// write up to buflen bytes into buf, starting at the given offset in the file.
// return the number of bytes written on success.
// return negative on failure.
ssize_t fskit_write( struct fskit_core* core, struct fskit_file_handle* fh, char const* buf, size_t buflen, off_t offset ) {
fskit_file_handle_rlock( fh );
// sanity check
if( (fh->flags & (O_RDWR | O_WRONLY)) == 0 ) {
fskit_file_handle_unlock( fh );
return -EBADF;
}
ssize_t num_written = fskit_run_user_write( core, fh->path, fh->fent, buf, buflen, offset, fh->app_data );
if( num_written >= 0 ) {
// update metadata
fskit_entry_wlock( fh->fent );
fskit_entry_set_mtime( fh->fent, NULL );
fskit_entry_set_atime( fh->fent, NULL );
fh->fent->size = ((unsigned)(offset + buflen) > fh->fent->size ? offset + buflen : fh->fent->size);
fskit_entry_unlock( fh->fent );
}
fskit_file_handle_unlock( fh );
return num_written;
}
// i/o continuation, called with the same locks held as the trunc()
static int fskit_trunc_cont( struct fskit_core* core, struct fskit_entry* fent, off_t new_size, ssize_t trunc_rc ) {
if( trunc_rc == 0 ) {
// update metadata
fskit_entry_set_mtime( fent, NULL );
fskit_entry_set_atime( fent, NULL );
fent->size = new_size;
}
return 0;
}
// continuation for successful write
// fent must be write-locked
int fskit_write_cont( struct fskit_core* core, struct fskit_entry* fent, off_t offset, ssize_t num_written ) {
if( num_written >= 0 ) {
fskit_entry_set_mtime( fent, NULL );
fskit_entry_set_atime( fent, NULL );
off_t size_delta = 0;
if( offset + num_written > fent->size ) {
size_delta = (offset + num_written) - fent->size;
}
fent->size += size_delta;
}
return 0;
}
// update timestamps on an inode on write/truncate
// always succeeds
// NOTE: inode->entry must be write-locked!
int UG_write_timestamp_update( struct UG_inode* inode, struct timespec* ts ) {
fskit_entry_set_mtime( UG_inode_fskit_entry( inode ), ts );
return 0;
}