[PATCH v3 4/4] ext4: support uncached buffered I/O
From: 陈涛涛 Taotao Chen <hidden>
Date: 2025-06-27 11:03:37
Also in:
dri-devel, intel-gfx, linux-block, linux-ext4, linux-fsdevel, linux-mm, lkml
Subsystem:
ext4 file system, filesystems (vfs and infrastructure), the rest · Maintainers:
"Theodore Ts'o", Alexander Viro, Christian Brauner, Linus Torvalds
From: Taotao Chen <redacted> Set FOP_DONTCACHE in ext4_file_operations to declare support for uncached buffered I/O. To handle this flag, add processing for IOCB_DONTCACHE in ext4_write_begin() and ext4_da_write_begin() by passing FGP_DONTCACHE to page cache lookups. Part of a series refactoring address_space_operations write_begin and write_end callbacks to use struct kiocb for passing write context and flags. Signed-off-by: Taotao Chen <redacted> --- fs/ext4/file.c | 3 ++- fs/ext4/inode.c | 6 ++++++ 2 files changed, 8 insertions(+), 1 deletion(-)
diff --git a/fs/ext4/file.c b/fs/ext4/file.c
index 21df81347147..274b41a476c8 100644
--- a/fs/ext4/file.c
+++ b/fs/ext4/file.c@@ -977,7 +977,8 @@ const struct file_operations ext4_file_operations = { .splice_write = iter_file_splice_write, .fallocate = ext4_fallocate, .fop_flags = FOP_MMAP_SYNC | FOP_BUFFER_RASYNC | - FOP_DIO_PARALLEL_WRITE, + FOP_DIO_PARALLEL_WRITE | + FOP_DONTCACHE, }; const struct inode_operations ext4_file_inode_operations = {
diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 08c10200d6fe..639e2e231c4b 100644
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c@@ -1270,6 +1270,9 @@ static int ext4_write_begin(const struct kiocb *iocb, if (unlikely(ret)) return ret; + if (iocb->ki_flags & IOCB_DONTCACHE) + fgp |= FGP_DONTCACHE; + trace_ext4_write_begin(inode, pos, len); /* * Reserve one block more for addition to orphan list in case
@@ -3068,6 +3071,9 @@ static int ext4_da_write_begin(const struct kiocb *iocb, return 0; } + if (iocb->ki_flags & IOCB_DONTCACHE) + fgp |= FGP_DONTCACHE; + retry: fgp |= fgf_set_order(len); folio = __filemap_get_folio(mapping, index, fgp,
--
2.34.1