After reading a bitmap block for i-nodes or blocks, recheck the count of

free i-nodes or blocks to handle a race where another thread might have
allocated the last i-node or block while we were waiting for the buffer.

Tested by:	dougb

1 files changed, 18 insertions, 0 deletions

diff --git a/sys/fs/ext2fs/ext2_alloc.c b/sys/fs/ext2fs/ext2_alloc.c
index baab4a5677d1..7abfe2b2bf09 100644
--- a/sys/fs/ext2fs/ext2_alloc.c
+++ b/sys/fs/ext2fs/ext2_alloc.c
@@ -650,6 +650,15 @@ ext2_alloccg(struct inode *ip, int cg, daddr_t bpref, int size)
 		EXT2_LOCK(ump);
 		return (0);
 	}
+	if (fs->e2fs_gd[cg].ext2bgd_nbfree == 0) {
+		/*
+		 * Another thread allocated the last block in this
+		 * group while we were waiting for the buffer.
+		 */
+		brelse(bp);
+		EXT2_LOCK(ump);
+		return (0);
+	}
 	bbp = (char *)bp->b_data;
 
 	if (dtog(fs, bpref) != cg)
@@ -776,6 +785,15 @@ ext2_nodealloccg(struct inode *ip, int cg, daddr_t ipref, int mode)
 		EXT2_LOCK(ump);
 		return (0);
 	}
+	if (fs->e2fs_gd[cg].ext2bgd_nifree == 0) {
+		/*
+		 * Another thread allocated the last i-node in this
+		 * group while we were waiting for the buffer.
+		 */
+		brelse(bp);
+		EXT2_LOCK(ump);
+		return (0);
+	}
 	ibp = (char *)bp->b_data;
 	if (ipref) {
 		ipref %= fs->e2fs->e2fs_ipg;