Man page 9 : __generic_file_aio_write

__generic_file_aio_write - write data to a file

ssize_t __generic_file_aio_write(struct kiocb *  iocb , const struct iovec *  iov , unsigned long  nr_segs , loff_t *  ppos );

iocb
    IO state structure (file, offset, etc.)

iov
    vector with data to write

nr_segs
    number of segments in the vector

ppos
    position where to write

This function does all the work needed for actually writing data to a file. It does all basic checks, removes SUID from the file, updates modification times and calls proper subroutines depending on whether we do direct IO or a standard buffered write.

It expects i_mutex to be grabbed unless we work on a block device or similar object which does not need locking at all.

This function does *not* take care of syncing data in case of O_SYNC write. A caller has to handle it. This is mainly due to the fact that we want to avoid syncing under i_mutex.