Re: [PATCH v7 03/19] xfs: Add xfs_has_attr and subroutines

Allison Collins
2020-02-26T02:33:23Z

On 2/25/20 6:25 AM, Brian Foster wrote:
> On Mon, Feb 24, 2020 at 02:18:35PM -0700, Allison Collins wrote:
>>
>>
>> On 2/24/20 6:08 AM, Brian Foster wrote:
>>> On Sat, Feb 22, 2020 at 07:05:55PM -0700, Allison Collins wrote:
>>>> From: Allison Henderson <allison.henderson@oracle.com>
>>>>
>>>> This patch adds a new functions to check for the existence of an attribute.
>>>> Subroutines are also added to handle the cases of leaf blocks, nodes or shortform.
>>>> Common code that appears in existing attr add and remove functions have been
>>>> factored out to help reduce the appearance of duplicated code. We will need these
>>>> routines later for delayed attributes since delayed operations cannot return error
>>>> codes.
>>>>
>>>> Signed-off-by: Allison Collins <allison.henderson@oracle.com>
>>>> ---
>>>> fs/xfs/libxfs/xfs_attr.c | 171 ++++++++++++++++++++++++++++--------------
>>>> fs/xfs/libxfs/xfs_attr.h | 1 +
>>>> fs/xfs/libxfs/xfs_attr_leaf.c | 111 +++++++++++++++++----------
>>>> fs/xfs/libxfs/xfs_attr_leaf.h | 3 +
>>>> 4 files changed, 188 insertions(+), 98 deletions(-)
>>>>
>>>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>>>> index 9acdb23..2255060 100644
>>>> --- a/fs/xfs/libxfs/xfs_attr.c
>>>> +++ b/fs/xfs/libxfs/xfs_attr.c
>>> ...
>>>> @@ -310,6 +313,37 @@ xfs_attr_set_args(
>>>> }
>>>> /*
>>>> + * Return EEXIST if attr is found, or ENOATTR if not
>>>> + */
>>>> +int
>>>> +xfs_has_attr(
>>>> + struct xfs_da_args *args)
>>>> +{
>>>> + struct xfs_inode *dp = args->dp;
>>>> + struct xfs_buf *bp = NULL;
>>>> + int error;
>>>> +
>>>> + if (!xfs_inode_hasattr(dp))
>>>> + return -ENOATTR;
>>>> +
>>>> + if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
>>>> + ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
>>>> + return xfs_attr_sf_findname(args, NULL, NULL);
>>>
>>> Nit: any reason we use "findname" here and "hasname" for the other two
>>> variants?
>> It was asked for in the v4 review. Reason being we also return the location
>> of the sf entry and byte offset.
>>
>
> Ok.
>
>>>
>>> Just a few other nit level things..
>>>
>>>> + }
>>>> +
>>>> + if (xfs_bmap_one_block(dp, XFS_ATTR_FORK)) {
>>>> + error = xfs_attr_leaf_hasname(args, &bp);
>>>> +
>>>> + if (bp)
>>>> + xfs_trans_brelse(args->trans, bp);
>>>> +
>>>> + return error;
>>>> + }
>>>> +
>>>> + return xfs_attr_node_hasname(args, NULL);
>>>> +}
>>>> +
>>>> +/*
>>>> * Remove the attribute specified in @args.
>>>> */
>>>> int
>>> ...
>>>> @@ -773,12 +822,11 @@ xfs_attr_leaf_removename(
>>>> * Remove the attribute.
>>>> */
>>>> dp = args->dp;
>>>> - args->blkno = 0;
>>>> - error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, &bp);
>>>> - if (error)
>>>> +
>>>> + error = xfs_attr_leaf_hasname(args, &bp);
>>>> + if (error != -ENOATTR && error != -EEXIST)
>>>> return error;
>>>> - error = xfs_attr3_leaf_lookup_int(bp, args);
>>>> if (error == -ENOATTR) {
>>>
>>> It looks like some of these error checks could be cleaned up where the
>>> helper function is used. I.e., something like the following here:
>>>
>>> if (error == -ENOATTR) {
>>> xfs_trans_brelse(...);
>>> return error;
>>> } else if (error != -EEXIST)
>>> return error;
>> Sure, I'm starting to get more pressure in other reviews to change this api
>> to a boolean return type though (1: y, 0: no, <0: error). I think we talked
>> about this in v3, but decided to stick with this original api for now. I'm
>> thinking maybe adding a patch at the end to shift the api might be a good
>> compromise? Thoughts?
>>
>
> I think Dave commented on this earlier with regard to some of these API
> cleanups being orthogonal to this work. The big challenge with this
> series is really taking apart this big tangle of xattr code such that it
> has smaller components and is thus mostly reusable between dfops context
> for parent pointers etc. and the traditional codepath. I can see the
> appeal of such API cleanups (so it's good feedback overall), but I agree
> that it's probably wiser to allow this series to work with the interface
> style we have in the existing code and consider that type of thing as a
> follow on cleanup when the subsystem itself is more stabilized.
>
> Brian
Alrighty, sounds good for now. We'll come back and touch on it at a
later time once we get through all the bigger stuff

Allison

>
>>>
>>>> xfs_trans_brelse(args->trans, bp);
>>>> return error;
>>>> @@ -817,12 +865,10 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
>>>> trace_xfs_attr_leaf_get(args);
>>>> - args->blkno = 0;
>>>> - error = xfs_attr3_leaf_read(args->trans, args->dp, args->blkno, &bp);
>>>> - if (error)
>>>> + error = xfs_attr_leaf_hasname(args, &bp);
>>>> + if (error != -ENOATTR && error != -EEXIST)
>>>> return error;
>>>> - error = xfs_attr3_leaf_lookup_int(bp, args);
>>>> if (error != -EEXIST) {
>>>> xfs_trans_brelse(args->trans, bp);
>>>> return error;
>>>
>>> Similar thing here, just reordering the checks simplifies the logic.
>> Sure, will do.
>>
>>>
>>>> @@ -832,6 +878,41 @@ xfs_attr_leaf_get(xfs_da_args_t *args)
>>>> return error;
>>>> }
>>>> +/*
>>>> + * Return EEXIST if attr is found, or ENOATTR if not
>>>> + * statep: If not null is set to point at the found state. Caller will
>>>> + * be responsible for freeing the state in this case.
>>>> + */
>>>> +STATIC int
>>>> +xfs_attr_node_hasname(
>>>> + struct xfs_da_args *args,
>>>> + struct xfs_da_state **statep)
>>>> +{
>>>> + struct xfs_da_state *state;
>>>> + int retval, error;
>>>> +
>>>> + state = xfs_da_state_alloc();
>>>> + state->args = args;
>>>> + state->mp = args->dp->i_mount;
>>>> +
>>>> + if (statep != NULL)
>>>> + *statep = NULL;
>>>> +
>>>> + /*
>>>> + * Search to see if name exists, and get back a pointer to it.
>>>> + */
>>>> + error = xfs_da3_node_lookup_int(state, &retval);
>>>> + if (error == 0) {
>>>> + if (statep != NULL)
>>>> + *statep = state;
>>>> + return retval;
>>>> + }
>>>> +
>>>> + xfs_da_state_free(state);
>>>> +
>>>> + return error;
>>>> +}
>>>> +
>>>> /*========================================================================
>>>> * External routines when attribute list size > geo->blksize
>>>> *========================================================================*/
>>> ...
>>>> @@ -1316,31 +1381,23 @@ xfs_attr_node_get(xfs_da_args_t *args)
>>>> {
>>>> xfs_da_state_t *state;
>>>> xfs_da_state_blk_t *blk;
>>>> - int error, retval;
>>>> + int error;
>>>> int i;
>>>> trace_xfs_attr_node_get(args);
>>>> - state = xfs_da_state_alloc();
>>>> - state->args = args;
>>>> - state->mp = args->dp->i_mount;
>>>> -
>>>> /*
>>>> * Search to see if name exists, and get back a pointer to it.
>>>> */
>>>> - error = xfs_da3_node_lookup_int(state, &retval);
>>>> - if (error) {
>>>> - retval = error;
>>>> - goto out_release;
>>>> - }
>>>> - if (retval != -EEXIST)
>>>> + error = xfs_attr_node_hasname(args, &state);
>>>> + if (error != -EEXIST)
>>>> goto out_release;
>>>> /*
>>>> * Get the value, local or "remote"
>>>> */
>>>> blk = &state->path.blk[state->path.active - 1];
>>>> - retval = xfs_attr3_leaf_getvalue(blk->bp, args);
>>>> + error = xfs_attr3_leaf_getvalue(blk->bp, args);
>>>> /*
>>>> * If not in a transaction, we have to release all the buffers.
>>>> @@ -1352,7 +1409,7 @@ xfs_attr_node_get(xfs_da_args_t *args)
>>>> }
>>>> xfs_da_state_free(state);
>>>
>>> Do we need an 'if (state)' check here like the other node funcs?
>> I think so, because if xfs_attr_node_hasname errors out it releases the
>> state. Will add.
>>
>>>
>>>> - return retval;
>>>> + return error;
>>>> }
>>>> /* Returns true if the attribute entry name is valid. */
>>> ...
>>>> diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c b/fs/xfs/libxfs/xfs_attr_leaf.c
>>>> index cb5ef66..9d6b68c 100644
>>>> --- a/fs/xfs/libxfs/xfs_attr_leaf.c
>>>> +++ b/fs/xfs/libxfs/xfs_attr_leaf.c
>>>> @@ -654,18 +654,66 @@ xfs_attr_shortform_create(xfs_da_args_t *args)
>>>> }
>>>> /*
>>>> + * Return -EEXIST if attr is found, or -ENOATTR if not
>>>> + * args: args containing attribute name and namelen
>>>> + * sfep: If not null, pointer will be set to the last attr entry found on
>>>> + -EEXIST. On -ENOATTR pointer is left at the last entry in the list
>>>> + * basep: If not null, pointer is set to the byte offset of the entry in the
>>>> + * list on -EEXIST. On -ENOATTR, pointer is left at the byte offset of
>>>> + * the last entry in the list
>>>> + */
>>>> +int
>>>> +xfs_attr_sf_findname(
>>>> + struct xfs_da_args *args,
>>>> + struct xfs_attr_sf_entry **sfep,
>>>> + unsigned int *basep)
>>>> +{
>>>> + struct xfs_attr_shortform *sf;
>>>> + struct xfs_attr_sf_entry *sfe;
>>>> + unsigned int base = sizeof(struct xfs_attr_sf_hdr);
>>>> + int size = 0;
>>>> + int end;
>>>> + int i;
>>>> +
>>>> + sf = (struct xfs_attr_shortform *)args->dp->i_afp->if_u1.if_data;
>>>> + sfe = &sf->list[0];
>>>> + end = sf->hdr.count;
>>>> + for (i = 0; i < end; sfe = XFS_ATTR_SF_NEXTENTRY(sfe),
>>>> + base += size, i++) {
>>>
>>> Slightly more readable to align indendation with the sfe assignment
>>> above.
>> Sure, will fix. Thanks!
>>
>> Allison
>>
>>>
>>> Brian
>>>
>>>> + size = XFS_ATTR_SF_ENTSIZE(sfe);
>>>> + if (sfe->namelen != args->name.len)
>>>> + continue;
>>>> + if (memcmp(sfe->nameval, args->name.name, args->name.len) != 0)
>>>> + continue;
>>>> + if (!xfs_attr_namesp_match(args->name.type, sfe->flags))
>>>> + continue;
>>>> + break;
>>>> + }
>>>> +
>>>> + if (sfep != NULL)
>>>> + *sfep = sfe;
>>>> +
>>>> + if (basep != NULL)
>>>> + *basep = base;
>>>> +
>>>> + if (i == end)
>>>> + return -ENOATTR;
>>>> + return -EEXIST;
>>>> +}
>>>> +
>>>> +/*
>>>> * Add a name/value pair to the shortform attribute list.
>>>> * Overflow from the inode has already been checked for.
>>>> */
>>>> void
>>>> -xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
>>>> +xfs_attr_shortform_add(struct xfs_da_args *args, int forkoff)
>>>> {
>>>> - xfs_attr_shortform_t *sf;
>>>> - xfs_attr_sf_entry_t *sfe;
>>>> - int i, offset, size;
>>>> - xfs_mount_t *mp;
>>>> - xfs_inode_t *dp;
>>>> - struct xfs_ifork *ifp;
>>>> + struct xfs_attr_shortform *sf;
>>>> + struct xfs_attr_sf_entry *sfe;
>>>> + int offset, size, error;
>>>> + struct xfs_mount *mp;
>>>> + struct xfs_inode *dp;
>>>> + struct xfs_ifork *ifp;
>>>> trace_xfs_attr_sf_add(args);
>>>> @@ -676,18 +724,8 @@ xfs_attr_shortform_add(xfs_da_args_t *args, int forkoff)
>>>> ifp = dp->i_afp;
>>>> ASSERT(ifp->if_flags & XFS_IFINLINE);
>>>> sf = (xfs_attr_shortform_t *)ifp->if_u1.if_data;
>>>> - sfe = &sf->list[0];
>>>> - for (i = 0; i < sf->hdr.count; sfe = XFS_ATTR_SF_NEXTENTRY(sfe), i++) {
>>>> -#ifdef DEBUG
>>>> - if (sfe->namelen != args->name.len)
>>>> - continue;
>>>> - if (memcmp(args->name.name, sfe->nameval, args->name.len) != 0)
>>>> - continue;
>>>> - if (!xfs_attr_namesp_match(args->name.type, sfe->flags))
>>>> - continue;
>>>> - ASSERT(0);
>>>> -#endif
>>>> - }
>>>> + error = xfs_attr_sf_findname(args, &sfe, NULL);
>>>> + ASSERT(error != -EEXIST);
>>>> offset = (char *)sfe - (char *)sf;
>>>> size = XFS_ATTR_SF_ENTSIZE_BYNAME(args->name.len, args->valuelen);
>>>> @@ -730,35 +768,26 @@ xfs_attr_fork_remove(
>>>> * Remove an attribute from the shortform attribute list structure.
>>>> */
>>>> int
>>>> -xfs_attr_shortform_remove(xfs_da_args_t *args)
>>>> +xfs_attr_shortform_remove(struct xfs_da_args *args)
>>>> {
>>>> - xfs_attr_shortform_t *sf;
>>>> - xfs_attr_sf_entry_t *sfe;
>>>> - int base, size=0, end, totsize, i;
>>>> - xfs_mount_t *mp;
>>>> - xfs_inode_t *dp;
>>>> + struct xfs_attr_shortform *sf;
>>>> + struct xfs_attr_sf_entry *sfe;
>>>> + int size = 0, end, totsize;
>>>> + unsigned int base;
>>>> + struct xfs_mount *mp;
>>>> + struct xfs_inode *dp;
>>>> + int error;
>>>> trace_xfs_attr_sf_remove(args);
>>>> dp = args->dp;
>>>> mp = dp->i_mount;
>>>> - base = sizeof(xfs_attr_sf_hdr_t);
>>>> sf = (xfs_attr_shortform_t *)dp->i_afp->if_u1.if_data;
>>>> - sfe = &sf->list[0];
>>>> - end = sf->hdr.count;
>>>> - for (i = 0; i < end; sfe = XFS_ATTR_SF_NEXTENTRY(sfe),
>>>> - base += size, i++) {
>>>> - size = XFS_ATTR_SF_ENTSIZE(sfe);
>>>> - if (sfe->namelen != args->name.len)
>>>> - continue;
>>>> - if (memcmp(sfe->nameval, args->name.name, args->name.len) != 0)
>>>> - continue;
>>>> - if (!xfs_attr_namesp_match(args->name.type, sfe->flags))
>>>> - continue;
>>>> - break;
>>>> - }
>>>> - if (i == end)
>>>> - return -ENOATTR;
>>>> +
>>>> + error = xfs_attr_sf_findname(args, &sfe, &base);
>>>> + if (error != -EEXIST)
>>>> + return error;
>>>> + size = XFS_ATTR_SF_ENTSIZE(sfe);
>>>> /*
>>>> * Fix up the attribute fork data, covering the hole
>>>> diff --git a/fs/xfs/libxfs/xfs_attr_leaf.h b/fs/xfs/libxfs/xfs_attr_leaf.h
>>>> index 73615b1..0e9c87c 100644
>>>> --- a/fs/xfs/libxfs/xfs_attr_leaf.h
>>>> +++ b/fs/xfs/libxfs/xfs_attr_leaf.h
>>>> @@ -53,6 +53,9 @@ int xfs_attr_shortform_getvalue(struct xfs_da_args *args);
>>>> int xfs_attr_shortform_to_leaf(struct xfs_da_args *args,
>>>> struct xfs_buf **leaf_bp);
>>>> int xfs_attr_shortform_remove(struct xfs_da_args *args);
>>>> +int xfs_attr_sf_findname(struct xfs_da_args *args,
>>>> + struct xfs_attr_sf_entry **sfep,
>>>> + unsigned int *basep);
>>>> int xfs_attr_shortform_allfit(struct xfs_buf *bp, struct xfs_inode *dp);
>>>> int xfs_attr_shortform_bytesfit(struct xfs_inode *dp, int bytes);
>>>> xfs_failaddr_t xfs_attr_shortform_verify(struct xfs_inode *ip);
>>>> --
>>>> 2.7.4
>>>>
>>>
>>
>