xfs: cleanup xfs_find_handle

Remove the superflous igrab by keeping a reference on the path/file all the
time and clean up various bits of surrounding code.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Felix Blyakher <felixb@sgi.com>

1 files changed, 44 insertions, 62 deletions

diff --git a/fs/xfs/linux-2.6/xfs_ioctl.c b/fs/xfs/linux-2.6/xfs_ioctl.c
index 4bd112313f33..6f04493b8aba 100644
--- a/fs/xfs/linux-2.6/xfs_ioctl.c
+++ b/fs/xfs/linux-2.6/xfs_ioctl.c
@@ -78,92 +78,74 @@ xfs_find_handle(
         int                     hsize;
         xfs_handle_t            handle;
         struct inode            *inode;
+        struct file             *file = NULL;
+        struct path             path;
+        int                     error;
+        struct xfs_inode        *ip;
 
-        memset((char *)&handle, 0, sizeof(handle));
-
-        switch (cmd) {
-        case XFS_IOC_PATH_TO_FSHANDLE:
-        case XFS_IOC_PATH_TO_HANDLE: {
-                struct path path;
-                int error = user_lpath((const char __user *)hreq->path, &path);
+        if (cmd == XFS_IOC_FD_TO_HANDLE) {
+                file = fget(hreq->fd);
+                if (!file)
+                        return -EBADF;
+                inode = file->f_path.dentry->d_inode;
+        } else {
+                error = user_lpath((const char __user *)hreq->path, &path);
                 if (error)
                         return error;
-
-                ASSERT(path.dentry);
-                ASSERT(path.dentry->d_inode);
-                inode = igrab(path.dentry->d_inode);
-                path_put(&path);
-                break;
+                inode = path.dentry->d_inode;
         }
+        ip = XFS_I(inode);
 
-        case XFS_IOC_FD_TO_HANDLE: {
-                struct file     *file;
-
-                file = fget(hreq->fd);
-                if (!file)
-                    return -EBADF;
+        /*
+         * We can only generate handles for inodes residing on a XFS filesystem,
+         * and only for regular files, directories or symbolic links.
+         */
+        error = -EINVAL;
+        if (inode->i_sb->s_magic != XFS_SB_MAGIC)
+                goto out_put;
 
-                ASSERT(file->f_path.dentry);
-                ASSERT(file->f_path.dentry->d_inode);
-                inode = igrab(file->f_path.dentry->d_inode);
-                fput(file);
-                break;
-        }
+        error = -EBADF;
+        if (!S_ISREG(inode->i_mode) &&
+            !S_ISDIR(inode->i_mode) &&
+            !S_ISLNK(inode->i_mode))
+                goto out_put;
 
-        default:
-                ASSERT(0);
-                return -XFS_ERROR(EINVAL);
-        }
 
-        if (inode->i_sb->s_magic != XFS_SB_MAGIC) {
-                /* we're not in XFS anymore, Toto */
-                iput(inode);
-                return -XFS_ERROR(EINVAL);
-        }
+        memcpy(&handle.ha_fsid, ip->i_mount->m_fixedfsid, sizeof(xfs_fsid_t));
 
-        switch (inode->i_mode & S_IFMT) {
-        case S_IFREG:
-        case S_IFDIR:
-        case S_IFLNK:
-                break;
-        default:
-                iput(inode);
-                return -XFS_ERROR(EBADF);
-        }
-
-        /* now we can grab the fsid */
-        memcpy(&handle.ha_fsid, XFS_I(inode)->i_mount->m_fixedfsid,
-                        sizeof(xfs_fsid_t));
-        hsize = sizeof(xfs_fsid_t);
-
-        if (cmd != XFS_IOC_PATH_TO_FSHANDLE) {
-                xfs_inode_t     *ip = XFS_I(inode);
+        if (cmd == XFS_IOC_PATH_TO_FSHANDLE) {
+                /*
+                 * This handle only contains an fsid, zero the rest.
+                 */
+                memset(&handle.ha_fid, 0, sizeof(handle.ha_fid));
+                hsize = sizeof(xfs_fsid_t);
+        } else {
                 int             lock_mode;
 
-                /* need to get access to the xfs_inode to read the generation */
                 lock_mode = xfs_ilock_map_shared(ip);
-
-                /* fill in fid section of handle from inode */
                 handle.ha_fid.fid_len = sizeof(xfs_fid_t) -
                                         sizeof(handle.ha_fid.fid_len);
                 handle.ha_fid.fid_pad = 0;
                 handle.ha_fid.fid_gen = ip->i_d.di_gen;
                 handle.ha_fid.fid_ino = ip->i_ino;
-
                 xfs_iunlock_map_shared(ip, lock_mode);
 
                 hsize = XFS_HSIZE(handle);
         }
 
-        /* now copy our handle into the user buffer & write out the size */
+        error = -EFAULT;
         if (copy_to_user(hreq->ohandle, &handle, hsize) ||
-            copy_to_user(hreq->ohandlen, &hsize, sizeof(__s32))) {
-                iput(inode);
-                return -XFS_ERROR(EFAULT);
-        }
+            copy_to_user(hreq->ohandlen, &hsize, sizeof(__s32)))
+                goto out_put;
 
-        iput(inode);
-        return 0;
+        error = 0;
+
+ out_put:
+        if (cmd == XFS_IOC_FD_TO_HANDLE)
+                fput(file);
+        else
+                path_put(&path);
+        return error;
 }
 
 /*