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Commit a5dff681 authored by Eric Biggers's avatar Eric Biggers Committed by Jaegeuk Kim
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f2fs: call unlock_new_inode() before d_instantiate() 



xfstest generic/429 sometimes hangs on f2fs, caused by a thread being
unable to take a directory's i_rwsem for write in vfs_rmdir().  In the
test, one thread repeatedly creates and removes a directory, and other
threads repeatedly look up a file in the directory.  The bug is that
f2fs_mkdir() calls d_instantiate() before unlock_new_inode(), resulting
in the directory inode being exposed to lookups before it has been fully
initialized.  And with CONFIG_DEBUG_LOCK_ALLOC, unlock_new_inode()
reinitializes ->i_rwsem, corrupting its state when it is already held.

Fix it by calling unlock_new_inode() before d_instantiate().  This
matches what other filesystems do.

Fixes: 57397d86 ("f2fs: add inode operations for special inodes")
Signed-off-by: default avatarEric Biggers <ebiggers@google.com>
Signed-off-by: default avatarJaegeuk Kim <jaegeuk@kernel.org>
parent 967f45c7

fs/f2fs/namei.c

+4 −4
Original line number Diff line number Diff line
@@ -290,8 +290,8 @@ static int f2fs_create(struct inode *dir, struct dentry *dentry, umode_t mode, 


	alloc_nid_done(sbi, ino);



	d_instantiate(dentry, inode);

	unlock_new_inode(inode);

	d_instantiate(dentry, inode);



	if (IS_DIRSYNC(dir))

		f2fs_sync_fs(sbi->sb, 1);
@@ -591,8 +591,8 @@ static int f2fs_symlink(struct inode *dir, struct dentry *dentry, 
	err = page_symlink(inode, disk_link.name, disk_link.len);



err_out:

	d_instantiate(dentry, inode);

	unlock_new_inode(inode);

	d_instantiate(dentry, inode);



	/*

	 * Let's flush symlink data in order to avoid broken symlink as much as
@@ -653,8 +653,8 @@ static int f2fs_mkdir(struct inode *dir, struct dentry *dentry, umode_t mode) 


	alloc_nid_done(sbi, inode->i_ino);



	d_instantiate(dentry, inode);

	unlock_new_inode(inode);

	d_instantiate(dentry, inode);



	if (IS_DIRSYNC(dir))

		f2fs_sync_fs(sbi->sb, 1);
@@ -705,8 +705,8 @@ static int f2fs_mknod(struct inode *dir, struct dentry *dentry, 


	alloc_nid_done(sbi, inode->i_ino);



	d_instantiate(dentry, inode);

	unlock_new_inode(inode);

	d_instantiate(dentry, inode);



	if (IS_DIRSYNC(dir))

		f2fs_sync_fs(sbi->sb, 1);