Commit e0770e91 authored Oct 15, 2020 by Jan Kara Committed by Theodore Ts'o Oct 18, 2020

ext4: Detect already used quota file early



When we try to use file already used as a quota file again (for the same
or different quota type), strange things can happen. At the very least
lockdep annotations may be wrong but also inode flags may be wrongly set
/ reset. When the file is used for two quota types at once we can even
corrupt the file and likely crash the kernel. Catch all these cases by
checking whether passed file is already used as quota file and bail
early in that case.

This fixes occasional generic/219 failure due to lockdep complaint.

Reviewed-by: Andreas Dilger <adilger@dilger.ca>
Reported-by: Ritesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201015110330.28716-1-jack@suse.cz


Signed-off-by: Theodore Ts'o <tytso@mit.edu>

parent fc750a3b

fs/ext4/super.c

+5 −0

Original line number	Diff line number	Diff line
		@@ -6225,6 +6225,11 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id,
		/* Quotafile not on the same filesystem? */
		if (path->dentry->d_sb != sb)
		return -EXDEV;

		/* Quota already enabled for this file? */
		if (IS_NOQUOTA(d_inode(path->dentry)))
		return -EBUSY;

		/* Journaling quota? */
		if (EXT4_SB(sb)->s_qf_names[type]) {
		/* Quotafile not in fs root? */

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