Re: [PATCH 02/29] xfs: merge xfs_attr_remove into xfs_attr_set

Allison Collins
2020-01-25T04:17:30Z

On 1/21/20 10:28 AM, Darrick J. Wong wrote:
> On Tue, Jan 14, 2020 at 09:10:24AM +0100, Christoph Hellwig wrote:
>> The Linux xattr and acl APIs use a single call for set an remove. Modify
>> the high-level XFS API to match that and let xfs_attr_set handle removing
>> attributes as well. With a little bit of reordering this removes a lot
>> of code.
>>
>> Signed-off-by: Christoph Hellwig <hch@lst.de>
>> ---
>> fs/xfs/libxfs/xfs_attr.c | 174 +++++++++++++--------------------------
>> fs/xfs/libxfs/xfs_attr.h | 2 -
>> fs/xfs/xfs_acl.c | 33 +++-----
>> fs/xfs/xfs_ioctl.c | 4 +-
>> fs/xfs/xfs_xattr.c | 9 +-
>> 5 files changed, 73 insertions(+), 149 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>> index e6149720ce02..04431ab9f5f5 100644
>> --- a/fs/xfs/libxfs/xfs_attr.c
>> +++ b/fs/xfs/libxfs/xfs_attr.c
>> @@ -350,149 +350,92 @@ xfs_attr_set(
>
> xfs_attr_set() ought to gain a comment noting that a NULL @value
> will remove the attribute.
>
>> struct xfs_trans_res tres;
>> int rsvd = (flags & ATTR_ROOT) != 0;
>> int error, local;
>> -
>> - XFS_STATS_INC(mp, xs_attr_set);
>> + unsigned int total;
>>
>> if (XFS_FORCED_SHUTDOWN(dp->i_mount))
>> return -EIO;
>>
>> - error = xfs_attr_args_init(&args, dp, name, namelen, flags);
>> - if (error)
>> - return error;
>> -
>> - args.value = value;
>> - args.valuelen = valuelen;
>> - args.op_flags = XFS_DA_OP_ADDNAME | XFS_DA_OP_OKNOENT;
>> - args.total = xfs_attr_calc_size(&args, &local);
>> -
>> error = xfs_qm_dqattach(dp);
>> if (error)
>> return error;
>>
>> - /*
>> - * If the inode doesn't have an attribute fork, add one.
>> - * (inode must not be locked when we call this routine)
>> - */
>> - if (XFS_IFORK_Q(dp) == 0) {
>> - int sf_size = sizeof(xfs_attr_sf_hdr_t) +
>> - XFS_ATTR_SF_ENTSIZE_BYNAME(args.namelen, valuelen);
>> -
>> - error = xfs_bmap_add_attrfork(dp, sf_size, rsvd);
>> - if (error)
>> - return error;
>> - }
>> -
>> - tres.tr_logres = M_RES(mp)->tr_attrsetm.tr_logres +
>> - M_RES(mp)->tr_attrsetrt.tr_logres * args.total;
>> - tres.tr_logcount = XFS_ATTRSET_LOG_COUNT;
>> - tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
>> -
>> - /*
>> - * Root fork attributes can use reserved data blocks for this
>> - * operation if necessary
>> - */
>> - error = xfs_trans_alloc(mp, &tres, args.total, 0,
>> - rsvd ? XFS_TRANS_RESERVE : 0, &args.trans);
>> + error = xfs_attr_args_init(&args, dp, name, namelen, flags);
>> if (error)
>> return error;
>>
>> - xfs_ilock(dp, XFS_ILOCK_EXCL);
>> - error = xfs_trans_reserve_quota_nblks(args.trans, dp, args.total, 0,
>> - rsvd ? XFS_QMOPT_RES_REGBLKS | XFS_QMOPT_FORCE_RES :
>> - XFS_QMOPT_RES_REGBLKS);
>> - if (error)
>> - goto out_trans_cancel;
>> -
>> - xfs_trans_ijoin(args.trans, dp, 0);
>> - error = xfs_attr_set_args(&args);
>> - if (error)
>> - goto out_trans_cancel;
>> - if (!args.trans) {
>> - /* shortform attribute has already been committed */
>> - goto out_unlock;
>> - }
>> -
>> - /*
>> - * If this is a synchronous mount, make sure that the
>> - * transaction goes to disk before returning to the user.
>> - */
>> - if (mp->m_flags & XFS_MOUNT_WSYNC)
>> - xfs_trans_set_sync(args.trans);
>> -
>> - if ((flags & ATTR_KERNOTIME) == 0)
>> - xfs_trans_ichgtime(args.trans, dp, XFS_ICHGTIME_CHG);
>> + args.value = value;
>> + args.valuelen = valuelen;
>>
>> /*
>> - * Commit the last in the sequence of transactions.
>> + * We have no control over the attribute names that userspace passes us
>> + * to remove, so we have to allow the name lookup prior to attribute
>> + * removal to fail as well.
>> */
>> - xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
>> - error = xfs_trans_commit(args.trans);
>> -out_unlock:
>> - xfs_iunlock(dp, XFS_ILOCK_EXCL);
>> - return error;
>> -
>> -out_trans_cancel:
>> - if (args.trans)
>> - xfs_trans_cancel(args.trans);
>> - goto out_unlock;
>> -}
>> + args.op_flags = XFS_DA_OP_OKNOENT;
>>
>> -/*
>> - * Generic handler routine to remove a name from an attribute list.
>> - * Transitions attribute list from Btree to shortform as necessary.
>> - */
>> -int
>> -xfs_attr_remove(
>> - struct xfs_inode *dp,
>> - const unsigned char *name,
>> - size_t namelen,
>> - int flags)
>> -{
>> - struct xfs_mount *mp = dp->i_mount;
>> - struct xfs_da_args args;
>> - int error;
>> + if (value) {
>> + XFS_STATS_INC(mp, xs_attr_set);
>>
>> - XFS_STATS_INC(mp, xs_attr_remove);
>> + args.op_flags |= XFS_DA_OP_ADDNAME;
>> + args.total = xfs_attr_calc_size(&args, &local);
>>
>> - if (XFS_FORCED_SHUTDOWN(dp->i_mount))
>> - return -EIO;
>> + /*
>> + * If the inode doesn't have an attribute fork, add one.
>> + * (inode must not be locked when we call this routine)
>> + */
>> + if (XFS_IFORK_Q(dp) == 0) {
>> + int sf_size = sizeof(struct xfs_attr_sf_hdr) +
>> + XFS_ATTR_SF_ENTSIZE_BYNAME(args.namelen,
>> + valuelen);
>>
>> - error = xfs_attr_args_init(&args, dp, name, namelen, flags);
>> - if (error)
>> - return error;
>> + error = xfs_bmap_add_attrfork(dp, sf_size, rsvd);
>> + if (error)
>> + return error;
>> + }
>>
>> - /*
>> - * we have no control over the attribute names that userspace passes us
>> - * to remove, so we have to allow the name lookup prior to attribute
>> - * removal to fail.
>> - */
>> - args.op_flags = XFS_DA_OP_OKNOENT;
>> + tres.tr_logres = M_RES(mp)->tr_attrsetm.tr_logres +
>> + M_RES(mp)->tr_attrsetrt.tr_logres * args.total;
>> + tres.tr_logcount = XFS_ATTRSET_LOG_COUNT;
>> + tres.tr_logflags = XFS_TRANS_PERM_LOG_RES;
>> + total = args.total;
>> + } else {
>> + XFS_STATS_INC(mp, xs_attr_remove);
>>
>> - error = xfs_qm_dqattach(dp);
>> - if (error)
>> - return error;
>> + tres = M_RES(mp)->tr_attrrm;
>> + total = XFS_ATTRRM_SPACE_RES(mp);
>> + }
>>
>> /*
>> * Root fork attributes can use reserved data blocks for this
>> * operation if necessary
>> */
>> - error = xfs_trans_alloc(mp, &M_RES(mp)->tr_attrrm,
>> - XFS_ATTRRM_SPACE_RES(mp), 0,
>> - (flags & ATTR_ROOT) ? XFS_TRANS_RESERVE : 0,
>> - &args.trans);
>> + error = xfs_trans_alloc(mp, &tres, total, 0,
>> + rsvd ? XFS_TRANS_RESERVE : 0, &args.trans);
>> if (error)
>> return error;
>>
>> xfs_ilock(dp, XFS_ILOCK_EXCL);
>> - /*
>> - * No need to make quota reservations here. We expect to release some
>> - * blocks not allocate in the common case.
>> - */
>> xfs_trans_ijoin(args.trans, dp, 0);
>> + if (value) {
>> + unsigned int quota_flags = XFS_QMOPT_RES_REGBLKS;
>>
>> - error = xfs_attr_remove_args(&args);
>> - if (error)
>> - goto out;
>> + if (rsvd)
>> + quota_flags |= XFS_QMOPT_FORCE_RES;
>> + error = xfs_trans_reserve_quota_nblks(args.trans, dp,
>> + args.total, 0, quota_flags);
>> + if (error)
>> + goto out_trans_cancel;
>> + error = xfs_attr_set_args(&args);
>> + if (error)
>> + goto out_trans_cancel;
>> + /* shortform attribute has already been committed */
>> + if (!args.trans)
>> + goto out_unlock;
>> + } else {
>> + error = xfs_attr_remove_args(&args);
>> + if (error)
>> + goto out_trans_cancel;
>> + }
>>
>> /*
>> * If this is a synchronous mount, make sure that the
>> @@ -509,15 +452,14 @@ xfs_attr_remove(
>> */
>> xfs_trans_log_inode(args.trans, dp, XFS_ILOG_CORE);
>> error = xfs_trans_commit(args.trans);
>> +out_unlock:
>> xfs_iunlock(dp, XFS_ILOCK_EXCL);
>> -
>> return error;
>>
>> -out:
>> +out_trans_cancel:
>> if (args.trans)
>> xfs_trans_cancel(args.trans);
>> - xfs_iunlock(dp, XFS_ILOCK_EXCL);
>> - return error;
>> + goto out_unlock;
>> }
>>
>> /*========================================================================
>> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
>> index 71bcf1298e4c..db58a6c7dea5 100644
>> --- a/fs/xfs/libxfs/xfs_attr.h
>> +++ b/fs/xfs/libxfs/xfs_attr.h
>> @@ -152,8 +152,6 @@ int xfs_attr_get(struct xfs_inode *ip, const unsigned char *name,
>> int xfs_attr_set(struct xfs_inode *dp, const unsigned char *name,
>> size_t namelen, unsigned char *value, int valuelen, int flags);
>> int xfs_attr_set_args(struct xfs_da_args *args);
>> -int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name,
>> - size_t namelen, int flags);
>> int xfs_attr_remove_args(struct xfs_da_args *args);
>> int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
>> int flags, struct attrlist_cursor_kern *cursor);
>> diff --git a/fs/xfs/xfs_acl.c b/fs/xfs/xfs_acl.c
>> index cd743fad8478..2628f8530bf0 100644
>> --- a/fs/xfs/xfs_acl.c
>> +++ b/fs/xfs/xfs_acl.c
>> @@ -168,6 +168,8 @@ __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
>> {
>> struct xfs_inode *ip = XFS_I(inode);
>> unsigned char *ea_name;
>> + struct xfs_acl *xfs_acl = NULL;
>> + int len = 0;
>> int error;
>>
>> switch (type) {
>> @@ -184,9 +186,7 @@ __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
>> }
>>
>> if (acl) {
>> - struct xfs_acl *xfs_acl;
>> - int len = XFS_ACL_MAX_SIZE(ip->i_mount);
>> -
>> + len = XFS_ACL_MAX_SIZE(ip->i_mount);
>> xfs_acl = kmem_zalloc_large(len, 0);
>> if (!xfs_acl)
>> return -ENOMEM;
>> @@ -196,26 +196,17 @@ __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
>> /* subtract away the unused acl entries */
>> len -= sizeof(struct xfs_acl_entry) *
>> (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
>> -
>> - error = xfs_attr_set(ip, ea_name, strlen(ea_name),
>> - (unsigned char *)xfs_acl, len, ATTR_ROOT);
>> -
>> - kmem_free(xfs_acl);
>> - } else {
>> - /*
>> - * A NULL ACL argument means we want to remove the ACL.
>> - */
>> - error = xfs_attr_remove(ip, ea_name,
>> - strlen(ea_name),
>> - ATTR_ROOT);
>> -
>> - /*
>> - * If the attribute didn't exist to start with that's fine.
>> - */
>> - if (error == -ENOATTR)
>> - error = 0;
>> }
>>
>> + error = xfs_attr_set(ip, ea_name, strlen(ea_name),
>> + (unsigned char *)xfs_acl, len, ATTR_ROOT);
>> + kmem_free(xfs_acl);
>> +
>> + /*
>> + * If the attribute didn't exist to start with that's fine.
>> + */
>> + if (error == -ENOATTR)
>
> if (!acl && error == -ENOATTR)
>
> ...because that's a behavior change w.r.t. error codes. I didn't see
> anywhere in the attr code where setting a value would actually return
> this, but let's not leave a logic bomb in case we ever do.
>
> (The first thing my brain thought was, "ENOATTR on a set operation
> suggests to me that something's seriously broken in the attr code; why
> would you mask it?")
>
> --D

Would either of you mind if I were to pick up this patch and make a mini
set that resolves some of the overlap between our sets? I'll fix the
nits here. Let me know, thanks!

Allison

>
>> + error = 0;
>> if (!error)
>> set_cached_acl(inode, type, acl);
>> return error;
>> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
>> index d42de92cb283..8e35887f62fa 100644
>> --- a/fs/xfs/xfs_ioctl.c
>> +++ b/fs/xfs/xfs_ioctl.c
>> @@ -415,12 +415,10 @@ xfs_attrmulti_attr_remove(
>> uint32_t flags)
>> {
>> int error;
>> - size_t namelen;
>>
>> if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
>> return -EPERM;
>> - namelen = strlen(name);
>> - error = xfs_attr_remove(XFS_I(inode), name, namelen, flags);
>> + error = xfs_attr_set(XFS_I(inode), name, strlen(name), NULL, 0, flags);
>> if (!error)
>> xfs_forget_acl(inode, name, flags);
>> return error;
>> diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
>> index b0fedb543f97..1670bfbc9ad2 100644
>> --- a/fs/xfs/xfs_xattr.c
>> +++ b/fs/xfs/xfs_xattr.c
>> @@ -69,7 +69,6 @@ xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
>> int xflags = handler->flags;
>> struct xfs_inode *ip = XFS_I(inode);
>> int error;
>> - size_t namelen = strlen(name);
>>
>> /* Convert Linux syscall to XFS internal ATTR flags */
>> if (flags & XATTR_CREATE)
>> @@ -77,14 +76,10 @@ xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
>> if (flags & XATTR_REPLACE)
>> xflags |= ATTR_REPLACE;
>>
>> - if (value)
>> - error = xfs_attr_set(ip, name, namelen, (void *)value, size,
>> - xflags);
>> - else
>> - error = xfs_attr_remove(ip, name, namelen, xflags);
>> + error = xfs_attr_set(ip, (unsigned char *)name, strlen(name),
>> + (void *)value, size, xflags);
>> if (!error)
>> xfs_forget_acl(inode, name, xflags);
>> -
>> return error;
>> }
>>
>> --
>> 2.24.1
>>