On Mon, Aug 07, 2017 at 11:46:45AM -0400, nate@xxxxxxxxxx wrote:
> From: Vitaly Zolotusky <vitaly@xxxxxxxxx>
>
> If the IOCB_DSYNC flag is set a sync is not being performed by
> fuse_file_write_iter. Honor IOCB_DSYNC by invoking generic_write_sync
> when a write has been successful. generic_write_sync appropriatly syncs
> the data which was written when IOCB_DSYNC flag is set.
I fear that sending a separate FSYNC request after each write might be a
performance regression for some use cases. Also we already have a way to
communicate dsync/sync to the filesystem on writes: the flags field of
fuse_write_in. Following patch updates the flags sent along with the WRITE
request to correctly reflect the sync state in the kiocb.
Please test.
Thanks,
Miklos
---
From: Miklos Szeredi <mszeredi@xxxxxxxxxx>
Subject: fuse: honor iocb sync flags on write
If the IOCB_DSYNC flag is set a sync is not being performed by
fuse_file_write_iter.
Honor IOCB_DSYNC/IOCB_SYNC by setting O_DYSNC/O_SYNC respectively in the
flags filed of the write request.
We don't need to sync data or metadata, since fuse_perform_write() does
write-through and the filesystem is responsible for updating file times.
Original patch by Vitaly Zolotusky.
Reported-by: Nate Clark <nate@xxxxxxxxxx>
Cc: Vitaly Zolotusky <vitaly@xxxxxxxxx>.
Signed-off-by: Miklos Szeredi <mszeredi@xxxxxxxxxx>
---
fs/fuse/cuse.c | 4 ++--
fs/fuse/file.c | 41 ++++++++++++++++++++++++-----------------
fs/fuse/fuse_i.h | 5 ++---
3 files changed, 28 insertions(+), 22 deletions(-)
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -645,7 +645,7 @@ static size_t fuse_async_req_send(struct
static size_t fuse_send_read(struct fuse_req *req, struct fuse_io_priv *io,
loff_t pos, size_t count, fl_owner_t owner)
{
- struct file *file = io->file;
+ struct file *file = io->iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
@@ -707,7 +707,8 @@ static void fuse_short_read(struct fuse_
static int fuse_do_readpage(struct file *file, struct page *page)
{
- struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(file);
+ struct kiocb iocb;
+ struct fuse_io_priv io;
struct inode *inode = page->mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
@@ -735,6 +736,8 @@ static int fuse_do_readpage(struct file
req->num_pages = 1;
req->pages[0] = page;
req->page_descs[0].length = count;
+ init_sync_kiocb(&iocb, file);
+ io = (struct fuse_io_priv) FUSE_IO_PRIV_SYNC(&iocb);
num_read = fuse_send_read(req, &io, pos, count, NULL);
err = req->out.h.error;
@@ -957,13 +960,18 @@ static void fuse_write_fill(struct fuse_
static size_t fuse_send_write(struct fuse_req *req, struct fuse_io_priv *io,
loff_t pos, size_t count, fl_owner_t owner)
{
- struct file *file = io->file;
+ struct kiocb *iocb = io->iocb;
+ struct file *file = iocb->ki_filp;
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
struct fuse_write_in *inarg = &req->misc.write.in;
fuse_write_fill(req, ff, pos, count);
inarg->flags = file->f_flags;
+ if (iocb->ki_flags & IOCB_DSYNC)
+ inarg->flags |= O_DSYNC;
+ if (iocb->ki_flags & IOCB_SYNC)
+ inarg->flags |= O_SYNC;
if (owner != NULL) {
inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
inarg->lock_owner = fuse_lock_owner_id(fc, owner);
@@ -993,14 +1001,14 @@ bool fuse_write_update_size(struct inode
return ret;
}
-static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
+static size_t fuse_send_write_pages(struct fuse_req *req, struct kiocb *iocb,
struct inode *inode, loff_t pos,
size_t count)
{
size_t res;
unsigned offset;
unsigned i;
- struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(file);
+ struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
for (i = 0; i < req->num_pages; i++)
fuse_wait_on_page_writeback(inode, req->pages[i]->index);
@@ -1100,7 +1108,7 @@ static inline unsigned fuse_wr_pages(lof
FUSE_MAX_PAGES_PER_REQ);
}
-static ssize_t fuse_perform_write(struct file *file,
+static ssize_t fuse_perform_write(struct kiocb *iocb,
struct address_space *mapping,
struct iov_iter *ii, loff_t pos)
{
@@ -1133,7 +1141,7 @@ static ssize_t fuse_perform_write(struct
} else {
size_t num_written;
- num_written = fuse_send_write_pages(req, file, inode,
+ num_written = fuse_send_write_pages(req, iocb, inode,
pos, count);
err = req->out.h.error;
if (!err) {
@@ -1201,7 +1209,7 @@ static ssize_t fuse_file_write_iter(stru
pos += written;
- written_buffered = fuse_perform_write(file, mapping, from, pos);
+ written_buffered = fuse_perform_write(iocb, mapping, from, pos);
if (written_buffered < 0) {
err = written_buffered;
goto out;
@@ -1220,13 +1228,15 @@ static ssize_t fuse_file_write_iter(stru
written += written_buffered;
iocb->ki_pos = pos + written_buffered;
} else {
- written = fuse_perform_write(file, mapping, from, iocb->ki_pos);
+ written = fuse_perform_write(iocb, mapping, from, iocb->ki_pos);
if (written >= 0)
iocb->ki_pos += written;
}
out:
current->backing_dev_info = NULL;
inode_unlock(inode);
+ if (written > 0)
+ written = generic_write_sync(iocb, written);
return written ? written : err;
}
@@ -1317,7 +1327,7 @@ ssize_t fuse_direct_io(struct fuse_io_pr
{
int write = flags & FUSE_DIO_WRITE;
int cuse = flags & FUSE_DIO_CUSE;
- struct file *file = io->file;
+ struct file *file = io->iocb->ki_filp;
struct inode *inode = file->f_mapping->host;
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
@@ -1399,8 +1409,7 @@ static ssize_t __fuse_direct_read(struct
loff_t *ppos)
{
ssize_t res;
- struct file *file = io->file;
- struct inode *inode = file_inode(file);
+ struct inode *inode = file_inode(io->iocb->ki_filp);
if (is_bad_inode(inode))
return -EIO;
@@ -1414,15 +1423,14 @@ static ssize_t __fuse_direct_read(struct
static ssize_t fuse_direct_read_iter(struct kiocb *iocb, struct iov_iter *to)
{
- struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb->ki_filp);
+ struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
return __fuse_direct_read(&io, to, &iocb->ki_pos);
}
static ssize_t fuse_direct_write_iter(struct kiocb *iocb, struct iov_iter *from)
{
- struct file *file = iocb->ki_filp;
- struct inode *inode = file_inode(file);
- struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(file);
+ struct inode *inode = file_inode(iocb->ki_filp);
+ struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(iocb);
ssize_t res;
if (is_bad_inode(inode))
@@ -2871,7 +2879,6 @@ fuse_direct_IO(struct kiocb *iocb, struc
io->offset = offset;
io->write = (iov_iter_rw(iter) == WRITE);
io->err = 0;
- io->file = file;
/*
* By default, we want to optimize all I/Os with async request
* submission to the client filesystem if supported.
--- a/fs/fuse/cuse.c
+++ b/fs/fuse/cuse.c
@@ -90,7 +90,7 @@ static struct list_head *cuse_conntbl_he
static ssize_t cuse_read_iter(struct kiocb *kiocb, struct iov_iter *to)
{
- struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(kiocb->ki_filp);
+ struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(kiocb);
loff_t pos = 0;
return fuse_direct_io(&io, to, &pos, FUSE_DIO_CUSE);
@@ -98,7 +98,7 @@ static ssize_t cuse_read_iter(struct kio
static ssize_t cuse_write_iter(struct kiocb *kiocb, struct iov_iter *from)
{
- struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(kiocb->ki_filp);
+ struct fuse_io_priv io = FUSE_IO_PRIV_SYNC(kiocb);
loff_t pos = 0;
/*
* No locking or generic_write_checks(), the server is
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -252,16 +252,15 @@ struct fuse_io_priv {
bool should_dirty;
int err;
struct kiocb *iocb;
- struct file *file;
struct completion *done;
bool blocking;
};
-#define FUSE_IO_PRIV_SYNC(f) \
+#define FUSE_IO_PRIV_SYNC(i) \
{ \
.refcnt = KREF_INIT(1), \
.async = 0, \
- .file = f, \
+ .iocb = i, \
}
/**
