X-Git-Url: http://pilppa.org/gitweb/gitweb.cgi?a=blobdiff_plain;f=fs%2Fxfs%2Fxfs_ialloc.c;h=aad8c5da38afadb158518d7ee5dc51a3309726f2;hb=9144f3821d2cba9f16cdf3ff1b881384f4b68b53;hp=a64dfbd565a563b3886d934ec19d77df4f4ed526;hpb=eddeb0e2d863e3941d8768e70cb50c6120e61fa0;p=linux-2.6-omap-h63xx.git

diff --git a/fs/xfs/xfs_ialloc.c b/fs/xfs/xfs_ialloc.c
index a64dfbd565a..aad8c5da38a 100644
--- a/fs/xfs/xfs_ialloc.c
+++ b/fs/xfs/xfs_ialloc.c
@@ -147,6 +147,7 @@ xfs_ialloc_ag_alloc(
 	int		version;	/* inode version number to use */
 	int		isaligned = 0;	/* inode allocation at stripe unit */
 					/* boundary */
+	unsigned int	gen;
 
 	args.tp = tp;
 	args.mp = tp->t_mountp;
@@ -290,6 +291,14 @@ xfs_ialloc_ag_alloc(
 	else
 		version = XFS_DINODE_VERSION_1;
 
+	/*
+	 * Seed the new inode cluster with a random generation number. This
+	 * prevents short-term reuse of generation numbers if a chunk is
+	 * freed and then immediately reallocated. We use random numbers
+	 * rather than a linear progression to prevent the next generation
+	 * number from being easily guessable.
+	 */
+	gen = random32();
 	for (j = 0; j < nbufs; j++) {
 		/*
 		 * Get the block.
@@ -309,6 +318,7 @@ xfs_ialloc_ag_alloc(
 			free = XFS_MAKE_IPTR(args.mp, fbuf, i);
 			free->di_core.di_magic = cpu_to_be16(XFS_DINODE_MAGIC);
 			free->di_core.di_version = version;
+			free->di_core.di_gen = cpu_to_be32(gen);
 			free->di_next_unlinked = cpu_to_be32(NULLAGINO);
 			xfs_ialloc_log_di(tp, fbuf, i,
 				XFS_DI_CORE_BITS | XFS_DI_NEXT_UNLINKED);