xfs: introduce vectored scrub mode

Introduce a variant on XFS_SCRUB_METADATA that allows for a vectored
mode.  The caller specifies the principal metadata object that they want
to scrub (allocation group, inode, etc.) once, followed by an array of
scrub types they want called on that object.  The kernel runs the scrub
operations and writes the output flags and errno code to the
corresponding array element.

A new pseudo scrub type BARRIER is introduced to force the kernel to
return to userspace if any corruptions have been found when scrubbing
the previous scrub types in the array.  This enables userspace to
schedule, for example, the sequence:

 1. data fork
 2. barrier
 3. directory

If the data fork scrub is clean, then the kernel will perform the
directory scrub.  If not, the barrier in 2 will exit back to userspace.

The alternative would have been an interface where userspace passes a
pointer to an empty buffer, and the kernel formats that with
xfs_scrub_vecs that tell userspace what it scrubbed and what the outcome
was.  With that the kernel would have to communicate that the buffer
needed to have been at least X size, even though for our cases
XFS_SCRUB_TYPE_NR + 2 would always be enough.

Compared to that, this design keeps all the dependency policy and
ordering logic in userspace where it already resides instead of
duplicating it in the kernel. The downside of that is that it needs the
barrier logic.

When running fstests in "rebuild all metadata after each test" mode, I
observed a 10% reduction in runtime due to fewer transitions across the
system call boundary.

Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>

diff --git a/fs/xfs/libxfs/xfs_fs.h b/fs/xfs/libxfs/xfs_fs.h
index 7ae1912cdbfc24054bc382c90e3f45841d601fae..97996cb79aaaa87bf815193429662c069c7d218b 100644 (file)
--- a/fs/xfs/libxfs/xfs_fs.h
+++ b/fs/xfs/libxfs/xfs_fs.h
@@ -725,6 +725,15 @@ struct xfs_scrub_metadata {
 /* Number of scrub subcommands. */
 #define XFS_SCRUB_TYPE_NR      29
 
+/*
+ * This special type code only applies to the vectored scrub implementation.
+ *
+ * If any of the previous scrub vectors recorded runtime errors or have
+ * sv_flags bits set that match the OFLAG bits in the barrier vector's
+ * sv_flags, set the barrier's sv_ret to -ECANCELED and return to userspace.
+ */
+#define XFS_SCRUB_TYPE_BARRIER (0xFFFFFFFF)
+
 /* i: Repair this metadata. */
 #define XFS_SCRUB_IFLAG_REPAIR         (1u << 0)
 
@@ -769,6 +778,29 @@ struct xfs_scrub_metadata {
                                 XFS_SCRUB_OFLAG_NO_REPAIR_NEEDED)
 #define XFS_SCRUB_FLAGS_ALL    (XFS_SCRUB_FLAGS_IN | XFS_SCRUB_FLAGS_OUT)
 
+/* Vectored scrub calls to reduce the number of kernel transitions. */
+
+struct xfs_scrub_vec {
+       __u32 sv_type;          /* XFS_SCRUB_TYPE_* */
+       __u32 sv_flags;         /* XFS_SCRUB_FLAGS_* */
+       __s32 sv_ret;           /* 0 or a negative error code */
+       __u32 sv_reserved;      /* must be zero */
+};
+
+/* Vectored metadata scrub control structure. */
+struct xfs_scrub_vec_head {
+       __u64 svh_ino;          /* inode number. */
+       __u32 svh_gen;          /* inode generation. */
+       __u32 svh_agno;         /* ag number. */
+       __u32 svh_flags;        /* XFS_SCRUB_VEC_FLAGS_* */
+       __u16 svh_rest_us;      /* wait this much time between vector items */
+       __u16 svh_nr;           /* number of svh_vectors */
+       __u64 svh_reserved;     /* must be zero */
+       __u64 svh_vectors;      /* pointer to buffer of xfs_scrub_vec */
+};
+
+#define XFS_SCRUB_VEC_FLAGS_ALL                (0)
+
 /*
  * ioctl limits
  */
@@ -928,6 +960,7 @@ struct xfs_getparents_by_handle {
 #define XFS_IOC_AG_GEOMETRY    _IOWR('X', 61, struct xfs_ag_geometry)
 #define XFS_IOC_GETPARENTS     _IOWR('X', 62, struct xfs_getparents)
 #define XFS_IOC_GETPARENTS_BY_HANDLE _IOWR('X', 63, struct xfs_getparents_by_handle)
+#define XFS_IOC_SCRUBV_METADATA        _IOWR('X', 64, struct xfs_scrub_vec_head)
 
 /*
  * ioctl commands that replace IRIX syssgi()'s

diff --git a/fs/xfs/scrub/scrub.c b/fs/xfs/scrub/scrub.c
index 1456cc11c406dc632f5be1720eb9fd09791b905c..78b00ab85c9c9572cb69e541d3c841587e9f8d14 100644 (file)
--- a/fs/xfs/scrub/scrub.c
+++ b/fs/xfs/scrub/scrub.c
@@ -21,6 +21,7 @@
 #include "xfs_exchmaps.h"
 #include "xfs_dir2.h"
 #include "xfs_parent.h"
+#include "xfs_icache.h"
 #include "scrub/scrub.h"
 #include "scrub/common.h"
 #include "scrub/trace.h"
@@ -749,3 +750,151 @@ xfs_ioc_scrub_metadata(
 
        return 0;
 }
+
+/* Decide if there have been any scrub failures up to this point. */
+static inline int
+xfs_scrubv_check_barrier(
+       struct xfs_mount                *mp,
+       const struct xfs_scrub_vec      *vectors,
+       const struct xfs_scrub_vec      *stop_vec)
+{
+       const struct xfs_scrub_vec      *v;
+       __u32                           failmask;
+
+       failmask = stop_vec->sv_flags & XFS_SCRUB_FLAGS_OUT;
+
+       for (v = vectors; v < stop_vec; v++) {
+               if (v->sv_type == XFS_SCRUB_TYPE_BARRIER)
+                       continue;
+
+               /*
+                * Runtime errors count as a previous failure, except the ones
+                * used to ask userspace to retry.
+                */
+               switch (v->sv_ret) {
+               case -EBUSY:
+               case -ENOENT:
+               case -EUSERS:
+               case 0:
+                       break;
+               default:
+                       return -ECANCELED;
+               }
+
+               /*
+                * If any of the out-flags on the scrub vector match the mask
+                * that was set on the barrier vector, that's a previous fail.
+                */
+               if (v->sv_flags & failmask)
+                       return -ECANCELED;
+       }
+
+       return 0;
+}
+
+/* Vectored scrub implementation to reduce ioctl calls. */
+int
+xfs_ioc_scrubv_metadata(
+       struct file                     *file,
+       void                            __user *arg)
+{
+       struct xfs_scrub_vec_head       head;
+       struct xfs_scrub_vec_head       __user *uhead = arg;
+       struct xfs_scrub_vec            *vectors;
+       struct xfs_scrub_vec            __user *uvectors;
+       struct xfs_inode                *ip_in = XFS_I(file_inode(file));
+       struct xfs_mount                *mp = ip_in->i_mount;
+       struct xfs_scrub_vec            *v;
+       size_t                          vec_bytes;
+       unsigned int                    i;
+       int                             error = 0;
+
+       if (!capable(CAP_SYS_ADMIN))
+               return -EPERM;
+
+       if (copy_from_user(&head, uhead, sizeof(head)))
+               return -EFAULT;
+
+       if (head.svh_reserved)
+               return -EINVAL;
+       if (head.svh_flags & ~XFS_SCRUB_VEC_FLAGS_ALL)
+               return -EINVAL;
+       if (head.svh_nr == 0)
+               return 0;
+
+       vec_bytes = array_size(head.svh_nr, sizeof(struct xfs_scrub_vec));
+       if (vec_bytes > PAGE_SIZE)
+               return -ENOMEM;
+
+       uvectors = (void __user *)(uintptr_t)head.svh_vectors;
+       vectors = memdup_user(uvectors, vec_bytes);
+       if (IS_ERR(vectors))
+               return PTR_ERR(vectors);
+
+       trace_xchk_scrubv_start(ip_in, &head);
+
+       for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
+               if (v->sv_reserved) {
+                       error = -EINVAL;
+                       goto out_free;
+               }
+
+               if (v->sv_type == XFS_SCRUB_TYPE_BARRIER &&
+                   (v->sv_flags & ~XFS_SCRUB_FLAGS_OUT)) {
+                       error = -EINVAL;
+                       goto out_free;
+               }
+
+               trace_xchk_scrubv_item(mp, &head, i, v);
+       }
+
+       /* Run all the scrubbers. */
+       for (i = 0, v = vectors; i < head.svh_nr; i++, v++) {
+               struct xfs_scrub_metadata       sm = {
+                       .sm_type                = v->sv_type,
+                       .sm_flags               = v->sv_flags,
+                       .sm_ino                 = head.svh_ino,
+                       .sm_gen                 = head.svh_gen,
+                       .sm_agno                = head.svh_agno,
+               };
+
+               if (v->sv_type == XFS_SCRUB_TYPE_BARRIER) {
+                       v->sv_ret = xfs_scrubv_check_barrier(mp, vectors, v);
+                       if (v->sv_ret) {
+                               trace_xchk_scrubv_barrier_fail(mp, &head, i, v);
+                               break;
+                       }
+
+                       continue;
+               }
+
+               v->sv_ret = xfs_scrub_metadata(file, &sm);
+               v->sv_flags = sm.sm_flags;
+
+               trace_xchk_scrubv_outcome(mp, &head, i, v);
+
+               if (head.svh_rest_us) {
+                       ktime_t         expires;
+
+                       expires = ktime_add_ns(ktime_get(),
+                                       head.svh_rest_us * 1000);
+                       set_current_state(TASK_KILLABLE);
+                       schedule_hrtimeout(&expires, HRTIMER_MODE_ABS);
+               }
+
+               if (fatal_signal_pending(current)) {
+                       error = -EINTR;
+                       goto out_free;
+               }
+       }
+
+       if (copy_to_user(uvectors, vectors, vec_bytes) ||
+           copy_to_user(uhead, &head, sizeof(head))) {
+               error = -EFAULT;
+               goto out_free;
+       }
+
+out_free:
+       kfree(vectors);
+       return error;
+}

diff --git a/fs/xfs/scrub/trace.h b/fs/xfs/scrub/trace.h
index b3756722bee1d53b4d75afb7b75e1f56afd5528b..8ce74bd8530a640c11bd776727f2f2e4676fdb04 100644 (file)
--- a/fs/xfs/scrub/trace.h
+++ b/fs/xfs/scrub/trace.h
@@ -69,6 +69,7 @@ TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_QUOTACHECK);
 TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_NLINKS);
 TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_HEALTHY);
 TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_DIRTREE);
+TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_BARRIER);
 
 #define XFS_SCRUB_TYPE_STRINGS \
        { XFS_SCRUB_TYPE_PROBE,         "probe" }, \
@@ -99,7 +100,8 @@ TRACE_DEFINE_ENUM(XFS_SCRUB_TYPE_DIRTREE);
        { XFS_SCRUB_TYPE_QUOTACHECK,    "quotacheck" }, \
        { XFS_SCRUB_TYPE_NLINKS,        "nlinks" }, \
        { XFS_SCRUB_TYPE_HEALTHY,       "healthy" }, \
-       { XFS_SCRUB_TYPE_DIRTREE,       "dirtree" }
+       { XFS_SCRUB_TYPE_DIRTREE,       "dirtree" }, \
+       { XFS_SCRUB_TYPE_BARRIER,       "barrier" }
 
 #define XFS_SCRUB_FLAG_STRINGS \
        { XFS_SCRUB_IFLAG_REPAIR,               "repair" }, \
@@ -208,6 +210,81 @@ DEFINE_EVENT(xchk_fsgate_class, name, \
 DEFINE_SCRUB_FSHOOK_EVENT(xchk_fsgates_enable);
 DEFINE_SCRUB_FSHOOK_EVENT(xchk_fsgates_disable);
 
+DECLARE_EVENT_CLASS(xchk_vector_head_class,
+       TP_PROTO(struct xfs_inode *ip, struct xfs_scrub_vec_head *vhead),
+       TP_ARGS(ip, vhead),
+       TP_STRUCT__entry(
+               __field(dev_t, dev)
+               __field(xfs_ino_t, ino)
+               __field(xfs_agnumber_t, agno)
+               __field(xfs_ino_t, inum)
+               __field(unsigned int, gen)
+               __field(unsigned int, flags)
+               __field(unsigned short, rest_us)
+               __field(unsigned short, nr_vecs)
+       ),
+       TP_fast_assign(
+               __entry->dev = ip->i_mount->m_super->s_dev;
+               __entry->ino = ip->i_ino;
+               __entry->agno = vhead->svh_agno;
+               __entry->inum = vhead->svh_ino;
+               __entry->gen = vhead->svh_gen;
+               __entry->flags = vhead->svh_flags;
+               __entry->rest_us = vhead->svh_rest_us;
+               __entry->nr_vecs = vhead->svh_nr;
+       ),
+       TP_printk("dev %d:%d ino 0x%llx agno 0x%x inum 0x%llx gen 0x%x flags 0x%x rest_us %u nr_vecs %u",
+                 MAJOR(__entry->dev), MINOR(__entry->dev),
+                 __entry->ino,
+                 __entry->agno,
+                 __entry->inum,
+                 __entry->gen,
+                 __entry->flags,
+                 __entry->rest_us,
+                 __entry->nr_vecs)
+)
+#define DEFINE_SCRUBV_HEAD_EVENT(name) \
+DEFINE_EVENT(xchk_vector_head_class, name, \
+       TP_PROTO(struct xfs_inode *ip, struct xfs_scrub_vec_head *vhead), \
+       TP_ARGS(ip, vhead))
+
+DEFINE_SCRUBV_HEAD_EVENT(xchk_scrubv_start);
+
+DECLARE_EVENT_CLASS(xchk_vector_class,
+       TP_PROTO(struct xfs_mount *mp, struct xfs_scrub_vec_head *vhead,
+                unsigned int vec_nr, struct xfs_scrub_vec *v),
+       TP_ARGS(mp, vhead, vec_nr, v),
+       TP_STRUCT__entry(
+               __field(dev_t, dev)
+               __field(unsigned int, vec_nr)
+               __field(unsigned int, vec_type)
+               __field(unsigned int, vec_flags)
+               __field(int, vec_ret)
+       ),
+       TP_fast_assign(
+               __entry->dev = mp->m_super->s_dev;
+               __entry->vec_nr = vec_nr;
+               __entry->vec_type = v->sv_type;
+               __entry->vec_flags = v->sv_flags;
+               __entry->vec_ret = v->sv_ret;
+       ),
+       TP_printk("dev %d:%d vec[%u] type %s flags %s ret %d",
+                 MAJOR(__entry->dev), MINOR(__entry->dev),
+                 __entry->vec_nr,
+                 __print_symbolic(__entry->vec_type, XFS_SCRUB_TYPE_STRINGS),
+                 __print_flags(__entry->vec_flags, "|", XFS_SCRUB_FLAG_STRINGS),
+                 __entry->vec_ret)
+)
+#define DEFINE_SCRUBV_EVENT(name) \
+DEFINE_EVENT(xchk_vector_class, name, \
+       TP_PROTO(struct xfs_mount *mp, struct xfs_scrub_vec_head *vhead, \
+                unsigned int vec_nr, struct xfs_scrub_vec *v), \
+       TP_ARGS(mp, vhead, vec_nr, v))
+
+DEFINE_SCRUBV_EVENT(xchk_scrubv_barrier_fail);
+DEFINE_SCRUBV_EVENT(xchk_scrubv_item);
+DEFINE_SCRUBV_EVENT(xchk_scrubv_outcome);
+
 TRACE_EVENT(xchk_op_error,
        TP_PROTO(struct xfs_scrub *sc, xfs_agnumber_t agno,
                 xfs_agblock_t bno, int error, void *ret_ip),

diff --git a/fs/xfs/scrub/xfs_scrub.h b/fs/xfs/scrub/xfs_scrub.h
index 02c930f175d0b77024911e35b5a4efe9d2c1148a..f17173b83e6f34e917bcf2fc48dcac3e709e060e 100644 (file)
--- a/fs/xfs/scrub/xfs_scrub.h
+++ b/fs/xfs/scrub/xfs_scrub.h
@@ -8,8 +8,10 @@
 
 #ifndef CONFIG_XFS_ONLINE_SCRUB
 # define xfs_ioc_scrub_metadata(f, a)  (-ENOTTY)
+# define xfs_ioc_scrubv_metadata(f, a) (-ENOTTY)
 #else
 int xfs_ioc_scrub_metadata(struct file *file, void __user *arg);
+int xfs_ioc_scrubv_metadata(struct file *file, void __user *arg);
 #endif /* CONFIG_XFS_ONLINE_SCRUB */
 
 #endif /* __XFS_SCRUB_H__ */

diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
index 857b19428984a3f1c9af16d2e12a9e3717989f57..f0117188f3021a52d9641ac8511d28f209c7a946 100644 (file)
--- a/fs/xfs/xfs_ioctl.c
+++ b/fs/xfs/xfs_ioctl.c
@@ -1413,6 +1413,8 @@ xfs_file_ioctl(
        case FS_IOC_GETFSMAP:
                return xfs_ioc_getfsmap(ip, arg);
 
+       case XFS_IOC_SCRUBV_METADATA:
+               return xfs_ioc_scrubv_metadata(filp, arg);
        case XFS_IOC_SCRUB_METADATA:
                return xfs_ioc_scrub_metadata(filp, arg);