linux-stable/include/linux/quotaops.h
Jan Kara f00c9e44ad quota: Fix deadlock during path resolution
As Al Viro pointed out path resolution during Q_QUOTAON calls to quotactl
is prone to deadlocks. We hold s_umount semaphore for reading during the
path resolution and resolution itself may need to acquire the semaphore
for writing when e. g. autofs mountpoint is passed.

Solve the problem by performing the resolution before we get hold of the
superblock (and thus s_umount semaphore). The whole thing is complicated
by the fact that some filesystems (OCFS2) ignore the path argument. So to
distinguish between filesystem which want the path and which do not we
introduce new .quota_on_meta callback which does not get the path. OCFS2
then uses this callback instead of old .quota_on.

CC: Al Viro <viro@ZenIV.linux.org.uk>
CC: Christoph Hellwig <hch@lst.de>
CC: Ted Ts'o <tytso@mit.edu>
CC: Joel Becker <joel.becker@oracle.com>
Signed-off-by: Jan Kara <jack@suse.cz>
2011-01-12 19:14:55 +01:00

360 lines
9.3 KiB
C

/*
* Definitions for diskquota-operations. When diskquota is configured these
* macros expand to the right source-code.
*
* Author: Marco van Wieringen <mvw@planets.elm.net>
*/
#ifndef _LINUX_QUOTAOPS_
#define _LINUX_QUOTAOPS_
#include <linux/fs.h>
#define DQUOT_SPACE_WARN 0x1
#define DQUOT_SPACE_RESERVE 0x2
#define DQUOT_SPACE_NOFAIL 0x4
static inline struct quota_info *sb_dqopt(struct super_block *sb)
{
return &sb->s_dquot;
}
/* i_mutex must being held */
static inline bool is_quota_modification(struct inode *inode, struct iattr *ia)
{
return (ia->ia_valid & ATTR_SIZE && ia->ia_size != inode->i_size) ||
(ia->ia_valid & ATTR_UID && ia->ia_uid != inode->i_uid) ||
(ia->ia_valid & ATTR_GID && ia->ia_gid != inode->i_gid);
}
#if defined(CONFIG_QUOTA)
#define quota_error(sb, fmt, args...) \
__quota_error((sb), __func__, fmt , ## args)
extern __attribute__((format (printf, 3, 4)))
void __quota_error(struct super_block *sb, const char *func,
const char *fmt, ...);
/*
* declaration of quota_function calls in kernel.
*/
void inode_add_rsv_space(struct inode *inode, qsize_t number);
void inode_claim_rsv_space(struct inode *inode, qsize_t number);
void inode_sub_rsv_space(struct inode *inode, qsize_t number);
void dquot_initialize(struct inode *inode);
void dquot_drop(struct inode *inode);
struct dquot *dqget(struct super_block *sb, unsigned int id, int type);
void dqput(struct dquot *dquot);
int dquot_scan_active(struct super_block *sb,
int (*fn)(struct dquot *dquot, unsigned long priv),
unsigned long priv);
struct dquot *dquot_alloc(struct super_block *sb, int type);
void dquot_destroy(struct dquot *dquot);
int __dquot_alloc_space(struct inode *inode, qsize_t number, int flags);
void __dquot_free_space(struct inode *inode, qsize_t number, int flags);
int dquot_alloc_inode(const struct inode *inode);
int dquot_claim_space_nodirty(struct inode *inode, qsize_t number);
void dquot_free_inode(const struct inode *inode);
int dquot_disable(struct super_block *sb, int type, unsigned int flags);
/* Suspend quotas on remount RO */
static inline int dquot_suspend(struct super_block *sb, int type)
{
return dquot_disable(sb, type, DQUOT_SUSPENDED);
}
int dquot_resume(struct super_block *sb, int type);
int dquot_commit(struct dquot *dquot);
int dquot_acquire(struct dquot *dquot);
int dquot_release(struct dquot *dquot);
int dquot_commit_info(struct super_block *sb, int type);
int dquot_mark_dquot_dirty(struct dquot *dquot);
int dquot_file_open(struct inode *inode, struct file *file);
int dquot_enable(struct inode *inode, int type, int format_id,
unsigned int flags);
int dquot_quota_on(struct super_block *sb, int type, int format_id,
struct path *path);
int dquot_quota_on_mount(struct super_block *sb, char *qf_name,
int format_id, int type);
int dquot_quota_off(struct super_block *sb, int type);
int dquot_quota_sync(struct super_block *sb, int type, int wait);
int dquot_get_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);
int dquot_set_dqinfo(struct super_block *sb, int type, struct if_dqinfo *ii);
int dquot_get_dqblk(struct super_block *sb, int type, qid_t id,
struct fs_disk_quota *di);
int dquot_set_dqblk(struct super_block *sb, int type, qid_t id,
struct fs_disk_quota *di);
int __dquot_transfer(struct inode *inode, struct dquot **transfer_to);
int dquot_transfer(struct inode *inode, struct iattr *iattr);
static inline struct mem_dqinfo *sb_dqinfo(struct super_block *sb, int type)
{
return sb_dqopt(sb)->info + type;
}
/*
* Functions for checking status of quota
*/
static inline bool sb_has_quota_usage_enabled(struct super_block *sb, int type)
{
return sb_dqopt(sb)->flags &
dquot_state_flag(DQUOT_USAGE_ENABLED, type);
}
static inline bool sb_has_quota_limits_enabled(struct super_block *sb, int type)
{
return sb_dqopt(sb)->flags &
dquot_state_flag(DQUOT_LIMITS_ENABLED, type);
}
static inline bool sb_has_quota_suspended(struct super_block *sb, int type)
{
return sb_dqopt(sb)->flags &
dquot_state_flag(DQUOT_SUSPENDED, type);
}
static inline unsigned sb_any_quota_suspended(struct super_block *sb)
{
unsigned type, tmsk = 0;
for (type = 0; type < MAXQUOTAS; type++)
tmsk |= sb_has_quota_suspended(sb, type) << type;
return tmsk;
}
/* Does kernel know about any quota information for given sb + type? */
static inline bool sb_has_quota_loaded(struct super_block *sb, int type)
{
/* Currently if anything is on, then quota usage is on as well */
return sb_has_quota_usage_enabled(sb, type);
}
static inline unsigned sb_any_quota_loaded(struct super_block *sb)
{
unsigned type, tmsk = 0;
for (type = 0; type < MAXQUOTAS; type++)
tmsk |= sb_has_quota_loaded(sb, type) << type;
return tmsk;
}
static inline bool sb_has_quota_active(struct super_block *sb, int type)
{
return sb_has_quota_loaded(sb, type) &&
!sb_has_quota_suspended(sb, type);
}
/*
* Operations supported for diskquotas.
*/
extern const struct dquot_operations dquot_operations;
extern const struct quotactl_ops dquot_quotactl_ops;
#else
static inline int sb_has_quota_usage_enabled(struct super_block *sb, int type)
{
return 0;
}
static inline int sb_has_quota_limits_enabled(struct super_block *sb, int type)
{
return 0;
}
static inline int sb_has_quota_suspended(struct super_block *sb, int type)
{
return 0;
}
static inline int sb_any_quota_suspended(struct super_block *sb)
{
return 0;
}
/* Does kernel know about any quota information for given sb + type? */
static inline int sb_has_quota_loaded(struct super_block *sb, int type)
{
return 0;
}
static inline int sb_any_quota_loaded(struct super_block *sb)
{
return 0;
}
static inline int sb_has_quota_active(struct super_block *sb, int type)
{
return 0;
}
static inline void dquot_initialize(struct inode *inode)
{
}
static inline void dquot_drop(struct inode *inode)
{
}
static inline int dquot_alloc_inode(const struct inode *inode)
{
return 0;
}
static inline void dquot_free_inode(const struct inode *inode)
{
}
static inline int dquot_transfer(struct inode *inode, struct iattr *iattr)
{
return 0;
}
static inline int __dquot_alloc_space(struct inode *inode, qsize_t number,
int flags)
{
if (!(flags & DQUOT_SPACE_RESERVE))
inode_add_bytes(inode, number);
return 0;
}
static inline void __dquot_free_space(struct inode *inode, qsize_t number,
int flags)
{
if (!(flags & DQUOT_SPACE_RESERVE))
inode_sub_bytes(inode, number);
}
static inline int dquot_claim_space_nodirty(struct inode *inode, qsize_t number)
{
inode_add_bytes(inode, number);
return 0;
}
static inline int dquot_disable(struct super_block *sb, int type,
unsigned int flags)
{
return 0;
}
static inline int dquot_suspend(struct super_block *sb, int type)
{
return 0;
}
static inline int dquot_resume(struct super_block *sb, int type)
{
return 0;
}
#define dquot_file_open generic_file_open
#endif /* CONFIG_QUOTA */
static inline int dquot_alloc_space_nodirty(struct inode *inode, qsize_t nr)
{
return __dquot_alloc_space(inode, nr, DQUOT_SPACE_WARN);
}
static inline void dquot_alloc_space_nofail(struct inode *inode, qsize_t nr)
{
__dquot_alloc_space(inode, nr, DQUOT_SPACE_WARN|DQUOT_SPACE_NOFAIL);
mark_inode_dirty_sync(inode);
}
static inline int dquot_alloc_space(struct inode *inode, qsize_t nr)
{
int ret;
ret = dquot_alloc_space_nodirty(inode, nr);
if (!ret) {
/*
* Mark inode fully dirty. Since we are allocating blocks, inode
* would become fully dirty soon anyway and it reportedly
* reduces inode_lock contention.
*/
mark_inode_dirty(inode);
}
return ret;
}
static inline int dquot_alloc_block_nodirty(struct inode *inode, qsize_t nr)
{
return dquot_alloc_space_nodirty(inode, nr << inode->i_blkbits);
}
static inline void dquot_alloc_block_nofail(struct inode *inode, qsize_t nr)
{
dquot_alloc_space_nofail(inode, nr << inode->i_blkbits);
}
static inline int dquot_alloc_block(struct inode *inode, qsize_t nr)
{
return dquot_alloc_space(inode, nr << inode->i_blkbits);
}
static inline int dquot_prealloc_block_nodirty(struct inode *inode, qsize_t nr)
{
return __dquot_alloc_space(inode, nr << inode->i_blkbits, 0);
}
static inline int dquot_prealloc_block(struct inode *inode, qsize_t nr)
{
int ret;
ret = dquot_prealloc_block_nodirty(inode, nr);
if (!ret)
mark_inode_dirty_sync(inode);
return ret;
}
static inline int dquot_reserve_block(struct inode *inode, qsize_t nr)
{
return __dquot_alloc_space(inode, nr << inode->i_blkbits,
DQUOT_SPACE_WARN|DQUOT_SPACE_RESERVE);
}
static inline int dquot_claim_block(struct inode *inode, qsize_t nr)
{
int ret;
ret = dquot_claim_space_nodirty(inode, nr << inode->i_blkbits);
if (!ret)
mark_inode_dirty_sync(inode);
return ret;
}
static inline void dquot_free_space_nodirty(struct inode *inode, qsize_t nr)
{
__dquot_free_space(inode, nr, 0);
}
static inline void dquot_free_space(struct inode *inode, qsize_t nr)
{
dquot_free_space_nodirty(inode, nr);
mark_inode_dirty_sync(inode);
}
static inline void dquot_free_block_nodirty(struct inode *inode, qsize_t nr)
{
dquot_free_space_nodirty(inode, nr << inode->i_blkbits);
}
static inline void dquot_free_block(struct inode *inode, qsize_t nr)
{
dquot_free_space(inode, nr << inode->i_blkbits);
}
static inline void dquot_release_reservation_block(struct inode *inode,
qsize_t nr)
{
__dquot_free_space(inode, nr << inode->i_blkbits, DQUOT_SPACE_RESERVE);
}
#endif /* _LINUX_QUOTAOPS_ */