[f2fs-dev] [PATCH v2] f2fs: fix to avoid page count leak

[Chao Yu]

In f2fs_read_data_pages(), once we add page into radix tree, we need to
release reference count of that page, however when f2fs_read_multi_pages()
fails, we didn't handle that case correctly, fix it.

Fixes: 4c8ff7095bef ("f2fs: support data compression")
Signed-off-by: Chao Yu <yuch...@huawei.com>
---
v2:
- add Fixes tag
- improve commit message a bit
 fs/f2fs/compress.c | 2 +-
 fs/f2fs/data.c     | 6 +++++-
 fs/f2fs/f2fs.h     | 1 +
 3 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/f2fs/compress.c b/fs/f2fs/compress.c
index 498e0c2ba6ea..dbe3fa359a29 100644
--- a/fs/f2fs/compress.c
+++ b/fs/f2fs/compress.c
@@ -79,7 +79,7 @@ static void f2fs_drop_rpages(struct compress_ctx *cc, int 
len, bool unlock)
        }
 }
 
-static void f2fs_put_rpages(struct compress_ctx *cc)
+void f2fs_put_rpages(struct compress_ctx *cc)
 {
        f2fs_drop_rpages(cc, cc->cluster_size, false);
 }
diff --git a/fs/f2fs/data.c b/fs/f2fs/data.c
index 1139d8cf4b8d..22a31e2401cf 100644
--- a/fs/f2fs/data.c
+++ b/fs/f2fs/data.c
@@ -2138,7 +2138,7 @@ int f2fs_read_multi_pages(struct compress_ctx *cc, struct 
bio **bio_ret,
                } else if (!PageUptodate(page)) {
                        continue;
                }
-               unlock_page(page);
+               f2fs_put_page(page, 1);
                cc->rpages[i] = NULL;
                cc->nr_rpages--;
        }
@@ -2303,6 +2303,8 @@ int f2fs_mpage_readpages(struct address_space *mapping,
                                                        max_nr_pages,
                                                        &last_block_in_bio,
                                                        is_readahead, false);
+                               if (ret)
+                                       f2fs_put_rpages(&cc);
                                f2fs_destroy_compress_ctx(&cc);
                                if (ret)
                                        goto set_error_page;
@@ -2346,6 +2348,8 @@ int f2fs_mpage_readpages(struct address_space *mapping,
                                                        max_nr_pages,
                                                        &last_block_in_bio,
                                                        is_readahead, false);
+                               if (ret)
+                                       f2fs_put_rpages(&cc);
                                f2fs_destroy_compress_ctx(&cc);
                        }
                }
diff --git a/fs/f2fs/f2fs.h b/fs/f2fs/f2fs.h
index da5e9dd747fa..94d044feffd0 100644
--- a/fs/f2fs/f2fs.h
+++ b/fs/f2fs/f2fs.h
@@ -3803,6 +3803,7 @@ static inline bool f2fs_post_read_required(struct inode 
*inode)
  */
 #ifdef CONFIG_F2FS_FS_COMPRESSION
 bool f2fs_is_compressed_page(struct page *page);
+void f2fs_put_rpages(struct compress_ctx *cc);
 struct page *f2fs_compress_control_page(struct page *page);
 int f2fs_prepare_compress_overwrite(struct inode *inode,
                        struct page **pagep, pgoff_t index, void **fsdata);
-- 
2.18.0.rc1



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