On Tue, 30 Nov 2010 10:54:30 +0300 Pavel Shilovsky <[email protected]> wrote:
> Add cifs_file_aio_read where we read from the cache if we have at least > Level II oplock - otherwise read from the server. > > Signed-off-by: Pavel Shilovsky <[email protected]> > --- > fs/cifs/cifsfs.c | 44 ++++++++++++++++++++++++++++++++++++++++++-- > 1 files changed, 42 insertions(+), 2 deletions(-) > > diff --git a/fs/cifs/cifsfs.c b/fs/cifs/cifsfs.c > index 9c37897..370acdc 100644 > --- a/fs/cifs/cifsfs.c > +++ b/fs/cifs/cifsfs.c > @@ -568,6 +568,46 @@ cifs_do_mount(struct file_system_type *fs_type, > return dget(sb->s_root); > } > > +static ssize_t cifs_file_aio_read(struct kiocb *iocb, const struct iovec > *iov, > + unsigned long nr_segs, loff_t pos) > +{ > + struct inode *inode; > + struct cifs_sb_info *cifs_sb; > + ssize_t read = 0, retval; > + unsigned long i; > + > + inode = iocb->ki_filp->f_path.dentry->d_inode; > + cifs_sb = CIFS_SB(iocb->ki_filp->f_path.dentry->d_sb); > + > + if ((cifs_sb->mnt_cifs_flags & CIFS_MOUNT_STRICT_IO) == 0 || > + CIFS_I(inode)->clientCanCacheRead) > + return generic_file_aio_read(iocb, iov, nr_segs, pos); > + > + /* > + * In strict cache mode we need to read from the server all the time > + * if we don't have level II oplock because the server can delay mtime > + * change - so we can't make a decision about inode invalidating. > + * And we can also fail with pagereading if there are mandatory locks > + * on pages affected by this read but not on the region from pos to > + * pos+len-1. > + */ > + > + for (i = 0; i < nr_segs; i++) { > + retval = cifs_user_read(iocb->ki_filp, iov[i].iov_base, > + iov[i].iov_len, &pos); > + if (retval < 0) { > + read = read ? read : retval; > + break; > + } > + > + read += retval; > + } > + Hmmm...that looks a little ugly. There is no batching here, so if the application sends you an array of very small iovecs, then that becomes a set of very small reads on the wire. I don't think that's what you want. > + iocb->ki_pos = pos; > + > + return read; > +} > + > static ssize_t cifs_file_aio_write(struct kiocb *iocb, const struct iovec > *iov, > unsigned long nr_segs, loff_t pos) > { > @@ -690,7 +730,7 @@ const struct inode_operations cifs_symlink_inode_ops = { > const struct file_operations cifs_file_ops = { > .read = do_sync_read, > .write = do_sync_write, > - .aio_read = generic_file_aio_read, > + .aio_read = cifs_file_aio_read, > .aio_write = cifs_file_aio_write, > .open = cifs_open, > .release = cifs_close, > @@ -727,7 +767,7 @@ const struct file_operations cifs_file_direct_ops = { > const struct file_operations cifs_file_nobrl_ops = { > .read = do_sync_read, > .write = do_sync_write, > - .aio_read = generic_file_aio_read, > + .aio_read = cifs_file_aio_read, > .aio_write = cifs_file_aio_write, > .open = cifs_open, > .release = cifs_close, -- Jeff Layton <[email protected]> -- To unsubscribe from this list: send the line "unsubscribe linux-cifs" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
