[PATCH] f2fs:Fix concurrent access issue in the function recover_dentry

[Nicholas Krause <xerofoify@gmail.com>]

This fixes a concurrent access in the function recover_dentry by
locking the superblock representation in memory with f2fs_lock_op
before calling the function __f2fs_add_link and unlocking the
superblock afterwards with f2fs_unlock_op in order to avoid
concurrent access here as neither recover_dentry nor its callers

Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
---
 fs/f2fs/recovery.c | 9 ++++++++-
 1 file changed, 8 insertions(+), 1 deletion(-)

diff --git a/fs/f2fs/recovery.c b/fs/f2fs/recovery.c
index faec2ca..6bb03f8 100644
--- a/fs/f2fs/recovery.c
+++ b/fs/f2fs/recovery.c
@@ -70,6 +70,7 @@ static struct fsync_inode_entry *get_fsync_inode(struct list_head *head,
 static int recover_dentry(struct inode *inode, struct page *ipage)
 {
 	struct f2fs_inode *raw_inode = F2FS_INODE(ipage);
+	struct f2fs_sb_info *sbi = F2FS_I_SB(inode);
 	nid_t pino = le32_to_cpu(raw_inode->i_pino);
 	struct f2fs_dir_entry *de;
 	struct qstr name;
@@ -119,9 +120,15 @@ retry:
 		iput(einode);
 		goto retry;
 	}
+
+
+	f2fs_lock_op(sbi);
 	err = __f2fs_add_link(dir, &name, inode, inode->i_ino, inode->i_mode);
-	if (err)
+	if (err) {
+		f2fs_unlock_op(sbi);
 		goto out_err;
+	}
+	f2fs_unlock_op(sbi);
 
 	if (is_inode_flag_set(F2FS_I(dir), FI_DELAY_IPUT)) {
 		iput(dir);
-- 
2.1.4


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