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Message-Id: <20230519074047.1739879-17-dhowells@redhat.com>
Date: Fri, 19 May 2023 08:40:31 +0100
From: David Howells <dhowells@...hat.com>
To: Jens Axboe <axboe@...nel.dk>, Al Viro <viro@...iv.linux.org.uk>,
Christoph Hellwig <hch@...radead.org>
Cc: David Howells <dhowells@...hat.com>,
Matthew Wilcox <willy@...radead.org>, Jan Kara <jack@...e.cz>,
Jeff Layton <jlayton@...nel.org>,
David Hildenbrand <david@...hat.com>,
Jason Gunthorpe <jgg@...dia.com>,
Logan Gunthorpe <logang@...tatee.com>,
Hillf Danton <hdanton@...a.com>,
Christian Brauner <brauner@...nel.org>,
Linus Torvalds <torvalds@...ux-foundation.org>,
linux-fsdevel@...r.kernel.org, linux-block@...r.kernel.org,
linux-kernel@...r.kernel.org, linux-mm@...ck.org,
Christoph Hellwig <hch@....de>,
Jaegeuk Kim <jaegeuk@...nel.org>, Chao Yu <chao@...nel.org>,
linux-f2fs-devel@...ts.sourceforge.net
Subject: [PATCH v20 16/32] f2fs: Provide a splice-read stub
Provide a splice_read stub for f2fs. This does some checks and tracing
before proceeding and will switch from direct-I/O to buffered I/O if forced
or if misaligned. It also updates the iostats after doing a buffered I/O.
[Note: I wonder if I should only do the tracing if I call
filemap_splice_read() as direct_splice_read() will call
f2fs_file_read_iter().]
Signed-off-by: David Howells <dhowells@...hat.com>
cc: Christoph Hellwig <hch@....de>
cc: Al Viro <viro@...iv.linux.org.uk>
cc: Jens Axboe <axboe@...nel.dk>
cc: Jaegeuk Kim <jaegeuk@...nel.org>
cc: Chao Yu <chao@...nel.org>
cc: linux-f2fs-devel@...ts.sourceforge.net
cc: linux-fsdevel@...r.kernel.org
cc: linux-block@...r.kernel.org
cc: linux-mm@...ck.org
---
fs/f2fs/file.c | 68 ++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 60 insertions(+), 8 deletions(-)
diff --git a/fs/f2fs/file.c b/fs/f2fs/file.c
index 5ac53d2627d2..3723387f4a87 100644
--- a/fs/f2fs/file.c
+++ b/fs/f2fs/file.c
@@ -4367,22 +4367,23 @@ static ssize_t f2fs_dio_read_iter(struct kiocb *iocb, struct iov_iter *to)
return ret;
}
-static void f2fs_trace_rw_file_path(struct kiocb *iocb, size_t count, int rw)
+static void f2fs_trace_rw_file_path(struct file *file, loff_t pos, size_t count,
+ int rw)
{
- struct inode *inode = file_inode(iocb->ki_filp);
+ struct inode *inode = file_inode(file);
char *buf, *path;
buf = f2fs_getname(F2FS_I_SB(inode));
if (!buf)
return;
- path = dentry_path_raw(file_dentry(iocb->ki_filp), buf, PATH_MAX);
+ path = dentry_path_raw(file_dentry(file), buf, PATH_MAX);
if (IS_ERR(path))
goto free_buf;
if (rw == WRITE)
- trace_f2fs_datawrite_start(inode, iocb->ki_pos, count,
+ trace_f2fs_datawrite_start(inode, pos, count,
current->pid, path, current->comm);
else
- trace_f2fs_dataread_start(inode, iocb->ki_pos, count,
+ trace_f2fs_dataread_start(inode, pos, count,
current->pid, path, current->comm);
free_buf:
f2fs_putname(buf);
@@ -4398,7 +4399,8 @@ static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
return -EOPNOTSUPP;
if (trace_f2fs_dataread_start_enabled())
- f2fs_trace_rw_file_path(iocb, iov_iter_count(to), READ);
+ f2fs_trace_rw_file_path(iocb->ki_filp, iocb->ki_pos,
+ iov_iter_count(to), READ);
if (f2fs_should_use_dio(inode, iocb, to)) {
ret = f2fs_dio_read_iter(iocb, to);
@@ -4413,6 +4415,55 @@ static ssize_t f2fs_file_read_iter(struct kiocb *iocb, struct iov_iter *to)
return ret;
}
+static ssize_t f2fs_file_splice_read(struct file *in, loff_t *ppos,
+ struct pipe_inode_info *pipe,
+ size_t len, unsigned int flags)
+{
+ struct inode *inode = file_inode(in);
+ const loff_t pos = *ppos;
+ ssize_t ret;
+
+ if (!f2fs_is_compress_backend_ready(inode))
+ return -EOPNOTSUPP;
+
+ if (trace_f2fs_dataread_start_enabled())
+ f2fs_trace_rw_file_path(in, pos, len, READ);
+
+ if (in->f_flags & O_DIRECT) {
+ if (f2fs_force_buffered_io(inode, READ))
+ goto buffered;
+
+ /*
+ * Direct I/O not aligned to the disk's logical_block_size will
+ * be attempted, but will fail with -EINVAL.
+ *
+ * f2fs additionally requires that direct I/O be aligned to the
+ * filesystem block size, which is often a stricter
+ * requirement. However, f2fs traditionally falls back to
+ * buffered I/O on requests that are logical_block_size-aligned
+ * but not fs-block aligned.
+ *
+ * The below logic implements this behavior.
+ */
+ if (!IS_ALIGNED(pos, i_blocksize(inode)) &&
+ IS_ALIGNED(pos, bdev_logical_block_size(inode->i_sb->s_bdev)))
+ goto buffered;
+ ret = direct_splice_read(in, ppos, pipe, len, flags);
+ goto done;
+ }
+
+buffered:
+ ret = filemap_splice_read(in, ppos, pipe, len, flags);
+ if (ret > 0)
+ f2fs_update_iostat(F2FS_I_SB(inode), inode,
+ APP_BUFFERED_READ_IO, ret);
+
+done:
+ if (trace_f2fs_dataread_end_enabled())
+ trace_f2fs_dataread_end(inode, pos, ret);
+ return ret;
+}
+
static ssize_t f2fs_write_checks(struct kiocb *iocb, struct iov_iter *from)
{
struct file *file = iocb->ki_filp;
@@ -4714,7 +4765,8 @@ static ssize_t f2fs_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
ret = preallocated;
} else {
if (trace_f2fs_datawrite_start_enabled())
- f2fs_trace_rw_file_path(iocb, orig_count, WRITE);
+ f2fs_trace_rw_file_path(iocb->ki_filp, iocb->ki_pos,
+ orig_count, WRITE);
/* Do the actual write. */
ret = dio ?
@@ -4919,7 +4971,7 @@ const struct file_operations f2fs_file_operations = {
#ifdef CONFIG_COMPAT
.compat_ioctl = f2fs_compat_ioctl,
#endif
- .splice_read = generic_file_splice_read,
+ .splice_read = f2fs_file_splice_read,
.splice_write = iter_file_splice_write,
.fadvise = f2fs_file_fadvise,
};
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