I have a setup composed of a apache webdav server and a client using davfs2.

When content is added to a file on the server, it requires to read to be visible on the client.

Step to reproduce:

SERVER# date > /srv/www/dav/TEST
CLIENT# cat /mnt/dav/TEST
SERVER# date >> /srv/www/dav/TEST
CLIENT# cat /mnt/dav/TEST

The last client read shows only the old content, another cat on the TEST file shows the new content.

In dav_fuse, on open/read/close sequence, fuse_lookup is called before fuse_read to get the file attributes, but the size set to fuse_entry_out reflects the old size, not the new one. So when the read is performed, more data is written to the /dev/fuse device than the file size attribute. On the next read, the file size attribute is set to the size of the updated cache file, that's why it requires two read to get the updated content.

I'm proposing a patch to always call update_cache_file on dav_lookup. Please let me know what do you think.