Add support for on-line resizing ala the resize inode. This patch

is taken from Fedora Core 3's e2fsprogs 1.35-11.2.src.rpm's 
e2fsprogs-resize.patch.

1 files changed, 176 insertions, 0 deletions

diff --git a/lib/ext2fs/res_gdt.c b/lib/ext2fs/res_gdt.c
new file mode 100644
index 00000000..727b8267
--- /dev/null
+++ b/lib/ext2fs/res_gdt.c
@@ -0,0 +1,176 @@
+/*
+ * res_gdt.h --- reserve blocks for growing the group descriptor table
+ *               during online resizing.
+ *
+ * Copyright (C) 2002 Andreas Dilger
+ *
+ * %Begin-Header%
+ * This file may be redistributed under the terms of the GNU Public
+ * License.
+ * %End-Header%
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <time.h>
+#include "ext2_fs.h"
+#include "ext2fs.h"
+
+/*
+ * This code assumes that the reserved blocks have already been marked in-use
+ * during ext2fs_initialize(), so that they are not allocated for other
+ * uses before we can add them to the resize inode (which has to come
+ * after the creation of the inode table).
+ */
+errcode_t ext2fs_create_resize_inode(ext2_filsys fs)
+{
+	errcode_t		retval, retval2;
+	struct ext2_super_block	*sb;
+	struct ext2_inode	inode;
+	__u32			*dindir_buf, *gdt_buf;
+	int			rsv_add;
+	unsigned long long	apb, inode_size;
+	blk_t			dindir_blk, rsv_off, gdt_off, gdt_blk;
+	int			dindir_dirty = 0, inode_dirty = 0;
+
+	EXT2_CHECK_MAGIC(fs, EXT2_ET_MAGIC_EXT2FS_FILSYS);
+
+	sb = fs->super;
+	if (!sb->s_reserved_gdt_blocks)
+		return 0;
+
+	retval = ext2fs_get_mem(2 * fs->blocksize, (void **)&dindir_buf);
+	if (retval)
+		goto out_free;
+	gdt_buf = (__u32 *)((char *)dindir_buf + fs->blocksize);
+
+	retval = ext2fs_read_inode(fs, EXT2_RESIZE_INO, &inode);
+	if (retval)
+		goto out_free;
+
+	/* Maximum possible file size (we donly use the dindirect blocks) */
+	apb = EXT2_ADDR_PER_BLOCK(sb);
+	rsv_add = fs->blocksize / 512;
+	if ((dindir_blk = inode.i_block[EXT2_DIND_BLOCK])) {
+		printf("reading GDT dindir %u\n", dindir_blk);
+		retval = io_channel_read_blk(fs->io, dindir_blk, 1, dindir_buf);
+		if (retval)
+			goto out_inode;
+	} else {
+		blk_t goal = 3 + sb->s_reserved_gdt_blocks +
+			fs->desc_blocks + fs->inode_blocks_per_group;
+
+		retval = ext2fs_alloc_block(fs, goal, 0, &dindir_blk);
+		if (retval)
+			goto out_free;
+		inode.i_mode = LINUX_S_IFREG | 0600;
+		inode.i_links_count = 1;
+		inode.i_block[EXT2_DIND_BLOCK] = dindir_blk;
+		inode.i_blocks = rsv_add;
+		memset(dindir_buf, 0, fs->blocksize);
+#ifdef RES_GDT_DEBUG
+		printf("allocated GDT dindir %u\n", dindir_blk);
+#endif
+		dindir_dirty = inode_dirty = 1;
+		inode_size = apb*apb + apb + EXT2_NDIR_BLOCKS;
+		inode_size *= fs->blocksize;
+		inode.i_size = inode_size & 0xFFFFFFFF;
+		inode.i_size_high = (inode_size >> 32) & 0xFFFFFFFF;
+		if(inode.i_size_high) {
+			sb->s_feature_ro_compat |=
+				EXT2_FEATURE_RO_COMPAT_LARGE_FILE;
+		}
+		inode.i_ctime = time(0);
+	}
+
+	for (rsv_off = 0, gdt_off = fs->desc_blocks,
+	     gdt_blk = sb->s_first_data_block + 1 + gdt_off;
+	     rsv_off < sb->s_reserved_gdt_blocks;
+	     rsv_off++, gdt_off++, gdt_blk++) {
+		unsigned int three = 1, five = 5, seven = 7;
+		unsigned int grp, last = 0;
+		int gdt_dirty = 0;
+
+		gdt_off %= apb;
+		if (!dindir_buf[gdt_off]) {
+			/* FIXME XXX XXX
+			blk_t new_blk;
+
+			retval = ext2fs_new_block(fs, gdt_blk, 0, &new_blk);
+			if (retval)
+				goto out_free;
+			if (new_blk != gdt_blk) {
+				// XXX free block
+				retval = -1; // XXX
+			}
+			*/
+			gdt_dirty = dindir_dirty = inode_dirty = 1;
+			memset(gdt_buf, 0, fs->blocksize);
+			dindir_buf[gdt_off] = gdt_blk;
+			inode.i_blocks += rsv_add;
+#ifdef RES_GDT_DEBUG
+			printf("added primary GDT block %u at %u[%u]\n",
+			       gdt_blk, dindir_blk, gdt_off);
+#endif
+		} else if (dindir_buf[gdt_off] == gdt_blk) {
+			printf("reading primary GDT block %u\n", gdt_blk);
+			retval = io_channel_read_blk(fs->io,gdt_blk,1,gdt_buf);
+			if (retval)
+				goto out_dindir;
+		} else {
+			printf("bad primary GDT %u != %u at %u[%u]\n",
+			       dindir_buf[gdt_off], gdt_blk,dindir_blk,gdt_off);
+			retval = -1; // XXX
+			goto out_dindir;
+		}
+
+		while ((grp = ext2fs_list_backups(fs, &three, &five, &seven)) <
+		       fs->group_desc_count) {
+			blk_t expect = gdt_blk + grp * sb->s_blocks_per_group;
+
+			if (!gdt_buf[last]) {
+#ifdef RES_GDT_DEBUG
+				printf("added backup GDT %u grp %u@%u[%u]\n",
+				       expect, grp, gdt_blk, last);
+#endif
+				gdt_buf[last] = expect;
+				inode.i_blocks += rsv_add;
+				gdt_dirty = inode_dirty = 1;
+			} else if (gdt_buf[last] != expect) {
+				printf("bad backup GDT %u != %u at %u[%u]\n",
+				       gdt_buf[last], expect, gdt_blk, last);
+				retval = -1; // XXX
+				goto out_dindir;
+			}
+			last++;
+		}
+		if (gdt_dirty) {
+#ifdef RES_GDT_DEBUG
+			printf("writing primary GDT block %u\n", gdt_blk);
+#endif
+			retval = io_channel_write_blk(fs->io,gdt_blk,1,gdt_buf);
+			if (retval)
+				goto out_dindir;
+		}
+	}
+
+out_dindir:
+	if (dindir_dirty) {
+		retval2 = io_channel_write_blk(fs->io, dindir_blk,1,dindir_buf);
+		if (!retval)
+			retval = retval2;
+	}
+out_inode:
+	printf("inode.i_blocks = %u, i_size = %u\n", inode.i_blocks,
+	       inode.i_size);
+	if (inode_dirty) {
+		inode.i_atime = inode.i_mtime = time(0);
+		retval2 = ext2fs_write_inode(fs, EXT2_RESIZE_INO, &inode);
+		if (!retval)
+			retval = retval2;
+	}
+out_free:
+	ext2fs_free_mem((void **)&dindir_buf);
+	return retval;
+}
+