ext4: check dioread_nolock on remount

commit 261cb20cb2f0737a247aaf08dff7eb065e3e5b66 upstream.

Currently we allow enabling dioread_nolock mount option on remount for
filesystems where blocksize < PAGE_CACHE_SIZE.  This isn't really
supported so fix the bug by moving the check for blocksize !=
PAGE_CACHE_SIZE into parse_options(). Change the original PAGE_SIZE to
PAGE_CACHE_SIZE along the way because that's what we are really
interested in.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Reviewed-by: Eric Sandeen <sandeen@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index f8d5fcef92bd9b7599776d3d609d4c7f0f947f67..4e03de4da83f78b3a07babde1b58a6a5a7c2bf97 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -1942,6 +1942,16 @@ set_qf_format:
                }
        }
 #endif
+       if (test_opt(sb, DIOREAD_NOLOCK)) {
+               int blocksize =
+                       BLOCK_SIZE << le32_to_cpu(sbi->s_es->s_log_block_size);
+
+               if (blocksize < PAGE_CACHE_SIZE) {
+                       ext4_msg(sb, KERN_ERR, "can't mount with "
+                                "dioread_nolock if block size != PAGE_SIZE");
+                       return 0;
+               }
+       }
        return 1;
 }
 
@@ -3367,15 +3377,6 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
                        clear_opt(sb, DELALLOC);
        }
 
-       blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
-       if (test_opt(sb, DIOREAD_NOLOCK)) {
-               if (blocksize < PAGE_SIZE) {
-                       ext4_msg(sb, KERN_ERR, "can't mount with "
-                                "dioread_nolock if block size != PAGE_SIZE");
-                       goto failed_mount;
-               }
-       }
-
        sb->s_flags = (sb->s_flags & ~MS_POSIXACL) |
                (test_opt(sb, POSIX_ACL) ? MS_POSIXACL : 0);
 
@@ -3417,6 +3418,7 @@ static int ext4_fill_super(struct super_block *sb, void *data, int silent)
        if (!ext4_feature_set_ok(sb, (sb->s_flags & MS_RDONLY)))
                goto failed_mount;
 
+       blocksize = BLOCK_SIZE << le32_to_cpu(es->s_log_block_size);
        if (blocksize < EXT4_MIN_BLOCK_SIZE ||
            blocksize > EXT4_MAX_BLOCK_SIZE) {
                ext4_msg(sb, KERN_ERR,