btrfs: fix upper limit for max_inline for page size 64K

The mount option max_inline ranges from 0 to the sectorsize (which is
now equal to page size). But we parse the mount options too early and
before the actual sectorsize is read from the superblock. So the upper
limit of max_inline is unaware of the actual sectorsize and is limited
by the temporary sectorsize 4096, even on a system where the default
sectorsize is 64K.

Fix this by reading the superblock sectorsize before the mount option
parse.
Reported-by: NAlexander Tsvetkov <alexander.tsvetkov@oracle.com>
CC: stable@vger.kernel.org # 5.4+
Signed-off-by: NAnand Jain <anand.jain@oracle.com>
Reviewed-by: NDavid Sterba <dsterba@suse.com>
Signed-off-by: NDavid Sterba <dsterba@suse.com>

fs/btrfs/disk-io.c

@@ -3314,6 +3314,30 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	 */
 	fs_info->compress_type = BTRFS_COMPRESS_ZLIB;
 
+	/*
+	 * Flag our filesystem as having big metadata blocks if they are bigger
+	 * than the page size.
+	 */
+	if (btrfs_super_nodesize(disk_super) > PAGE_SIZE) {
+		if (!(features & BTRFS_FEATURE_INCOMPAT_BIG_METADATA))
+			btrfs_info(fs_info,
+				"flagging fs with big metadata feature");
+		features |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
+	}
+
+	/* Set up fs_info before parsing mount options */
+	nodesize = btrfs_super_nodesize(disk_super);
+	sectorsize = btrfs_super_sectorsize(disk_super);
+	stripesize = sectorsize;
+	fs_info->dirty_metadata_batch = nodesize * (1 + ilog2(nr_cpu_ids));
+	fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
+
+	fs_info->nodesize = nodesize;
+	fs_info->sectorsize = sectorsize;
+	fs_info->sectorsize_bits = ilog2(sectorsize);
+	fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size;
+	fs_info->stripesize = stripesize;
+
 	ret = btrfs_parse_options(fs_info, options, sb->s_flags);
 	if (ret) {
 		err = ret;
@@ -3340,30 +3364,6 @@ int __cold open_ctree(struct super_block *sb, struct btrfs_fs_devices *fs_device
 	if (features & BTRFS_FEATURE_INCOMPAT_SKINNY_METADATA)
 		btrfs_info(fs_info, "has skinny extents");
 
-	/*
-	 * flag our filesystem as having big metadata blocks if
-	 * they are bigger than the page size
-	 */
-	if (btrfs_super_nodesize(disk_super) > PAGE_SIZE) {
-		if (!(features & BTRFS_FEATURE_INCOMPAT_BIG_METADATA))
-			btrfs_info(fs_info,
-				"flagging fs with big metadata feature");
-		features |= BTRFS_FEATURE_INCOMPAT_BIG_METADATA;
-	}
-
-	nodesize = btrfs_super_nodesize(disk_super);
-	sectorsize = btrfs_super_sectorsize(disk_super);
-	stripesize = sectorsize;
-	fs_info->dirty_metadata_batch = nodesize * (1 + ilog2(nr_cpu_ids));
-	fs_info->delalloc_batch = sectorsize * 512 * (1 + ilog2(nr_cpu_ids));
-
-	/* Cache block sizes */
-	fs_info->nodesize = nodesize;
-	fs_info->sectorsize = sectorsize;
-	fs_info->sectorsize_bits = ilog2(sectorsize);
-	fs_info->csums_per_leaf = BTRFS_MAX_ITEM_SIZE(fs_info) / fs_info->csum_size;
-	fs_info->stripesize = stripesize;
-
 	/*
 	 * mixed block groups end up with duplicate but slightly offset
 	 * extent buffers for the same range.  It leads to corruptions