ops = {
+        .show = xfs_errortag_attr_show,
+        .store = xfs_errortag_attr_store,
+};
+
+#define XFS_ERRORTAG_ATTR_RW(_name, _tag) \
+static struct xfs_errortag_attr xfs_errortag_attr_##_name = {           \
+        .attr = {.name = __stringify(_name),                            \
+                 .mode = VERIFY_OCTAL_PERMISSIONS(S_IWUSR | S_IRUGO) }, \
+        .tag    = (_tag),                                               \
+}
+
+#define XFS_ERRORTAG_ATTR_LIST(_name) &xfs_errortag_attr_##_name.attr
+
+XFS_ERRORTAG_ATTR_RW(noerror,           XFS_ERRTAG_NOERROR);
+XFS_ERRORTAG_ATTR_RW(iflush1,           XFS_ERRTAG_IFLUSH_1);
+XFS_ERRORTAG_ATTR_RW(iflush2,           XFS_ERRTAG_IFLUSH_2);
+XFS_ERRORTAG_ATTR_RW(iflush3,           XFS_ERRTAG_IFLUSH_3);
+XFS_ERRORTAG_ATTR_RW(iflush4,           XFS_ERRTAG_IFLUSH_4);
+XFS_ERRORTAG_ATTR_RW(iflush5,           XFS_ERRTAG_IFLUSH_5);
+XFS_ERRORTAG_ATTR_RW(iflush6,           XFS_ERRTAG_IFLUSH_6);
+XFS_ERRORTAG_ATTR_RW(dareadbuf,         XFS_ERRTAG_DA_READ_BUF);
+XFS_ERRORTAG_ATTR_RW(btree_chk_lblk,    XFS_ERRTAG_BTREE_CHECK_LBLOCK);
+XFS_ERRORTAG_ATTR_RW(btree_chk_sblk,    XFS_ERRTAG_BTREE_CHECK_SBLOCK);
+XFS_ERRORTAG_ATTR_RW(readagf,           XFS_ERRTAG_ALLOC_READ_AGF);
+XFS_ERRORTAG_ATTR_RW(readagi,           XFS_ERRTAG_IALLOC_READ_AGI);
+XFS_ERRORTAG_ATTR_RW(itobp,             XFS_ERRTAG_ITOBP_INOTOBP);
+XFS_ERRORTAG_ATTR_RW(iunlink,           XFS_ERRTAG_IUNLINK);
+XFS_ERRORTAG_ATTR_RW(iunlinkrm,         XFS_ERRTAG_IUNLINK_REMOVE);
+XFS_ERRORTAG_ATTR_RW(dirinovalid,       XFS_ERRTAG_DIR_INO_VALIDATE);
+XFS_ERRORTAG_ATTR_RW(bulkstat,          XFS_ERRTAG_BULKSTAT_READ_CHUNK);
+XFS_ERRORTAG_ATTR_RW(logiodone,         XFS_ERRTAG_IODONE_IOERR);
+XFS_ERRORTAG_ATTR_RW(stratread,         XFS_ERRTAG_STRATREAD_IOERR);
+XFS_ERRORTAG_ATTR_RW(stratcmpl,         XFS_ERRTAG_STRATCMPL_IOERR);
+XFS_ERRORTAG_ATTR_RW(diowrite,          XFS_ERRTAG_DIOWRITE_IOERR);
+XFS_ERRORTAG_ATTR_RW(bmapifmt,          XFS_ERRTAG_BMAPIFORMAT);
+XFS_ERRORTAG_ATTR_RW(free_extent,       XFS_ERRTAG_FREE_EXTENT);
+XFS_ERRORTAG_ATTR_RW(rmap_finish_one,   XFS_ERRTAG_RMAP_FINISH_ONE);
+XFS_ERRORTAG_ATTR_RW(refcount_continue_update,  XFS_ERRTAG_REFCOUNT_CONTINUE_UPDATE);
+XFS_ERRORTAG_ATTR_RW(refcount_finish_one,       XFS_ERRTAG_REFCOUNT_FINISH_ONE);
+XFS_ERRORTAG_ATTR_RW(bmap_finish_one,   XFS_ERRTAG_BMAP_FINISH_ONE);
+XFS_ERRORTAG_ATTR_RW(ag_resv_critical,  XFS_ERRTAG_AG_RESV_CRITICAL);
+
+static struct attribute *xfs_errortag_attrs[] = {
+        XFS_ERRORTAG_ATTR_LIST(noerror),
+        XFS_ERRORTAG_ATTR_LIST(iflush1),
+        XFS_ERRORTAG_ATTR_LIST(iflush2),
+        XFS_ERRORTAG_ATTR_LIST(iflush3),
+        XFS_ERRORTAG_ATTR_LIST(iflush4),
+        XFS_ERRORTAG_ATTR_LIST(iflush5),
+        XFS_ERRORTAG_ATTR_LIST(iflush6),
+        XFS_ERRORTAG_ATTR_LIST(dareadbuf),
+        XFS_ERRORTAG_ATTR_LIST(btree_chk_lblk),
+        XFS_ERRORTAG_ATTR_LIST(btree_chk_sblk),
+        XFS_ERRORTAG_ATTR_LIST(readagf),
+        XFS_ERRORTAG_ATTR_LIST(readagi),
+        XFS_ERRORTAG_ATTR_LIST(itobp),
+        XFS_ERRORTAG_ATTR_LIST(iunlink),
+        XFS_ERRORTAG_ATTR_LIST(iunlinkrm),
+        XFS_ERRORTAG_ATTR_LIST(dirinovalid),
+        XFS_ERRORTAG_ATTR_LIST(bulkstat),
+        XFS_ERRORTAG_ATTR_LIST(logiodone),
+        XFS_ERRORTAG_ATTR_LIST(stratread),
+        XFS_ERRORTAG_ATTR_LIST(stratcmpl),
+        XFS_ERRORTAG_ATTR_LIST(diowrite),
+        XFS_ERRORTAG_ATTR_LIST(bmapifmt),
+        XFS_ERRORTAG_ATTR_LIST(free_extent),
+        XFS_ERRORTAG_ATTR_LIST(rmap_finish_one),
+        XFS_ERRORTAG_ATTR_LIST(refcount_continue_update),
+        XFS_ERRORTAG_ATTR_LIST(refcount_finish_one),
+        XFS_ERRORTAG_ATTR_LIST(bmap_finish_one),
+        XFS_ERRORTAG_ATTR_LIST(ag_resv_critical),
+        NULL,
+};
+
+struct kobj_type xfs_errortag_ktype = {
+        .release = xfs_sysfs_release,
+        .sysfs_ops = &xfs_errortag_sysfs_ops,
+        .default_attrs = xfs_errortag_attrs,
+};
+
 int
 xfs_errortag_init(
         struct xfs_mount        *mp)
@@ -64,13 +204,16 @@ xfs_errortag_init(
                         KM_SLEEP | KM_MAYFAIL);
         if (!mp->m_errortag)
                 return -ENOMEM;
-        return 0;
+
+        return xfs_sysfs_init(&mp->m_errortag_kobj, &xfs_errortag_ktype,
+                               &mp->m_kobj, "errortag");
 }
 
 void
 xfs_errortag_del(
         struct xfs_mount        *mp)
 {
+        xfs_sysfs_del(&mp->m_errortag_kobj);
         kmem_free(mp->m_errortag);
 }
 
@@ -96,6 +239,17 @@ xfs_errortag_test(
 }
 
 int
+xfs_errortag_get(
+        struct xfs_mount        *mp,
+        unsigned int            error_tag)
+{
+        if (error_tag >= XFS_ERRTAG_MAX)
+                return -EINVAL;
+
+        return mp->m_errortag[error_tag];
+}
+
+int
 xfs_errortag_set(
         struct xfs_mount        *mp,
         unsigned int            error_tag,
diff --git a/fs/xfs/xfs_error.h b/fs/xfs/xfs_error.h
index b4316d39e1ca..8915bdeb6128 100644
--- a/fs/xfs/xfs_error.h
+++ b/fs/xfs/xfs_error.h
@@ -138,6 +138,7 @@ extern bool xfs_errortag_test(struct xfs_mount *mp, const char *expression,
 #define XFS_TEST_ERROR(expr, mp, tag, rf)               \
         ((expr) || xfs_errortag_test((mp), #expr, __FILE__, __LINE__, (tag)))
 
+extern int xfs_errortag_get(struct xfs_mount *mp, unsigned int error_tag);
 extern int xfs_errortag_set(struct xfs_mount *mp, unsigned int error_tag,
                 unsigned int tag_value);
 extern int xfs_errortag_add(struct xfs_mount *mp, unsigned int error_tag);
diff --git a/fs/xfs/xfs_mount.h b/fs/xfs/xfs_mount.h
index e002ac52a4e6..931e9fc21a1c 100644
--- a/fs/xfs/xfs_mount.h
+++ b/fs/xfs/xfs_mount.h
@@ -204,6 +204,7 @@ typedef struct xfs_mount {
          * error triggers.  1 = always, 2 = half the time, etc.
          */
         unsigned int            *m_errortag;
+        struct xfs_kobj         m_errortag_kobj;
 
         /*
          * DEBUG mode instrumentation to test and/or trigger delayed allocation