Re: [PATCH 6/9] xfs: Add xfs_has_attr and subroutines

[Allison Henderson <allison.henderson@xxxxxxxxxx>]

On 4/14/19 7:46 PM, Su Yue wrote:
> On 2019/4/13 6:50 AM, Allison Henderson wrote:
> > 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.  We will need this later
> > for delayed attributes since delayed operations cannot return
> > error codes.
> >
> > Signed-off-by: Allison Henderson <allison.henderson@xxxxxxxxxx>
> > ---
> >   fs/xfs/libxfs/xfs_attr.c      | 78 
> > +++++++++++++++++++++++++++++++++++++++++++
> >   fs/xfs/libxfs/xfs_attr.h      |  1 +
> >   fs/xfs/libxfs/xfs_attr_leaf.c | 33 ++++++++++++++++++
> >   fs/xfs/libxfs/xfs_attr_leaf.h |  1 +
> >   4 files changed, 113 insertions(+)
> >
> > diff --git a/fs/xfs/libxfs/xfs_attr.c b/fs/xfs/libxfs/xfs_attr.c
> > index c3477fa7..0042708 100644
> > --- a/fs/xfs/libxfs/xfs_attr.c
> > +++ b/fs/xfs/libxfs/xfs_attr.c
> > @@ -53,6 +53,7 @@ STATIC int xfs_attr_shortform_addname(xfs_da_args_t 
> > *args);
> >   STATIC int xfs_attr_leaf_get(xfs_da_args_t *args);
> >   STATIC int xfs_attr_leaf_addname(xfs_da_args_t *args, bool roll_trans);
> >   STATIC int xfs_attr_leaf_removename(xfs_da_args_t *args, bool 
> > roll_trans);
> > +STATIC int xfs_leaf_has_attr(xfs_da_args_t *args);
> >
> >   /*
> >    * Internal routines when attribute list is more than one block.
> > @@ -60,6 +61,7 @@ STATIC int xfs_attr_leaf_removename(xfs_da_args_t 
> > *args, bool roll_trans);
> >   STATIC int xfs_attr_node_get(xfs_da_args_t *args);
> >   STATIC int xfs_attr_node_addname(xfs_da_args_t *args, bool roll_trans);
> >   STATIC int xfs_attr_node_removename(xfs_da_args_t *args, bool 
> > roll_trans);
> > +STATIC int xfs_attr_node_hasname(xfs_da_args_t *args);
> >   STATIC int xfs_attr_fillstate(xfs_da_state_t *state);
> >   STATIC int xfs_attr_refillstate(xfs_da_state_t *state);
> >
> > @@ -301,6 +303,29 @@ xfs_attr_set_args(
> >   }
> >
> >   /*
> > + * Return successful if attr is found, or ENOATTR if not
> > + */
> > +int
> > +xfs_has_attr(
> > +    struct xfs_da_args      *args)
> > +{
> > +    struct xfs_inode        *dp = args->dp;
> > +    int                     error;
> > +
> > +    if (!xfs_inode_hasattr(dp))
> > +        error = -ENOATTR;
> > +    else if (dp->i_d.di_aformat == XFS_DINODE_FMT_LOCAL) {
> > +        ASSERT(dp->i_afp->if_flags & XFS_IFINLINE);
> > +        error = xfs_shortform_has_attr(args);
> > +    } else if (xfs_bmap_one_block(dp, XFS_ATTR_FORK))
> > +        error = xfs_leaf_has_attr(args);
> > +    else
> > +        error = xfs_attr_node_hasname(args);
> > +
> > +    return error;
> > +}
> > +
> > +/*
> >    * Remove the attribute specified in @args.
> >    */
> >   int
> > @@ -836,6 +861,29 @@ xfs_attr_leaf_addname(
> >   }
> >
> >   /*
> > + * Return successful if attr is found, or ENOATTR if not
> > + */
> > +STATIC int
> > +xfs_leaf_has_attr(
> > +    struct xfs_da_args      *args)
> > +{
> > +    struct xfs_buf          *bp;
> > +    int                     error = 0;
> > +
> > +    args->blkno = 0;
> > +    error = xfs_attr3_leaf_read(args->trans, args->dp,
> > +            args->blkno, -1, &bp);
> > +    if (error)
> > +        return error;
> > +
> > +    error = xfs_attr3_leaf_lookup_int(bp, args);
> > +    error = (error == -ENOATTR) ? -ENOATTR : 0;
> > +    xfs_trans_brelse(args->trans, bp);
> > +
> > +    return error;
> > +}
> > +
> > +/*
> >    * Remove a name from the leaf attribute list structure
> >    *
> >    * This leaf block cannot have a "remote" value, we only call this 
> > routine
> > @@ -1166,6 +1214,36 @@ xfs_attr_node_addname(
> >   }
> >
> >   /*
> > + * Return successful if attr is found, or ENOATTR if not
> > + */
> > +STATIC int
> > +xfs_attr_node_hasname(
> > +    struct xfs_da_args    *args)
> > +{
> > +    struct xfs_da_state    *state;
> > +    struct xfs_inode    *dp;
> > +    int            retval, error;
> > +
> > +    /*
> > +     * Tie a string around our finger to remind us where we are.
> > +     */
> > +    dp = args->dp;
> > +    state = xfs_da_state_alloc();
>
> The corresponding xfs_da_state_free(state) seems lost...
>
> ---
> Su

Good catch, you are right.  I will add that in the next version.

Thanks!
Allison

> > +    state->args = args;
> > +    state->mp = 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 != -EEXIST)) {
> > +        if (error == 0)
> > +            error = retval;
> > +    }
> > +    return error;
> > +}
> > +
> > +/*
> >    * Remove a name from a B-tree attribute list.
> >    *
> >    * This will involve walking down the Btree, and may involve joining
> > diff --git a/fs/xfs/libxfs/xfs_attr.h b/fs/xfs/libxfs/xfs_attr.h
> > index 83b3621..974c963 100644
> > --- a/fs/xfs/libxfs/xfs_attr.h
> > +++ b/fs/xfs/libxfs/xfs_attr.h
> > @@ -168,6 +168,7 @@ int xfs_attr_set_args(struct xfs_da_args *args, 
> > struct xfs_buf **leaf_bp,
> >            bool roll_trans);
> >   int xfs_attr_remove(struct xfs_inode *dp, const unsigned char *name,
> >               size_t namelen, int flags);
> > +int xfs_has_attr(struct xfs_da_args *args);
> >   int xfs_attr_remove_args(struct xfs_da_args *args, bool roll_trans);
> >   int xfs_attr_list(struct xfs_inode *dp, char *buffer, int bufsize,
> >             int flags, struct attrlist_cursor_kern *cursor);
> > diff --git a/fs/xfs/libxfs/xfs_attr_leaf.c 
> > b/fs/xfs/libxfs/xfs_attr_leaf.c
> > index 128bfe9..e9f2f53 100644
> > --- a/fs/xfs/libxfs/xfs_attr_leaf.c
> > +++ b/fs/xfs/libxfs/xfs_attr_leaf.c
> > @@ -622,6 +622,39 @@ xfs_attr_fork_remove(
> >   }
> >
> >   /*
> > + * Return successful if attr is found, or ENOATTR if not
> > + */
> > +int
> > +xfs_shortform_has_attr(
> > +    struct xfs_da_args     *args)
> > +{
> > +    struct xfs_attr_shortform *sf;
> > +    struct xfs_attr_sf_entry *sfe;
> > +    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++) {
> > +        size = XFS_ATTR_SF_ENTSIZE(sfe);
> > +        if (sfe->namelen != args->namelen)
> > +            continue;
> > +        if (memcmp(sfe->nameval, args->name, args->namelen) != 0)
> > +            continue;
> > +        if (!xfs_attr_namesp_match(args->flags, sfe->flags))
> > +            continue;
> > +        break;
> > +    }
> > +    if (i == end)
> > +        return -ENOATTR;
> > +    return 0;
> > +}
> > +
> > +/*
> >    * Remove an attribute from the shortform attribute list structure.
> >    */
> >   int
> > diff --git a/fs/xfs/libxfs/xfs_attr_leaf.h 
> > b/fs/xfs/libxfs/xfs_attr_leaf.h
> > index 9d830ec..98dd169 100644
> > --- a/fs/xfs/libxfs/xfs_attr_leaf.h
> > +++ b/fs/xfs/libxfs/xfs_attr_leaf.h
> > @@ -39,6 +39,7 @@ 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_shortform_has_attr(struct xfs_da_args *args);
> >   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);