[PATCH 5/6] fuse: truncate file if async dio failed

From: Maxim V. Patlasov
Date: Fri Dec 14 2012 - 10:21:28 EST


The patch improves error handling in fuse_direct_IO(): if we successfully
submitted several fuse requests on behalf of synchronous direct write
extending file and some of them failed, let's try to do our best to clean-up.

Signed-off-by: Maxim Patlasov <mpatlasov@xxxxxxxxxxxxx>
---
fs/fuse/file.c | 55 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
1 files changed, 53 insertions(+), 2 deletions(-)

diff --git a/fs/fuse/file.c b/fs/fuse/file.c
index 05eed23..b6e9b8d 100644
--- a/fs/fuse/file.c
+++ b/fs/fuse/file.c
@@ -2340,6 +2340,53 @@ int fuse_notify_poll_wakeup(struct fuse_conn *fc,
return 0;
}

+static void fuse_do_truncate(struct file *file)
+{
+ struct fuse_file *ff = file->private_data;
+ struct inode *inode = file->f_mapping->host;
+ struct fuse_conn *fc = get_fuse_conn(inode);
+ struct fuse_req *req;
+ struct fuse_setattr_in inarg;
+ struct fuse_attr_out outarg;
+ int err;
+
+ req = fuse_get_req_nopages(fc);
+ if (IS_ERR(req)) {
+ printk(KERN_WARNING "failed to allocate req for truncate "
+ "(%ld)\n", PTR_ERR(req));
+ return;
+ }
+
+ memset(&inarg, 0, sizeof(inarg));
+ memset(&outarg, 0, sizeof(outarg));
+
+ inarg.valid |= FATTR_SIZE;
+ inarg.size = i_size_read(inode);
+
+ inarg.valid |= FATTR_FH;
+ inarg.fh = ff->fh;
+
+ req->in.h.opcode = FUSE_SETATTR;
+ req->in.h.nodeid = get_node_id(inode);
+ req->in.numargs = 1;
+ req->in.args[0].size = sizeof(inarg);
+ req->in.args[0].value = &inarg;
+ req->out.numargs = 1;
+ if (fc->minor < 9)
+ req->out.args[0].size = FUSE_COMPAT_ATTR_OUT_SIZE;
+ else
+ req->out.args[0].size = sizeof(outarg);
+ req->out.args[0].value = &outarg;
+
+ fuse_request_send(fc, req);
+ err = req->out.h.error;
+ fuse_put_request(fc, req);
+
+ if (err)
+ printk(KERN_WARNING "failed to truncate to %lld with error "
+ "%d\n", i_size_read(inode), err);
+}
+
static ssize_t
fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
loff_t offset, unsigned long nr_segs)
@@ -2400,8 +2447,12 @@ fuse_direct_IO(int rw, struct kiocb *iocb, const struct iovec *iov,
kfree(io);
}

- if (rw == WRITE && ret > 0)
- fuse_write_update_size(inode, pos);
+ if (rw == WRITE) {
+ if (ret > 0)
+ fuse_write_update_size(inode, pos);
+ else if (ret < 0 && offset + count > i_size)
+ fuse_do_truncate(file);
+ }

return ret;
}

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