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    Subject[PATCH v18 11/22] vfs: Cache base_acl objects in inodes
    Date
    POSIX ACLs and richacls are both objects allocated by kmalloc() with a
    reference count which are freed by kfree_rcu(). An inode can either
    cache an access and a default POSIX ACL, or a richacl (richacls do not
    have default acls). To allow an inode to cache either of the two kinds
    of acls, introduce a new base_acl type and convert i_acl and
    i_default_acl to that type. In most cases, the vfs then doesn't care which
    kind of acl an inode caches (if any).

    Signed-off-by: Andreas Gruenbacher <agruenba@redhat.com>
    Reviewed-by: Andreas Dilger <adilger@dilger.ca>
    ---
    drivers/staging/lustre/lustre/llite/llite_lib.c | 2 +-
    fs/f2fs/acl.c | 4 +--
    fs/inode.c | 4 +--
    fs/jffs2/acl.c | 10 ++++--
    fs/posix_acl.c | 41 +++++++++++++------------
    fs/richacl_base.c | 4 +--
    include/linux/fs.h | 34 ++++++++++++++++++--
    include/linux/posix_acl.h | 12 +++-----
    include/linux/richacl.h | 9 +++---
    9 files changed, 75 insertions(+), 45 deletions(-)

    diff --git a/drivers/staging/lustre/lustre/llite/llite_lib.c b/drivers/staging/lustre/lustre/llite/llite_lib.c
    index b2fc5b3..b587944 100644
    --- a/drivers/staging/lustre/lustre/llite/llite_lib.c
    +++ b/drivers/staging/lustre/lustre/llite/llite_lib.c
    @@ -1073,7 +1073,7 @@ void ll_clear_inode(struct inode *inode)
    }
    #ifdef CONFIG_FS_POSIX_ACL
    else if (lli->lli_posix_acl) {
    - LASSERT(atomic_read(&lli->lli_posix_acl->a_refcount) == 1);
    + LASSERT(base_acl_refcount(&lli->lli_posix_acl->a_base) == 1);
    LASSERT(lli->lli_remote_perms == NULL);
    posix_acl_release(lli->lli_posix_acl);
    lli->lli_posix_acl = NULL;
    diff --git a/fs/f2fs/acl.c b/fs/f2fs/acl.c
    index c8f25f7..9646197 100644
    --- a/fs/f2fs/acl.c
    +++ b/fs/f2fs/acl.c
    @@ -270,7 +270,7 @@ static struct posix_acl *f2fs_acl_clone(const struct posix_acl *acl,
    sizeof(struct posix_acl_entry);
    clone = kmemdup(acl, size, flags);
    if (clone)
    - atomic_set(&clone->a_refcount, 1);
    + base_acl_init(&clone->a_base);
    }
    return clone;
    }
    @@ -282,7 +282,7 @@ static int f2fs_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
    umode_t mode = *mode_p;
    int not_equiv = 0;

    - /* assert(atomic_read(acl->a_refcount) == 1); */
    + /* assert(base_acl_refcount(&acl->a_base) == 1); */

    FOREACH_ACL_ENTRY(pa, acl, pe) {
    switch(pa->e_tag) {
    diff --git a/fs/inode.c b/fs/inode.c
    index 69b8b52..101d806 100644
    --- a/fs/inode.c
    +++ b/fs/inode.c
    @@ -239,9 +239,9 @@ void __destroy_inode(struct inode *inode)

    #ifdef CONFIG_FS_POSIX_ACL
    if (inode->i_acl && inode->i_acl != ACL_NOT_CACHED)
    - posix_acl_release(inode->i_acl);
    + base_acl_put(inode->i_acl);
    if (inode->i_default_acl && inode->i_default_acl != ACL_NOT_CACHED)
    - posix_acl_release(inode->i_default_acl);
    + base_acl_put(inode->i_default_acl);
    #endif
    this_cpu_dec(nr_inodes);
    }
    diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c
    index 2f7a3c0..569cb1b 100644
    --- a/fs/jffs2/acl.c
    +++ b/fs/jffs2/acl.c
    @@ -294,13 +294,19 @@ int jffs2_init_acl_post(struct inode *inode)
    int rc;

    if (inode->i_default_acl) {
    - rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl);
    + struct posix_acl *default_acl = container_of(
    + inode->i_default_acl, struct posix_acl, a_base);
    +
    + rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, default_acl);
    if (rc)
    return rc;
    }

    if (inode->i_acl) {
    - rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl);
    + struct posix_acl *acl = container_of(
    + inode->i_acl, struct posix_acl, a_base);
    +
    + rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, acl);
    if (rc)
    return rc;
    }
    diff --git a/fs/posix_acl.c b/fs/posix_acl.c
    index 55f2445..743b6dc 100644
    --- a/fs/posix_acl.c
    +++ b/fs/posix_acl.c
    @@ -21,7 +21,7 @@
    #include <linux/export.h>
    #include <linux/user_namespace.h>

    -static struct posix_acl **acl_by_type(struct inode *inode, int type)
    +static struct base_acl **acl_by_type(struct inode *inode, int type)
    {
    switch (type) {
    case ACL_TYPE_ACCESS:
    @@ -35,63 +35,64 @@ static struct posix_acl **acl_by_type(struct inode *inode, int type)

    struct posix_acl *get_cached_acl(struct inode *inode, int type)
    {
    - struct posix_acl **p = acl_by_type(inode, type);
    - struct posix_acl *acl = ACCESS_ONCE(*p);
    + struct base_acl **p = acl_by_type(inode, type);
    + struct base_acl *acl = ACCESS_ONCE(*p);
    if (acl) {
    spin_lock(&inode->i_lock);
    acl = *p;
    if (acl != ACL_NOT_CACHED)
    - acl = posix_acl_dup(acl);
    + base_acl_get(acl);
    spin_unlock(&inode->i_lock);
    }
    - return acl;
    + return container_of(acl, struct posix_acl, a_base);
    }
    EXPORT_SYMBOL(get_cached_acl);

    struct posix_acl *get_cached_acl_rcu(struct inode *inode, int type)
    {
    - return rcu_dereference(*acl_by_type(inode, type));
    + struct base_acl *acl = rcu_dereference(*acl_by_type(inode, type));
    + return container_of(acl, struct posix_acl, a_base);
    }
    EXPORT_SYMBOL(get_cached_acl_rcu);

    void set_cached_acl(struct inode *inode, int type, struct posix_acl *acl)
    {
    - struct posix_acl **p = acl_by_type(inode, type);
    - struct posix_acl *old;
    + struct base_acl **p = acl_by_type(inode, type);
    + struct base_acl *old;
    spin_lock(&inode->i_lock);
    old = *p;
    - rcu_assign_pointer(*p, posix_acl_dup(acl));
    + rcu_assign_pointer(*p, &posix_acl_dup(acl)->a_base);
    spin_unlock(&inode->i_lock);
    if (old != ACL_NOT_CACHED)
    - posix_acl_release(old);
    + base_acl_put(old);
    }
    EXPORT_SYMBOL(set_cached_acl);

    void forget_cached_acl(struct inode *inode, int type)
    {
    - struct posix_acl **p = acl_by_type(inode, type);
    - struct posix_acl *old;
    + struct base_acl **p = acl_by_type(inode, type);
    + struct base_acl *old;
    spin_lock(&inode->i_lock);
    old = *p;
    *p = ACL_NOT_CACHED;
    spin_unlock(&inode->i_lock);
    if (old != ACL_NOT_CACHED)
    - posix_acl_release(old);
    + base_acl_put(old);
    }
    EXPORT_SYMBOL(forget_cached_acl);

    void forget_all_cached_acls(struct inode *inode)
    {
    - struct posix_acl *old_access, *old_default;
    + struct base_acl *old_access, *old_default;
    spin_lock(&inode->i_lock);
    old_access = inode->i_acl;
    old_default = inode->i_default_acl;
    inode->i_acl = inode->i_default_acl = ACL_NOT_CACHED;
    spin_unlock(&inode->i_lock);
    if (old_access != ACL_NOT_CACHED)
    - posix_acl_release(old_access);
    + base_acl_put(old_access);
    if (old_default != ACL_NOT_CACHED)
    - posix_acl_release(old_default);
    + base_acl_put(old_default);
    }
    EXPORT_SYMBOL(forget_all_cached_acls);

    @@ -128,7 +129,7 @@ EXPORT_SYMBOL(get_acl);
    void
    posix_acl_init(struct posix_acl *acl, int count)
    {
    - atomic_set(&acl->a_refcount, 1);
    + base_acl_init(&acl->a_base);
    acl->a_count = count;
    }
    EXPORT_SYMBOL(posix_acl_init);
    @@ -161,7 +162,7 @@ posix_acl_clone(const struct posix_acl *acl, gfp_t flags)
    sizeof(struct posix_acl_entry);
    clone = kmemdup(acl, size, flags);
    if (clone)
    - atomic_set(&clone->a_refcount, 1);
    + base_acl_init(&clone->a_base);
    }
    return clone;
    }
    @@ -383,7 +384,7 @@ static int posix_acl_create_masq(struct posix_acl *acl, umode_t *mode_p)
    umode_t mode = *mode_p;
    int not_equiv = 0;

    - /* assert(atomic_read(acl->a_refcount) == 1); */
    + /* assert(base_acl_refcount(&acl->a_base) == 1); */

    FOREACH_ACL_ENTRY(pa, acl, pe) {
    switch(pa->e_tag) {
    @@ -438,7 +439,7 @@ static int __posix_acl_chmod_masq(struct posix_acl *acl, umode_t mode)
    struct posix_acl_entry *group_obj = NULL, *mask_obj = NULL;
    struct posix_acl_entry *pa, *pe;

    - /* assert(atomic_read(acl->a_refcount) == 1); */
    + /* assert(base_acl_refcount(&acl->a_base) == 1); */

    FOREACH_ACL_ENTRY(pa, acl, pe) {
    switch(pa->e_tag) {
    diff --git a/fs/richacl_base.c b/fs/richacl_base.c
    index 69b806c..5826842 100644
    --- a/fs/richacl_base.c
    +++ b/fs/richacl_base.c
    @@ -33,7 +33,7 @@ richacl_alloc(int count, gfp_t gfp)
    struct richacl *acl = kzalloc(size, gfp);

    if (acl) {
    - atomic_set(&acl->a_refcount, 1);
    + base_acl_init(&acl->a_base);
    acl->a_count = count;
    }
    return acl;
    @@ -52,7 +52,7 @@ richacl_clone(const struct richacl *acl, gfp_t gfp)

    if (dup) {
    memcpy(dup, acl, size);
    - atomic_set(&dup->a_refcount, 1);
    + base_acl_init(&dup->a_base);
    }
    return dup;
    }
    diff --git a/include/linux/fs.h b/include/linux/fs.h
    index 0f560b7..3db7729 100644
    --- a/include/linux/fs.h
    +++ b/include/linux/fs.h
    @@ -578,6 +578,12 @@ static inline void mapping_allow_writable(struct address_space *mapping)
    #define i_size_ordered_init(inode) do { } while (0)
    #endif

    +struct base_acl {
    + union {
    + atomic_t ba_refcount;
    + struct rcu_head ba_rcu;
    + };
    +};
    struct posix_acl;
    #define ACL_NOT_CACHED ((void *)(-1))

    @@ -597,9 +603,9 @@ struct inode {
    kgid_t i_gid;
    unsigned int i_flags;

    -#ifdef CONFIG_FS_POSIX_ACL
    - struct posix_acl *i_acl;
    - struct posix_acl *i_default_acl;
    +#if defined(CONFIG_FS_POSIX_ACL)
    + struct base_acl *i_acl;
    + struct base_acl *i_default_acl;
    #endif

    const struct inode_operations *i_op;
    @@ -3097,4 +3103,26 @@ static inline bool dir_relax(struct inode *inode)
    extern bool path_noexec(const struct path *path);
    extern void inode_nohighmem(struct inode *inode);

    +static inline void base_acl_get(struct base_acl *acl)
    +{
    + if (acl)
    + atomic_inc(&acl->ba_refcount);
    +}
    +
    +static inline void base_acl_put(struct base_acl *acl)
    +{
    + if (acl && atomic_dec_and_test(&acl->ba_refcount))
    + kfree_rcu(acl, ba_rcu);
    +}
    +
    +static inline void base_acl_init(struct base_acl *acl)
    +{
    + atomic_set(&acl->ba_refcount, 1);
    +}
    +
    +static inline int base_acl_refcount(struct base_acl *acl)
    +{
    + return atomic_read(&acl->ba_refcount);
    +}
    +
    #endif /* _LINUX_FS_H */
    diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h
    index 5b5a80c..cef5428 100644
    --- a/include/linux/posix_acl.h
    +++ b/include/linux/posix_acl.h
    @@ -43,10 +43,7 @@ struct posix_acl_entry {
    };

    struct posix_acl {
    - union {
    - atomic_t a_refcount;
    - struct rcu_head a_rcu;
    - };
    + struct base_acl a_base; /* must be first, see posix_acl_release() */
    unsigned int a_count;
    struct posix_acl_entry a_entries[0];
    };
    @@ -61,8 +58,7 @@ struct posix_acl {
    static inline struct posix_acl *
    posix_acl_dup(struct posix_acl *acl)
    {
    - if (acl)
    - atomic_inc(&acl->a_refcount);
    + base_acl_get(&acl->a_base);
    return acl;
    }

    @@ -72,8 +68,8 @@ posix_acl_dup(struct posix_acl *acl)
    static inline void
    posix_acl_release(struct posix_acl *acl)
    {
    - if (acl && atomic_dec_and_test(&acl->a_refcount))
    - kfree_rcu(acl, a_rcu);
    + BUILD_BUG_ON(offsetof(struct posix_acl, a_base) != 0);
    + base_acl_put(&acl->a_base);
    }


    diff --git a/include/linux/richacl.h b/include/linux/richacl.h
    index 1d9f5f7..7628fad 100644
    --- a/include/linux/richacl.h
    +++ b/include/linux/richacl.h
    @@ -31,7 +31,7 @@ struct richace {
    };

    struct richacl {
    - atomic_t a_refcount;
    + struct base_acl a_base; /* must be first, see richacl_put() */
    unsigned int a_owner_mask;
    unsigned int a_group_mask;
    unsigned int a_other_mask;
    @@ -56,8 +56,7 @@ struct richacl {
    static inline struct richacl *
    richacl_get(struct richacl *acl)
    {
    - if (acl)
    - atomic_inc(&acl->a_refcount);
    + base_acl_get(&acl->a_base);
    return acl;
    }

    @@ -67,8 +66,8 @@ richacl_get(struct richacl *acl)
    static inline void
    richacl_put(struct richacl *acl)
    {
    - if (acl && atomic_dec_and_test(&acl->a_refcount))
    - kfree(acl);
    + BUILD_BUG_ON(offsetof(struct richacl, a_base) != 0);
    + base_acl_put(&acl->a_base);
    }

    /**
    --
    2.4.3
    \
     
     \ /
      Last update: 2016-02-29 10:01    [W:3.372 / U:1.400 seconds]
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