Increase default superblock size to 1MB

Also - add an option to bcachefs format for specifying it,
--superblock_size

Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>

diff --git a/cmd_format.c b/cmd_format.c
index bcd69783f0f74ed5e24a8a573674f2bf147548ba..b88ffe91f6c05c8751d285a2293725dfb5d93234 100644 (file)
--- a/cmd_format.c
+++ b/cmd_format.c
@@ -36,6 +36,7 @@ x(0,  no_passphrase,          no_argument)            \
 x('L', label,                  required_argument)      \
 x('U', uuid,                   required_argument)      \
 x(0,   fs_size,                required_argument)      \
+x(0,   superblock_size,        required_argument)      \
 x(0,   bucket_size,            required_argument)      \
 x('g', group,                  required_argument)      \
 x(0,   discard,                no_argument)            \
@@ -62,6 +63,7 @@ static void usage(void)
             "      --no_passphrase         Don't encrypt master encryption key\n"
             "  -L, --label=label\n"
             "  -U, --uuid=uuid\n"
+            "      --superblock_size=size\n"
             "\n"
             "Device specific options:");
 
@@ -164,6 +166,12 @@ int cmd_format(int argc, char *argv[])
 
                        dev_opts.size >>= 9;
                        break;
+               case O_superblock_size:
+                       if (bch2_strtouint_h(optarg, &opts.superblock_size))
+                               die("invalid filesystem size");
+
+                       opts.superblock_size >>= 9;
+                       break;
                case O_bucket_size:
                        dev_opts.bucket_size =
                                hatoi_validate(optarg, "bucket size");

diff --git a/cmd_migrate.c b/cmd_migrate.c
index 0beebc9cf81dcc4a62079c4e9c984c99912e1e6b..a0d27427a13487adb0c3169472ade84f48aa4f47 100644 (file)
--- a/cmd_migrate.c
+++ b/cmd_migrate.c
@@ -599,7 +599,9 @@ static void copy_fs(struct bch_fs *c, int src_fd, const char *src_path,
        bch2_alloc_write(c, false);
 }
 
-static void find_superblock_space(ranges extents, struct dev_opts *dev)
+static void find_superblock_space(ranges extents,
+                                 struct format_opts opts,
+                                 struct dev_opts *dev)
 {
        struct range *i;
 
@@ -609,9 +611,10 @@ static void find_superblock_space(ranges extents, struct dev_opts *dev)
                u64 end = round_down(i->end,
                                     dev->bucket_size << 9);
 
-               if (start + (128 << 10) <= end) {
+               /* Need space for two superblocks: */
+               if (start + (opts.superblock_size << 9) * 2 <= end) {
                        dev->sb_offset  = start >> 9;
-                       dev->sb_end     = dev->sb_offset + 256;
+                       dev->sb_end     = dev->sb_offset + opts.superblock_size * 2;
                        return;
                }
        }
@@ -673,7 +676,7 @@ static int migrate_fs(const char            *fs_path,
                                get_size(dev.path, dev.fd) / 5,
                                &bcachefs_inum, stat.st_dev, force);
 
-       find_superblock_space(extents, &dev);
+       find_superblock_space(extents, format_opts, &dev);
 
        struct bch_sb *sb = bch2_format(fs_opt_strs,
                                        fs_opts,format_opts, &dev, 1);

diff --git a/libbcachefs.c b/libbcachefs.c
index 081f7ec64a840d35d017a6e788404075afe8376e..1ae9b9ab1da9dc8904e0164dea4a66036d1ff76c 100644 (file)
--- a/libbcachefs.c
+++ b/libbcachefs.c
@@ -35,52 +35,35 @@ static u64 min_size(unsigned bucket_size)
        return BCH_MIN_NR_NBUCKETS * bucket_size;
 }
 
-static void init_layout(struct bch_sb_layout *l, unsigned block_size,
+static void init_layout(struct bch_sb_layout *l,
+                       unsigned block_size,
+                       unsigned sb_size,
                        u64 start, u64 end)
 {
-       unsigned sb_size;
-       u64 backup; /* offset of 2nd sb */
+       unsigned i;
 
        memset(l, 0, sizeof(*l));
 
-       if (start != BCH_SB_SECTOR)
-               start = round_up(start, block_size);
-       end = round_down(end, block_size);
-
-       if (start >= end)
-               die("insufficient space for superblocks");
-
-       /*
-        * Create two superblocks in the allowed range: reserve a maximum of 64k
-        */
-       sb_size = min_t(u64, 128, end - start / 2);
-
-       backup = start + sb_size;
-       backup = round_up(backup, block_size);
-
-       backup = min(backup, end);
-
-       sb_size = min(end - backup, backup- start);
-       sb_size = rounddown_pow_of_two(sb_size);
-
-       if (sb_size < 8)
-               die("insufficient space for superblocks");
-
        l->magic                = BCACHE_MAGIC;
        l->layout_type          = 0;
        l->nr_superblocks       = 2;
        l->sb_max_size_bits     = ilog2(sb_size);
-       l->sb_offset[0]         = cpu_to_le64(start);
-       l->sb_offset[1]         = cpu_to_le64(backup);
+
+       /* Create two superblocks in the allowed range: */
+       for (i = 0; i < l->nr_superblocks; i++) {
+               if (start != BCH_SB_SECTOR)
+                       start = round_up(start, block_size);
+
+               l->sb_offset[i] = cpu_to_le64(start);
+               start += sb_size;
+       }
+
+       if (start >= end)
+               die("insufficient space for superblocks");
 }
 
 void bch2_pick_bucket_size(struct bch_opts opts, struct dev_opts *dev)
 {
-       if (!dev->sb_offset) {
-               dev->sb_offset  = BCH_SB_SECTOR;
-               dev->sb_end     = BCH_SB_SECTOR + 256;
-       }
-
        if (!dev->size)
                dev->size = get_size(dev->path, dev->fd) >> 9;
 
@@ -300,7 +283,13 @@ struct bch_sb *bch2_format(struct bch_opt_strs     fs_opt_strs,
        for (i = devs; i < devs + nr_devs; i++) {
                sb.sb->dev_idx = i - devs;
 
+               if (!i->sb_offset) {
+                       i->sb_offset    = BCH_SB_SECTOR;
+                       i->sb_end       = i->size;
+               }
+
                init_layout(&sb.sb->layout, fs_opts.block_size,
+                           opts.superblock_size,
                            i->sb_offset, i->sb_end);
 
                if (i->sb_offset == BCH_SB_SECTOR) {

diff --git a/libbcachefs.h b/libbcachefs.h
index abc25ba0edb16ddae5c0e6d150f9710658ca92d9..59c62df33592ca39ee3aeb72d225a9a57cd9244e 100644 (file)
--- a/libbcachefs.h
+++ b/libbcachefs.h
@@ -12,6 +12,8 @@
 
 /* option parsing */
 
+#define SUPERBLOCK_SIZE_DEFAULT                2048    /* 1 MB */
+
 struct bch_opt_strs {
 union {
        char                    *by_id[bch2_opts_nr];
@@ -31,9 +33,8 @@ struct format_opts {
        char            *label;
        uuid_le         uuid;
        unsigned        version;
-
+       unsigned        superblock_size;
        unsigned        encoded_extent_max;
-
        bool            encrypted;
        char            *passphrase;
 };
@@ -42,6 +43,7 @@ static inline struct format_opts format_opts_default()
 {
        return (struct format_opts) {
                .version                = bcachefs_metadata_version_current,
+               .superblock_size        = SUPERBLOCK_SIZE_DEFAULT,
                .encoded_extent_max     = 128,
        };
 }