f2fs: fix incorrect FI_NO_EXTENT handling in __destroy_extent_node()

When __destroy_extent_node() sets the inode flag FI_NO_EXTENT, it does
not reset the length of the largest extent to 0 and update the inode
folio. Since modifications to the extent tree are disallowed afterward,
the cached largest extent may become stale. This can trigger the
following error in xfstests generic/388:

F2FS-fs (dm-0): sanity_check_extent_cache: inode (ino=1761) extent info [220057, 57, 6] is incorrect, run fsck to fix

In the f2fs_drop_inode path, __destroy_extent_node() does not need to
guarantee that et->node_cnt is 0, because concurrency with writeback
is expected in this path, and writeback may update the extent cache.

This patch reverts commit ed78aeebef05 ("f2fs: fix node_cnt race between
extent node destroy and writeback"), and remove the unnecessary zero
check of et->node_cnt.

Fixes: ed78aeebef05 ("f2fs: fix node_cnt race between extent node destroy and writeback")
Cc: stable@vger.kernel.org
Reported-by: Chao Yu <chao@kernel.org>
Suggested-by: Chao Yu <chao@kernel.org>
Signed-off-by: Yongpeng Yang <yangyongpeng@xiaomi.com>
Reviewed-by: Chao Yu <chao@kernel.org>
Signed-off-by: Jaegeuk Kim <jaegeuk@kernel.org>

diff --git a/fs/f2fs/extent_cache.c b/fs/f2fs/extent_cache.c
index d2e006420f040c9cb47318876ed194cc42c24d1d..61f6b971436639d6922b2a9a9996dd2de9e3fc3a 100644 (file)
--- a/fs/f2fs/extent_cache.c
+++ b/fs/f2fs/extent_cache.c
@@ -119,10 +119,9 @@ static bool __may_extent_tree(struct inode *inode, enum extent_type type)
        if (!__init_may_extent_tree(inode, type))
                return false;
 
-       if (is_inode_flag_set(inode, FI_NO_EXTENT))
-               return false;
-
        if (type == EX_READ) {
+               if (is_inode_flag_set(inode, FI_NO_EXTENT))
+                       return false;
                if (is_inode_flag_set(inode, FI_COMPRESSED_FILE) &&
                                 !f2fs_sb_has_readonly(F2FS_I_SB(inode)))
                        return false;
@@ -645,14 +644,10 @@ static unsigned int __destroy_extent_node(struct inode *inode,
 
        while (atomic_read(&et->node_cnt)) {
                write_lock(&et->lock);
-               if (!is_inode_flag_set(inode, FI_NO_EXTENT))
-                       set_inode_flag(inode, FI_NO_EXTENT);
                node_cnt += __free_extent_tree(sbi, et, nr_shrink);
                write_unlock(&et->lock);
        }
 
-       f2fs_bug_on(sbi, atomic_read(&et->node_cnt));
-
        return node_cnt;
 }
 
@@ -691,12 +686,12 @@ static void __update_extent_tree_range(struct inode *inode,
 
        write_lock(&et->lock);
 
-       if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
-               write_unlock(&et->lock);
-               return;
-       }
-
        if (type == EX_READ) {
+               if (is_inode_flag_set(inode, FI_NO_EXTENT)) {
+                       write_unlock(&et->lock);
+                       return;
+               }
+
                prev = et->largest;
                dei.len = 0;