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Fri, 07 Aug 2026 17:35:54 -0700 (PDT) Received: from pop-os.attlocal.net ([2600:1700:6476:1430:891e:7b31:87a7:701f]) by smtp.gmail.com with ESMTPSA id 00721157ae682-823f577c580sm19024407b3.27.2026.08.07.17.35.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 07 Aug 2026 17:35:53 -0700 (PDT) From: Viacheslav Dubeyko To: konishi.ryusuke@gmail.com, hch@lst.de Cc: linux-nilfs@vger.kernel.org, linux-fsdevel@vger.kernel.org, lilinmao@kylinos.cn, Viacheslav Dubeyko Subject: [PATCH v2 2/2] nilfs2: switch O_DIRECT to iomap based operations Date: Fri, 7 Aug 2026 17:35:23 -0700 Message-ID: <20260808003523.2760509-3-slava@dubeyko.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260808003523.2760509-1-slava@dubeyko.com> References: <20260808003523.2760509-1-slava@dubeyko.com> Precedence: bulk X-Mailing-List: linux-nilfs@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit The patch eliminates blockdev_direct_IO() from nilfs2 entirely: - nilfs_file_open() now sets FMODE_CAN_ODIRECT explicitly, since permission to open the file O_DIRECT was previously implied by aops->direct_IO being non-NULL. - nilfs_file_read_iter() dispatches O_DIRECT reads to iomap_dio_rw() using nilfs_iomap_ops; everything else still goes through generic_file_read_iter() as before. - nilfs_file_write_iter() strips IOCB_DIRECT and falls through to generic_file_write_iter()'s ordinary buffered path. NILFS2 cannot perform true direct I/O writes: new blocks are delay-allocated and only given a real disk address by the segment constructor, which works on buffer_head lists, not iomap. This reproduces today's actual behavior: the old nilfs_direct_IO() already just returned 0 for WRITE. - nilfs_direct_IO() and the .direct_IO callback on nilfs_aops are removed. - drop the unnecessary "select LEGACY_DIRECT_IO" from Kconfig in favor of "select FS_IOMAP". Signed-off-by: Viacheslav Dubeyko cc: Christoph Hellwig cc: Ryusuke Konishi cc: linux-nilfs@vger.kernel.org cc: linux-fsdevel@vger.kernel.org --- fs/nilfs2/Kconfig | 2 +- fs/nilfs2/file.c | 40 +++++++++++++++++++++++++++++++++++++--- fs/nilfs2/inode.c | 13 ------------- 3 files changed, 38 insertions(+), 17 deletions(-) diff --git a/fs/nilfs2/Kconfig b/fs/nilfs2/Kconfig index 7dae168e346e..0a5ace60e6ab 100644 --- a/fs/nilfs2/Kconfig +++ b/fs/nilfs2/Kconfig @@ -3,7 +3,7 @@ config NILFS2_FS tristate "NILFS2 file system support" select BUFFER_HEAD select CRC32 - select LEGACY_DIRECT_IO + select FS_IOMAP help NILFS2 is a log-structured file system (LFS) supporting continuous snapshotting. In addition to versioning capability of the entire diff --git a/fs/nilfs2/file.c b/fs/nilfs2/file.c index f93b68c4877c..ad2e87c049c9 100644 --- a/fs/nilfs2/file.c +++ b/fs/nilfs2/file.c @@ -10,9 +10,12 @@ #include #include #include +#include +#include #include #include "nilfs.h" #include "segment.h" +#include "iomap.h" int nilfs_sync_file(struct file *file, loff_t start, loff_t end, int datasync) { @@ -133,20 +136,51 @@ static int nilfs_file_mmap_prepare(struct vm_area_desc *desc) return 0; } +static int nilfs_file_open(struct inode *inode, struct file *file) +{ + file->f_mode |= FMODE_CAN_ODIRECT; + return generic_file_open(inode, file); +} + +static ssize_t nilfs_file_read_iter(struct kiocb *iocb, struct iov_iter *to) +{ + if (iocb->ki_flags & IOCB_DIRECT) { + return iomap_dio_rw(iocb, to, &nilfs_iomap_ops, + NULL, 0, NULL, 0); + } else + return generic_file_read_iter(iocb, to); +} + +static ssize_t nilfs_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + /* + * NILFS2 cannot perform true direct I/O writes: new blocks are + * delay-allocated and are only given a real disk address when + * the segment constructor writes them out as part of a log, + * which works directly on buffer_head lists rather than + * through iomap. Fall back to the ordinary buffered write path + * for O_DIRECT writes. + */ + if (iocb->ki_flags & IOCB_DIRECT) + iocb->ki_flags &= ~IOCB_DIRECT; + + return generic_file_write_iter(iocb, from); +} + /* * We have mostly NULL's here: the current defaults are ok for * the nilfs filesystem. */ const struct file_operations nilfs_file_operations = { .llseek = generic_file_llseek, - .read_iter = generic_file_read_iter, - .write_iter = generic_file_write_iter, + .read_iter = nilfs_file_read_iter, + .write_iter = nilfs_file_write_iter, .unlocked_ioctl = nilfs_ioctl, #ifdef CONFIG_COMPAT .compat_ioctl = nilfs_compat_ioctl, #endif /* CONFIG_COMPAT */ .mmap_prepare = nilfs_file_mmap_prepare, - .open = generic_file_open, + .open = nilfs_file_open, /* .release = nilfs_release_file, */ .fsync = nilfs_sync_file, .splice_read = filemap_splice_read, diff --git a/fs/nilfs2/inode.c b/fs/nilfs2/inode.c index 51f7e125a311..f4a9d9ea9c3f 100644 --- a/fs/nilfs2/inode.c +++ b/fs/nilfs2/inode.c @@ -257,18 +257,6 @@ static int nilfs_write_end(const struct kiocb *iocb, return err ? : copied; } -static ssize_t -nilfs_direct_IO(struct kiocb *iocb, struct iov_iter *iter) -{ - struct inode *inode = file_inode(iocb->ki_filp); - - if (iov_iter_rw(iter) == WRITE) - return 0; - - /* Needs synchronization with the cleaner */ - return blockdev_direct_IO(iocb, inode, iter, nilfs_get_block); -} - const struct address_space_operations nilfs_aops = { .read_folio = nilfs_read_folio, .writepages = nilfs_writepages, @@ -277,7 +265,6 @@ const struct address_space_operations nilfs_aops = { .write_begin = nilfs_write_begin, .write_end = nilfs_write_end, .invalidate_folio = block_invalidate_folio, - .direct_IO = nilfs_direct_IO, .migrate_folio = buffer_migrate_folio_norefs, .is_partially_uptodate = block_is_partially_uptodate, }; -- 2.43.0