SYS_open uses calls flip_open to do the (open) job
filp_open calls dentry_open to do the (open) job
dentry_open calls file->f_op->open for the actual open job
i've read in a VFS document that only a few file systems implements the f_op->open call, so .. this means that the default behaviour of the VFS is sufficient in some cases .. it least it must increase the usage counter of the file we want to open .. but i couldn't find the piece of code that does such a behaviour .. all that is done is looking for the file wanted to be opened, getting a file descriptor, filling it's fields, calling f-op->open if defined, and then installing it then it's done
so if f_op->open is not implemented the underlying file system is not touched while openning a file (except for some calls to read_inode while the path lookup)
so how could the most file systems do open files without the f_op->open ? or this is not right and the f_op->open is the only way to do the open job on the underlying file system ? correct me please
Thanks in advance
MHD.
-- Kernelnewbies: Help each other learn about the Linux kernel. Archive: http://mail.nl.linux.org/kernelnewbies/ FAQ: http://kernelnewbies.org/faq/
