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Code Issues Releases Wiki Activity

quota: Fix rcu annotations of inode dquot pointers 

Dquot pointers in i_dquot array in the inode are protected by
dquot_srcu. Annotate the array pointers with __rcu, perform the locked
dereferences with srcu_dereference_check() instead of plain reads, and
set the array elements with rcu_assign_pointer().

Fixes: b9ba6f94b2 ("quota: remove dqptr_sem")
Reported-by: kernel test robot <lkp@intel.com>
Closes: https://lore.kernel.org/oe-kbuild-all/202402061900.rTuYDlo6-lkp@intel.com/
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2024-02-06 15:32:09 +01:00
parent 4243bf80c7
commit 179b8c97eb
1 changed files with 39 additions and 27 deletions
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66
fs/quota/dquot.c
View File

@ -399,7 +399,7 @@ int dquot_mark_dquot_dirty(struct dquot *dquot)
EXPORT_SYMBOL(dquot_mark_dquot_dirty);
/* Dirtify all the dquots - this can block when journalling */
static inline int mark_all_dquot_dirty(struct dquot * const *dquots)
static inline int mark_all_dquot_dirty(struct dquot __rcu * const *dquots)
{
int ret, err, cnt;
struct dquot *dquot;
@ -996,14 +996,15 @@ out:
}
EXPORT_SYMBOL(dqget);
static inline struct dquot **i_dquot(struct inode *inode)
static inline struct dquot __rcu **i_dquot(struct inode *inode)
{
return inode->i_sb->s_op->get_dquots(inode);
/* Force __rcu for now until filesystems are fixed */
return (struct dquot __rcu **)inode->i_sb->s_op->get_dquots(inode);
}
static int dqinit_needed(struct inode *inode, int type)
{
struct dquot * const *dquots;
struct dquot __rcu * const *dquots;
int cnt;
if (IS_NOQUOTA(inode))
@ -1093,14 +1094,16 @@ static void remove_dquot_ref(struct super_block *sb, int type)
*/
spin_lock(&dq_data_lock);
if (!IS_NOQUOTA(inode)) {
struct dquot **dquots = i_dquot(inode);
struct dquot *dquot = dquots[type];
struct dquot __rcu **dquots = i_dquot(inode);
struct dquot *dquot = srcu_dereference_check(
dquots[type], &dquot_srcu,
lockdep_is_held(&dq_data_lock));
#ifdef CONFIG_QUOTA_DEBUG
if (unlikely(inode_get_rsv_space(inode) > 0))
reserved = 1;
#endif
dquots[type] = NULL;
rcu_assign_pointer(dquots[type], NULL);
if (dquot)
dqput(dquot);
}
@ -1453,7 +1456,8 @@ static int inode_quota_active(const struct inode *inode)
static int __dquot_initialize(struct inode *inode, int type)
{
int cnt, init_needed = 0;
struct dquot **dquots, *got[MAXQUOTAS] = {};
struct dquot __rcu **dquots;
struct dquot *got[MAXQUOTAS] = {};
struct super_block *sb = inode->i_sb;
qsize_t rsv;
int ret = 0;
@ -1528,7 +1532,7 @@ static int __dquot_initialize(struct inode *inode, int type)
if (!got[cnt])
continue;
if (!dquots[cnt]) {
dquots[cnt] = got[cnt];
rcu_assign_pointer(dquots[cnt], got[cnt]);
got[cnt] = NULL;
/*
* Make quota reservation system happy if someone
@ -1536,12 +1540,16 @@ static int __dquot_initialize(struct inode *inode, int type)
*/
rsv = inode_get_rsv_space(inode);
if (unlikely(rsv)) {
struct dquot *dquot = srcu_dereference_check(
dquots[cnt], &dquot_srcu,
lockdep_is_held(&dq_data_lock));
spin_lock(&inode->i_lock);
/* Get reservation again under proper lock */
rsv = __inode_get_rsv_space(inode);
spin_lock(&dquots[cnt]->dq_dqb_lock);
dquots[cnt]->dq_dqb.dqb_rsvspace += rsv;
spin_unlock(&dquots[cnt]->dq_dqb_lock);
spin_lock(&dquot->dq_dqb_lock);
dquot->dq_dqb.dqb_rsvspace += rsv;
spin_unlock(&dquot->dq_dqb_lock);
spin_unlock(&inode->i_lock);
}
}
@ -1563,7 +1571,7 @@ EXPORT_SYMBOL(dquot_initialize);
bool dquot_initialize_needed(struct inode *inode)
{
struct dquot **dquots;
struct dquot __rcu **dquots;
int i;
if (!inode_quota_active(inode))
@ -1588,13 +1596,14 @@ EXPORT_SYMBOL(dquot_initialize_needed);
static void __dquot_drop(struct inode *inode)
{
int cnt;
struct dquot **dquots = i_dquot(inode);
struct dquot __rcu **dquots = i_dquot(inode);
struct dquot *put[MAXQUOTAS];
spin_lock(&dq_data_lock);
for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
put[cnt] = dquots[cnt];
dquots[cnt] = NULL;
put[cnt] = srcu_dereference_check(dquots[cnt], &dquot_srcu,
lockdep_is_held(&dq_data_lock));
rcu_assign_pointer(dquots[cnt], NULL);
}
spin_unlock(&dq_data_lock);
dqput_all(put);
@ -1602,7 +1611,7 @@ static void __dquot_drop(struct inode *inode)
void dquot_drop(struct inode *inode)
{
struct dquot * const *dquots;
struct dquot __rcu * const *dquots;
int cnt;
if (IS_NOQUOTA(inode))
@ -1675,7 +1684,7 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags)
int cnt, ret = 0, index;
struct dquot_warn warn[MAXQUOTAS];
int reserve = flags & DQUOT_SPACE_RESERVE;
struct dquot **dquots;
struct dquot __rcu **dquots;
struct dquot *dquot;
if (!inode_quota_active(inode)) {
@ -1745,7 +1754,7 @@ int dquot_alloc_inode(struct inode *inode)
{
int cnt, ret = 0, index;
struct dquot_warn warn[MAXQUOTAS];
struct dquot * const *dquots;
struct dquot __rcu * const *dquots;
struct dquot *dquot;
if (!inode_quota_active(inode))
@ -1790,7 +1799,7 @@ EXPORT_SYMBOL(dquot_alloc_inode);
*/
void dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
{
struct dquot **dquots;
struct dquot __rcu **dquots;
struct dquot *dquot;
int cnt, index;
@ -1832,7 +1841,7 @@ EXPORT_SYMBOL(dquot_claim_space_nodirty);
*/
void dquot_reclaim_space_nodirty(struct inode *inode, qsize_t number)
{
struct dquot **dquots;
struct dquot __rcu **dquots;
struct dquot *dquot;
int cnt, index;
@ -1876,7 +1885,7 @@ void __dquot_free_space(struct inode *inode, qsize_t number, int flags)
{
unsigned int cnt;
struct dquot_warn warn[MAXQUOTAS];
struct dquot **dquots;
struct dquot __rcu **dquots;
struct dquot *dquot;
int reserve = flags & DQUOT_SPACE_RESERVE, index;
@ -1933,7 +1942,7 @@ void dquot_free_inode(struct inode *inode)
{
unsigned int cnt;
struct dquot_warn warn[MAXQUOTAS];
struct dquot * const *dquots;
struct dquot __rcu * const *dquots;
struct dquot *dquot;
int index;
@ -1980,6 +1989,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
qsize_t cur_space;
qsize_t rsv_space = 0;
qsize_t inode_usage = 1;
struct dquot __rcu **dquots;
struct dquot *transfer_from[MAXQUOTAS] = {};
int cnt, index, ret = 0;
char is_valid[MAXQUOTAS] = {};
@ -2012,6 +2022,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
}
cur_space = __inode_get_bytes(inode);
rsv_space = __inode_get_rsv_space(inode);
dquots = i_dquot(inode);
/*
* Build the transfer_from list, check limits, and update usage in
* the target structures.
@ -2026,7 +2037,8 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
if (!sb_has_quota_active(inode->i_sb, cnt))
continue;
is_valid[cnt] = 1;
transfer_from[cnt] = i_dquot(inode)[cnt];
transfer_from[cnt] = srcu_dereference_check(dquots[cnt],
&dquot_srcu, lockdep_is_held(&dq_data_lock));
ret = dquot_add_inodes(transfer_to[cnt], inode_usage,
&warn_to[cnt]);
if (ret)
@ -2065,7 +2077,7 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
rsv_space);
spin_unlock(&transfer_from[cnt]->dq_dqb_lock);
}
i_dquot(inode)[cnt] = transfer_to[cnt];
rcu_assign_pointer(dquots[cnt], transfer_to[cnt]);
}
spin_unlock(&inode->i_lock);
spin_unlock(&dq_data_lock);
@ -2076,8 +2088,8 @@ int __dquot_transfer(struct inode *inode, struct dquot **transfer_to)
* mark_all_dquot_dirty().
*/
index = srcu_read_lock(&dquot_srcu);
mark_all_dquot_dirty(transfer_from);
mark_all_dquot_dirty(transfer_to);
mark_all_dquot_dirty((struct dquot __rcu **)transfer_from);
mark_all_dquot_dirty((struct dquot __rcu **)transfer_to);
srcu_read_unlock(&dquot_srcu, index);
flush_warnings(warn_to);