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fuse: make fuse_direct_io() aware about AIO
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The patch implements passing "struct fuse_io_priv *io" down the stack up to
fuse_send_read/write where it is used to submit request asynchronously.
io->async==0 designates synchronous processing.

Non-trivial part of the patch is changes in fuse_direct_io(): resources
like fuse requests and user pages cannot be released immediately in async
case.

Signed-off-by: Maxim Patlasov <mpatlasov@parallels.com>
Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
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Maxim Patlasov authored and Miklos Szeredi committed Apr 17, 2013
1 parent 01e9d11 commit 36cf66e
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Showing 4 changed files with 58 additions and 21 deletions.
6 changes: 4 additions & 2 deletions fs/fuse/cuse.c
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Original file line number Diff line number Diff line change
Expand Up @@ -92,21 +92,23 @@ static ssize_t cuse_read(struct file *file, char __user *buf, size_t count,
{
loff_t pos = 0;
struct iovec iov = { .iov_base = buf, .iov_len = count };
struct fuse_io_priv io = { .async = 0, .file = file };

return fuse_direct_io(file, &iov, 1, count, &pos, 0);
return fuse_direct_io(&io, &iov, 1, count, &pos, 0);
}

static ssize_t cuse_write(struct file *file, const char __user *buf,
size_t count, loff_t *ppos)
{
loff_t pos = 0;
struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
struct fuse_io_priv io = { .async = 0, .file = file };

/*
* No locking or generic_write_checks(), the server is
* responsible for locking and sanity checks.
*/
return fuse_direct_io(file, &iov, 1, count, &pos, 1);
return fuse_direct_io(&io, &iov, 1, count, &pos, 1);
}

static int cuse_open(struct inode *inode, struct file *file)
Expand Down
2 changes: 1 addition & 1 deletion fs/fuse/dev.c
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Original file line number Diff line number Diff line change
Expand Up @@ -111,7 +111,7 @@ static void restore_sigs(sigset_t *oldset)
sigprocmask(SIG_SETMASK, oldset, NULL);
}

static void __fuse_get_request(struct fuse_req *req)
void __fuse_get_request(struct fuse_req *req)
{
atomic_inc(&req->count);
}
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64 changes: 47 additions & 17 deletions fs/fuse/file.c
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Original file line number Diff line number Diff line change
Expand Up @@ -593,14 +593,16 @@ static size_t fuse_async_req_send(struct fuse_conn *fc, struct fuse_req *req,
req->io = io;
req->end = fuse_aio_complete_req;

__fuse_get_request(req);
fuse_request_send_background(fc, req);

return num_bytes;
}

static size_t fuse_send_read(struct fuse_req *req, struct file *file,
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 fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;

Expand All @@ -611,6 +613,10 @@ static size_t fuse_send_read(struct fuse_req *req, struct file *file,
inarg->read_flags |= FUSE_READ_LOCKOWNER;
inarg->lock_owner = fuse_lock_owner_id(fc, owner);
}

if (io->async)
return fuse_async_req_send(fc, req, count, io);

fuse_request_send(fc, req);
return req->out.args[0].size;
}
Expand All @@ -631,6 +637,7 @@ static void fuse_read_update_size(struct inode *inode, loff_t size,

static int fuse_readpage(struct file *file, struct page *page)
{
struct fuse_io_priv io = { .async = 0, .file = file };
struct inode *inode = page->mapping->host;
struct fuse_conn *fc = get_fuse_conn(inode);
struct fuse_req *req;
Expand Down Expand Up @@ -663,7 +670,7 @@ static int fuse_readpage(struct file *file, struct page *page)
req->num_pages = 1;
req->pages[0] = page;
req->page_descs[0].length = count;
num_read = fuse_send_read(req, file, pos, count, NULL);
num_read = fuse_send_read(req, &io, pos, count, NULL);
err = req->out.h.error;
fuse_put_request(fc, req);

Expand Down Expand Up @@ -873,9 +880,10 @@ static void fuse_write_fill(struct fuse_req *req, struct fuse_file *ff,
req->out.args[0].value = outarg;
}

static size_t fuse_send_write(struct fuse_req *req, struct file *file,
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 fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
struct fuse_write_in *inarg = &req->misc.write.in;
Expand All @@ -886,6 +894,10 @@ static size_t fuse_send_write(struct fuse_req *req, struct file *file,
inarg->write_flags |= FUSE_WRITE_LOCKOWNER;
inarg->lock_owner = fuse_lock_owner_id(fc, owner);
}

if (io->async)
return fuse_async_req_send(fc, req, count, io);

fuse_request_send(fc, req);
return req->misc.write.out.size;
}
Expand All @@ -909,11 +921,12 @@ static size_t fuse_send_write_pages(struct fuse_req *req, struct file *file,
size_t res;
unsigned offset;
unsigned i;
struct fuse_io_priv io = { .async = 0, .file = file };

for (i = 0; i < req->num_pages; i++)
fuse_wait_on_page_writeback(inode, req->pages[i]->index);

res = fuse_send_write(req, file, pos, count, NULL);
res = fuse_send_write(req, &io, pos, count, NULL);

offset = req->page_descs[0].offset;
count = res;
Expand Down Expand Up @@ -1251,10 +1264,11 @@ static inline int fuse_iter_npages(const struct iov_iter *ii_p)
return min(npages, FUSE_MAX_PAGES_PER_REQ);
}

ssize_t fuse_direct_io(struct file *file, const struct iovec *iov,
ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
unsigned long nr_segs, size_t count, loff_t *ppos,
int write)
{
struct file *file = io->file;
struct fuse_file *ff = file->private_data;
struct fuse_conn *fc = ff->fc;
size_t nmax = write ? fc->max_write : fc->max_read;
Expand All @@ -1280,11 +1294,12 @@ ssize_t fuse_direct_io(struct file *file, const struct iovec *iov,
}

if (write)
nres = fuse_send_write(req, file, pos, nbytes, owner);
nres = fuse_send_write(req, io, pos, nbytes, owner);
else
nres = fuse_send_read(req, file, pos, nbytes, owner);
nres = fuse_send_read(req, io, pos, nbytes, owner);

fuse_release_user_pages(req, !write);
if (!io->async)
fuse_release_user_pages(req, !write);
if (req->out.h.error) {
if (!res)
res = req->out.h.error;
Expand Down Expand Up @@ -1314,16 +1329,18 @@ ssize_t fuse_direct_io(struct file *file, const struct iovec *iov,
}
EXPORT_SYMBOL_GPL(fuse_direct_io);

static ssize_t __fuse_direct_read(struct file *file, const struct iovec *iov,
static ssize_t __fuse_direct_read(struct fuse_io_priv *io,
const struct iovec *iov,
unsigned long nr_segs, loff_t *ppos)
{
ssize_t res;
struct file *file = io->file;
struct inode *inode = file_inode(file);

if (is_bad_inode(inode))
return -EIO;

res = fuse_direct_io(file, iov, nr_segs, iov_length(iov, nr_segs),
res = fuse_direct_io(io, iov, nr_segs, iov_length(iov, nr_segs),
ppos, 0);

fuse_invalidate_attr(inode);
Expand All @@ -1334,21 +1351,24 @@ static ssize_t __fuse_direct_read(struct file *file, const struct iovec *iov,
static ssize_t fuse_direct_read(struct file *file, char __user *buf,
size_t count, loff_t *ppos)
{
struct fuse_io_priv io = { .async = 0, .file = file };
struct iovec iov = { .iov_base = buf, .iov_len = count };
return __fuse_direct_read(file, &iov, 1, ppos);
return __fuse_direct_read(&io, &iov, 1, ppos);
}

static ssize_t __fuse_direct_write(struct file *file, const struct iovec *iov,
static ssize_t __fuse_direct_write(struct fuse_io_priv *io,
const struct iovec *iov,
unsigned long nr_segs, loff_t *ppos)
{
struct file *file = io->file;
struct inode *inode = file_inode(file);
size_t count = iov_length(iov, nr_segs);
ssize_t res;

res = generic_write_checks(file, ppos, &count, 0);
if (!res) {
res = fuse_direct_io(file, iov, nr_segs, count, ppos, 1);
if (res > 0)
res = fuse_direct_io(io, iov, nr_segs, count, ppos, 1);
if (!io->async && res > 0)
fuse_write_update_size(inode, *ppos);
}

Expand All @@ -1363,13 +1383,14 @@ static ssize_t fuse_direct_write(struct file *file, const char __user *buf,
struct iovec iov = { .iov_base = (void __user *)buf, .iov_len = count };
struct inode *inode = file_inode(file);
ssize_t res;
struct fuse_io_priv io = { .async = 0, .file = file };

if (is_bad_inode(inode))
return -EIO;

/* Don't allow parallel writes to the same file */
mutex_lock(&inode->i_mutex);
res = __fuse_direct_write(file, &iov, 1, ppos);
res = __fuse_direct_write(&io, &iov, 1, ppos);
mutex_unlock(&inode->i_mutex);

return res;
Expand Down Expand Up @@ -2339,14 +2360,23 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
ssize_t ret = 0;
struct file *file = NULL;
loff_t pos = 0;
struct fuse_io_priv *io;

file = iocb->ki_filp;
pos = offset;

io = kzalloc(sizeof(struct fuse_io_priv), GFP_KERNEL);
if (!io)
return -ENOMEM;

io->file = file;

if (rw == WRITE)
ret = __fuse_direct_write(file, iov, nr_segs, &pos);
ret = __fuse_direct_write(io, iov, nr_segs, &pos);
else
ret = __fuse_direct_read(file, iov, nr_segs, &pos);
ret = __fuse_direct_read(io, iov, nr_segs, &pos);

kfree(io);

return ret;
}
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7 changes: 6 additions & 1 deletion fs/fuse/fuse_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -732,6 +732,11 @@ struct fuse_req *fuse_get_req(struct fuse_conn *fc, unsigned npages);
struct fuse_req *fuse_get_req_for_background(struct fuse_conn *fc,
unsigned npages);

/*
* Increment reference count on request
*/
void __fuse_get_request(struct fuse_req *req);

/**
* Get a request, may fail with -ENOMEM,
* useful for callers who doesn't use req->pages[]
Expand Down Expand Up @@ -846,7 +851,7 @@ int fuse_reverse_inval_entry(struct super_block *sb, u64 parent_nodeid,

int fuse_do_open(struct fuse_conn *fc, u64 nodeid, struct file *file,
bool isdir);
ssize_t fuse_direct_io(struct file *file, const struct iovec *iov,
ssize_t fuse_direct_io(struct fuse_io_priv *io, const struct iovec *iov,
unsigned long nr_segs, size_t count, loff_t *ppos,
int write);
long fuse_do_ioctl(struct file *file, unsigned int cmd, unsigned long arg,
Expand Down

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