ext2fs: Optimize for Direct I/O

Allocate various memory structures to be properly aligned to avoid
needing to use a bounce buffer when doing direct I/O read/writes.
This should also help on FreeBSD systems which require aligned buffers
unconditionally.

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

diff --git a/lib/ext2fs/inode.c b/lib/ext2fs/inode.c
index 988caff..5088f9b 100644 (file)
--- a/lib/ext2fs/inode.c
+++ b/lib/ext2fs/inode.c
@@ -156,9 +156,8 @@ errcode_t ext2fs_open_inode_scan(ext2_filsys fs, int buffer_blocks,
                         (fs->blocksize / scan->inode_size - 1)) *
                        scan->inode_size / fs->blocksize;
        }
-       retval = ext2fs_get_array(scan->inode_buffer_blocks,
-                                         fs->blocksize,
-                               &scan->inode_buffer);
+       retval = ext2fs_get_memalign(scan->inode_buffer_blocks * fs->blocksize,
+                                    fs->blocksize, &scan->inode_buffer);
        scan->done_group = 0;
        scan->done_group_data = 0;
        scan->bad_block_ptr = 0;

diff --git a/lib/ext2fs/openfs.c b/lib/ext2fs/openfs.c
index 52157d8..d638da0 100644 (file)
--- a/lib/ext2fs/openfs.c
+++ b/lib/ext2fs/openfs.c
@@ -131,7 +131,7 @@ errcode_t ext2fs_open2(const char *name, const char *io_options,
                goto cleanup;
        fs->image_io = fs->io;
        fs->io->app_data = fs;
-       retval = ext2fs_get_mem(SUPERBLOCK_SIZE, &fs->super);
+       retval = ext2fs_get_memalign(SUPERBLOCK_SIZE, 512, &fs->super);
        if (retval)
                goto cleanup;
        if (flags & EXT2_FLAG_IMAGE_FILE) {

diff --git a/lib/ext2fs/rw_bitmaps.c b/lib/ext2fs/rw_bitmaps.c
index cfa3369..4e77a8f 100644 (file)
--- a/lib/ext2fs/rw_bitmaps.c
+++ b/lib/ext2fs/rw_bitmaps.c
@@ -52,7 +52,8 @@ static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
        inode_nbytes = block_nbytes = 0;
        if (do_block) {
                block_nbytes = EXT2_BLOCKS_PER_GROUP(fs->super) / 8;
-               retval = ext2fs_get_mem(fs->blocksize, &block_buf);
+               retval = ext2fs_get_memalign(fs->blocksize, fs->blocksize,
+                                            &block_buf);
                if (retval)
                        return retval;
                memset(block_buf, 0xff, fs->blocksize);
@@ -60,7 +61,8 @@ static errcode_t write_bitmaps(ext2_filsys fs, int do_inode, int do_block)
        if (do_inode) {
                inode_nbytes = (size_t)
                        ((EXT2_INODES_PER_GROUP(fs->super)+7) / 8);
-               retval = ext2fs_get_mem(fs->blocksize, &inode_buf);
+               retval = ext2fs_get_memalign(fs->blocksize, fs->blocksize,
+                                            &inode_buf);
                if (retval)
                        return retval;
                memset(inode_buf, 0xff, fs->blocksize);
@@ -169,8 +171,13 @@ static errcode_t read_bitmaps(ext2_filsys fs, int do_inode, int do_block)
                retval = ext2fs_allocate_block_bitmap(fs, buf, &fs->block_map);
                if (retval)
                        goto cleanup;
-               retval = ext2fs_get_mem(do_image ? fs->blocksize :
-                                       (unsigned) block_nbytes, &block_bitmap);
+               if (do_image)
+                       retval = ext2fs_get_mem(fs->blocksize, &block_bitmap);
+               else
+                       retval = ext2fs_get_memalign((unsigned) block_nbytes,
+                                                    fs->blocksize,
+                                                    &block_bitmap);
+                       
                if (retval)
                        goto cleanup;
        } else