ext4: Add fallback for find_group_flex

(cherry picked from commit 05bf9e839d9de4e8a094274a0a2fd07beb47eaf1)

This is a workaround for find_group_flex() which badly needs to be
replaced.  One of its problems (besides ignoring the Orlov algorithm)
is that it is a bit hyperactive about returning failure under
suspicious circumstances.  This can lead to spurious ENOSPC failures
even when there are inodes still available.

Work around this for now by retrying the search using
find_group_other() if find_group_flex() returns -1.  If
find_group_other() succeeds when find_group_flex() has failed, log a
warning message.

A better block/inode allocator that will fix this problem for real has
been queued up for the next merge window.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/fs/ext4/ialloc.c b/fs/ext4/ialloc.c
index b994854dae6261774e1db226a5997c7caf318dd6..cce841fe44909226b7a1f652141176f9482cb27b 100644 (file)
--- a/fs/ext4/ialloc.c
+++ b/fs/ext4/ialloc.c
@@ -702,6 +702,13 @@ struct inode *ext4_new_inode(handle_t *handle, struct inode * dir, int mode)
 
        if (sbi->s_log_groups_per_flex) {
                ret2 = find_group_flex(sb, dir, &group);
+               if (ret2 == -1) {
+                       ret2 = find_group_other(sb, dir, &group);
+                       if (ret2 == 0 && printk_ratelimit())
+                               printk(KERN_NOTICE "ext4: find_group_flex "
+                                      "failed, fallback succeeded dir %lu\n",
+                                      dir->i_ino);
+               }
                goto got_group;
        }