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Date: Thu, 15 Oct 2020 13:03:30 +0200 From: Jan Kara <jack@...e.cz> To: Ted Tso <tytso@....edu> Cc: <linux-ext4@...r.kernel.org>, Andreas Dilger <adilger@...ger.ca>, Jan Kara <jack@...e.cz> Subject: [PATCH v2] 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@...ger.ca> Reported-by: Ritesh Harjani <riteshh@...ux.ibm.com> Signed-off-by: Jan Kara <jack@...e.cz> --- fs/ext4/super.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/fs/ext4/super.c b/fs/ext4/super.c index ea425b49b345..d31ae5a87859 100644 --- a/fs/ext4/super.c +++ b/fs/ext4/super.c @@ -6042,6 +6042,11 @@ 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? */ -- 2.16.4
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