Commit e0770e91 authored by Jan Kara's avatar Jan Kara Committed by Theodore Ts'o

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: default avatarAndreas Dilger <adilger@dilger.ca>
Reported-by: default avatarRitesh Harjani <riteshh@linux.ibm.com>
Signed-off-by: default avatarJan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20201015110330.28716-1-jack@suse.czSigned-off-by: default avatarTheodore Ts'o <tytso@mit.edu>
parent fc750a3b
...@@ -6225,6 +6225,11 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id, ...@@ -6225,6 +6225,11 @@ static int ext4_quota_on(struct super_block *sb, int type, int format_id,
/* Quotafile not on the same filesystem? */ /* Quotafile not on the same filesystem? */
if (path->dentry->d_sb != sb) if (path->dentry->d_sb != sb)
return -EXDEV; return -EXDEV;
/* Quota already enabled for this file? */
if (IS_NOQUOTA(d_inode(path->dentry)))
return -EBUSY;
/* Journaling quota? */ /* Journaling quota? */
if (EXT4_SB(sb)->s_qf_names[type]) { if (EXT4_SB(sb)->s_qf_names[type]) {
/* Quotafile not in fs root? */ /* Quotafile not in fs root? */
......
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