On Tue, 11 Oct 2011 13:30:14 +0400
Pavel Shilovsky <piastryyy@xxxxxxxxx> wrote:
> 2011/9/6 Jeff Layton <jlayton@xxxxxxxxxx>:
> > ...which will allow cifs to do an asynchronous read call to the server.
> > The caller will allocate and set up cifs_readdata for each READ_AND_X
> > call that should be issued on the wire. The pages passed in are added
> > to the pagecache, but not placed on the LRU list yet (as we need the
> > page->lru to keep the pages on the list in the readdata).
> >
> > When cifsd identifies the mid, it will see that there is a special
> > receive handler for the call, and use that to receive the rest of the
> > frame. cifs_readv_receive will then marshal up a kvec array with
> > kmapped pages from the pagecache, which eliminates one copy of the
> > data. Once the data is received, the pages are added to the LRU list,
> > set uptodate, and unlocked.
> >
> > Signed-off-by: Jeff Layton <jlayton@xxxxxxxxxx>
> > ---
> > fs/cifs/cifsproto.h | 24 ++++
> > fs/cifs/cifssmb.c | 356 +++++++++++++++++++++++++++++++++++++++++++++++++++
> > fs/cifs/connect.c | 26 ++--
> > 3 files changed, 393 insertions(+), 13 deletions(-)
> >
> > diff --git a/fs/cifs/cifsproto.h b/fs/cifs/cifsproto.h
> > index 51c0ebc..38406e5 100644
> > --- a/fs/cifs/cifsproto.h
> > +++ b/fs/cifs/cifsproto.h
> > @@ -152,6 +152,12 @@ extern struct cifs_ntsd *get_cifs_acl(struct cifs_sb_info *, struct inode *,
> > extern int set_cifs_acl(struct cifs_ntsd *, __u32, struct inode *,
> > const char *);
> >
> > +extern void dequeue_mid(struct mid_q_entry *mid, bool malformed);
> > +extern int cifs_read_from_socket(struct TCP_Server_Info *server, char *buf,
> > + unsigned int to_read);
> > +extern int cifs_readv_from_socket(struct TCP_Server_Info *server,
> > + struct kvec *iov_orig, unsigned int nr_segs,
> > + unsigned int to_read);
> > extern void cifs_setup_cifs_sb(struct smb_vol *pvolume_info,
> > struct cifs_sb_info *cifs_sb);
> > extern int cifs_match_super(struct super_block *, void *);
> > @@ -441,6 +447,24 @@ extern int E_md4hash(const unsigned char *passwd, unsigned char *p16);
> > extern int SMBencrypt(unsigned char *passwd, const unsigned char *c8,
> > unsigned char *p24);
> >
> > +/* asynchronous read support */
> > +struct cifs_readdata {
> > + struct cifsFileInfo *cfile;
> > + struct address_space *mapping;
> > + __u64 offset;
> > + unsigned int bytes;
> > + pid_t pid;
> > + int result;
> > + struct list_head pages;
> > + struct work_struct work;
> > + unsigned int nr_iov;
> > + struct kvec iov[1];
> > +};
> > +
> > +struct cifs_readdata *cifs_readdata_alloc(unsigned int nr_pages);
> > +void cifs_readdata_free(struct cifs_readdata *rdata);
> > +int cifs_async_readv(struct cifs_readdata *rdata);
> > +
> > /* asynchronous write support */
> > struct cifs_writedata {
> > struct kref refcount;
> > diff --git a/fs/cifs/cifssmb.c b/fs/cifs/cifssmb.c
> > index ae1ce01..ac72f28 100644
> > --- a/fs/cifs/cifssmb.c
> > +++ b/fs/cifs/cifssmb.c
> > @@ -33,6 +33,8 @@
> > #include <linux/slab.h>
> > #include <linux/posix_acl_xattr.h>
> > #include <linux/pagemap.h>
> > +#include <linux/swap.h>
> > +#include <linux/task_io_accounting_ops.h>
> > #include <asm/uaccess.h>
> > #include "cifspdu.h"
> > #include "cifsglob.h"
> > @@ -40,6 +42,7 @@
> > #include "cifsproto.h"
> > #include "cifs_unicode.h"
> > #include "cifs_debug.h"
> > +#include "fscache.h"
> >
> > #ifdef CONFIG_CIFS_POSIX
> > static struct {
> > @@ -83,6 +86,9 @@ static struct {
> > #endif /* CONFIG_CIFS_WEAK_PW_HASH */
> > #endif /* CIFS_POSIX */
> >
> > +/* Forward declarations */
> > +static void cifs_readv_complete(struct work_struct *work);
> > +
> > /* Mark as invalid, all open files on tree connections since they
> > were closed when session to server was lost */
> > static void mark_open_files_invalid(struct cifs_tcon *pTcon)
> > @@ -1375,6 +1381,356 @@ openRetry:
> > return rc;
> > }
> >
> > +struct cifs_readdata *
> > +cifs_readdata_alloc(unsigned int nr_pages)
> > +{
> > + struct cifs_readdata *rdata;
> > +
> > + /* readdata + 1 kvec for each page */
> > + rdata = kzalloc(sizeof(*rdata) +
> > + sizeof(struct kvec) * nr_pages, GFP_KERNEL);
> > + if (rdata != NULL) {
> > + INIT_WORK(&rdata->work, cifs_readv_complete);
> > + INIT_LIST_HEAD(&rdata->pages);
> > + }
> > + return rdata;
> > +}
> > +
> > +void
> > +cifs_readdata_free(struct cifs_readdata *rdata)
> > +{
> > + cifsFileInfo_put(rdata->cfile);
> > + kfree(rdata);
> > +}
> > +
> > +/*
> > + * Discard any remaining data in the current SMB. To do this, we borrow the
> > + * current bigbuf.
> > + */
> > +static int
> > +cifs_readv_discard(struct TCP_Server_Info *server, struct mid_q_entry *mid)
> > +{
> > + READ_RSP *rsp = (READ_RSP *)server->smallbuf;
> > + unsigned int rfclen = be32_to_cpu(rsp->hdr.smb_buf_length);
> > + int remaining = rfclen + 4 - server->total_read;
> > + struct cifs_readdata *rdata = mid->callback_data;
> > +
> > + while (remaining > 0) {
> > + int length;
> > +
> > + length = cifs_read_from_socket(server, server->bigbuf,
> > + min_t(unsigned int, remaining,
> > + CIFSMaxBufSize + MAX_CIFS_HDR_SIZE));
> > + if (length < 0)
> > + return length;
> > + server->total_read += length;
> > + remaining -= length;
> > + }
> > +
> > + dequeue_mid(mid, rdata->result);
> > + return 0;
> > +}
> > +
> > +static int
> > +cifs_readv_receive(struct TCP_Server_Info *server, struct mid_q_entry *mid)
> > +{
> > + int length, len;
> > + unsigned int data_offset, remaining, data_len;
> > + struct cifs_readdata *rdata = mid->callback_data;
> > + READ_RSP *rsp = (READ_RSP *)server->smallbuf;
> > + unsigned int rfclen = be32_to_cpu(rsp->hdr.smb_buf_length) + 4;
> > + u64 eof;
> > + pgoff_t eof_index;
> > + struct page *page, *tpage;
> > +
> > + cFYI(1, "%s: mid=%u offset=%llu bytes=%u", __func__,
> > + mid->mid, rdata->offset, rdata->bytes);
> > +
> > + /*
> > + * read the rest of READ_RSP header (sans Data array), or whatever we
> > + * can if there's not enough data. At this point, we've read down to
> > + * the Mid.
> > + */
> > + len = min_t(unsigned int, rfclen, sizeof(*rsp)) -
> > + sizeof(struct smb_hdr) + 1;
> > +
> > + rdata->iov[0].iov_base = server->smallbuf + sizeof(struct smb_hdr) - 1;
> > + rdata->iov[0].iov_len = len;
> > +
> > + length = cifs_readv_from_socket(server, rdata->iov, 1, len);
> > + if (length < 0)
> > + return length;
> > + server->total_read += length;
> > +
> > + /* Was the SMB read successful? */
> > + rdata->result = map_smb_to_linux_error(&rsp->hdr, false);
> > + if (rdata->result != 0) {
> > + cFYI(1, "%s: server returned error %d", __func__,
> > + rdata->result);
> > + return cifs_readv_discard(server, mid);
> > + }
> > +
> > + /* Is there enough to get to the rest of the READ_RSP header? */
> > + if (server->total_read < sizeof(READ_RSP)) {
> > + cFYI(1, "%s: server returned short header. got=%u expected=%lu",
> > + __func__, server->total_read, sizeof(READ_RSP));
>
> sizeof should be casted to unsigned long to prevent compiler warnings.
>
Actually...I think what I need to do here and in the other places you
pointed out is to use "%z". I'll fix and respin.
Thanks for the review...
--
Jeff Layton <jlayton@xxxxxxxxxx>
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