Re: [PATCH V7 17/19] famfs_fuse: Add DAX address_space_operations with noop_dirty_folio
From: Joanne Koong <joannelkoong@gmail.com>
Date: 2026-01-30 23:13:32
Also in:
linux-cxl, linux-fsdevel, lkml, nvdimm
On Sun, Jan 18, 2026 at 2:33 PM John Groves [off-list ref] wrote:
From: John Groves <John@Groves.net> Famfs is memory-backed; there is no place to write back to, and no reason to mark pages dirty at all. Signed-off-by: John Groves <john@groves.net>
Reviewed-by: Joanne Koong <joannelkoong@gmail.com>
quoted hunk ↗ jump to hunk
--- fs/fuse/famfs.c | 11 +++++++++++ 1 file changed, 11 insertions(+)diff --git a/fs/fuse/famfs.c b/fs/fuse/famfs.c index b38e92d8f381..90325bd14354 100644 --- a/fs/fuse/famfs.c +++ b/fs/fuse/famfs.c@@ -14,6 +14,7 @@ #include <linux/mm.h> #include <linux/dax.h> #include <linux/iomap.h> +#include <linux/pagemap.h> #include <linux/path.h> #include <linux/namei.h> #include <linux/string.h>@@ -39,6 +40,15 @@ static const struct dax_holder_operations famfs_fuse_dax_holder_ops = { .notify_failure = famfs_dax_notify_failure, }; +/* + * DAX address_space_operations for famfs. + * famfs doesn't need dirty tracking - writes go directly to + * memory with no writeback required. + */ +static const struct address_space_operations famfs_dax_aops = { + .dirty_folio = noop_dirty_folio, +}; + /*****************************************************************************/ /*@@ -627,6 +637,7 @@ famfs_file_init_dax( if (famfs_meta_set(fi, meta) == NULL) { i_size_write(inode, meta->file_size); inode->i_flags |= S_DAX; + inode->i_data.a_ops = &famfs_dax_aops; } else { pr_debug("%s: file already had metadata\n", __func__); __famfs_meta_free(meta); --2.52.0