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authorMiklos Szeredi <mszeredi@suse.cz>2015-01-06 10:45:35 +0100
committerMiklos Szeredi <mszeredi@suse.cz>2015-01-06 10:45:35 +0100
commit9759bd51899458af4f4bcc11046f01285642ca10 (patch)
tree9e50d89d7772cbff8a7502a19353c984a948d1a6 /fs
parent21f621741a770c119e7529a3f5c0e6b7c91383a3 (diff)
downloadlinux-9759bd51899458af4f4bcc11046f01285642ca10.tar.bz2
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>
Diffstat (limited to 'fs')
-rw-r--r--fs/fuse/dev.c15
-rw-r--r--fs/fuse/fuse_i.h2
-rw-r--r--fs/fuse/inode.c2
3 files changed, 16 insertions, 3 deletions
diff --git a/fs/fuse/dev.c b/fs/fuse/dev.c
index c847d6b225e2..ed19a7d622fa 100644
--- a/fs/fuse/dev.c
+++ b/fs/fuse/dev.c
@@ -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);
diff --git a/fs/fuse/fuse_i.h b/fs/fuse/fuse_i.h
index e0fc6725d1d0..1cdfb07c1376 100644
--- a/fs/fuse/fuse_i.h
+++ b/fs/fuse/fuse_i.h
@@ -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 */
diff --git a/fs/fuse/inode.c b/fs/fuse/inode.c
index 6a20f2ff2c2e..f38256e4476e 100644
--- a/fs/fuse/inode.c
+++ b/fs/fuse/inode.c
@@ -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);
}