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quota: decouple fs reserved space from quota reservation
Currently inode_reservation is managed by fs itself and this reservation is transfered on dquot_transfer(). This means what inode_reservation must always be in sync with dquot->dq_dqb.dqb_rsvspace. Otherwise dquot_transfer() will result in incorrect quota(WARN_ON in dquot_claim_reserved_space() will be triggered) This is not easy because of complex locking order issues for example http://bugzilla.kernel.org/show_bug.cgi?id=14739 The patch introduce quota reservation field for each fs-inode (fs specific inode is used in order to prevent bloating generic vfs inode). This reservation is managed by quota code internally similar to i_blocks/i_bytes and may not be always in sync with internal fs reservation. Also perform some code rearrangement: - Unify dquot_reserve_space() and dquot_reserve_space() - Unify dquot_release_reserved_space() and dquot_free_space() - Also this patch add missing warning update to release_rsv() dquot_release_reserved_space() must call flush_warnings() as dquot_free_space() does. Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Dmitry Monakhov
Jan Kara
parent
b462707e7c
commit
fd8fbfc170
2 changed files with 125 additions and 99 deletions
219
fs/quota/dquot.c
219
fs/quota/dquot.c
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@ -1318,6 +1318,67 @@ void vfs_dq_drop(struct inode *inode)
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}
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EXPORT_SYMBOL(vfs_dq_drop);
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/*
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* inode_reserved_space is managed internally by quota, and protected by
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* i_lock similar to i_blocks+i_bytes.
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*/
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static qsize_t *inode_reserved_space(struct inode * inode)
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{
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/* Filesystem must explicitly define it's own method in order to use
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* quota reservation interface */
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BUG_ON(!inode->i_sb->dq_op->get_reserved_space);
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return inode->i_sb->dq_op->get_reserved_space(inode);
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}
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static void inode_add_rsv_space(struct inode *inode, qsize_t number)
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{
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spin_lock(&inode->i_lock);
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*inode_reserved_space(inode) += number;
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spin_unlock(&inode->i_lock);
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}
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static void inode_claim_rsv_space(struct inode *inode, qsize_t number)
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{
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spin_lock(&inode->i_lock);
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*inode_reserved_space(inode) -= number;
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__inode_add_bytes(inode, number);
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spin_unlock(&inode->i_lock);
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}
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static void inode_sub_rsv_space(struct inode *inode, qsize_t number)
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{
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spin_lock(&inode->i_lock);
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*inode_reserved_space(inode) -= number;
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spin_unlock(&inode->i_lock);
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}
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static qsize_t inode_get_rsv_space(struct inode *inode)
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{
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qsize_t ret;
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spin_lock(&inode->i_lock);
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ret = *inode_reserved_space(inode);
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spin_unlock(&inode->i_lock);
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return ret;
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}
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static void inode_incr_space(struct inode *inode, qsize_t number,
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int reserve)
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{
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if (reserve)
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inode_add_rsv_space(inode, number);
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else
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inode_add_bytes(inode, number);
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}
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static void inode_decr_space(struct inode *inode, qsize_t number, int reserve)
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{
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if (reserve)
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inode_sub_rsv_space(inode, number);
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else
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inode_sub_bytes(inode, number);
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}
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/*
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* Following four functions update i_blocks+i_bytes fields and
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* quota information (together with appropriate checks)
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@ -1336,6 +1397,21 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number,
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int cnt, ret = QUOTA_OK;
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char warntype[MAXQUOTAS];
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/*
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* First test before acquiring mutex - solves deadlocks when we
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* re-enter the quota code and are already holding the mutex
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*/
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if (IS_NOQUOTA(inode)) {
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inode_incr_space(inode, number, reserve);
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goto out;
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}
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down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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if (IS_NOQUOTA(inode)) {
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inode_incr_space(inode, number, reserve);
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goto out_unlock;
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}
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for (cnt = 0; cnt < MAXQUOTAS; cnt++)
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warntype[cnt] = QUOTA_NL_NOWARN;
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@ -1346,7 +1422,8 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number,
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if (check_bdq(inode->i_dquot[cnt], number, warn, warntype+cnt)
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== NO_QUOTA) {
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ret = NO_QUOTA;
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goto out_unlock;
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spin_unlock(&dq_data_lock);
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goto out_flush_warn;
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}
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}
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for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
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@ -1357,64 +1434,32 @@ int __dquot_alloc_space(struct inode *inode, qsize_t number,
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else
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dquot_incr_space(inode->i_dquot[cnt], number);
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}
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if (!reserve)
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inode_add_bytes(inode, number);
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out_unlock:
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inode_incr_space(inode, number, reserve);
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spin_unlock(&dq_data_lock);
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if (reserve)
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goto out_flush_warn;
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/* Dirtify all the dquots - this can block when journalling */
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for (cnt = 0; cnt < MAXQUOTAS; cnt++)
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if (inode->i_dquot[cnt])
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mark_dquot_dirty(inode->i_dquot[cnt]);
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out_flush_warn:
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flush_warnings(inode->i_dquot, warntype);
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out_unlock:
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up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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out:
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return ret;
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}
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int dquot_alloc_space(struct inode *inode, qsize_t number, int warn)
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{
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int cnt, ret = QUOTA_OK;
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/*
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* First test before acquiring mutex - solves deadlocks when we
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* re-enter the quota code and are already holding the mutex
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*/
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if (IS_NOQUOTA(inode)) {
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inode_add_bytes(inode, number);
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goto out;
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}
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down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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if (IS_NOQUOTA(inode)) {
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inode_add_bytes(inode, number);
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goto out_unlock;
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}
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ret = __dquot_alloc_space(inode, number, warn, 0);
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if (ret == NO_QUOTA)
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goto out_unlock;
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/* Dirtify all the dquots - this can block when journalling */
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for (cnt = 0; cnt < MAXQUOTAS; cnt++)
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if (inode->i_dquot[cnt])
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mark_dquot_dirty(inode->i_dquot[cnt]);
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out_unlock:
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up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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out:
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return ret;
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return __dquot_alloc_space(inode, number, warn, 0);
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}
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EXPORT_SYMBOL(dquot_alloc_space);
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int dquot_reserve_space(struct inode *inode, qsize_t number, int warn)
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{
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int ret = QUOTA_OK;
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if (IS_NOQUOTA(inode))
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goto out;
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down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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if (IS_NOQUOTA(inode))
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goto out_unlock;
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ret = __dquot_alloc_space(inode, number, warn, 1);
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out_unlock:
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up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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out:
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return ret;
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return __dquot_alloc_space(inode, number, warn, 1);
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}
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EXPORT_SYMBOL(dquot_reserve_space);
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@ -1471,14 +1516,14 @@ int dquot_claim_space(struct inode *inode, qsize_t number)
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int ret = QUOTA_OK;
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if (IS_NOQUOTA(inode)) {
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inode_add_bytes(inode, number);
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inode_claim_rsv_space(inode, number);
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goto out;
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}
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down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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if (IS_NOQUOTA(inode)) {
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up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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inode_add_bytes(inode, number);
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inode_claim_rsv_space(inode, number);
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goto out;
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}
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@ -1490,7 +1535,7 @@ int dquot_claim_space(struct inode *inode, qsize_t number)
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number);
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}
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/* Update inode bytes */
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inode_add_bytes(inode, number);
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inode_claim_rsv_space(inode, number);
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spin_unlock(&dq_data_lock);
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/* Dirtify all the dquots - this can block when journalling */
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for (cnt = 0; cnt < MAXQUOTAS; cnt++)
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@ -1502,39 +1547,10 @@ int dquot_claim_space(struct inode *inode, qsize_t number)
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}
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EXPORT_SYMBOL(dquot_claim_space);
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/*
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* Release reserved quota space
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*/
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void dquot_release_reserved_space(struct inode *inode, qsize_t number)
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{
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int cnt;
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if (IS_NOQUOTA(inode))
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goto out;
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down_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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if (IS_NOQUOTA(inode))
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goto out_unlock;
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spin_lock(&dq_data_lock);
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/* Release reserved dquots */
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for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
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if (inode->i_dquot[cnt])
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dquot_free_reserved_space(inode->i_dquot[cnt], number);
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}
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spin_unlock(&dq_data_lock);
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out_unlock:
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up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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out:
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return;
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}
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EXPORT_SYMBOL(dquot_release_reserved_space);
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/*
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* This operation can block, but only after everything is updated
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*/
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int dquot_free_space(struct inode *inode, qsize_t number)
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int __dquot_free_space(struct inode *inode, qsize_t number, int reserve)
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{
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unsigned int cnt;
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char warntype[MAXQUOTAS];
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@ -1543,7 +1559,7 @@ int dquot_free_space(struct inode *inode, qsize_t number)
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* re-enter the quota code and are already holding the mutex */
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if (IS_NOQUOTA(inode)) {
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out_sub:
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inode_sub_bytes(inode, number);
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inode_decr_space(inode, number, reserve);
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return QUOTA_OK;
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}
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@ -1558,20 +1574,42 @@ int dquot_free_space(struct inode *inode, qsize_t number)
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if (!inode->i_dquot[cnt])
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continue;
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warntype[cnt] = info_bdq_free(inode->i_dquot[cnt], number);
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dquot_decr_space(inode->i_dquot[cnt], number);
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if (reserve)
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dquot_free_reserved_space(inode->i_dquot[cnt], number);
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else
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dquot_decr_space(inode->i_dquot[cnt], number);
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}
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inode_sub_bytes(inode, number);
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inode_decr_space(inode, number, reserve);
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spin_unlock(&dq_data_lock);
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if (reserve)
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goto out_unlock;
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/* Dirtify all the dquots - this can block when journalling */
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for (cnt = 0; cnt < MAXQUOTAS; cnt++)
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if (inode->i_dquot[cnt])
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mark_dquot_dirty(inode->i_dquot[cnt]);
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out_unlock:
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flush_warnings(inode->i_dquot, warntype);
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up_read(&sb_dqopt(inode->i_sb)->dqptr_sem);
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return QUOTA_OK;
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}
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int dquot_free_space(struct inode *inode, qsize_t number)
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{
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return __dquot_free_space(inode, number, 0);
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}
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EXPORT_SYMBOL(dquot_free_space);
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/*
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* Release reserved quota space
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*/
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void dquot_release_reserved_space(struct inode *inode, qsize_t number)
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{
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__dquot_free_space(inode, number, 1);
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}
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EXPORT_SYMBOL(dquot_release_reserved_space);
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/*
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* This operation can block, but only after everything is updated
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*/
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@ -1609,19 +1647,6 @@ int dquot_free_inode(const struct inode *inode, qsize_t number)
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}
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EXPORT_SYMBOL(dquot_free_inode);
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/*
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* call back function, get reserved quota space from underlying fs
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*/
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qsize_t dquot_get_reserved_space(struct inode *inode)
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{
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qsize_t reserved_space = 0;
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if (sb_any_quota_active(inode->i_sb) &&
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inode->i_sb->dq_op->get_reserved_space)
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reserved_space = inode->i_sb->dq_op->get_reserved_space(inode);
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return reserved_space;
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}
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/*
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* Transfer the number of inode and blocks from one diskquota to an other.
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*
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@ -1665,7 +1690,7 @@ int dquot_transfer(struct inode *inode, struct iattr *iattr)
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}
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spin_lock(&dq_data_lock);
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cur_space = inode_get_bytes(inode);
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rsv_space = dquot_get_reserved_space(inode);
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rsv_space = inode_get_rsv_space(inode);
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space = cur_space + rsv_space;
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/* Build the transfer_from list and check the limits */
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for (cnt = 0; cnt < MAXQUOTAS; cnt++) {
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@ -315,8 +315,9 @@ struct dquot_operations {
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int (*claim_space) (struct inode *, qsize_t);
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/* release rsved quota for delayed alloc */
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void (*release_rsv) (struct inode *, qsize_t);
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/* get reserved quota for delayed alloc */
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qsize_t (*get_reserved_space) (struct inode *);
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/* get reserved quota for delayed alloc, value returned is managed by
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* quota code only */
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qsize_t *(*get_reserved_space) (struct inode *);
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};
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/* Operations handling requests from userspace */
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