allocation

[Peter Teoh]

John Nelson wrote:
> does ext3 allocate space for files anywhere on the disk where there is 
> free space or does it try to keep them all in one area like how ntfs 
> or fat do?
>
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>
In fs/ext3/ialloc.c:

/*
 * There are two policies for allocating an inode.  If the new inode is
 * a directory, then a forward search is made for a block group with both
 * free space and a low directory-to-inode ratio; if that fails, then of
 * the groups with above-average free space, that group with the fewest
 * directories already is chosen.
 *
 * For other inodes, search forward from the parent directory\'s block
 * group to find a free inode.
 */
static int find_group_dir(struct super_block *sb, struct inode *parent)
{
        int ngroups = EXT3_SB(sb)->s_groups_count;
        unsigned int freei, avefreei;
        struct ext3_group_desc *desc, *best_desc = NULL;
        int group, best_group = -1;

And this:

/*
 * There are two policies for allocating an inode.  If the new inode is
 * a directory, then a forward search is made for a block group with both
 * free space and a low directory-to-inode ratio; if that fails, then of
 * the groups with above-average free space, that group with the fewest
 * directories already is chosen.
 *
 * For other inodes, search forward from the parent directory's block
 * group to find a free inode.
 */
struct inode *ext3_new_inode(handle_t *handle, struct inode * dir, int mode)
{
        struct super_block *sb;
        struct buffer_head *bitmap_bh = NULL;
        struct buffer_head *bh2;
        int group;
        unsigned long ino = 0;


Possibly u can look further from here.   it is new to me too.