mke2fs: Disentangle lazy_bg from uninit_bg's lazy inode table initialization

Instead of using -O lazy_bg,uninit_bg as the way of requesting that
the inode table be lazy unitialized, use the parameter
lazy_itable_init, which can either be set via mke2fs's -E option, or
via /etc/mke2fs.conf.

Also fix some random problems in mke2fs's man page, including
documenting the extent feature, which had been missing.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/misc/mke2fs.8.in b/misc/mke2fs.8.in
index e12b42eb00e4dcf00ded563f9ff2026f6ccea384..1e9a203d7fac84c1ef16213af38d5f613fad22d8 100644 (file)
--- a/misc/mke2fs.8.in
+++ b/misc/mke2fs.8.in
@@ -189,7 +189,7 @@ Configure the filesystem for a RAID array with
 filesystem blocks. This is the number of blocks read or written to disk
 before moving to next disk. This mostly affects placement of filesystem
 metadata like bitmaps at
-.BR mke2fs (2)
+.B mke2fs
 time to avoid placing them on a single disk, which can hurt the performanace.
 It may also be used by block allocator.
 .TP
@@ -205,6 +205,15 @@ parity in a RAID stripe if possible when the data is written.
 Reserve enough space so that the block group descriptor table can grow
 to support a filesystem that has max-online-resize blocks.
 .TP
+.B lazy_itable_init= \fI<0 to disable, 1 to enable>
+If enabled and the uninit_bg feature is enabled, the inode table will
+not fully initialized by 
+.BR mke2fs .
+This speeds up filesystem
+initialization noitceably, but it requires the kernel to finish
+initializing the filesystem in the background when the filesystem is
+first mounted.
+.TP
 .B test_fs
 Set a flag in the filesystem superblock indicating that it may be
 mounted using experimental kernel code, such as the ext4dev filesystem.
@@ -449,11 +458,20 @@ option).
 @JDEV@must be created with the same
 @JDEV@block size as the filesystems that will be using it.
 .TP
+.B extent
+Instead of using the indirect block scheme for storing the location of
+data blocks in an inode, use extents instead.  This is a much more
+efficient encoding which speeds up filesystem access, especially for
+large files.
+.TP
 .B uninit_bg
-Create a filesystem without initializing all of the groups.  This speeds
-up filesystem creation time noticably, and can also reduce
+Create a filesystem without initializing all of the block groups.  This 
+feature also enables checksums and highest-inode-used statistics in each
+blockgroup.  This feature can
+speed up filesystem creation time noticably (if lazy_itable_init is
+enabled), and can also reduce
 .BR e2fsck time
-dramatically.  This feature is only supported by the ext4 filesystem in
+dramatically.  It is only supported by the ext4 filesystem in
 recent Linux kernels.
 .TP
 .B resize_inode
@@ -523,7 +541,7 @@ If this option is is not specified,
 .B mke2fs
 will pick a single default usage type based on the size of the filesystem to
 be created.  If the filesystem size is less than or equal to 3 megabytes,
-.BR mke2fs (8)
+.B mke2fs
 will use the filesystem type
 .IR floppy .
 If the filesystem size is greater than 3 but less than or equal to

diff --git a/misc/mke2fs.c b/misc/mke2fs.c
index a58b1165206e870628ff40f1c3e8f74a91c79dba..9940d3f1ac58fcdf75ce298f46ae8144c8736448 100644 (file)
--- a/misc/mke2fs.c
+++ b/misc/mke2fs.c
@@ -77,6 +77,7 @@ int   force;
 int    noaction;
 int    journal_size;
 int    journal_flags;
+int    lazy_itable_init;
 char   *bad_blocks_filename;
 __u32  fs_stride;
 
@@ -399,14 +400,13 @@ static errcode_t zero_blocks(ext2_filsys fs, blk_t blk, int num,
        return 0;
 }      
 
-static void write_inode_tables(ext2_filsys fs)
+static void write_inode_tables(ext2_filsys fs, int lazy_flag)
 {
        errcode_t       retval;
        blk_t           blk;
        dgrp_t          i;
        int             num;
        struct progress_struct progress;
-       int             lazy_flag = 0;
 
        if (quiet)
                memset(&progress, 0, sizeof(progress));
@@ -886,6 +886,13 @@ static void parse_extended_opts(struct ext2_super_block *param,
                        }
                } else if (!strcmp(token, "test_fs")) {
                        param->s_flags |= EXT2_FLAGS_TEST_FILESYS;
+               } else if (!strcmp(token, "lazy_itable_init")) {
+                       if (!arg) {
+                               r_usage++;
+                               badopt = token;
+                               continue;
+                       }
+                       lazy_itable_init = strtoul(arg, &p, 0);
                } else {
                        r_usage++;
                        badopt = token;
@@ -899,8 +906,9 @@ static void parse_extended_opts(struct ext2_super_block *param,
                        "Valid extended options are:\n"
                        "\tstride=<RAID per-disk data chunk in blocks>\n"
                        "\tstripe-width=<RAID stride * data disks in blocks>\n"
-                       "\tresize=<resize maximum size in blocks>\n\n"
-                       "\ttest_fs\n"),
+                       "\tresize=<resize maximum size in blocks>\n"
+                       "\tlazy_itable_init=<0 to disable, 1 to enable>\n"
+                       "\ttest_fs\n\n"),
                        badopt ? badopt : "");
                free(buf);
                exit(1);
@@ -1120,6 +1128,16 @@ static int get_int_from_profile(char **fs_types, const char *opt, int def_val)
        return ret;
 }
 
+static int get_bool_from_profile(char **fs_types, const char *opt, int def_val)
+{
+       int ret;
+       char **cpp;
+
+       profile_get_boolean(profile, "defaults", opt, 0, def_val, &ret);
+       for (cpp = fs_types; *cpp; cpp++)
+               profile_get_boolean(profile, "fs_types", *cpp, opt, ret, &ret);
+       return ret;
+}
 
 extern const char *mke2fs_default_profile;
 static const char *default_files[] = { "<default>", 0 };
@@ -1645,6 +1663,9 @@ static void PRS(int argc, char *argv[])
                int_log2(blocksize >> EXT2_MIN_BLOCK_LOG_SIZE);
 
        blocksize = EXT2_BLOCK_SIZE(&fs_param);
+
+       lazy_itable_init = get_bool_from_profile(fs_types, 
+                                                "lazy_itable_init", 0);
        
        if (extended_opts)
                parse_extended_opts(&fs_param, extended_opts);
@@ -1660,6 +1681,17 @@ static void PRS(int argc, char *argv[])
                exit(1);
        }
 
+       if (EXT2_HAS_RO_COMPAT_FEATURE(&fs_param,
+                                      EXT4_FEATURE_RO_COMPAT_GDT_CSUM) &&
+           EXT2_HAS_COMPAT_FEATURE(&fs_param, EXT2_FEATURE_COMPAT_LAZY_BG)) {
+               com_err(program_name, 0,
+                       _("lazy_bg and uninit_bg can not be enabled "
+                         "at the same time;\n\t"
+                         "use -E lazy_itable_init=1 to defer zeroing the "
+                         "inode table."));
+               exit(1);
+       }
+
        if (fs_param.s_blocks_per_group) {
                if (fs_param.s_blocks_per_group < 256 ||
                    fs_param.s_blocks_per_group > 8 * (unsigned) blocksize) {
@@ -1886,7 +1918,7 @@ int main (int argc, char *argv[])
                                ret_blk);
                }
                setup_lazy_bg(fs);
-               write_inode_tables(fs);
+               write_inode_tables(fs, lazy_itable_init);
                create_root_dir(fs);
                create_lost_and_found(fs);
                reserve_inodes(fs);

diff --git a/misc/mke2fs.conf.5.in b/misc/mke2fs.conf.5.in
index 1fc16e720c1cd2ee524556f8535a1d5f36dec5bb..6734bf396102878dc48aa97f95572e310b991069 100644 (file)
--- a/misc/mke2fs.conf.5.in
+++ b/misc/mke2fs.conf.5.in
@@ -282,6 +282,18 @@ command-line option to
 This relation specifies the default blocksize if the user does not
 specify a blocksize on the command line.
 .TP
+.I lazy_itable_init
+This relation is a boolean which specifies whether the inode table should 
+be lazily initialized.  It only has meaning if the uninit_bg feature is
+enabled.  If lazy_itable_init is true and the uninit_bg feature is
+enabled,  the inode table will
+not fully initialized by 
+.BR mke2fs (8).
+This speeds up filesystem
+initialization noitceably, but it requires the kernel to finish
+initializing the filesystem in the background when the filesystem is
+first mounted.
+.TP
 .I inode_ratio
 This relation specifies the default inode ratio if the user does not
 specify one on the command line.