CIFS: implement cifs_writepages to perform multi-page I/O
Signed-off-by: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Steve French <sfrench@us.ibm.com>
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 9487545..0473b22 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -21,11 +21,14 @@
* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
*/
#include <linux/fs.h>
+#include <linux/backing-dev.h>
#include <linux/stat.h>
#include <linux/fcntl.h>
+#include <linux/mpage.h>
#include <linux/pagemap.h>
#include <linux/pagevec.h>
#include <linux/smp_lock.h>
+#include <linux/writeback.h>
#include <asm/div64.h>
#include "cifsfs.h"
#include "cifspdu.h"
@@ -916,6 +919,16 @@
((open_file->pfile->f_flags & O_RDWR) ||
(open_file->pfile->f_flags & O_WRONLY))) {
read_unlock(&GlobalSMBSeslock);
+ if(open_file->invalidHandle) {
+ rc = cifs_reopen_file(cifs_inode->vfs_inode,
+ open_file->pfile, FALSE);
+ /* if it fails, try another handle - might be */
+ /* dangerous to hold up writepages with retry */
+ if(rc) {
+ read_lock(&GlobalSMBSeslock);
+ continue;
+ }
+ }
return open_file;
}
}
@@ -982,20 +995,181 @@
return rc;
}
-#if 0
+#ifdef CONFIG_CIFS_EXPERIMENTAL
static int cifs_writepages(struct address_space *mapping,
- struct writeback_control *wbc)
+ struct writeback_control *wbc)
{
- int rc = -EFAULT;
+ struct backing_dev_info *bdi = mapping->backing_dev_info;
+ unsigned int bytes_to_write;
+ unsigned int bytes_written;
+ struct cifs_sb_info *cifs_sb;
+ int done = 0;
+ pgoff_t end = -1;
+ pgoff_t index;
+ int is_range = 0;
+ struct kvec iov[32];
+ int n_iov = 0;
+ pgoff_t next;
+ int nr_pages;
+ __u64 offset = 0;
+ struct cifsFileInfo *open_file = NULL;
+ struct page *page;
+ struct pagevec pvec;
+ int rc = 0;
+ int scanned = 0;
int xid;
+ cifs_sb = CIFS_SB(mapping->host->i_sb);
+
+ /*
+ * If wsize is smaller that the page cache size, default to writing
+ * one page at a time via cifs_writepage
+ */
+ if (cifs_sb->wsize < PAGE_CACHE_SIZE)
+ return generic_writepages(mapping, wbc);
+
+ /*
+ * BB: Is this meaningful for a non-block-device file system?
+ * If it is, we should test it again after we do I/O
+ */
+ if (wbc->nonblocking && bdi_write_congested(bdi)) {
+ wbc->encountered_congestion = 1;
+ return 0;
+ }
+
xid = GetXid();
- /* Find contiguous pages then iterate through repeating
- call 16K write then Setpageuptodate or if LARGE_WRITE_X
- support then send larger writes via kevec so as to eliminate
- a memcpy */
+ pagevec_init(&pvec, 0);
+ if (wbc->sync_mode == WB_SYNC_NONE)
+ index = mapping->writeback_index; /* Start from prev offset */
+ else {
+ index = 0;
+ scanned = 1;
+ }
+ if (wbc->start || wbc->end) {
+ index = wbc->start >> PAGE_CACHE_SHIFT;
+ end = wbc->end >> PAGE_CACHE_SHIFT;
+ is_range = 1;
+ scanned = 1;
+ }
+retry:
+ while (!done && (index <= end) &&
+ (nr_pages = pagevec_lookup_tag(&pvec, mapping, &index,
+ PAGECACHE_TAG_DIRTY,
+ min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1))) {
+ int first;
+ unsigned int i;
+
+ if (!open_file) {
+ open_file = find_writable_file(CIFS_I(mapping->host));
+ if (!open_file) {
+ pagevec_release(&pvec);
+ cERROR(1, ("No writable handles for inode"));
+ return -EIO;
+ }
+ }
+
+ first = -1;
+ next = 0;
+ n_iov = 0;
+ bytes_to_write = 0;
+
+ for (i = 0; i < nr_pages; i++) {
+ page = pvec.pages[i];
+ /*
+ * At this point we hold neither mapping->tree_lock nor
+ * lock on the page itself: the page may be truncated or
+ * invalidated (changing page->mapping to NULL), or even
+ * swizzled back from swapper_space to tmpfs file
+ * mapping
+ */
+
+ if (first < 0)
+ lock_page(page);
+ else if (TestSetPageLocked(page))
+ break;
+
+ if (unlikely(page->mapping != mapping)) {
+ unlock_page(page);
+ break;
+ }
+
+ if (unlikely(is_range) && (page->index > end)) {
+ done = 1;
+ unlock_page(page);
+ break;
+ }
+
+ if (next && (page->index != next)) {
+ /* Not next consecutive page */
+ unlock_page(page);
+ break;
+ }
+
+ if (wbc->sync_mode != WB_SYNC_NONE)
+ wait_on_page_writeback(page);
+
+ if (PageWriteback(page) ||
+ !test_clear_page_dirty(page)) {
+ unlock_page(page);
+ break;
+ }
+ /*
+ * BB can we get rid of this? pages are held by pvec
+ */
+ page_cache_get(page);
+
+ /* reserve iov[0] for the smb header */
+ n_iov++;
+ iov[n_iov].iov_base = kmap(page);
+ iov[n_iov].iov_len = PAGE_CACHE_SIZE;
+ bytes_to_write += PAGE_CACHE_SIZE;
+
+ if (first < 0) {
+ first = i;
+ offset = page_offset(page);
+ }
+ next = page->index + 1;
+ if (bytes_to_write + PAGE_CACHE_SIZE > cifs_sb->wsize)
+ break;
+ }
+ if (n_iov) {
+ rc = CIFSSMBWrite2(xid, cifs_sb->tcon,
+ open_file->netfid, bytes_to_write,
+ offset, &bytes_written, iov, n_iov,
+ 1);
+ if (rc || bytes_written < bytes_to_write) {
+ cERROR(1,("CIFSSMBWrite2 returned %d, written = %x",
+ rc, bytes_written));
+ set_bit(AS_EIO, &mapping->flags);
+ SetPageError(page);
+ }
+ for (i = 0; i < n_iov; i++) {
+ page = pvec.pages[first + i];
+ kunmap(page);
+ unlock_page(page);
+ page_cache_release(page);
+ }
+ if ((wbc->nr_to_write -= n_iov) <= 0)
+ done = 1;
+ index = next;
+ }
+ pagevec_release(&pvec);
+ }
+ if (!scanned && !done) {
+ /*
+ * We hit the last page and there is more work to be done: wrap
+ * back to the start of the file
+ */
+ scanned = 1;
+ index = 0;
+ goto retry;
+ }
+ if (!is_range)
+ mapping->writeback_index = index;
+
FreeXid(xid);
+
return rc;
}
#endif
@@ -1635,6 +1809,9 @@
.readpage = cifs_readpage,
.readpages = cifs_readpages,
.writepage = cifs_writepage,
+#ifdef CONFIG_CIFS_EXPERIMENTAL
+ .writepages = cifs_writepages,
+#endif
.prepare_write = cifs_prepare_write,
.commit_write = cifs_commit_write,
.set_page_dirty = __set_page_dirty_nobuffers,
