ext4: move check under lock scope to close a race. (280227a7) · Commits · 戴 / test

fallocate() checks that the file is extent-based and returns EOPNOTSUPP in case is not. Other tasks can convert from and to indirect and extent so it's safe to check only after grabbing the inode mutex. Signed-off-by:

Davide Italiano <dccitaliano@gmail.com> Signed-off-by:

Theodore Ts'o <tytso@mit.edu> Cc: stable@vger.kernel.org

fs/ext4/extents.c

+8 −7

Original line number	Diff line number	Diff line
		@@ -4927,13 +4927,6 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
		if (ret)
		return ret;

		/*
		* currently supporting (pre)allocate mode for extent-based
		* files _only_
		*/
		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
		return -EOPNOTSUPP;

		if (mode & FALLOC_FL_COLLAPSE_RANGE)
		return ext4_collapse_range(inode, offset, len);

		@@ -4955,6 +4948,14 @@ long ext4_fallocate(struct file *file, int mode, loff_t offset, loff_t len)

		mutex_lock(&inode->i_mutex);

		/*
		* We only support preallocation for extent-based files only
		*/
		if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
		ret = -EOPNOTSUPP;
		goto out;
		}

		if (!(mode & FALLOC_FL_KEEP_SIZE) &&
		offset + len > i_size_read(inode)) {
		new_size = offset + len;

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