[XFS] Add versioning to the on disk inode which we increment on each

flush call. This is used during recovery to avoid replaying an
older copy of the inode from the log. We can do this without
versioning the filesystem as the pad space we borrowed was
always zero and will be ignored by old kernels.

SGI Modid: 2.5.x-xfs:slinx:155189a

fs/xfs/xfs_dinode.h

@@ -72,7 +72,8 @@ typedef struct xfs_dinode_core
 	__uint32_t	di_gid;		/* owner's group id */
 	__uint32_t	di_nlink;	/* number of links to file */
 	__uint16_t	di_projid;	/* owner's project id */
-	__uint8_t	di_pad[10];	/* unused, zeroed space */
+	__uint8_t	di_pad[8];	/* unused, zeroed space */
+	__uint16_t	di_flushiter;	/* incremented on flush */
 	xfs_timestamp_t	di_atime;	/* time last accessed */
 	xfs_timestamp_t	di_mtime;	/* time last modified */
 	xfs_timestamp_t	di_ctime;	/* time created/inode modified */
@@ -89,6 +90,8 @@ typedef struct xfs_dinode_core
 	__uint32_t	di_gen;		/* generation number */
 } xfs_dinode_core_t;
 
+#define DI_MAX_FLUSH 0xffff
+
 typedef struct xfs_dinode
 {
 	xfs_dinode_core_t	di_core;

fs/xfs/xfs_inode.c

@@ -825,6 +825,8 @@ xfs_xlate_dinode_core(
 			sizeof(buf_core->di_pad));
 	}
 
+	INT_XLATE(buf_core->di_flushiter, mem_core->di_flushiter, dir, arch);
+
 	INT_XLATE(buf_core->di_atime.t_sec, mem_core->di_atime.t_sec,
 			dir, arch);
 	INT_XLATE(buf_core->di_atime.t_nsec, mem_core->di_atime.t_nsec,
@@ -956,6 +958,7 @@ xfs_iread(
 		ip->i_d.di_magic = INT_GET(dip->di_core.di_magic, ARCH_CONVERT);
 		ip->i_d.di_version = INT_GET(dip->di_core.di_version, ARCH_CONVERT);
 		ip->i_d.di_gen = INT_GET(dip->di_core.di_gen, ARCH_CONVERT);
+		ip->i_d.di_flushiter = INT_GET(dip->di_core.di_flushiter, ARCH_CONVERT);
 		/*
 		 * Make sure to pull in the mode here as well in
 		 * case the inode is released without being used.
@@ -3232,6 +3235,13 @@ xfs_iflush_int(
 			ip->i_ino, ip->i_d.di_forkoff, ip);
 		goto corrupt_out;
 	}
+	/*
+	 * bump the flush iteration count, used to detect flushes which
+	 * postdate a log record during recovery.
+	 */
+
+	ip->i_d.di_flushiter++;
+
 	/*
 	 * Copy the dirty parts of the inode into the on-disk
 	 * inode.  We always copy out the core of the inode,
@@ -3241,6 +3251,10 @@ xfs_iflush_int(
 	xfs_xlate_dinode_core((xfs_caddr_t)&(dip->di_core), &(ip->i_d),
 		-1, ARCH_CONVERT);
 
+	/* Wrap, we never let the log put out DI_MAX_FLUSH */
+	if (ip->i_d.di_flushiter == DI_MAX_FLUSH)
+		ip->i_d.di_flushiter = 0;
+
 	/*
 	 * If this is really an old format inode and the superblock version
 	 * has not been updated to support only new format inodes, then

fs/xfs/xfs_log_recover.c

@@ -2326,6 +2326,26 @@ xlog_recover_do_inode_trans(
 				 XFS_ERRLEVEL_LOW, mp);
 		return XFS_ERROR(EFSCORRUPTED);
 	}
+
+	/* Skip replay when the on disk inode is newer than the log one */
+	if (dicp->di_flushiter <
+	    INT_GET(dip->di_core.di_flushiter, ARCH_CONVERT)) {
+		/*
+		 * Deal with the wrap case, DI_MAX_FLUSH is less
+		 * than smaller numbers
+		 */
+		if ((INT_GET(dip->di_core.di_flushiter, ARCH_CONVERT)
+							== DI_MAX_FLUSH) &&
+		    (dicp->di_flushiter < (DI_MAX_FLUSH>>1))) {
+			/* do nothing */
+		} else {
+			xfs_buf_relse(bp);
+			return 0;
+		}
+	}
+	/* Take the opportunity to reset the flush iteration count */
+	dicp->di_flushiter = 0;
+
 	if (unlikely((dicp->di_mode & IFMT) == IFREG)) {
 		if ((dicp->di_format != XFS_DINODE_FMT_EXTENTS) &&
 		    (dicp->di_format != XFS_DINODE_FMT_BTREE)) {

fs/xfs/xfsidbg.c

@@ -3033,11 +3033,12 @@ xfs_prdinode_core(xfs_dinode_core_t *dip, int convert)
 		INT_GET(dip->di_format, convert),
 		xfs_fmtformat(
 		    (xfs_dinode_fmt_t)INT_GET(dip->di_format, convert)));
-	kdb_printf("nlink 0x%x uid 0x%x gid 0x%x projid 0x%x\n",
+	kdb_printf("nlink %d uid %d gid %d projid %d flushiter %u\n",
 		INT_GET(dip->di_nlink, convert),
 		INT_GET(dip->di_uid, convert),
 		INT_GET(dip->di_gid, convert),
-		(uint)INT_GET(dip->di_projid, convert));
+		(uint)INT_GET(dip->di_projid, convert),
+		(uint)INT_GET(dip->di_flushiter, convert));
 	kdb_printf("atime 0x%x:%x mtime 0x%x:%x ctime 0x%x:%x\n",
 		INT_GET(dip->di_atime.t_sec, convert),
 		INT_GET(dip->di_atime.t_nsec, convert),