create: Check with OROM limit before setting default chunk size

Make create check with the appropriate meta data handler and see what the
largest chunk size is supported. The current 512K default is not supported
by existing imsm OROM.

[dan.j.williams@intel.com: trim the upper limit to 512k for future oroms]
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>

diff --git a/Create.c b/Create.c
index b04388f5e338205c3136e7ef6ec9a14ea7063a8a..43e5f37e8b7c4685a7565e80a48631ee386c5415 100644 (file)
--- a/Create.c
+++ b/Create.c
@@ -235,9 +235,13 @@ int Create(struct supertype *st, char *mddev,
        case 6:
        case 0:
                if (chunk == 0) {
-                       chunk = 512;
+                       if (st && st->ss->default_chunk)
+                               chunk = st->ss->default_chunk(st);
+
+                       chunk = chunk ? : 512;
+
                        if (verbose > 0)
-                               fprintf(stderr, Name ": chunk size defaults to 512K\n");
+                               fprintf(stderr, Name ": chunk size defaults to %dK\n", chunk);
                }
                break;
        case LEVEL_LINEAR:

diff --git a/mdadm.h b/mdadm.h
index 1bf5ac0a44de67ad51088d339a1365f5e807450b..142868ad34ed8cd73aa70573b632c78d21ca46df 100644 (file)
--- a/mdadm.h
+++ b/mdadm.h
@@ -609,6 +609,8 @@ extern struct superswitch {
        struct mdinfo *(*container_content)(struct supertype *st);
        /* Allow a metadata handler to override mdadm's default layouts */
        int (*default_layout)(int level); /* optional */
+       /* query the supertype for default chunk size */
+       int (*default_chunk)(struct supertype *st); /* optional */
 
 /* for mdmon */
        int (*open_new)(struct supertype *c, struct active_array *a,

diff --git a/platform-intel.h b/platform-intel.h
index bbdc9f9508b4c95e6322b6ac5e8f776e4c939780..908843618de969bfc86120cecada0513a9d9c389 100644 (file)
--- a/platform-intel.h
+++ b/platform-intel.h
@@ -115,6 +115,55 @@ static inline int imsm_orom_has_chunk(const struct imsm_orom *orom, int chunk)
        return !!(orom->sss & (1 << (fs - 1)));
 }
 
+/**
+ * fls - find last (most-significant) bit set
+ * @x: the word to search
+ * The funciton is borrowed from Linux kernel code
+ * include/asm-generic/bitops/fls.h
+ */
+static inline int fls(int x)
+{
+       int r = 32;
+
+       if (!x)
+               return 0;
+       if (!(x & 0xffff0000u)) {
+               x <<= 16;
+               r -= 16;
+       }
+       if (!(x & 0xff000000u)) {
+               x <<= 8;
+               r -= 8;
+       }
+       if (!(x & 0xf0000000u)) {
+               x <<= 4;
+               r -= 4;
+       }
+       if (!(x & 0xc0000000u)) {
+               x <<= 2;
+               r -= 2;
+       }
+       if (!(x & 0x80000000u)) {
+               x <<= 1;
+               r -= 1;
+       }
+       return r;
+}
+
+/**
+ * imsm_orom_default_chunk - return the largest chunk size supported via orom
+ * @orom: orom pointer from find_imsm_orom
+ */
+static inline int imsm_orom_default_chunk(const struct imsm_orom *orom)
+{
+       int fs = fls(orom->sss);
+
+       if (!fs)
+               return 0;
+
+       return min(512, (1 << fs));
+}
+
 struct sys_dev {
        char *path;
        struct sys_dev *next;

diff --git a/super-intel.c b/super-intel.c
index 394ace419dbf8c13e2547057c4b7187f562b3d89..e212d9a0602865e80b2b9aa519063304263aa430 100644 (file)
--- a/super-intel.c
+++ b/super-intel.c
@@ -4003,6 +4003,17 @@ static int validate_geometry_imsm(struct supertype *st, int level, int layout,
        close(cfd);
        return 0;
 }
+
+static int default_chunk_imsm(struct supertype *st)
+{
+       struct intel_super *super = st->sb;
+
+       if (!super->orom)
+               return 0;
+
+       return imsm_orom_default_chunk(super->orom);
+}
+
 #endif /* MDASSEMBLE */
 
 static int is_rebuilding(struct imsm_dev *dev)
@@ -5240,6 +5251,7 @@ struct superswitch super_imsm = {
        .brief_detail_super = brief_detail_super_imsm,
        .write_init_super = write_init_super_imsm,
        .validate_geometry = validate_geometry_imsm,
+       .default_chunk  = default_chunk_imsm,
        .add_to_super   = add_to_super_imsm,
        .detail_platform = detail_platform_imsm,
 #endif