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Groups > linux.kernel > #1262624
| From | Andreas Gruenbacher <agruenba@redhat.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v13 10/51] vfs: Cache base_acl objects in inodes |
| Date | 2015-11-04 23:00 +0100 |
| Message-ID | <qreg2-62z-7@gated-at.bofh.it> (permalink) |
| References | <qqLxo-4or-5@gated-at.bofh.it> <qqLxo-4or-19@gated-at.bofh.it> <qqSpb-nO-1@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
Andreas,
On Tue, Nov 3, 2015 at 11:29 PM, Andreas Dilger <adilger@dilger.ca> wrote:
> On Nov 3, 2015, at 8:16 AM, Andreas Gruenbacher <agruenba@redhat.com> wrote:
>>
>> 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 have to
>> care which kind of acl an inode caches (if any).
>
> For new wrapper functions like this better to name them as "NOUN_VERB" so
> rather than "VERB_NOUN" so that related functions sort together, like
> base_acl_init(), base_acl_get(), base_acl_put(), base_acl_refcount(), etc.
That's better, yes. I agree with all your comments and I've changed
things accordingly.
>> @@ -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);
>> + atomic_set(&clone->a_base.ba_refcount, 1);
>
> This should be base_acl_init() since this should also reset the RCU state
> if it was just copied from "acl" above.
Yes. The rcu_head doesn't need initializing or resetting though.
> That wouldn't be quite correct if
> there are other fields added to struct base_acl that don't need to be
> initialized when it is copied, so possibly base_acl_reinit() would be better
> here and below if that will be the case in the near future (I haven't looked
> through the whole patch series yet).
We won't need a base_acl_reinit() function for now.
>> @@ -25,9 +25,9 @@ struct posix_acl **acl_by_type(struct inode *inode, int type)
>> {
>> switch (type) {
>> case ACL_TYPE_ACCESS:
>> - return &inode->i_acl;
>> + return (struct posix_acl **)&inode->i_acl;
>> case ACL_TYPE_DEFAULT:
>> - return &inode->i_default_acl;
>> + return (struct posix_acl **)&inode->i_default_acl;
>
> This would be better to use container_of() to unwrap struct base_acl from
> struct posix_acl. That avoids the hard requirement (which isn't documented
> anywhere) that base_acl needs to be the first member of struct posix_acl.
>
> I was originally going to write that you should add a comment that base_acl
> needs to be the first member of both richacl and posix_acl, but container_of()
> is both cleaner and safer.
>
> Looking further down, that IS actually needed due to the way kfree is used on
> the base_acl pointer, but using container_of() is still cleaner and safer
> than directly casting double pointers (which some compilers and static
> analysis tools will be unhappy with).
Well, we would end up with &container_of() here which doesn't work and
doesn't make sense, either. Let me change acl_by_type to return a
base_acl ** to clean this up.
>> @@ -576,6 +576,12 @@ 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;
>
> Is this forward declaration of struct posix_acl even needed anymore after
> the change below? There shouldn't be references to the struct in the common
> code anymore (at least not by the end of the patch series.
The get_acl and set_acl inode operations expect struct posix_acl to be declared.
> Hmm, using the base_acl pointer as the pointer to kfree means that the
> base_acl structure DOES need to be the first one in both struct posix_acl
> and struct richacl, so that needs to be commented at each structure so
> it doesn't accidentally break in the future.
Yes. I've added comments; there are also BUILD_BUG_ON() asserts in
posix_acl_release and richacl_put.
>> @@ -57,7 +57,7 @@ static inline struct richacl *
>> richacl_get(struct richacl *acl)
>> {
>> if (acl)
>> - atomic_inc(&acl->a_refcount);
>> + atomic_inc(&acl->a_base.ba_refcount);
>> return acl;
>
> This should also use base_acl_get() for consistency. That said, where is
> the call to base_acl_put() in the richacl code?
> Also, where is the change to struct richacl? It looks like this patch would
> not be able to compile by itself.
Ah, a little problem in how the patches are split. I've fixed it. This
code doesn't get pulled into the build because nothing requires
CONFIG_FS_RICHACL at that point; that's why I didn't notice.
Thanks,
Andreas
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[PATCH v13 00/51] Richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
[PATCH v13 08/51] richacl: Compute maximum file masks from an acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
[PATCH v13 10/51] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
Re: [PATCH v13 10/51] vfs: Cache base_acl objects in inodes Andreas Dilger <adilger@dilger.ca> - 2015-11-03 23:40 +0100
Re: [PATCH v13 10/51] vfs: Cache base_acl objects in inodes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 23:00 +0100
[PATCH v13 07/51] richacl: Permission mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
[PATCH v13 02/51] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
Re: [PATCH v13 02/51] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:40 +0100
Re: [PATCH v13 02/51] vfs: Add MAY_CREATE_FILE and MAY_CREATE_DIR permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 04:10 +0100
[PATCH v13 11/51] vfs: Add get_richacl and set_richacl inode operations Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
[PATCH v13 04/51] vfs: Make the inode passed to inode_change_ok non-const Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
[PATCH v13 12/51] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
Re: [PATCH v13 12/51] vfs: Cache richacl in struct inode Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:10 +0100
Re: [PATCH v13 12/51] vfs: Cache richacl in struct inode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 23:20 +0100
[PATCH v13 05/51] vfs: Add permission flags for setting file attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
[PATCH v13 06/51] richacl: In-memory representation and helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:20 +0100
[PATCH v13 29/51] richacl: Move everyone@ aces down the acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 50/51] nfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 30/51] richacl: Propagate everyone@ permissions to other aces Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 40/51] nfsd: Add support for the MAY_CREATE_{FILE,DIR} permissions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 43/51] ext4: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
Re: [PATCH v13 43/51] ext4: Don't allow unmapped identifiers in richacls Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:30 +0100
[PATCH v13 26/51] xfs: Plug memory leak in xfs_attrmulti_attr_set Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
Re: [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to encode into Trond Myklebust <trond.myklebust@primarydata.com> - 2015-11-03 17:30 +0100
Re: [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-05 12:10 +0100
Re: [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to encode into Trond Myklebust <trond.myklebust@primarydata.com> - 2015-11-05 17:00 +0100
Re: [PATCH v13 45/51] sunrpc: Allow to demand-allocate pages to encode into Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-08 23:20 +0100
[PATCH v13 48/51] nfs: Remove unused xdr page offsets in getacl/setacl arguments Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 51/51] nfs: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 39/51] nfsd: Add support for the v4.1 dacl attribute Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 32/51] richacl: Set the other permissions to the other mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 33/51] richacl: Isolate the owner and group classes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 28/51] richacl: acl editing helper functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 47/51] nfs: Fix GETATTR bitmap verification Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
Re: [PATCH v13 47/51] nfs: Fix GETATTR bitmap verification Trond Myklebust <trond.myklebust@primarydata.com> - 2015-11-03 17:40 +0100
[PATCH v13 42/51] nfsd: Add support for unmapped richace identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 19/51] vfs: Add richacl permission checking Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 25/51] xfs: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 44/51] xfs: Don't allow unmapped identifiers in richacls Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 46/51] sunrpc: Add xdr_init_encode_pages Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 49/51] nfs: Distinguish missing users and groups from nobody Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 41/51] richacl: Add support for unmapped identifiers Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 38/51] nfsd: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 36/51] nfsd: Keep list of acls to dispose of in compoundargs Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:30 +0100
[PATCH v13 37/51] nfsd: Use richacls as internal acl representation Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:40 +0100
[PATCH v13 35/51] richacl: Create richacl from mode values Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:40 +0100
[PATCH v13 31/51] richacl: Set the owner permissions to the owner mask Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:50 +0100
[PATCH v13 34/51] richacl: Apply the file masks to a richacl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:50 +0100
[PATCH v13 27/51] xfs: Fix richacl access by ioctl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 16:50 +0100
[PATCH v13 16/51] richacl: Automatic Inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
[PATCH v13 15/51] richacl: Create-time inheritance Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
[PATCH v13 24/51] xfs: Change how listxattr generates synthetic attributes Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
[PATCH v13 21/51] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
Re: [PATCH v13 21/51] ext4: Add richacl feature flag Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:20 +0100
Re: [PATCH v13 21/51] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 03:30 +0100
Re: [PATCH v13 21/51] ext4: Add richacl feature flag Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 03:50 +0100
[PATCH v13 14/51] richacl: Check if an acl is equivalent to a file mode Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
[PATCH v13 20/51] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
Re: [PATCH v13 20/51] ext4: Add richacl support Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-04 03:20 +0100
Re: [PATCH v13 20/51] ext4: Add richacl support Andreas Dilger <adilger@dilger.ca> - 2015-11-04 03:20 +0100
[PATCH v13 18/51] richacl: Add richacl xattr handler Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
[PATCH v13 22/51] xfs: Fix error path in xfs_get_acl Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
[PATCH v13 23/51] xfs: Make xfs_set_mode non-static Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
[PATCH v13 13/51] richacl: Update the file masks in chmod() Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:00 +0100
[PATCH v13 09/51] richacl: Permission check algorithm Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:10 +0100
[PATCH v13 17/51] richacl: xattr mapping functions Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:10 +0100
[PATCH v13 03/51] vfs: Add MAY_DELETE_SELF and MAY_DELETE_CHILD permission flags Andreas Gruenbacher <agruenba@redhat.com> - 2015-11-03 17:20 +0100
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