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quota: Fix possible corruption of dqi_flags 

dqi_flags modifications are protected by dq_data_lock. However the
modifications in vfs_load_quota_inode() and in mark_info_dirty() were
not which could lead to corruption of dqi_flags. Since modifications to
dqi_flags are rare, this is hard to observe in practice but in theory it
could happen. Fix the problem by always using dq_data_lock for
protection.

Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2017-06-09 11:56:06 +02:00
parent f98bbe37ae
commit 15512377bd
2 changed files with 10 additions and 3 deletions
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9
fs/quota/dquot.c
View File

@ -389,7 +389,9 @@ static inline int clear_dquot_dirty(struct dquot *dquot)
void mark_info_dirty(struct super_block *sb, int type)
{
set_bit(DQF_INFO_DIRTY_B, &sb_dqopt(sb)->info[type].dqi_flags);
spin_lock(&dq_data_lock);
sb_dqopt(sb)->info[type].dqi_flags |= DQF_INFO_DIRTY;
spin_unlock(&dq_data_lock);
}
EXPORT_SYMBOL(mark_info_dirty);
@ -2316,8 +2318,11 @@ static int vfs_load_quota_inode(struct inode *inode, int type, int format_id,
error = dqopt->ops[type]->read_file_info(sb, type);
if (error < 0)
goto out_file_init;
if (dqopt->flags & DQUOT_QUOTA_SYS_FILE)
if (dqopt->flags & DQUOT_QUOTA_SYS_FILE) {
spin_lock(&dq_data_lock);
dqopt->info[type].dqi_flags |= DQF_SYS_FILE;
spin_unlock(&dq_data_lock);
}
spin_lock(&dq_state_lock);
dqopt->flags |= dquot_state_flag(flags, type);
spin_unlock(&dq_state_lock);

4
fs/quota/quota_v1.c
View File

@ -189,7 +189,6 @@ static int v1_write_file_info(struct super_block *sb, int type)
int ret;
down_write(&dqopt->dqio_sem);
dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
ret = sb->s_op->quota_read(sb, type, (char *)&dqblk,
sizeof(struct v1_disk_dqblk), v1_dqoff(0));
if (ret != sizeof(struct v1_disk_dqblk)) {
@ -197,8 +196,11 @@ static int v1_write_file_info(struct super_block *sb, int type)
ret = -EIO;
goto out;
}
spin_lock(&dq_data_lock);
dqopt->info[type].dqi_flags &= ~DQF_INFO_DIRTY;
dqblk.dqb_itime = dqopt->info[type].dqi_igrace;
dqblk.dqb_btime = dqopt->info[type].dqi_bgrace;
spin_unlock(&dq_data_lock);
ret = sb->s_op->quota_write(sb, type, (char *)&dqblk,
sizeof(struct v1_disk_dqblk), v1_dqoff(0));
if (ret == sizeof(struct v1_disk_dqblk))