Transition the cifs filesystem from using the old ->readpages() method to
using the new ->readahead() method.
For the moment, this removes any invocation of fscache to read data from
the local cache, leaving that to another patch.
Signed-off-by: David Howells <dhowells@xxxxxxxxxx>
cc: Steve French <smfrench@xxxxxxxxx>
cc: Shyam Prasad N <nspmangalore@xxxxxxxxx>
cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
cc: Jeff Layton <jlayton@xxxxxxxxxx>
cc: linux-cifs@xxxxxxxxxxxxxxx
cc: linux-cachefs@xxxxxxxxxx
---
fs/cifs/file.c | 172 +++++++++++---------------------------------------------
1 file changed, 35 insertions(+), 137 deletions(-)
diff --git a/fs/cifs/file.c b/fs/cifs/file.c
index 59334be9ed3b..be62dc29dc54 100644
--- a/fs/cifs/file.c
+++ b/fs/cifs/file.c
@@ -4269,8 +4269,6 @@ cifs_readv_complete(struct work_struct *work)
for (i = 0; i < rdata->nr_pages; i++) {
struct page *page = rdata->pages[i];
- lru_cache_add(page);
-
if (rdata->result == 0 ||
(rdata->result == -EAGAIN && got_bytes)) {
flush_dcache_page(page);
@@ -4340,7 +4338,6 @@ readpages_fill_pages(struct TCP_Server_Info *server,
* fill them until the writes are flushed.
*/
zero_user(page, 0, PAGE_SIZE);
- lru_cache_add(page);
flush_dcache_page(page);
SetPageUptodate(page);
unlock_page(page);
@@ -4350,7 +4347,6 @@ readpages_fill_pages(struct TCP_Server_Info *server,
continue;
} else {
/* no need to hold page hostage */
- lru_cache_add(page);
unlock_page(page);
put_page(page);
rdata->pages[i] = NULL;
@@ -4393,92 +4389,16 @@ cifs_readpages_copy_into_pages(struct TCP_Server_Info *server,
return readpages_fill_pages(server, rdata, iter, iter->count);
}
-static int
-readpages_get_pages(struct address_space *mapping, struct list_head *page_list,
- unsigned int rsize, struct list_head *tmplist,
- unsigned int *nr_pages, loff_t *offset, unsigned int *bytes)
+static void cifs_readahead(struct readahead_control *ractl)
{
- struct page *page, *tpage;
- unsigned int expected_index;
int rc;
- gfp_t gfp = readahead_gfp_mask(mapping);
-
- INIT_LIST_HEAD(tmplist);
-
- page = lru_to_page(page_list);
-
- /*
- * 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.
- */
- __SetPageLocked(page);
- rc = add_to_page_cache_locked(page, mapping,
- page->index, gfp);
-
- /* give up if we can't stick it in the cache */
- if (rc) {
- __ClearPageLocked(page);
- return rc;
- }
-
- /* move first page to the tmplist */
- *offset = (loff_t)page->index << PAGE_SHIFT;
- *bytes = PAGE_SIZE;
- *nr_pages = 1;
- 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_SIZE > rsize)
- break;
-
- __SetPageLocked(page);
- rc = add_to_page_cache_locked(page, mapping, page->index, gfp);
- if (rc) {
- __ClearPageLocked(page);
- break;
- }
- list_move_tail(&page->lru, tmplist);
- (*bytes) += PAGE_SIZE;
- expected_index++;
- (*nr_pages)++;
- }
- return rc;
-}
-
-static int cifs_readpages(struct file *file, struct address_space *mapping,
- struct list_head *page_list, unsigned num_pages)
-{
- int rc;
- int err = 0;
- struct list_head tmplist;
- struct cifsFileInfo *open_file = file->private_data;
- struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(file);
+ struct cifsFileInfo *open_file = ractl->file->private_data;
+ struct cifs_sb_info *cifs_sb = CIFS_FILE_SB(ractl->file);
struct TCP_Server_Info *server;
pid_t pid;
- unsigned int xid;
+ unsigned int xid, last_batch_size = 0;
xid = get_xid();
- /*
- * Reads as many pages as possible from fscache. Returns -ENOBUFS
- * immediately if the cookie is negative
- *
- * After this point, every page in the list might have PG_fscache set,
- * so we will need to clean that up off of every page we don't use.
- */
- rc = cifs_readpages_from_fscache(mapping->host, mapping, page_list,
- &num_pages);
- if (rc == 0) {
- free_xid(xid);
- return rc;
- }
if (cifs_sb->mnt_cifs_flags & CIFS_MOUNT_RWPIDFORWARD)
pid = open_file->pid;
@@ -4489,39 +4409,32 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
server = cifs_pick_channel(tlink_tcon(open_file->tlink)->ses);
cifs_dbg(FYI, "%s: file=%p mapping=%p num_pages=%u\n",
- __func__, file, mapping, num_pages);
+ __func__, ractl->file, ractl->mapping, readahead_count(ractl));
/*
- * 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.
+ * Chop the readahead request up into rsize-sized read requests.
*/
- while (!list_empty(page_list) && !err) {
- unsigned int i, nr_pages, bytes, rsize;
- loff_t offset;
- struct page *page, *tpage;
+ while (readahead_count(ractl) - last_batch_size) {
+ unsigned int i, nr_pages, got, rsize;
+ struct page *page;
struct cifs_readdata *rdata;
struct cifs_credits credits_on_stack;
struct cifs_credits *credits = &credits_on_stack;
if (open_file->invalidHandle) {
rc = cifs_reopen_file(open_file, true);
- if (rc == -EAGAIN)
- continue;
- else if (rc)
+ if (rc) {
+ if (rc == -EAGAIN)
+ continue;
break;
+ }
}
rc = server->ops->wait_mtu_credits(server, cifs_sb->ctx->rsize,
&rsize, credits);
if (rc)
break;
+ nr_pages = min_t(size_t, rsize / PAGE_SIZE, readahead_count(ractl));
/*
* Give up immediately if rsize is too small to read an entire
@@ -4529,16 +4442,7 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
* reach this point however since we set ra_pages to 0 when the
* rsize is smaller than a cache page.
*/
- if (unlikely(rsize < PAGE_SIZE)) {
- add_credits_and_wake_if(server, credits, 0);
- free_xid(xid);
- return 0;
- }
-
- nr_pages = 0;
- err = readpages_get_pages(mapping, page_list, rsize, &tmplist,
- &nr_pages, &offset, &bytes);
- if (!nr_pages) {
+ if (unlikely(!nr_pages)) {
add_credits_and_wake_if(server, credits, 0);
break;
}
@@ -4546,36 +4450,31 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
rdata = cifs_readdata_alloc(nr_pages, cifs_readv_complete);
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(page);
- unlock_page(page);
- put_page(page);
- }
- rc = -ENOMEM;
add_credits_and_wake_if(server, credits, 0);
break;
}
- rdata->cfile = cifsFileInfo_get(open_file);
- rdata->server = server;
- rdata->mapping = mapping;
- rdata->offset = offset;
- rdata->bytes = bytes;
- rdata->pid = pid;
- rdata->pagesz = PAGE_SIZE;
- rdata->tailsz = PAGE_SIZE;
+ got = __readahead_batch(ractl, rdata->pages, nr_pages);
+ if (got != nr_pages) {
+ pr_warn("__readahead_batch() returned %u/%u\n",
+ got, nr_pages);
+ nr_pages = got;
+ }
+
+ rdata->nr_pages = nr_pages;
+ rdata->bytes = readahead_batch_length(ractl);
+ rdata->cfile = cifsFileInfo_get(open_file);
+ rdata->server = server;
+ rdata->mapping = ractl->mapping;
+ rdata->offset = readahead_pos(ractl);
+ rdata->pid = pid;
+ rdata->pagesz = PAGE_SIZE;
+ rdata->tailsz = PAGE_SIZE;
rdata->read_into_pages = cifs_readpages_read_into_pages;
rdata->copy_into_pages = cifs_readpages_copy_into_pages;
- rdata->credits = credits_on_stack;
-
- list_for_each_entry_safe(page, tpage, &tmplist, lru) {
- list_del(&page->lru);
- rdata->pages[rdata->nr_pages++] = page;
- }
+ rdata->credits = credits_on_stack;
rc = adjust_credits(server, &rdata->credits, rdata->bytes);
-
if (!rc) {
if (rdata->cfile->invalidHandle)
rc = -EAGAIN;
@@ -4587,7 +4486,6 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
add_credits_and_wake_if(server, &rdata->credits, 0);
for (i = 0; i < rdata->nr_pages; i++) {
page = rdata->pages[i];
- lru_cache_add(page);
unlock_page(page);
put_page(page);
}
@@ -4597,10 +4495,10 @@ static int cifs_readpages(struct file *file, struct address_space *mapping,
}
kref_put(&rdata->refcount, cifs_readdata_release);
+ last_batch_size = nr_pages;
}
free_xid(xid);
- return rc;
}
/*
@@ -4924,7 +4822,7 @@ void cifs_oplock_break(struct work_struct *work)
* In the non-cached mode (mount with cache=none), we shunt off direct read and write requests
* so this method should never be called.
*
- * Direct IO is not yet supported in the cached mode.
+ * Direct IO is not yet supported in the cached mode.
*/
static ssize_t
cifs_direct_io(struct kiocb *iocb, struct iov_iter *iter)
@@ -5006,7 +4904,7 @@ static int cifs_set_page_dirty(struct page *page)
const struct address_space_operations cifs_addr_ops = {
.readpage = cifs_readpage,
- .readpages = cifs_readpages,
+ .readahead = cifs_readahead,
.writepage = cifs_writepage,
.writepages = cifs_writepages,
.write_begin = cifs_write_begin,
--
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