ext4: enable block size larger than page size

Since block device (See commit 3c20917120ce ("block/bdev: enable large
folio support for large logical block sizes")) and page cache (See commit
ab95d23bab220ef8 ("filemap: allocate mapping_min_order folios in the page
cache")) has the ability to have a minimum order when allocating folio,
and ext4 has supported large folio in commit 7ac67301e82f ("ext4: enable
large folio for regular file"), now add support for block_size > PAGE_SIZE
in ext4.

set_blocksize() -> bdev_validate_blocksize() already validates the block
size, so ext4_load_super() does not need to perform additional checks.
Here we only need to add the FS_LBS bit to fs_flags.

In addition, block sizes larger than the page size are currently supported
only when CONFIG_TRANSPARENT_HUGEPAGE is enabled. To make this explicit,
a blocksize_gt_pagesize entry has been added under /sys/fs/ext4/feature/,
indicating whether bs > ps is supported. This allows mke2fs to check the
interface and determine whether a warning should be issued when formatting
a filesystem with block size larger than the page size.

Suggested-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Zhang Yi <yi.zhang@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Pankaj Raghav <p.raghav@samsung.com>
Reviewed-by: Ojaswin Mujoo <ojaswin@linux.ibm.com>
Message-ID: <20251121090654.631996-25-libaokun@huaweicloud.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>

diff --git a/fs/ext4/super.c b/fs/ext4/super.c
index 3d03a6eb0ea0c50cf5f6e0a7342b4d5350004811..87205660c5d026c3a73a64788757c288a03eaa5f 100644 (file)
--- a/fs/ext4/super.c
+++ b/fs/ext4/super.c
@@ -7453,7 +7453,8 @@ static struct file_system_type ext4_fs_type = {
        .init_fs_context        = ext4_init_fs_context,
        .parameters             = ext4_param_specs,
        .kill_sb                = ext4_kill_sb,
-       .fs_flags               = FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME,
+       .fs_flags               = FS_REQUIRES_DEV | FS_ALLOW_IDMAP | FS_MGTIME |
+                                 FS_LBS,
 };
 MODULE_ALIAS_FS("ext4");
 

diff --git a/fs/ext4/sysfs.c b/fs/ext4/sysfs.c
index 987bd00f916af25b23c836fc64d49b169a211cef..0018e09b867ec3ccd6e1bae52400ff8fcd231661 100644 (file)
--- a/fs/ext4/sysfs.c
+++ b/fs/ext4/sysfs.c
@@ -332,6 +332,9 @@ EXT4_ATTR_FEATURE(fast_commit);
 #if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
 EXT4_ATTR_FEATURE(encrypted_casefold);
 #endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+EXT4_ATTR_FEATURE(blocksize_gt_pagesize);
+#endif
 
 static struct attribute *ext4_feat_attrs[] = {
        ATTR_LIST(lazy_itable_init),
@@ -351,6 +354,9 @@ static struct attribute *ext4_feat_attrs[] = {
        ATTR_LIST(fast_commit),
 #if IS_ENABLED(CONFIG_UNICODE) && defined(CONFIG_FS_ENCRYPTION)
        ATTR_LIST(encrypted_casefold),
+#endif
+#ifdef CONFIG_TRANSPARENT_HUGEPAGE
+       ATTR_LIST(blocksize_gt_pagesize),
 #endif
        NULL,
 };