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Commit 280227a7 authored by Davide Italiano's avatar Davide Italiano Committed by Theodore Ts'o
Browse files

ext4: move check under lock scope to close a race. 



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: default avatarDavide Italiano <dccitaliano@gmail.com>
Signed-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
Cc: stable@vger.kernel.org
parent d2dc317d

fs/ext4/extents.c

+8 −7
Original line number Original line 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)

	if (ret)

		return 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)

	if (mode & FALLOC_FL_COLLAPSE_RANGE)

		return ext4_collapse_range(inode, offset, len);

		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);

	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) &&

	if (!(mode & FALLOC_FL_KEEP_SIZE) &&

	     offset + len > i_size_read(inode)) {

	     offset + len > i_size_read(inode)) {

		new_size = offset + len;

		new_size = offset + len;