btrfs: convert end_compressed_writeback() to use filemap_get_folios()

Converted function to use folios throughout.  This is in preparation for
the removal of find_get_pages_contig().  Now also supports large folios.

Since we may receive more than nr_pages pages, nr_pages may underflow.
Since nr_pages > 0 is equivalent to index <= end_index, we replaced it
with this check instead.

Also this function does not care about the pages being contiguous so we
can just use filemap_get_folios() to be more efficient.

Link: https://lkml.kernel.org/r/20220824004023.77310-4-vishal.moola@gmail.com
Signed-off-by: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Acked-by: David Sterba <dsterba@suse.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Chris Mason <clm@fb.com>
Cc: David Sterba <dsterb@suse.com>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ryusuke Konishi <konishi.ryusuke@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/fs/btrfs/compression.c b/fs/btrfs/compression.c
index e84d22c..05d228e 100644 (file)
--- a/fs/btrfs/compression.c
+++ b/fs/btrfs/compression.c
@@ -8,6 +8,7 @@
 #include <linux/file.h>
 #include <linux/fs.h>
 #include <linux/pagemap.h>
+#include <linux/pagevec.h>
 #include <linux/highmem.h>
 #include <linux/kthread.h>
 #include <linux/time.h>
@@ -222,8 +223,7 @@ static noinline void end_compressed_writeback(struct inode *inode,
        struct btrfs_fs_info *fs_info = btrfs_sb(inode->i_sb);
        unsigned long index = cb->start >> PAGE_SHIFT;
        unsigned long end_index = (cb->start + cb->len - 1) >> PAGE_SHIFT;
-       struct page *pages[16];
-       unsigned long nr_pages = end_index - index + 1;
+       struct folio_batch fbatch;
        const int errno = blk_status_to_errno(cb->status);
        int i;
        int ret;
@@ -231,24 +231,23 @@ static noinline void end_compressed_writeback(struct inode *inode,
        if (errno)
                mapping_set_error(inode->i_mapping, errno);
 
-       while (nr_pages > 0) {
-               ret = find_get_pages_contig(inode->i_mapping, index,
-                                    min_t(unsigned long,
-                                    nr_pages, ARRAY_SIZE(pages)), pages);
-               if (ret == 0) {
-                       nr_pages -= 1;
-                       index += 1;
-                       continue;
-               }
+       folio_batch_init(&fbatch);
+       while (index <= end_index) {
+               ret = filemap_get_folios(inode->i_mapping, &index, end_index,
+                               &fbatch);
+
+               if (ret == 0)
+                       return;
+
                for (i = 0; i < ret; i++) {
+                       struct folio *folio = fbatch.folios[i];
+
                        if (errno)
-                               SetPageError(pages[i]);
-                       btrfs_page_clamp_clear_writeback(fs_info, pages[i],
+                               folio_set_error(folio);
+                       btrfs_page_clamp_clear_writeback(fs_info, &folio->page,
                                                         cb->start, cb->len);
-                       put_page(pages[i]);
                }
-               nr_pages -= ret;
-               index += ret;
+               folio_batch_release(&fbatch);
        }
        /* the inode may be gone now */
 }