#include <linux/delay.h>
#include <linux/mount.h>
#include <linux/slab.h>
+#include <linux/swap.h>
#include <asm/div64.h>
#include "cifsfs.h"
#include "cifspdu.h"
return rc;
}
-
-static void cifs_copy_cache_pages(struct address_space *mapping,
- struct list_head *pages, int bytes_read, char *data)
-{
- struct page *page;
- char *target;
-
- while (bytes_read > 0) {
- if (list_empty(pages))
- break;
-
- page = list_entry(pages->prev, struct page, lru);
- list_del(&page->lru);
-
- if (add_to_page_cache_lru(page, mapping, page->index,
- GFP_KERNEL)) {
- page_cache_release(page);
- cFYI(1, "Add page cache failed");
- data += PAGE_CACHE_SIZE;
- bytes_read -= PAGE_CACHE_SIZE;
- continue;
- }
- page_cache_release(page);
-
- target = kmap_atomic(page, KM_USER0);
-
- if (PAGE_CACHE_SIZE > bytes_read) {
- memcpy(target, data, bytes_read);
- /* zero the tail end of this partial page */
- memset(target + bytes_read, 0,
- PAGE_CACHE_SIZE - bytes_read);
- bytes_read = 0;
- } else {
- memcpy(target, data, PAGE_CACHE_SIZE);
- bytes_read -= PAGE_CACHE_SIZE;
- }
- kunmap_atomic(target, KM_USER0);
-
- flush_dcache_page(page);
- SetPageUptodate(page);
- unlock_page(page);
- data += PAGE_CACHE_SIZE;
-
- /* add page to FS-Cache */
- cifs_readpage_to_fscache(mapping->host, page);
- }
- return;
-}
-
static int cifs_readpages(struct file *file, struct address_space *mapping,
struct list_head *page_list, unsigned num_pages)
{
- int rc = -EACCES;
- int xid;
- loff_t offset;
- struct page *page;
- struct cifs_sb_info *cifs_sb;
- struct cifs_tcon *pTcon;
- unsigned int bytes_read = 0;
- unsigned int read_size, i;
- char *smb_read_data = NULL;
- struct smb_com_read_rsp *pSMBr;
- struct cifsFileInfo *open_file;
- struct cifs_io_parms io_parms;
- int buf_type = CIFS_NO_BUFFER;
- __u32 pid;
+ int rc;
+ struct list_head tmplist;
+ struct cifsFileInfo *open_file = file->private_data;
+ struct cifs_sb_info *cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
+ unsigned int rsize = cifs_sb->rsize;
+ pid_t pid;
- xid = GetXid();
- if (file->private_data == NULL) {
- rc = -EBADF;
- FreeXid(xid);
- return rc;
- }
- open_file = file->private_data;
- cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
- pTcon = tlink_tcon(open_file->tlink);
+ /*
+ * Give up immediately if rsize is too small to read an entire page.
+ * The VFS will fall back to readpage. We should never reach this
+ * point however since we set ra_pages to 0 when the rsize is smaller
+ * than a cache page.
+ */
+ if (unlikely(rsize < PAGE_CACHE_SIZE))
+ return 0;
/*
* Reads as many pages as possible from fscache. Returns -ENOBUFS
rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list,
&num_pages);
if (rc == 0)
- goto read_complete;
+ return rc;
- cFYI(DBG2, "rpages: num pages %d", num_pages);
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
pid = open_file->pid;
else
pid = current->tgid;
- for (i = 0; i < num_pages; ) {
- unsigned contig_pages;
- struct page *tmp_page;
- unsigned long expected_index;
+ rc = 0;
+ INIT_LIST_HEAD(&tmplist);
- if (list_empty(page_list))
- break;
+ cFYI(1, "%s: file=%p mapping=%p num_pages=%u", __func__, file,
+ mapping, num_pages);
+
+ /*
+ * Start with the page at end of list and move it to private
+ * list. Do the same with any following pages until we hit
+ * the rsize limit, hit an index discontinuity, or run out of
+ * pages. Issue the async read and then start the loop again
+ * until the list is empty.
+ *
+ * Note that list order is important. The page_list is in
+ * the order of declining indexes. When we put the pages in
+ * the rdata->pages, then we want them in increasing order.
+ */
+ while (!list_empty(page_list)) {
+ unsigned int bytes = PAGE_CACHE_SIZE;
+ unsigned int expected_index;
+ unsigned int nr_pages = 1;
+ loff_t offset;
+ struct page *page, *tpage;
+ struct cifs_readdata *rdata;
page = list_entry(page_list->prev, struct page, lru);
+
+ /*
+ * Lock the page and put it in the cache. Since no one else
+ * should have access to this page, we're safe to simply set
+ * PG_locked without checking it first.
+ */
+ __set_page_locked(page);
+ rc = add_to_page_cache_locked(page, mapping,
+ page->index, GFP_KERNEL);
+
+ /* give up if we can't stick it in the cache */
+ if (rc) {
+ __clear_page_locked(page);
+ break;
+ }
+
+ /* move first page to the tmplist */
offset = (loff_t)page->index << PAGE_CACHE_SHIFT;
+ list_move_tail(&page->lru, &tmplist);
+
+ /* now try and add more pages onto the request */
+ expected_index = page->index + 1;
+ list_for_each_entry_safe_reverse(page, tpage, page_list, lru) {
+ /* discontinuity ? */
+ if (page->index != expected_index)
+ break;
+
+ /* would this page push the read over the rsize? */
+ if (bytes + PAGE_CACHE_SIZE > rsize)
+ break;
- /* count adjacent pages that we will read into */
- contig_pages = 0;
- expected_index =
- list_entry(page_list->prev, struct page, lru)->index;
- list_for_each_entry_reverse(tmp_page, page_list, lru) {
- if (tmp_page->index == expected_index) {
- contig_pages++;
- expected_index++;
- } else
+ __set_page_locked(page);
+ if (add_to_page_cache_locked(page, mapping,
+ page->index, GFP_KERNEL)) {
+ __clear_page_locked(page);
break;
+ }
+ list_move_tail(&page->lru, &tmplist);
+ bytes += PAGE_CACHE_SIZE;
+ expected_index++;
+ nr_pages++;
}
- if (contig_pages + i > num_pages)
- contig_pages = num_pages - i;
-
- /* for reads over a certain size could initiate async
- read ahead */
-
- read_size = contig_pages * PAGE_CACHE_SIZE;
- /* Read size needs to be in multiples of one page */
- read_size = min_t(const unsigned int, read_size,
- cifs_sb->rsize & PAGE_CACHE_MASK);
- cFYI(DBG2, "rpages: read size 0x%x contiguous pages %d",
- read_size, contig_pages);
- rc = -EAGAIN;
- while (rc == -EAGAIN) {
+
+ rdata = cifs_readdata_alloc(nr_pages);
+ if (!rdata) {
+ /* best to give up if we're out of mem */
+ list_for_each_entry_safe(page, tpage, &tmplist, lru) {
+ list_del(&page->lru);
+ lru_cache_add_file(page);
+ unlock_page(page);
+ page_cache_release(page);
+ }
+ rc = -ENOMEM;
+ break;
+ }
+
+ spin_lock(&cifs_file_list_lock);
+ cifsFileInfo_get(open_file);
+ spin_unlock(&cifs_file_list_lock);
+ rdata->cfile = open_file;
+ rdata->mapping = mapping;
+ rdata->offset = offset;
+ rdata->bytes = bytes;
+ rdata->pid = pid;
+ list_splice_init(&tmplist, &rdata->pages);
+
+ do {
if (open_file->invalidHandle) {
rc = cifs_reopen_file(open_file, true);
if (rc != 0)
- break;
+ continue;
}
- io_parms.netfid = open_file->netfid;
- io_parms.pid = pid;
- io_parms.tcon = pTcon;
- io_parms.offset = offset;
- io_parms.length = read_size;
- rc = CIFSSMBRead(xid, &io_parms, &bytes_read,
- &smb_read_data, &buf_type);
- /* BB more RC checks ? */
- if (rc == -EAGAIN) {
- if (smb_read_data) {
- if (buf_type == CIFS_SMALL_BUFFER)
- cifs_small_buf_release(smb_read_data);
- else if (buf_type == CIFS_LARGE_BUFFER)
- cifs_buf_release(smb_read_data);
- smb_read_data = NULL;
- }
- }
- }
- if ((rc < 0) || (smb_read_data == NULL)) {
- cFYI(1, "Read error in readpages: %d", rc);
- break;
- } else if (bytes_read > 0) {
- task_io_account_read(bytes_read);
- pSMBr = (struct smb_com_read_rsp *)smb_read_data;
- cifs_copy_cache_pages(mapping, page_list, bytes_read,
- smb_read_data + 4 /* RFC1001 hdr */ +
- le16_to_cpu(pSMBr->DataOffset));
-
- i += bytes_read >> PAGE_CACHE_SHIFT;
- cifs_stats_bytes_read(pTcon, bytes_read);
- if ((bytes_read & PAGE_CACHE_MASK) != bytes_read) {
- i++; /* account for partial page */
-
- /* server copy of file can have smaller size
- than client */
- /* BB do we need to verify this common case ?
- this case is ok - if we are at server EOF
- we will hit it on next read */
+ rc = cifs_async_readv(rdata);
+ } while (rc == -EAGAIN);
- /* break; */
+ if (rc != 0) {
+ list_for_each_entry_safe(page, tpage, &rdata->pages,
+ lru) {
+ list_del(&page->lru);
+ lru_cache_add_file(page);
+ unlock_page(page);
+ page_cache_release(page);
}
- } else {
- cFYI(1, "No bytes read (%d) at offset %lld . "
- "Cleaning remaining pages from readahead list",
- bytes_read, offset);
- /* BB turn off caching and do new lookup on
- file size at server? */
+ cifs_readdata_free(rdata);
break;
}
- if (smb_read_data) {
- if (buf_type == CIFS_SMALL_BUFFER)
- cifs_small_buf_release(smb_read_data);
- else if (buf_type == CIFS_LARGE_BUFFER)
- cifs_buf_release(smb_read_data);
- smb_read_data = NULL;
- }
- bytes_read = 0;
- }
-
-/* need to free smb_read_data buf before exit */
- if (smb_read_data) {
- if (buf_type == CIFS_SMALL_BUFFER)
- cifs_small_buf_release(smb_read_data);
- else if (buf_type == CIFS_LARGE_BUFFER)
- cifs_buf_release(smb_read_data);
- smb_read_data = NULL;
}
-read_complete:
- FreeXid(xid);
return rc;
}
git.openpandora.org / pandora-kernel.git / commitdiff