Add new debugfs command "set_block_group"

This command allows the user to set a value in the block group descriptors
for a particular block group.

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

diff --git a/debugfs/ChangeLog b/debugfs/ChangeLog
index d7fbed97c12ecf27c489336cffd669c3c878a0a4..8a3748cdeda1b8f92f88f86b7eed990fbc2bbd06 100644 (file)
--- a/debugfs/ChangeLog
+++ b/debugfs/ChangeLog
@@ -1,3 +1,8 @@
+2007-04-13  Theodore Tso  <tytso@mit.edu>
+
+       * set_fields.c (do_set_block_group_descriptor), debug_cmds.ct,
+               debugfs.8.in: Added set_block_group command:
+
 2007-04-10  Theodore Tso  <tytso@mit.edu>
 
        * util.c (string_to_time): Fix bug in date parser so that integer

diff --git a/debugfs/debug_cmds.ct b/debugfs/debug_cmds.ct
index a3d3e2dfec7e09e54d50d2834aeb3d90748ccbd2..a4a5a4c15c583bbc4a600eec253db255bd6a5683 100644 (file)
--- a/debugfs/debug_cmds.ct
+++ b/debugfs/debug_cmds.ct
@@ -127,6 +127,9 @@ request do_set_super, "Set superblock value",
 request do_set_inode, "Set inode field",
        set_inode_field, sif;
 
+request do_set_block_group_descriptor, "Set block group descriptor field",
+       set_block_group, set_bg;
+
 request do_logdump, "Dump the contents of the journal",
        logdump;
 

diff --git a/debugfs/debugfs.8.in b/debugfs/debugfs.8.in
index 8db23d5aff1ab14c32027eac7d2b170f282c21f1..a4d96704760b1133d0272f00de6ea5f924e784fb 100644 (file)
--- a/debugfs/debugfs.8.in
+++ b/debugfs/debugfs.8.in
@@ -387,6 +387,14 @@ blocks starting at block number
 .I block
 will be marked as allocated.
 .TP
+.I set_block_group bgnum field value
+Modify the block group descriptor specified by
+.I bgnum
+so that the block group descriptor field
+.I field
+has value
+.I value.
+.TP
 .I seti filespec
 Mark inode 
 .I filespec

diff --git a/debugfs/set_fields.c b/debugfs/set_fields.c
index c3de1cfad06adcf59225b735e41e4299f70abdb6..bd9b98ea1c43a8b96802c95ddeadc7c3d6f1de70 100644 (file)
--- a/debugfs/set_fields.c
+++ b/debugfs/set_fields.c
@@ -31,6 +31,7 @@
 
 static struct ext2_super_block set_sb;
 static struct ext2_inode set_inode;
+static struct ext2_group_desc set_gd;
 static ext2_ino_t set_ino;
 static int array_idx;
 
@@ -147,19 +148,38 @@ static struct field_set_info inode_fields[] = {
        { 0, 0, 0, 0 }
 };
 
+static struct field_set_info ext2_bg_fields[] = {
+       { "block_bitmap", &set_gd.bg_block_bitmap, 4, parse_uint },
+       { "inode_bitmap", &set_gd.bg_inode_bitmap, 4, parse_uint },
+       { "inode_table", &set_gd.bg_inode_table, 4, parse_uint },
+       { "free_blocks_count", &set_gd.bg_free_blocks_count, 2, parse_uint },
+       { "free_inodes_count", &set_gd.bg_free_inodes_count, 2, parse_uint },
+       { "used_dirs_count", &set_gd.bg_used_dirs_count, 2, parse_uint },
+       { "flags", &set_gd.bg_flags, 2, parse_uint },
+       { "reserved", &set_gd.bg_reserved, 2, parse_uint, FLAG_ARRAY, 2 },
+       { "itable_unused", &set_gd.bg_itable_unused, 2, parse_uint },
+       { "checksum", &set_gd.bg_checksum, 2, parse_uint },
+       { 0, 0, 0, 0 }
+};
+
+
 static struct field_set_info *find_field(struct field_set_info *fields,
                                         char *field)
 {
        struct field_set_info *ss;
        const char      *prefix;
        char            *arg, *delim, *idx, *tmp;
+       int             prefix_len;
 
        if (fields == super_fields)
                prefix = "s_";
-       else
+       else if (fields == inode_fields)
                prefix = "i_";
-       if (strncmp(field, prefix, 2) == 0)
-               field += 2;
+       else
+               prefix = "bg_";
+       prefix_len = strlen(prefix);
+       if (strncmp(field, prefix, prefix_len) == 0)
+               field += prefix_len;
 
        arg = malloc(strlen(field)+1);
        if (!arg)
@@ -362,9 +382,12 @@ static void print_possible_fields(struct field_set_info *fields)
        if (fields == super_fields) {
                type = "Superblock";
                cmd = "set_super_value";
-       } else {
+       } else if (fields == inode_fields) {
                type = "Inode";
                cmd = "set_inode";
+       } else {
+               type = "Block group descriptor";
+               cmd = "set_block_group";
        }
        f = open_pager();
 
@@ -460,3 +483,46 @@ void do_set_inode(int argc, char *argv[])
                        return;
        }
 }
+
+void do_set_block_group_descriptor(int argc, char *argv[])
+{
+       const char *usage = "<bg number> <field> <value>\n"
+               "\t\"set_block_group_descriptor -l\" will list the names of "
+               "the fields in a block group descriptor\n\twhich can be set.";
+       struct field_set_info   *ss;
+       dgrp_t                  set_bg;
+       char                    *end;
+
+       if ((argc == 2) && !strcmp(argv[1], "-l")) {
+               print_possible_fields(ext2_bg_fields);
+               return;
+       }
+
+       if (common_args_process(argc, argv, 4, 4, "set_block_group_descriptor",
+                               usage, CHECK_FS_RW))
+               return;
+
+       set_bg = strtoul(argv[1], &end, 0);
+       if (*end) {
+               com_err(argv[0], 0, "invalid block group number: %s", argv[1]);
+               return;
+       }
+
+       if (set_bg >= current_fs->group_desc_count) {
+               com_err(argv[0], 0, "block group number too big: %d", set_bg);
+               return;
+       }
+
+
+       if ((ss = find_field(ext2_bg_fields, argv[2])) == 0) {
+               com_err(argv[0], 0, "invalid field specifier: %s", argv[2]);
+               return;
+       }
+
+       set_gd = current_fs->group_desc[set_bg];
+
+       if (ss->func(ss, argv[3]) == 0) {
+               current_fs->group_desc[set_bg] = set_gd;
+               ext2fs_mark_super_dirty(current_fs);
+       }
+}