shmem: support RENAME_WHITEOUT (46fdb794) · Commits · 戴 / test

mm/shmem.c

+35 −1

Original line number	Diff line number	Diff line
		@@ -2345,6 +2345,32 @@ static int shmem_exchange(struct inode old_dir, struct dentry old_dentry, stru
		return 0;
		}

		static int shmem_whiteout(struct inode old_dir, struct dentry old_dentry)
		{
		struct dentry *whiteout;
		int error;

		whiteout = d_alloc(old_dentry->d_parent, &old_dentry->d_name);
		if (!whiteout)
		return -ENOMEM;

		error = shmem_mknod(old_dir, whiteout,
		S_IFCHR \| WHITEOUT_MODE, WHITEOUT_DEV);
		dput(whiteout);
		if (error)
		return error;

		/*
		* Cheat and hash the whiteout while the old dentry is still in
		* place, instead of playing games with FS_RENAME_DOES_D_MOVE.
		*
		* d_lookup() will consistently find one of them at this point,
		* not sure which one, but that isn't even important.
		*/
		d_rehash(whiteout);
		return 0;
		}

		/*
		* The VFS layer already does all the dentry stuff for rename,
		* we just have to decrement the usage count for the target if
		@@ -2356,7 +2382,7 @@ static int shmem_rename2(struct inode old_dir, struct dentry old_dentry, struc
		struct inode *inode = old_dentry->d_inode;
		int they_are_dirs = S_ISDIR(inode->i_mode);

		if (flags & ~(RENAME_NOREPLACE \| RENAME_EXCHANGE))
		if (flags & ~(RENAME_NOREPLACE \| RENAME_EXCHANGE \| RENAME_WHITEOUT))
		return -EINVAL;

		if (flags & RENAME_EXCHANGE)
		@@ -2365,6 +2391,14 @@ static int shmem_rename2(struct inode old_dir, struct dentry old_dentry, struc
		if (!simple_empty(new_dentry))
		return -ENOTEMPTY;

		if (flags & RENAME_WHITEOUT) {
		int error;

		error = shmem_whiteout(old_dir, old_dentry);
		if (error)
		return error;
		}

		if (new_dentry->d_inode) {
		(void) shmem_unlink(new_dir, new_dentry);
		if (they_are_dirs) {

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