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fuse: req use bitops
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Finer grained locking will mean there's no single lock to protect
modification of bitfileds in fuse_req.

So move to using bitops.  Can use the non-atomic variants for those which
happen while the request definitely has only one reference.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
Reviewed-by: Ashish Samant <ashish.samant@oracle.com>
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Miklos Szeredi committed Jul 1, 2015
1 parent 0d8e84b commit 825d6d3
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Showing 4 changed files with 71 additions and 72 deletions.
71 changes: 36 additions & 35 deletions fs/fuse/dev.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -181,8 +181,10 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
}

fuse_req_init_context(req);
req->waiting = 1;
req->background = for_background;
__set_bit(FR_WAITING, &req->flags);
if (for_background)
__set_bit(FR_BACKGROUND, &req->flags);

return req;

out:
Expand Down Expand Up @@ -272,15 +274,15 @@ struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
req = get_reserved_req(fc, file);

fuse_req_init_context(req);
req->waiting = 1;
req->background = 0;
__set_bit(FR_WAITING, &req->flags);
__clear_bit(FR_BACKGROUND, &req->flags);
return req;
}

void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
{
if (atomic_dec_and_test(&req->count)) {
if (unlikely(req->background)) {
if (test_bit(FR_BACKGROUND, &req->flags)) {
/*
* We get here in the unlikely case that a background
* request was allocated but not sent
Expand All @@ -291,9 +293,9 @@ void fuse_put_request(struct fuse_conn *fc, struct fuse_req *req)
spin_unlock(&fc->lock);
}

if (req->waiting) {
if (test_bit(FR_WAITING, &req->flags)) {
__clear_bit(FR_WAITING, &req->flags);
atomic_dec(&fc->num_waiting);
req->waiting = 0;
}

if (req->stolen_file)
Expand Down Expand Up @@ -385,9 +387,8 @@ __releases(fc->lock)
list_del_init(&req->list);
list_del_init(&req->intr_entry);
req->state = FUSE_REQ_FINISHED;
if (req->background) {
req->background = 0;

if (test_bit(FR_BACKGROUND, &req->flags)) {
clear_bit(FR_BACKGROUND, &req->flags);
if (fc->num_background == fc->max_background)
fc->blocked = 0;

Expand Down Expand Up @@ -442,12 +443,12 @@ __acquires(fc->lock)
if (req->state == FUSE_REQ_FINISHED)
return;

req->interrupted = 1;
set_bit(FR_INTERRUPTED, &req->flags);
if (req->state == FUSE_REQ_SENT)
queue_interrupt(fc, req);
}

if (!req->force) {
if (!test_bit(FR_FORCE, &req->flags)) {
sigset_t oldset;

/* Only fatal signals may interrupt this */
Expand Down Expand Up @@ -478,7 +479,7 @@ __acquires(fc->lock)

static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
{
BUG_ON(req->background);
BUG_ON(test_bit(FR_BACKGROUND, &req->flags));
spin_lock(&fc->lock);
if (!fc->connected)
req->out.h.error = -ENOTCONN;
Expand All @@ -496,9 +497,9 @@ static void __fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)

void fuse_request_send(struct fuse_conn *fc, struct fuse_req *req)
{
req->isreply = 1;
if (!req->waiting) {
req->waiting = 1;
__set_bit(FR_ISREPLY, &req->flags);
if (!test_bit(FR_WAITING, &req->flags)) {
__set_bit(FR_WAITING, &req->flags);
atomic_inc(&fc->num_waiting);
}
__fuse_request_send(fc, req);
Expand Down Expand Up @@ -578,12 +579,12 @@ ssize_t fuse_simple_request(struct fuse_conn *fc, struct fuse_args *args)
void fuse_request_send_background_locked(struct fuse_conn *fc,
struct fuse_req *req)
{
BUG_ON(!req->background);
if (!req->waiting) {
req->waiting = 1;
BUG_ON(!test_bit(FR_BACKGROUND, &req->flags));
if (!test_bit(FR_WAITING, &req->flags)) {
__set_bit(FR_WAITING, &req->flags);
atomic_inc(&fc->num_waiting);
}
req->isreply = 1;
__set_bit(FR_ISREPLY, &req->flags);
fc->num_background++;
if (fc->num_background == fc->max_background)
fc->blocked = 1;
Expand Down Expand Up @@ -617,7 +618,7 @@ static int fuse_request_send_notify_reply(struct fuse_conn *fc,
{
int err = -ENODEV;

req->isreply = 0;
__clear_bit(FR_ISREPLY, &req->flags);
req->in.h.unique = unique;
spin_lock(&fc->lock);
if (fc->connected) {
Expand All @@ -644,7 +645,7 @@ void fuse_force_forget(struct file *file, u64 nodeid)
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
req->isreply = 0;
__clear_bit(FR_ISREPLY, &req->flags);
__fuse_request_send(fc, req);
/* ignore errors */
fuse_put_request(fc, req);
Expand All @@ -660,10 +661,10 @@ static int lock_request(struct fuse_conn *fc, struct fuse_req *req)
int err = 0;
if (req) {
spin_lock(&fc->lock);
if (req->aborted)
if (test_bit(FR_ABORTED, &req->flags))
err = -ENOENT;
else
req->locked = 1;
set_bit(FR_LOCKED, &req->flags);
spin_unlock(&fc->lock);
}
return err;
Expand All @@ -678,10 +679,10 @@ static int unlock_request(struct fuse_conn *fc, struct fuse_req *req)
int err = 0;
if (req) {
spin_lock(&fc->lock);
if (req->aborted)
if (test_bit(FR_ABORTED, &req->flags))
err = -ENOENT;
else
req->locked = 0;
clear_bit(FR_LOCKED, &req->flags);
spin_unlock(&fc->lock);
}
return err;
Expand Down Expand Up @@ -902,7 +903,7 @@ static int fuse_try_move_page(struct fuse_copy_state *cs, struct page **pagep)

err = 0;
spin_lock(&cs->fc->lock);
if (cs->req->aborted)
if (test_bit(FR_ABORTED, &cs->req->flags))
err = -ENOENT;
else
*pagep = newpage;
Expand Down Expand Up @@ -1309,7 +1310,7 @@ static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
(struct fuse_arg *) in->args, 0);
fuse_copy_finish(cs);
spin_lock(&fc->lock);
req->locked = 0;
clear_bit(FR_LOCKED, &req->flags);
if (!fc->connected) {
request_end(fc, req);
return -ENODEV;
Expand All @@ -1319,12 +1320,12 @@ static ssize_t fuse_dev_do_read(struct fuse_conn *fc, struct file *file,
request_end(fc, req);
return err;
}
if (!req->isreply)
if (!test_bit(FR_ISREPLY, &req->flags)) {
request_end(fc, req);
else {
} else {
req->state = FUSE_REQ_SENT;
list_move_tail(&req->list, &fc->processing);
if (req->interrupted)
if (test_bit(FR_INTERRUPTED, &req->flags))
queue_interrupt(fc, req);
spin_unlock(&fc->lock);
}
Expand Down Expand Up @@ -1921,7 +1922,7 @@ static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
req->state = FUSE_REQ_WRITING;
list_move(&req->list, &fc->io);
req->out.h = oh;
req->locked = 1;
set_bit(FR_LOCKED, &req->flags);
cs->req = req;
if (!req->out.page_replace)
cs->move_pages = 0;
Expand All @@ -1931,7 +1932,7 @@ static ssize_t fuse_dev_do_write(struct fuse_conn *fc,
fuse_copy_finish(cs);

spin_lock(&fc->lock);
req->locked = 0;
clear_bit(FR_LOCKED, &req->flags);
if (!fc->connected)
err = -ENOENT;
else if (err)
Expand Down Expand Up @@ -2097,8 +2098,8 @@ __acquires(fc->lock)

list_for_each_entry_safe(req, next, &fc->io, list) {
req->out.h.error = -ECONNABORTED;
req->aborted = 1;
if (!req->locked)
set_bit(FR_ABORTED, &req->flags);
if (!test_bit(FR_LOCKED, &req->flags))
list_move(&req->list, &to_end);
}
while (!list_empty(&to_end)) {
Expand Down
17 changes: 9 additions & 8 deletions fs/fuse/file.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -96,17 +96,17 @@ static void fuse_file_put(struct fuse_file *ff, bool sync)
* Drop the release request when client does not
* implement 'open'
*/
req->background = 0;
__clear_bit(FR_BACKGROUND, &req->flags);
iput(req->misc.release.inode);
fuse_put_request(ff->fc, req);
} else if (sync) {
req->background = 0;
__clear_bit(FR_BACKGROUND, &req->flags);
fuse_request_send(ff->fc, req);
iput(req->misc.release.inode);
fuse_put_request(ff->fc, req);
} else {
req->end = fuse_release_end;
req->background = 1;
__set_bit(FR_BACKGROUND, &req->flags);
fuse_request_send_background(ff->fc, req);
}
kfree(ff);
Expand Down Expand Up @@ -299,8 +299,8 @@ void fuse_sync_release(struct fuse_file *ff, int flags)
{
WARN_ON(atomic_read(&ff->count) > 1);
fuse_prepare_release(ff, flags, FUSE_RELEASE);
ff->reserved_req->force = 1;
ff->reserved_req->background = 0;
__set_bit(FR_FORCE, &ff->reserved_req->flags);
__clear_bit(FR_BACKGROUND, &ff->reserved_req->flags);
fuse_request_send(ff->fc, ff->reserved_req);
fuse_put_request(ff->fc, ff->reserved_req);
kfree(ff);
Expand Down Expand Up @@ -426,7 +426,7 @@ static int fuse_flush(struct file *file, fl_owner_t id)
req->in.numargs = 1;
req->in.args[0].size = sizeof(inarg);
req->in.args[0].value = &inarg;
req->force = 1;
__set_bit(FR_FORCE, &req->flags);
fuse_request_send(fc, req);
err = req->out.h.error;
fuse_put_request(fc, req);
Expand Down Expand Up @@ -1611,7 +1611,8 @@ static int fuse_writepage_locked(struct page *page)
if (!req)
goto err;

req->background = 1; /* writeback always goes to bg_queue */
/* writeback always goes to bg_queue */
__set_bit(FR_BACKGROUND, &req->flags);
tmp_page = alloc_page(GFP_NOFS | __GFP_HIGHMEM);
if (!tmp_page)
goto err_free;
Expand Down Expand Up @@ -1830,7 +1831,7 @@ static int fuse_writepages_fill(struct page *page,
req->misc.write.in.write_flags |= FUSE_WRITE_CACHE;
req->misc.write.next = NULL;
req->in.argpages = 1;
req->background = 1;
__set_bit(FR_BACKGROUND, &req->flags);
req->num_pages = 0;
req->end = fuse_writepage_end;
req->inode = inode;
Expand Down
49 changes: 23 additions & 26 deletions fs/fuse/fuse_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -266,6 +266,27 @@ struct fuse_io_priv {
struct completion *done;
};

/**
* Request flags
*
* FR_ISREPLY: set if the request has reply
* FR_FORCE: force sending of the request even if interrupted
* FR_BACKGROUND: request is sent in the background
* FR_WAITING: request is counted as "waiting"
* FR_ABORTED: the request was aborted
* FR_INTERRUPTED: the request has been interrupted
* FR_LOCKED: data is being copied to/from the request
*/
enum fuse_req_flag {
FR_ISREPLY,
FR_FORCE,
FR_BACKGROUND,
FR_WAITING,
FR_ABORTED,
FR_INTERRUPTED,
FR_LOCKED,
};

/**
* A request to the client
*/
Expand All @@ -283,32 +304,8 @@ struct fuse_req {
/** Unique ID for the interrupt request */
u64 intr_unique;

/*
* The following bitfields are either set once before the
* request is queued or setting/clearing them is protected by
* fuse_conn->lock
*/

/** True if the request has reply */
unsigned isreply:1;

/** Force sending of the request even if interrupted */
unsigned force:1;

/** The request was aborted */
unsigned aborted:1;

/** Request is sent in the background */
unsigned background:1;

/** The request has been interrupted */
unsigned interrupted:1;

/** Data is being copied to/from the request */
unsigned locked:1;

/** Request is counted as "waiting" */
unsigned waiting:1;
/* Request flags, updated with test/set/clear_bit() */
unsigned long flags;

/** State of the request */
enum fuse_req_state state;
Expand Down
6 changes: 3 additions & 3 deletions fs/fuse/inode.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -362,8 +362,8 @@ static void fuse_send_destroy(struct fuse_conn *fc)
if (req && fc->conn_init) {
fc->destroy_req = NULL;
req->in.h.opcode = FUSE_DESTROY;
req->force = 1;
req->background = 0;
__set_bit(FR_FORCE, &req->flags);
__clear_bit(FR_BACKGROUND, &req->flags);
fuse_request_send(fc, req);
fuse_put_request(fc, req);
}
Expand Down Expand Up @@ -1060,7 +1060,7 @@ static int fuse_fill_super(struct super_block *sb, void *data, int silent)
init_req = fuse_request_alloc(0);
if (!init_req)
goto err_put_root;
init_req->background = 1;
__set_bit(FR_BACKGROUND, &init_req->flags);

if (is_bdev) {
fc->destroy_req = fuse_request_alloc(0);
Expand Down

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