Btrfs: Do more optimal file RA during shrinking and defrag

Signed-off-by: Chris Mason <chris.mason@oracle.com>

1 files changed, 7 insertions, 8 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 4d12aa532c5b..ab707c0930df 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -2814,14 +2814,12 @@ unsigned long btrfs_force_ra(struct address_space *mapping,
                               struct file_ra_state *ra, struct file *file,
                               pgoff_t offset, pgoff_t last_index)
 {
-        pgoff_t req_size;
+        pgoff_t req_size = last_index - offset + 1;
 
 #if LINUX_VERSION_CODE < KERNEL_VERSION(2,6,23)
-        req_size = last_index - offset + 1;
         offset = page_cache_readahead(mapping, ra, file, offset, req_size);
         return offset;
 #else
-        req_size = min(last_index - offset + 1, (pgoff_t)128);
         page_cache_sync_readahead(mapping, ra, file, offset, req_size);
         return offset + req_size;
 #endif
@@ -2833,7 +2831,8 @@ int btrfs_defrag_file(struct file *file) {
         struct extent_io_tree *io_tree = &BTRFS_I(inode)->io_tree;
         struct page *page;
         unsigned long last_index;
-        unsigned long ra_index = 0;
+        unsigned long ra_pages = root->fs_info->bdi.ra_pages;
+        unsigned long total_read = 0;
         u64 page_start;
         u64 page_end;
         unsigned long i;
@@ -2848,11 +2847,11 @@ int btrfs_defrag_file(struct file *file) {
         mutex_lock(&inode->i_mutex);
         last_index = inode->i_size >> PAGE_CACHE_SHIFT;
         for (i = 0; i <= last_index; i++) {
-                if (i == ra_index) {
-                        ra_index = btrfs_force_ra(inode->i_mapping,
-                                                  &file->f_ra,
-                                                  file, ra_index, last_index);
+                if (total_read % ra_pages == 0) {
+                        btrfs_force_ra(inode->i_mapping, &file->f_ra, file, i,
+                                       min(last_index, i + ra_pages - 1));
                 }
+                total_read++;
                 page = grab_cache_page(inode->i_mapping, i);
                 if (!page)
                         goto out_unlock;