The simplest file system to use for large blocksize support is ramfs. Note that ramfs does not use the lower layers (buffer I/O etc) so this case is useful for initial testing of changes to large buffer size support if one just wants to exercise the higher layers. The patch adds the ability to specify a mount parameter to modify the order for the pages that are allocated by ramfs. Here is an example of how to mount a volume with order 10 pages: mount -tramfs -o10 none /media Mounts a ramfs filesystem with 4MB sized pages. Then copy a file onto it. cp linux-2.6.21-rc7.tar.gz /media This will populate the ramfs volume. Note that we allocated 14 pages of 4M each instead of 13508. Get rid of the large pages again umount /media Signed-off-by: Christoph Lameter --- fs/ramfs/inode.c | 12 +++++++++--- 1 files changed, 9 insertions(+), 3 deletions(-) diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c index ef2b46d..b317f80 100644 --- a/fs/ramfs/inode.c +++ b/fs/ramfs/inode.c @@ -60,7 +60,8 @@ struct inode *ramfs_get_inode(struct super_block *sb, int mode, dev_t dev) inode->i_blocks = 0; inode->i_mapping->a_ops = &ramfs_aops; inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info; - mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); + mapping_setup(inode->i_mapping, GFP_HIGHUSER, + sb->s_blocksize_bits - PAGE_SHIFT); inode->i_atime = inode->i_mtime = inode->i_ctime = CURRENT_TIME; switch (mode & S_IFMT) { default: @@ -164,10 +165,15 @@ static int ramfs_fill_super(struct super_block * sb, void * data, int silent) { struct inode * inode; struct dentry * root; + int order = 0; + char *options = data; + + if (options && *options) + order = simple_strtoul(options, NULL, 10); sb->s_maxbytes = MAX_LFS_FILESIZE; - sb->s_blocksize = PAGE_CACHE_SIZE; - sb->s_blocksize_bits = PAGE_CACHE_SHIFT; + sb->s_blocksize = PAGE_CACHE_SIZE << order; + sb->s_blocksize_bits = order + PAGE_CACHE_SHIFT; sb->s_magic = RAMFS_MAGIC; sb->s_op = &ramfs_ops; sb->s_time_gran = 1; -- 1.5.2.4 -- - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/