[XFS] stop using uio in the readlink code

Simplify the readlink code to get rid of the last user of uio.

SGI-PV: 968563
SGI-Modid: xfs-linux-melb:xfs-kern:29479a

Signed-off-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: David Chinner <dgc@sgi.com>
Signed-off-by: Tim Shimmin <tes@sgi.com>

4 files changed, 121 insertions, 132 deletions

diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
index 5917808abbd6..47cfde6cfae2 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -349,19 +349,44 @@ xfs_open_by_handle(
         return new_fd;
 }
 
+/*
+ * This is a copy from fs/namei.c:vfs_readlink(), except for removing it's
+ * unused first argument.
+ */
+STATIC int
+do_readlink(
+        char __user             *buffer,
+        int                     buflen,
+        const char              *link)
+{
+        int len;
+
+        len = PTR_ERR(link);
+        if (IS_ERR(link))
+                goto out;
+
+        len = strlen(link);
+        if (len > (unsigned) buflen)
+                len = buflen;
+        if (copy_to_user(buffer, link, len))
+                len = -EFAULT;
+ out:
+        return len;
+}
+
+
 STATIC int
 xfs_readlink_by_handle(
         xfs_mount_t             *mp,
         void                    __user *arg,
         struct inode            *parinode)
 {
-        int                     error;
-        struct iovec            aiov;
-        struct uio              auio;
         struct inode            *inode;
         xfs_fsop_handlereq_t    hreq;
         bhv_vnode_t             *vp;
         __u32                   olen;
+        void                    *link;
+        int                     error;
 
         if (!capable(CAP_SYS_ADMIN))
                 return -XFS_ERROR(EPERM);
@@ -374,29 +399,31 @@ xfs_readlink_by_handle(
 
         /* Restrict this handle operation to symlinks only. */
         if (!S_ISLNK(inode->i_mode)) {
-                VN_RELE(vp);
-                return -XFS_ERROR(EINVAL);
+                error = -XFS_ERROR(EINVAL);
+                goto out_iput;
         }
 
         if (copy_from_user(&olen, hreq.ohandlen, sizeof(__u32))) {
-                VN_RELE(vp);
-                return -XFS_ERROR(EFAULT);
+                error = -XFS_ERROR(EFAULT);
+                goto out_iput;
         }
-        aiov.iov_len    = olen;
-        aiov.iov_base   = hreq.ohandle;
 
-        auio.uio_iov    = (struct kvec *)&aiov;
-        auio.uio_iovcnt = 1;
-        auio.uio_offset = 0;
-        auio.uio_segflg = UIO_USERSPACE;
-        auio.uio_resid  = olen;
+        link = kmalloc(MAXPATHLEN+1, GFP_KERNEL);
+        if (!link)
+                goto out_iput;
 
-        error = bhv_vop_readlink(vp, &auio, IO_INVIS, NULL);
-        VN_RELE(vp);
+        error = -bhv_vop_readlink(vp, link);
         if (error)
-                return -error;
+                goto out_kfree;
+        error = do_readlink(hreq.ohandle, olen, link);
+        if (error)
+                goto out_kfree;
 
-        return (olen - auio.uio_resid);
+ out_kfree:
+        kfree(link);
+ out_iput:
+        iput(inode);
+        return error;
 }
 
 STATIC int
diff --git a/fs/xfs/linux-2.6/xfs_iops.c b/fs/xfs/linux-2.6/xfs_iops.c
index 0b5fa124bef2..ef941f99b2bc 100644
--- a/fs/xfs/linux-2.6/xfs_iops.c
+++ b/fs/xfs/linux-2.6/xfs_iops.c
@@ -542,50 +542,26 @@ xfs_vn_follow_link(
         struct dentry           *dentry,
         struct nameidata        *nd)
 {
-        bhv_vnode_t             *vp;
-        uio_t                   *uio;
-        iovec_t                 iov;
-        int                     error;
+        bhv_vnode_t             *vp = vn_from_inode(dentry->d_inode);
         char                    *link;
-
-        ASSERT(dentry);
-        ASSERT(nd);
+        int                     error = -ENOMEM;
 
         link = kmalloc(MAXPATHLEN+1, GFP_KERNEL);
-        if (!link) {
-                nd_set_link(nd, ERR_PTR(-ENOMEM));
-                return NULL;
-        }
-
-        uio = kmalloc(sizeof(uio_t), GFP_KERNEL);
-        if (!uio) {
-                kfree(link);
-                nd_set_link(nd, ERR_PTR(-ENOMEM));
-                return NULL;
-        }
-
-        vp = vn_from_inode(dentry->d_inode);
+        if (!link)
+                goto out_err;
 
-        iov.iov_base = link;
-        iov.iov_len = MAXPATHLEN;
-
-        uio->uio_iov = &iov;
-        uio->uio_offset = 0;
-        uio->uio_segflg = UIO_SYSSPACE;
-        uio->uio_resid = MAXPATHLEN;
-        uio->uio_iovcnt = 1;
-
-        error = bhv_vop_readlink(vp, uio, 0, NULL);
-        if (unlikely(error)) {
-                kfree(link);
-                link = ERR_PTR(-error);
-        } else {
-                link[MAXPATHLEN - uio->uio_resid] = '\0';
-        }
-        kfree(uio);
+        error = -bhv_vop_readlink(vp, link);
+        if (unlikely(error))
+                goto out_kfree;
 
         nd_set_link(nd, link);
         return NULL;
+
+ out_kfree:
+        kfree(link);
+ out_err:
+        nd_set_link(nd, ERR_PTR(error));
+        return NULL;
 }
 
 STATIC void
diff --git a/fs/xfs/linux-2.6/xfs_vnode.h b/fs/xfs/linux-2.6/xfs_vnode.h
index 146c84ba6941..bddbdb904234 100644
--- a/fs/xfs/linux-2.6/xfs_vnode.h
+++ b/fs/xfs/linux-2.6/xfs_vnode.h
@@ -18,7 +18,6 @@
 #ifndef __XFS_VNODE_H__
 #define __XFS_VNODE_H__
 
-struct uio;
 struct file;
 struct bhv_vfs;
 struct bhv_vattr;
@@ -165,8 +164,7 @@ typedef int	(*vop_readdir_t)(bhv_desc_t *, void *dirent, size_t bufsize,
                                  xfs_off_t *offset, filldir_t filldir);
 typedef int     (*vop_symlink_t)(bhv_desc_t *, bhv_vname_t *, struct bhv_vattr*,
                                 char *, bhv_vnode_t **, struct cred *);
-typedef int     (*vop_readlink_t)(bhv_desc_t *, struct uio *, int,
-                                struct cred *);
+typedef int     (*vop_readlink_t)(bhv_desc_t *, char *);
 typedef int     (*vop_fsync_t)(bhv_desc_t *, int, struct cred *,
                                 xfs_off_t, xfs_off_t);
 typedef int     (*vop_inactive_t)(bhv_desc_t *, struct cred *);
@@ -271,8 +269,8 @@ typedef struct bhv_vnodeops {
                 VOP(vop_readdir, vp)(VNHEAD(vp),dirent,bufsize,offset,filldir)
 #define bhv_vop_symlink(dvp,d,vap,tnm,vpp,cr)                           \
                 VOP(vop_symlink, dvp)(VNHEAD(dvp),d,vap,tnm,vpp,cr)
-#define bhv_vop_readlink(vp,uiop,fl,cr)                                 \
-                VOP(vop_readlink, vp)(VNHEAD(vp),uiop,fl,cr)
+#define bhv_vop_readlink(vp,link)                                       \
+                VOP(vop_readlink, vp)(VNHEAD(vp), link)
 #define bhv_vop_fsync(vp,f,cr,b,e)      VOP(vop_fsync, vp)(VNHEAD(vp),f,cr,b,e)
 #define bhv_vop_inactive(vp,cr)         VOP(vop_inactive, vp)(VNHEAD(vp),cr)
 #define bhv_vop_release(vp)             VOP(vop_release, vp)(VNHEAD(vp))
diff --git a/fs/xfs/xfs_vnodeops.c b/fs/xfs/xfs_vnodeops.c
index 36318c66a7bf..bde4a1ad90f2 100644
--- a/fs/xfs/xfs_vnodeops.c
+++ b/fs/xfs/xfs_vnodeops.c
@@ -951,6 +951,53 @@ xfs_access(
  */
 #define SYMLINK_MAPS 2
 
+STATIC int
+xfs_readlink_bmap(
+        xfs_inode_t     *ip,
+        char            *link)
+{
+        xfs_mount_t     *mp = ip->i_mount;
+        int             pathlen = ip->i_d.di_size;
+        int             nmaps = SYMLINK_MAPS;
+        xfs_bmbt_irec_t mval[SYMLINK_MAPS];
+        xfs_daddr_t     d;
+        int             byte_cnt;
+        int             n;
+        xfs_buf_t       *bp;
+        int             error = 0;
+
+        error = xfs_bmapi(NULL, ip, 0, XFS_B_TO_FSB(mp, pathlen), 0, NULL, 0,
+                        mval, &nmaps, NULL, NULL);
+        if (error)
+                goto out;
+
+        for (n = 0; n < nmaps; n++) {
+                d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
+                byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
+
+                bp = xfs_buf_read(mp->m_ddev_targp, d, BTOBB(byte_cnt), 0);
+                error = XFS_BUF_GETERROR(bp);
+                if (error) {
+                        xfs_ioerror_alert("xfs_readlink",
+                                  ip->i_mount, bp, XFS_BUF_ADDR(bp));
+                        xfs_buf_relse(bp);
+                        goto out;
+                }
+                if (pathlen < byte_cnt)
+                        byte_cnt = pathlen;
+                pathlen -= byte_cnt;
+
+                memcpy(link, XFS_BUF_PTR(bp), byte_cnt);
+                xfs_buf_relse(bp);
+        }
+
+        link[ip->i_d.di_size] = '\0';
+        error = 0;
+
+ out:
+        return error;
+}
+
 /*
  * xfs_readlink
  *
@@ -958,29 +1005,14 @@ xfs_access(
 STATIC int
 xfs_readlink(
         bhv_desc_t      *bdp,
-        uio_t           *uiop,
-        int             ioflags,
-        cred_t          *credp)
+        char            *link)
 {
-        xfs_inode_t     *ip;
-        int             count;
-        xfs_off_t       offset;
+        xfs_inode_t     *ip = XFS_BHVTOI(bdp);
+        xfs_mount_t     *mp = ip->i_mount;
         int             pathlen;
-        bhv_vnode_t     *vp;
         int             error = 0;
-        xfs_mount_t     *mp;
-        int             nmaps;
-        xfs_bmbt_irec_t mval[SYMLINK_MAPS];
-        xfs_daddr_t     d;
-        int             byte_cnt;
-        int             n;
-        xfs_buf_t       *bp;
 
-        vp = BHV_TO_VNODE(bdp);
-        vn_trace_entry(vp, __FUNCTION__, (inst_t *)__return_address);
-
-        ip = XFS_BHVTOI(bdp);
-        mp = ip->i_mount;
+        vn_trace_entry(XFS_ITOV(ip), __FUNCTION__, (inst_t *)__return_address);
 
         if (XFS_FORCED_SHUTDOWN(mp))
                 return XFS_ERROR(EIO);
@@ -988,68 +1020,24 @@ xfs_readlink(
         xfs_ilock(ip, XFS_ILOCK_SHARED);
 
         ASSERT((ip->i_d.di_mode & S_IFMT) == S_IFLNK);
+        ASSERT(ip->i_d.di_size <= MAXPATHLEN);
 
-        offset = uiop->uio_offset;
-        count = uiop->uio_resid;
-
-        if (offset < 0) {
-                error = XFS_ERROR(EINVAL);
-                goto error_return;
-        }
-        if (count <= 0) {
-                error = 0;
-                goto error_return;
-        }
-
-        /*
-         * See if the symlink is stored inline.
-         */
-        pathlen = (int)ip->i_d.di_size;
+        pathlen = ip->i_d.di_size;
+        if (!pathlen)
+                goto out;
 
         if (ip->i_df.if_flags & XFS_IFINLINE) {
-                error = xfs_uio_read(ip->i_df.if_u1.if_data, pathlen, uiop);
-        }
-        else {
-                /*
-                 * Symlink not inline.  Call bmap to get it in.
-                 */
-                nmaps = SYMLINK_MAPS;
-
-                error = xfs_bmapi(NULL, ip, 0, XFS_B_TO_FSB(mp, pathlen),
-                                  0, NULL, 0, mval, &nmaps, NULL, NULL);
-
-                if (error) {
-                        goto error_return;
-                }
-
-                for (n = 0; n < nmaps; n++) {
-                        d = XFS_FSB_TO_DADDR(mp, mval[n].br_startblock);
-                        byte_cnt = XFS_FSB_TO_B(mp, mval[n].br_blockcount);
-                        bp = xfs_buf_read(mp->m_ddev_targp, d,
-                                      BTOBB(byte_cnt), 0);
-                        error = XFS_BUF_GETERROR(bp);
-                        if (error) {
-                                xfs_ioerror_alert("xfs_readlink",
-                                          ip->i_mount, bp, XFS_BUF_ADDR(bp));
-                                xfs_buf_relse(bp);
-                                goto error_return;
-                        }
-                        if (pathlen < byte_cnt)
-                                byte_cnt = pathlen;
-                        pathlen -= byte_cnt;
-
-                        error = xfs_uio_read(XFS_BUF_PTR(bp), byte_cnt, uiop);
-                        xfs_buf_relse (bp);
-                }
-
+                memcpy(link, ip->i_df.if_u1.if_data, pathlen);
+                link[pathlen] = '\0';
+        } else {
+                error = xfs_readlink_bmap(ip, link);
         }
 
-error_return:
+ out:
         xfs_iunlock(ip, XFS_ILOCK_SHARED);
         return error;
 }
 
-
 /*
  * xfs_fsync
  *