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fuse: add memory barrier to INIT 

Theoretically we need to order setting of various fields in fc with
fc->initialized.

No known bug reports related to this yet.

Signed-off-by: Miklos Szeredi <mszeredi@suse.cz>
This commit is contained in:
Miklos Szeredi 2015-01-06 10:45:35 +01:00
parent 21f621741a
commit 9759bd5189
3 changed files with 16 additions and 3 deletions
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15
fs/fuse/dev.c
View File

@ -131,6 +131,13 @@ static void fuse_req_init_context(struct fuse_req *req)
req->in.h.pid = current->pid;
}
void fuse_set_initialized(struct fuse_conn *fc)
{
/* Make sure stores before this are seen on another CPU */
smp_wmb();
fc->initialized = 1;
}
static bool fuse_block_alloc(struct fuse_conn *fc, bool for_background)
{
return !fc->initialized || (for_background && fc->blocked);
@ -155,6 +162,8 @@ static struct fuse_req *__fuse_get_req(struct fuse_conn *fc, unsigned npages,
if (intr)
goto out;
}
/* Matches smp_wmb() in fuse_set_initialized() */
smp_rmb();
err = -ENOTCONN;
if (!fc->connected)
@ -253,6 +262,8 @@ struct fuse_req *fuse_get_req_nofail_nopages(struct fuse_conn *fc,
atomic_inc(&fc->num_waiting);
wait_event(fc->blocked_waitq, fc->initialized);
/* Matches smp_wmb() in fuse_set_initialized() */
smp_rmb();
req = fuse_request_alloc(0);
if (!req)
req = get_reserved_req(fc, file);
@ -2163,7 +2174,7 @@ void fuse_abort_conn(struct fuse_conn *fc)
if (fc->connected) {
fc->connected = 0;
fc->blocked = 0;
fc->initialized = 1;
fuse_set_initialized(fc);
end_io_requests(fc);
end_queued_requests(fc);
end_polls(fc);
@ -2182,7 +2193,7 @@ int fuse_dev_release(struct inode *inode, struct file *file)
spin_lock(&fc->lock);
fc->connected = 0;
fc->blocked = 0;
fc->initialized = 1;
fuse_set_initialized(fc);
end_queued_requests(fc);
end_polls(fc);
wake_up_all(&fc->blocked_waitq);

2
fs/fuse/fuse_i.h
View File

@ -906,4 +906,6 @@ int fuse_write_inode(struct inode *inode, struct writeback_control *wbc);
int fuse_do_setattr(struct inode *inode, struct iattr *attr,
struct file *file);
void fuse_set_initialized(struct fuse_conn *fc);
#endif /* _FS_FUSE_I_H */

2
fs/fuse/inode.c
View File

@ -897,7 +897,7 @@ static void process_init_reply(struct fuse_conn *fc, struct fuse_req *req)
fc->max_write = max_t(unsigned, 4096, fc->max_write);
fc->conn_init = 1;
}
fc->initialized = 1;
fuse_set_initialized(fc);
wake_up_all(&fc->blocked_waitq);
}