[f2fs-dev] [bug report] f2fs: avoid reading already updated pages during GC

[Dan Carpenter <error27@gmail.com>]

Hello Jianan Huang,

Commit 570e2ccc7cb3 ("f2fs: avoid reading already updated pages
during GC") from Mar 5, 2026 (linux-next), leads to the following
Smatch static checker warning:

	fs/f2fs/gc.c:1291 ra_data_block()
	warn: missing error code 'err'

fs/f2fs/gc.c
    1220 static int ra_data_block(struct inode *inode, pgoff_t index)
    1221 {
    1222         struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
    1223         struct address_space *mapping = f2fs_is_cow_file(inode) ?
    1224                                 F2FS_I(inode)->atomic_inode->i_mapping : inode->i_mapping;
    1225         struct dnode_of_data dn;
    1226         struct folio *folio, *efolio;
    1227         struct f2fs_io_info fio = {
    1228                 .sbi = sbi,
    1229                 .ino = inode->i_ino,
    1230                 .type = DATA,
    1231                 .temp = COLD,
    1232                 .op = REQ_OP_READ,
    1233                 .op_flags = 0,
    1234                 .encrypted_page = NULL,
    1235                 .in_list = 0,
    1236         };
    1237         int err = 0;
    1238 
    1239         folio = f2fs_grab_cache_folio(mapping, index, true);
    1240         if (IS_ERR(folio))
    1241                 return PTR_ERR(folio);
    1242 
    1243         if (f2fs_lookup_read_extent_cache_block(inode, index,
    1244                                                 &dn.data_blkaddr)) {
    1245                 if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
    1246                                                 DATA_GENERIC_ENHANCE_READ))) {
    1247                         err = -EFSCORRUPTED;
    1248                         goto put_folio;
    1249                 }
    1250                 goto got_it;
    1251         }
    1252 
    1253         set_new_dnode(&dn, inode, NULL, NULL, 0);
    1254         err = f2fs_get_dnode_of_data(&dn, index, LOOKUP_NODE);
    1255         if (err)
    1256                 goto put_folio;
    1257         f2fs_put_dnode(&dn);
    1258 
    1259         if (!__is_valid_data_blkaddr(dn.data_blkaddr)) {
    1260                 err = -ENOENT;
    1261                 goto put_folio;
    1262         }
    1263         if (unlikely(!f2fs_is_valid_blkaddr(sbi, dn.data_blkaddr,
    1264                                                 DATA_GENERIC_ENHANCE))) {
    1265                 err = -EFSCORRUPTED;
    1266                 goto put_folio;
    1267         }
    1268 got_it:
    1269         /* read folio */
    1270         fio.folio = folio;
    1271         fio.new_blkaddr = fio.old_blkaddr = dn.data_blkaddr;
    1272 
    1273         /*
    1274          * don't cache encrypted data into meta inode until previous dirty
    1275          * data were writebacked to avoid racing between GC and flush.
    1276          */
    1277         f2fs_folio_wait_writeback(folio, DATA, true, true);
    1278 
    1279         f2fs_wait_on_block_writeback(inode, dn.data_blkaddr);
    1280 
    1281         efolio = f2fs_filemap_get_folio(META_MAPPING(sbi), dn.data_blkaddr,
    1282                                         FGP_LOCK | FGP_CREAT, GFP_NOFS);
    1283         if (IS_ERR(efolio)) {
    1284                 err = PTR_ERR(efolio);
    1285                 goto put_folio;
    1286         }
    1287 
    1288         fio.encrypted_page = &efolio->page;
    1289 
    1290         if (folio_test_uptodate(efolio))
--> 1291                 goto put_encrypted_page;

Should we set an error code here?

    1292 
    1293         err = f2fs_submit_page_bio(&fio);
    1294         if (err)
    1295                 goto put_encrypted_page;
    1296         f2fs_put_page(fio.encrypted_page, false);
    1297         f2fs_folio_put(folio, true);
    1298 
    1299         f2fs_update_iostat(sbi, inode, FS_DATA_READ_IO, F2FS_BLKSIZE);
    1300         f2fs_update_iostat(sbi, NULL, FS_GDATA_READ_IO, F2FS_BLKSIZE);
    1301 
    1302         return 0;
    1303 put_encrypted_page:
    1304         f2fs_put_page(fio.encrypted_page, true);
    1305 put_folio:
    1306         f2fs_folio_put(folio, true);
    1307         return err;
    1308 }

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regards,
dan carpenter


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