Re: [PATCH 1/9] xfs: Remove all strlen in all xfs_attr_* functions for attr names.

Allison Henderson
2019-04-15T20:11:03Z

On 4/14/19 4:02 PM, Dave Chinner wrote:
> On Fri, Apr 12, 2019 at 03:50:28PM -0700, Allison Henderson wrote:
>> This helps to pre-simplify the extra handling of the null terminator in
>> delayed operations which use memcpy rather than strlen. Later
>> when we introduce parent pointers, attribute names will become binary,
>> so strlen will not work at all. Removing uses of strlen now will
>> help reduce complexities later
>>
>> Signed-off-by: Allison Henderson <allison.henderson@oracle.com>
>> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
>
> Hmmm. If we are going to pass name/namelen pairs around everywhere,
> can we convert these to a struct xfs_name?
>
> I also wonder where we should convert the name/namelen pairs in the
> attr args struct to an xfs_name, too, then we can just do:
>
> args->name = *name;
>
> to copy in the string pointer and the name length in one go.
>
> And we might even be able to put the attribute flags (e.g.
> ATTR_ROOT) in the name.type field, and get rid of that parameter
> being passed around, too...
>
> Cheers,
>
> Dave.

I think a new struct xfs_name is reasonable. Or maybe a general purpose
xfs_array? The value/valuelen parameters have a similar relation that
could make use of that too. How would people feel about something like
this:

struct xfs_array {
unsigned char *bytes;
size_t len;
}

struct xfs_attribute {
struct xfs_array name;
int flags;
}

We could add the value member in here too. It tends to get passed
around just as much with the exception of attr remove operations which
only need the name. I think changing the actual members of xfs_da_args
should be another patch though, since that's a bigger change that
affects a wider scope of code. I can look into it though.

Also, do I still keep the old reviewed-by on the patch if the patch is
still going through changes? I have a few signed-off patches in the
parent pointer set that have changed quite a bit since we've started too.

Thanks!
Allison

>
>> ---
>> fs/xfs/libxfs/xfs_attr.c | 12 ++++++++----
>> fs/xfs/libxfs/xfs_attr.h | 9 ++++++---
>> fs/xfs/xfs_acl.c | 12 +++++++-----
>> fs/xfs/xfs_ioctl.c | 13 ++++++++++---
>> fs/xfs/xfs_iops.c | 6 ++++--
>> fs/xfs/xfs_xattr.c | 10 ++++++----
>> 6 files changed, 41 insertions(+), 21 deletions(-)
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
>> index 2dd9ee2..3da6b0d 100644
>> --- a/fs/xfs/libxfs/xfs_attr.c
>> +++ b/fs/xfs/libxfs/xfs_attr.c
>> @@ -67,6 +67,7 @@ xfs_attr_args_init(
>> struct xfs_da_args *args,
>> struct xfs_inode *dp,
>> const unsigned char *name,
>> + size_t namelen,
>> int flags)
>> {
>>
>> @@ -79,7 +80,7 @@ xfs_attr_args_init(
>> args->dp = dp;
>> args->flags = flags;
>> args->name = name;
>> - args->namelen = strlen((const char *)name);
>> + args->namelen = namelen;
>> if (args->namelen >= MAXNAMELEN)
>> return -EFAULT; /* match IRIX behaviour */
>>
>> @@ -125,6 +126,7 @@ int
>> xfs_attr_get(
>> struct xfs_inode *ip,
>> const unsigned char *name,
>> + size_t namelen,
>> unsigned char *value,
>> int *valuelenp,
>> int flags)
>> @@ -138,7 +140,7 @@ xfs_attr_get(
>> if (XFS_FORCED_SHUTDOWN(ip->i_mount))
>> return -EIO;
>>
>> - error = xfs_attr_args_init(&args, ip, name, flags);
>> + error = xfs_attr_args_init(&args, ip, name, namelen, flags);
>> if (error)
>> return error;
>>
>> @@ -317,6 +319,7 @@ int
>> xfs_attr_set(
>> struct xfs_inode *dp,
>> const unsigned char *name,
>> + size_t namelen,
>> unsigned char *value,
>> int valuelen,
>> int flags)
>> @@ -333,7 +336,7 @@ xfs_attr_set(
>> if (XFS_FORCED_SHUTDOWN(dp->i_mount))
>> return -EIO;
>>
>> - error = xfs_attr_args_init(&args, dp, name, flags);
>> + error = xfs_attr_args_init(&args, dp, name, namelen, flags);
>> if (error)
>> return error;
>>
>> @@ -425,6 +428,7 @@ int
>> xfs_attr_remove(
>> struct xfs_inode *dp,
>> const unsigned char *name,
>> + size_t namelen,
>> int flags)
>> {
>> struct xfs_mount *mp = dp->i_mount;
>> @@ -436,7 +440,7 @@ xfs_attr_remove(
>> if (XFS_FORCED_SHUTDOWN(dp->i_mount))
>> return -EIO;
>>
>> - error = xfs_attr_args_init(&args, dp, name, flags);
>> + error = xfs_attr_args_init(&args, dp, name, namelen, flags);
>> if (error)
>> return error;
>>
>> diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
>> index 2297d84..52f63dc 100644
>> --- a/fs/xfs/libxfs/xfs_attr.h
>> +++ b/fs/xfs/libxfs/xfs_attr.h
>> @@ -137,11 +137,14 @@ int xfs_attr_list_int(struct xfs_attr_list_context *);
>> int xfs_inode_hasattr(struct xfs_inode *ip);
>> int xfs_attr_get_ilocked(struct xfs_inode *ip, struct xfs_da_args *args);
>> int xfs_attr_get(struct xfs_inode *ip, const unsigned char *name,
>> - unsigned char *value, int *valuelenp, int flags);
>> + size_t namelen, unsigned char *value, int *valuelenp,
>> + int flags);
>> int xfs_attr_set(struct xfs_inode *dp, const unsigned char *name,
>> - unsigned char *value, int valuelen, int flags);
>> + size_t namelen, unsigned char *value, int valuelen,
>> + int flags);
>> int xfs_attr_set_args(struct xfs_da_args *args, struct xfs_buf **leaf_bp);
>> -int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name, int flags);
>> +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 8039e35..142de8d 100644
>> --- a/fs/xfs/xfs_acl.c
>> +++ b/fs/xfs/xfs_acl.c
>> @@ -141,8 +141,8 @@ xfs_get_acl(struct inode *inode, int type)
>> if (!xfs_acl)
>> return ERR_PTR(-ENOMEM);
>>
>> - error = xfs_attr_get(ip, ea_name, (unsigned char *)xfs_acl,
>> - &len, ATTR_ROOT);
>> + error = xfs_attr_get(ip, ea_name, strlen(ea_name),
>> + (unsigned char *)xfs_acl, &len, ATTR_ROOT);
>> if (error) {
>> /*
>> * If the attribute doesn't exist make sure we have a negative
>> @@ -192,15 +192,17 @@ __xfs_set_acl(struct inode *inode, struct posix_acl *acl, int type)
>> len -= sizeof(struct xfs_acl_entry) *
>> (XFS_ACL_MAX_ENTRIES(ip->i_mount) - acl->a_count);
>>
>> - error = xfs_attr_set(ip, ea_name, (unsigned char *)xfs_acl,
>> - len, ATTR_ROOT);
>> + 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, ATTR_ROOT);
>> + error = xfs_attr_remove(ip, ea_name,
>> + strlen(ea_name),
>> + ATTR_ROOT);
>>
>> /*
>> * If the attribute didn't exist to start with that's fine.
>> diff --git a/fs/xfs/xfs_ioctl.c b/fs/xfs/xfs_ioctl.c
>> index 6ecdbb3..ab341d6 100644
>> --- a/fs/xfs/xfs_ioctl.c
>> +++ b/fs/xfs/xfs_ioctl.c
>> @@ -437,6 +437,7 @@ xfs_attrmulti_attr_get(
>> {
>> unsigned char *kbuf;
>> int error = -EFAULT;
>> + size_t namelen;
>>
>> if (*len > XFS_XATTR_SIZE_MAX)
>> return -EINVAL;
>> @@ -444,7 +445,9 @@ xfs_attrmulti_attr_get(
>> if (!kbuf)
>> return -ENOMEM;
>>
>> - error = xfs_attr_get(XFS_I(inode), name, kbuf, (int *)len, flags);
>> + namelen = strlen(name);
>> + error = xfs_attr_get(XFS_I(inode), name, namelen,
>> + kbuf, (int *)len, flags);
>> if (error)
>> goto out_kfree;
>>
>> @@ -466,6 +469,7 @@ xfs_attrmulti_attr_set(
>> {
>> unsigned char *kbuf;
>> int error;
>> + size_t namelen;
>>
>> if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
>> return -EPERM;
>> @@ -476,7 +480,8 @@ xfs_attrmulti_attr_set(
>> if (IS_ERR(kbuf))
>> return PTR_ERR(kbuf);
>>
>> - error = xfs_attr_set(XFS_I(inode), name, kbuf, len, flags);
>> + namelen = strlen(name);
>> + error = xfs_attr_set(XFS_I(inode), name, namelen, kbuf, len, flags);
>> if (!error)
>> xfs_forget_acl(inode, name, flags);
>> kfree(kbuf);
>> @@ -490,10 +495,12 @@ xfs_attrmulti_attr_remove(
>> uint32_t flags)
>> {
>> int error;
>> + size_t namelen;
>>
>> if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
>> return -EPERM;
>> - error = xfs_attr_remove(XFS_I(inode), name, flags);
>> + namelen = strlen(name);
>> + error = xfs_attr_remove(XFS_I(inode), name, namelen, flags);
>> if (!error)
>> xfs_forget_acl(inode, name, flags);
>> return error;
>> diff --git a/fs/xfs/xfs_iops.c b/fs/xfs/xfs_iops.c
>> index 74047bd..e73c21a 100644
>> --- a/fs/xfs/xfs_iops.c
>> +++ b/fs/xfs/xfs_iops.c
>> @@ -59,8 +59,10 @@ xfs_initxattrs(
>> int error = 0;
>>
>> for (xattr = xattr_array; xattr->name != NULL; xattr++) {
>> - error = xfs_attr_set(ip, xattr->name, xattr->value,
>> - xattr->value_len, ATTR_SECURE);
>> + error = xfs_attr_set(ip, xattr->name,
>> + strlen(xattr->name),
>> + xattr->value, xattr->value_len,
>> + ATTR_SECURE);
>> if (error < 0)
>> break;
>> }
>> diff --git a/fs/xfs/xfs_xattr.c b/fs/xfs/xfs_xattr.c
>> index 9a63016..3013746 100644
>> --- a/fs/xfs/xfs_xattr.c
>> +++ b/fs/xfs/xfs_xattr.c
>> @@ -26,6 +26,7 @@ xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
>> int xflags = handler->flags;
>> struct xfs_inode *ip = XFS_I(inode);
>> int error, asize = size;
>> + size_t namelen = strlen(name);
>>
>> /* Convert Linux syscall to XFS internal ATTR flags */
>> if (!size) {
>> @@ -33,7 +34,7 @@ xfs_xattr_get(const struct xattr_handler *handler, struct dentry *unused,
>> value = NULL;
>> }
>>
>> - error = xfs_attr_get(ip, (unsigned char *)name, value, &asize, xflags);
>> + error = xfs_attr_get(ip, name, namelen, value, &asize, xflags);
>> if (error)
>> return error;
>> return asize;
>> @@ -69,6 +70,7 @@ 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)
>> @@ -77,9 +79,9 @@ xfs_xattr_set(const struct xattr_handler *handler, struct dentry *unused,
>> xflags |= ATTR_REPLACE;
>>
>> if (!value)
>> - return xfs_attr_remove(ip, (unsigned char *)name, xflags);
>> - error = xfs_attr_set(ip, (unsigned char *)name,
>> - (void *)value, size, xflags);
>> + return xfs_attr_remove(ip, name,
>> + namelen, xflags);
>> + error = xfs_attr_set(ip, name, namelen, (void *)value, size, xflags);
>> if (!error)
>> xfs_forget_acl(inode, name, xflags);
>>
>> --
>> 2.7.4
>>
>>
>