[PATCH] ext2/3 updates for 2.5.44 (3/11): Forward compatibility: inode size

# The following is the BitKeeper ChangeSet Log
# --------------------------------------------
# 02/10/20	[e-mail]	1.812
# Ext2/3 forward compatibility: inode size
# 
# This patch allows filesystems with expanded inodes to be mounted.
# (compatibility feature flags will be used to control whether or not the
# filesystem should be mounted in case the new inode fields will result in
# compatibility issues).  This allows for future compatibility with newer
# versions of ext2fs.
# --------------------------------------------
#
# ext2/ext2.h   |    7 +++++++
# ext2/ialloc.c |    1 +
# ext2/inode.c  |    7 +++++++
# ext2/super.c  |    4 +++-
# ext3/inode.c  |   14 +++++---------
# ext3/super.c  |    4 +++-
# 6 files changed, 26 insertions(+), 11 deletions(-)
#
diff -Nru a/fs/ext2/ext2.h b/fs/ext2/ext2.h
--- a/fs/ext2/ext2.h	Sun Oct 20 04:39:50 2002
+++ b/fs/ext2/ext2.h	Sun Oct 20 04:39:50 2002
@@ -10,6 +10,7 @@
 	__u32	i_faddr;
 	__u8	i_frag_no;
 	__u8	i_frag_size;
+	__u16	i_state;
 	__u32	i_file_acl;
 	__u32	i_dir_acl;
 	__u32	i_dtime;
@@ -22,6 +23,12 @@
 	rwlock_t i_meta_lock;
 	struct inode	vfs_inode;
 };
+
+/*
+ * Inode dynamic state flags
+ */
+#define EXT2_STATE_NEW			0x00000001 /* inode is newly created */
+
 
 /*
  * Function prototypes
diff -Nru a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
--- a/fs/ext2/ialloc.c	Sun Oct 20 04:39:50 2002
+++ b/fs/ext2/ialloc.c	Sun Oct 20 04:39:50 2002
@@ -386,6 +386,7 @@
 	ei->i_prealloc_block = 0;
 	ei->i_prealloc_count = 0;
 	ei->i_dir_start_lookup = 0;
+	ei->i_state = EXT2_STATE_NEW;
 	if (ei->i_flags & EXT2_SYNC_FL)
 		inode->i_flags |= S_SYNC;
 	if (ei->i_flags & EXT2_DIRSYNC_FL)
diff -Nru a/fs/ext2/inode.c b/fs/ext2/inode.c
--- a/fs/ext2/inode.c	Sun Oct 20 04:39:50 2002
+++ b/fs/ext2/inode.c	Sun Oct 20 04:39:50 2002
@@ -1012,6 +1012,7 @@
 		ei->i_dir_acl = le32_to_cpu(raw_inode->i_dir_acl);
 	ei->i_dtime = 0;
 	inode->i_generation = le32_to_cpu(raw_inode->i_generation);
+	ei->i_state = 0;
 	ei->i_next_alloc_block = 0;
 	ei->i_next_alloc_goal = 0;
 	ei->i_prealloc_count = 0;
@@ -1076,6 +1077,11 @@
 	if (IS_ERR(raw_inode))
  		return -EIO;
 
+	/* For fields not not tracking in the in-memory inode,
+	 * initialise them to zero for new inodes. */
+	if (ei->i_state & EXT2_STATE_NEW)
+		memset(raw_inode, 0, EXT2_SB(sb)->s_inode_size);
+
 	if (ino == EXT2_ACL_IDX_INO || ino == EXT2_ACL_DATA_INO) {
 		ext2_error (sb, "ext2_write_inode", "bad inode number: %lu",
 			    (unsigned long) ino);
@@ -1152,6 +1158,7 @@
 			err = -EIO;
 		}
 	}
+	ei->i_state &= ~EXT2_STATE_NEW;
 	brelse (bh);
 	return err;
 }
diff -Nru a/fs/ext2/super.c b/fs/ext2/super.c
--- a/fs/ext2/super.c	Sun Oct 20 04:39:50 2002
+++ b/fs/ext2/super.c	Sun Oct 20 04:39:50 2002
@@ -630,7 +630,9 @@
 	} else {
 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
-		if (sbi->s_inode_size != EXT2_GOOD_OLD_INODE_SIZE) {
+		if ((sbi->s_inode_size < EXT2_GOOD_OLD_INODE_SIZE) ||
+		    (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
+		    (sbi->s_inode_size > blocksize)) {
 			printk ("EXT2-fs: unsupported inode size: %d\n",
 				sbi->s_inode_size);
 			goto failed_mount;
diff -Nru a/fs/ext3/inode.c b/fs/ext3/inode.c
--- a/fs/ext3/inode.c	Sun Oct 20 04:39:50 2002
+++ b/fs/ext3/inode.c	Sun Oct 20 04:39:50 2002
@@ -2325,6 +2325,11 @@
 		if (err)
 			goto out_brelse;
 	}
+	/* For fields not not tracking in the in-memory inode,
+	 * initialise them to zero for new inodes. */
+	if (ei->i_state & EXT3_STATE_NEW)
+		memset(raw_inode, 0, EXT3_SB(inode->i_sb)->s_inode_size);
+
 	raw_inode->i_mode = cpu_to_le16(inode->i_mode);
 	if(!(test_opt(inode->i_sb, NO_UID32))) {
 		raw_inode->i_uid_low = cpu_to_le16(low_16_bits(inode->i_uid));
@@ -2362,15 +2367,6 @@
 	raw_inode->i_faddr = cpu_to_le32(ei->i_faddr);
 	raw_inode->i_frag = ei->i_frag_no;
 	raw_inode->i_fsize = ei->i_frag_size;
-#else
-	/* If we are not tracking these fields in the in-memory inode,
-	 * then preserve them on disk, but still initialise them to zero
-	 * for new inodes. */
-	if (ei->i_state & EXT3_STATE_NEW) {
-		raw_inode->i_faddr = 0;
-		raw_inode->i_frag = 0;
-		raw_inode->i_fsize = 0;
-	}
 #endif
 	raw_inode->i_file_acl = cpu_to_le32(ei->i_file_acl);
 	if (!S_ISREG(inode->i_mode)) {
diff -Nru a/fs/ext3/super.c b/fs/ext3/super.c
--- a/fs/ext3/super.c	Sun Oct 20 04:39:50 2002
+++ b/fs/ext3/super.c	Sun Oct 20 04:39:50 2002
@@ -1116,7 +1116,9 @@
 	} else {
 		sbi->s_inode_size = le16_to_cpu(es->s_inode_size);
 		sbi->s_first_ino = le32_to_cpu(es->s_first_ino);
-		if (sbi->s_inode_size != EXT3_GOOD_OLD_INODE_SIZE) {
+		if ((sbi->s_inode_size < EXT3_GOOD_OLD_INODE_SIZE) ||
+		    (sbi->s_inode_size & (sbi->s_inode_size - 1)) ||
+		    (sbi->s_inode_size > blocksize)) {
 			printk (KERN_ERR
 				"EXT3-fs: unsupported inode size: %d\n",
 				sbi->s_inode_size);