ext4: increase wait time needed before reuse of deleted inode numbers

[ Upstream commit a17a9d93 ]

Current wait times have proven to be too short to protect against inode
reuses that lead to metadata inconsistencies.

Now that we will retry the inode allocation if we can't find any
recently deleted inodes, it's a lot safer to increase the recently
deleted time from 5 seconds to a minute.

Link: https://lore.kernel.org/r/20200414023925.273867-1-tytso@mit.edu
Google-Bug-Id: 36602237
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Sasha Levin <sashal@kernel.org>

fs/ext4/ialloc.c

@@ -665,7 +665,7 @@ static int find_group_other(struct super_block *sb, struct inode *parent,
  * block has been written back to disk.  (Yes, these values are
  * somewhat arbitrary...)
  */
-#define RECENTCY_MIN	5
+#define RECENTCY_MIN	60
 #define RECENTCY_DIRTY	300
 
 static int recently_deleted(struct super_block *sb, ext4_group_t group, int ino)