On 2011-12-30, at 12:27 AM, Al Viro wrote:
> One kinda-sorta solution (besides kicking cleancache out of tree)
> would be to modify ->encode_fh() API - instead of dentry + connectable
> pass it inode + NULL-or-parent-inode, with ->d_lock held by caller. And
> demand it to be non-blocking, obviously... It would obviously break
> ceph ->encode_fh(), since that sucker apparently wants the name of last
> component anyway. OTOH, that's broken for reasons mentioned above.
> OTTH, fhandle encoding is bloody close to user-visible ABI ;-/
Is it possible to always pass d_parent if this is available, rather than
only if @connectable is passed? For network filesystems re-exporting NFS
it is desirable to always be passed the parent directory.
> diff --git a/fs/exportfs/expfs.c b/fs/exportfs/expfs.c
> index b05acb7..f8f7029 100644
> --- a/fs/exportfs/expfs.c
> +++ b/fs/exportfs/expfs.c
> @@ -304,24 +304,23 @@ out:
>
> /**
> * export_encode_fh - default export_operations->encode_fh function
> - * @dentry: the dentry to encode
> + * @inode: the object to encode
> * @fh: where to store the file handle fragment
> * @max_len: maximum length to store there
> - * @connectable: whether to store parent information
> + * @parent: parent directory inode, if wanted
> *
> * This default encode_fh function assumes that the 32 inode number
> * is suitable for locating an inode, and that the generation number
> * can be used to check that it is still valid. It places them in the
> * filehandle fragment where export_decode_fh expects to find them.
> */
> -static int export_encode_fh(struct dentry *dentry, struct fid *fid,
> - int *max_len, int connectable)
> +static int export_encode_fh(struct inode *inode, struct fid *fid,
> + int *max_len, struct inode *parent)
> {
> - struct inode * inode = dentry->d_inode;
> int len = *max_len;
> int type = FILEID_INO32_GEN;
>
> - if (connectable && (len < 4)) {
> + if (parent && (len < 4)) {
> *max_len = 4;
> return 255;
> } else if (len < 2) {
> @@ -332,14 +331,9 @@ static int export_encode_fh(struct dentry *dentry, struct fid *fid,
> len = 2;
> fid->i32.ino = inode->i_ino;
> fid->i32.gen = inode->i_generation;
> - if (connectable && !S_ISDIR(inode->i_mode)) {
> - struct inode *parent;
> -
> - spin_lock(&dentry->d_lock);
> - parent = dentry->d_parent->d_inode;
> + if (parent) {
> fid->i32.parent_ino = parent->i_ino;
> fid->i32.parent_gen = parent->i_generation;
> - spin_unlock(&dentry->d_lock);
> len = 4;
> type = FILEID_INO32_GEN_PARENT;
> }
> @@ -352,11 +346,19 @@ int exportfs_encode_fh(struct dentry *dentry, struct fid *fid, int *max_len,
> {
> const struct export_operations *nop = dentry->d_sb->s_export_op;
> int error;
> + struct inode *inode = dentry->d_inode, *parent = NULL;
>
> + if (connectable && !S_ISDIR(inode->i_mode)) {
> + spin_lock(&dentry->d_lock);
> + parent = dentry->d_parent->d_inode;
> + BUG_ON(!parent);
> + }
> if (nop->encode_fh)
> - error = nop->encode_fh(dentry, fid->raw, max_len, connectable);
> + error = nop->encode_fh(inode, fid->raw, max_len, parent);
> else
> - error = export_encode_fh(dentry, fid, max_len, connectable);
> + error = export_encode_fh(inode, fid, max_len, parent);
> + if (parent)
> + spin_unlock(&dentry->d_lock);
>
> return error;
> }
Cheers, Andreas
--
To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
