f2fs: introduce f2fs_read_single_page() for cleanup

This patch introduces f2fs_read_single_page() to wrap core operations
of reading one page in f2fs_mpage_readpages().

In addition, if we failed in f2fs_mpage_readpages(), propagate error
number to f2fs_read_data_page(), for f2fs_read_data_pages() path,
always return success.

Signed-off-by: Chao Yu <yuchao0@huawei.com>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 7a67d61..cf89e36 100644 (file)
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -1508,6 +1508,118 @@ out:
        return ret;
 }
 
+static int f2fs_read_single_page(struct inode *inode, struct page *page,
+                                       unsigned nr_pages,
+                                       struct f2fs_map_blocks *map,
+                                       struct bio **bio_ret,
+                                       sector_t *last_block_in_bio,
+                                       bool is_readahead)
+{
+       struct bio *bio = *bio_ret;
+       const unsigned blkbits = inode->i_blkbits;
+       const unsigned blocksize = 1 << blkbits;
+       sector_t block_in_file;
+       sector_t last_block;
+       sector_t last_block_in_file;
+       sector_t block_nr;
+       int ret = 0;
+
+       block_in_file = (sector_t)page->index;
+       last_block = block_in_file + nr_pages;
+       last_block_in_file = (i_size_read(inode) + blocksize - 1) >>
+                                                       blkbits;
+       if (last_block > last_block_in_file)
+               last_block = last_block_in_file;
+
+       /* just zeroing out page which is beyond EOF */
+       if (block_in_file >= last_block)
+               goto zero_out;
+       /*
+        * Map blocks using the previous result first.
+        */
+       if ((map->m_flags & F2FS_MAP_MAPPED) &&
+                       block_in_file > map->m_lblk &&
+                       block_in_file < (map->m_lblk + map->m_len))
+               goto got_it;
+
+       /*
+        * Then do more f2fs_map_blocks() calls until we are
+        * done with this page.
+        */
+       map->m_lblk = block_in_file;
+       map->m_len = last_block - block_in_file;
+
+       ret = f2fs_map_blocks(inode, map, 0, F2FS_GET_BLOCK_DEFAULT);
+       if (ret)
+               goto out;
+got_it:
+       if ((map->m_flags & F2FS_MAP_MAPPED)) {
+               block_nr = map->m_pblk + block_in_file - map->m_lblk;
+               SetPageMappedToDisk(page);
+
+               if (!PageUptodate(page) && !cleancache_get_page(page)) {
+                       SetPageUptodate(page);
+                       goto confused;
+               }
+
+               if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), block_nr,
+                                                       DATA_GENERIC)) {
+                       ret = -EFAULT;
+                       goto out;
+               }
+       } else {
+zero_out:
+               zero_user_segment(page, 0, PAGE_SIZE);
+               if (!PageUptodate(page))
+                       SetPageUptodate(page);
+               unlock_page(page);
+               goto out;
+       }
+
+       /*
+        * This page will go to BIO.  Do we need to send this
+        * BIO off first?
+        */
+       if (bio && (*last_block_in_bio != block_nr - 1 ||
+               !__same_bdev(F2FS_I_SB(inode), block_nr, bio))) {
+submit_and_realloc:
+               __submit_bio(F2FS_I_SB(inode), bio, DATA);
+               bio = NULL;
+       }
+       if (bio == NULL) {
+               bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
+                               is_readahead ? REQ_RAHEAD : 0);
+               if (IS_ERR(bio)) {
+                       ret = PTR_ERR(bio);
+                       bio = NULL;
+                       goto out;
+               }
+       }
+
+       /*
+        * If the page is under writeback, we need to wait for
+        * its completion to see the correct decrypted data.
+        */
+       f2fs_wait_on_block_writeback(inode, block_nr);
+
+       if (bio_add_page(bio, page, blocksize, 0) < blocksize)
+               goto submit_and_realloc;
+
+       inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
+       ClearPageError(page);
+       *last_block_in_bio = block_nr;
+       goto out;
+confused:
+       if (bio) {
+               __submit_bio(F2FS_I_SB(inode), bio, DATA);
+               bio = NULL;
+       }
+       unlock_page(page);
+out:
+       *bio_ret = bio;
+       return ret;
+}
+
 /*
  * This function was originally taken from fs/mpage.c, and customized for f2fs.
  * Major change was from block_size == page_size in f2fs by default.
@@ -1524,13 +1636,8 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
        struct bio *bio = NULL;
        sector_t last_block_in_bio = 0;
        struct inode *inode = mapping->host;
-       const unsigned blkbits = inode->i_blkbits;
-       const unsigned blocksize = 1 << blkbits;
-       sector_t block_in_file;
-       sector_t last_block;
-       sector_t last_block_in_file;
-       sector_t block_nr;
        struct f2fs_map_blocks map;
+       int ret = 0;
 
        map.m_pblk = 0;
        map.m_lblk = 0;
@@ -1553,98 +1660,13 @@ static int f2fs_mpage_readpages(struct address_space *mapping,
                                goto next_page;
                }
 
-               block_in_file = (sector_t)page->index;
-               last_block = block_in_file + nr_pages;
-               last_block_in_file = (i_size_read(inode) + blocksize - 1) >>
-                                                               blkbits;
-               if (last_block > last_block_in_file)
-                       last_block = last_block_in_file;
-
-               /* just zeroing out page which is beyond EOF */
-               if (block_in_file >= last_block)
-                       goto zero_out;
-               /*
-                * Map blocks using the previous result first.
-                */
-               if ((map.m_flags & F2FS_MAP_MAPPED) &&
-                               block_in_file > map.m_lblk &&
-                               block_in_file < (map.m_lblk + map.m_len))
-                       goto got_it;
-
-               /*
-                * Then do more f2fs_map_blocks() calls until we are
-                * done with this page.
-                */
-               map.m_lblk = block_in_file;
-               map.m_len = last_block - block_in_file;
-
-               if (f2fs_map_blocks(inode, &map, 0, F2FS_GET_BLOCK_DEFAULT))
-                       goto set_error_page;
-got_it:
-               if ((map.m_flags & F2FS_MAP_MAPPED)) {
-                       block_nr = map.m_pblk + block_in_file - map.m_lblk;
-                       SetPageMappedToDisk(page);
-
-                       if (!PageUptodate(page) && !cleancache_get_page(page)) {
-                               SetPageUptodate(page);
-                               goto confused;
-                       }
-
-                       if (!f2fs_is_valid_blkaddr(F2FS_I_SB(inode), block_nr,
-                                                               DATA_GENERIC))
-                               goto set_error_page;
-               } else {
-zero_out:
+               ret = f2fs_read_single_page(inode, page, nr_pages, &map, &bio,
+                                       &last_block_in_bio, is_readahead);
+               if (ret) {
+                       SetPageError(page);
                        zero_user_segment(page, 0, PAGE_SIZE);
-                       if (!PageUptodate(page))
-                               SetPageUptodate(page);
                        unlock_page(page);
-                       goto next_page;
                }
-
-               /*
-                * This page will go to BIO.  Do we need to send this
-                * BIO off first?
-                */
-               if (bio && (last_block_in_bio != block_nr - 1 ||
-                       !__same_bdev(F2FS_I_SB(inode), block_nr, bio))) {
-submit_and_realloc:
-                       __submit_bio(F2FS_I_SB(inode), bio, DATA);
-                       bio = NULL;
-               }
-               if (bio == NULL) {
-                       bio = f2fs_grab_read_bio(inode, block_nr, nr_pages,
-                                       is_readahead ? REQ_RAHEAD : 0);
-                       if (IS_ERR(bio)) {
-                               bio = NULL;
-                               goto set_error_page;
-                       }
-               }
-
-               /*
-                * If the page is under writeback, we need to wait for
-                * its completion to see the correct decrypted data.
-                */
-               f2fs_wait_on_block_writeback(inode, block_nr);
-
-               if (bio_add_page(bio, page, blocksize, 0) < blocksize)
-                       goto submit_and_realloc;
-
-               inc_page_count(F2FS_I_SB(inode), F2FS_RD_DATA);
-               ClearPageError(page);
-               last_block_in_bio = block_nr;
-               goto next_page;
-set_error_page:
-               SetPageError(page);
-               zero_user_segment(page, 0, PAGE_SIZE);
-               unlock_page(page);
-               goto next_page;
-confused:
-               if (bio) {
-                       __submit_bio(F2FS_I_SB(inode), bio, DATA);
-                       bio = NULL;
-               }
-               unlock_page(page);
 next_page:
                if (pages)
                        put_page(page);
@@ -1652,7 +1674,7 @@ next_page:
        BUG_ON(pages && !list_empty(pages));
        if (bio)
                __submit_bio(F2FS_I_SB(inode), bio, DATA);
-       return 0;
+       return pages ? 0 : ret;
 }
 
 static int f2fs_read_data_page(struct file *file, struct page *page)