NFS: Fix a couple of regressions in readdir.

Fix up the issue that array->eof_index needs to be able to be set
even if array->size == 0.

Ensure that we catch all important memory allocation error conditions
and/or kmap() failures.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 635ff65..c6ce8af 100644 (file)
--- a/fs/nfs/dir.c
+++ b/fs/nfs/dir.c
@@ -194,9 +194,13 @@ typedef struct {
 static
 struct nfs_cache_array *nfs_readdir_get_array(struct page *page)
 {
+       void *ptr;
        if (page == NULL)
                return ERR_PTR(-EIO);
-       return (struct nfs_cache_array *)kmap(page);
+       ptr = kmap(page);
+       if (ptr == NULL)
+               return ERR_PTR(-ENOMEM);
+       return ptr;
 }
 
 static
@@ -213,6 +217,9 @@ int nfs_readdir_clear_array(struct page *page, gfp_t mask)
 {
        struct nfs_cache_array *array = nfs_readdir_get_array(page);
        int i;
+
+       if (IS_ERR(array))
+               return PTR_ERR(array);
        for (i = 0; i < array->size; i++)
                kfree(array->array[i].string.name);
        nfs_readdir_release_array(page);
@@ -244,7 +251,7 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
 
        if (IS_ERR(array))
                return PTR_ERR(array);
-       ret = -EIO;
+       ret = -ENOSPC;
        if (array->size >= MAX_READDIR_ARRAY)
                goto out;
 
@@ -255,9 +262,9 @@ int nfs_readdir_add_to_array(struct nfs_entry *entry, struct page *page)
        if (ret)
                goto out;
        array->last_cookie = entry->cookie;
+       array->size++;
        if (entry->eof == 1)
                array->eof_index = array->size;
-       array->size++;
 out:
        nfs_readdir_release_array(page);
        return ret;
@@ -272,7 +279,7 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri
        if (diff < 0)
                goto out_eof;
        if (diff >= array->size) {
-               if (array->eof_index > 0)
+               if (array->eof_index >= 0)
                        goto out_eof;
                desc->current_index += array->size;
                return -EAGAIN;
@@ -281,8 +288,6 @@ int nfs_readdir_search_for_pos(struct nfs_cache_array *array, nfs_readdir_descri
        index = (unsigned int)diff;
        *desc->dir_cookie = array->array[index].cookie;
        desc->cache_entry_index = index;
-       if (index == array->eof_index)
-               desc->eof = 1;
        return 0;
 out_eof:
        desc->eof = 1;
@@ -296,17 +301,17 @@ int nfs_readdir_search_for_cookie(struct nfs_cache_array *array, nfs_readdir_des
        int status = -EAGAIN;
 
        for (i = 0; i < array->size; i++) {
-               if (i == array->eof_index) {
-                       desc->eof = 1;
-                       status = -EBADCOOKIE;
-               }
                if (array->array[i].cookie == *desc->dir_cookie) {
                        desc->cache_entry_index = i;
                        status = 0;
-                       break;
+                       goto out;
                }
        }
-
+       if (i == array->eof_index) {
+               desc->eof = 1;
+               status = -EBADCOOKIE;
+       }
+out:
        return status;
 }
 
@@ -449,7 +454,7 @@ out:
 
 /* Perform conversion from xdr to cache array */
 static
-void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
+int nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *entry,
                                void *xdr_page, struct page *page, unsigned int buflen)
 {
        struct xdr_stream stream;
@@ -471,21 +476,29 @@ void nfs_readdir_page_filler(nfs_readdir_descriptor_t *desc, struct nfs_entry *e
 
        do {
                status = xdr_decode(desc, entry, &stream);
-               if (status != 0)
+               if (status != 0) {
+                       if (status == -EAGAIN)
+                               status = 0;
                        break;
+               }
 
-               if (nfs_readdir_add_to_array(entry, page) == -1)
-                       break;
                if (desc->plus == 1)
                        nfs_prime_dcache(desc->file->f_path.dentry, entry);
+
+               status = nfs_readdir_add_to_array(entry, page);
+               if (status != 0)
+                       break;
        } while (!entry->eof);
 
        if (status == -EBADCOOKIE && entry->eof) {
                array = nfs_readdir_get_array(page);
-               array->eof_index = array->size - 1;
-               status = 0;
-               nfs_readdir_release_array(page);
+               if (!IS_ERR(array)) {
+                       array->eof_index = array->size;
+                       status = 0;
+                       nfs_readdir_release_array(page);
+               }
        }
+       return status;
 }
 
 static
@@ -537,7 +550,7 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
        struct nfs_entry entry;
        struct file     *file = desc->file;
        struct nfs_cache_array *array;
-       int status = 0;
+       int status = -ENOMEM;
        unsigned int array_size = ARRAY_SIZE(pages);
 
        entry.prev_cookie = 0;
@@ -549,6 +562,10 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
                goto out;
 
        array = nfs_readdir_get_array(page);
+       if (IS_ERR(array)) {
+               status = PTR_ERR(array);
+               goto out;
+       }
        memset(array, 0, sizeof(struct nfs_cache_array));
        array->eof_index = -1;
 
@@ -560,8 +577,13 @@ int nfs_readdir_xdr_to_array(nfs_readdir_descriptor_t *desc, struct page *page,
 
                if (status < 0)
                        break;
-               nfs_readdir_page_filler(desc, &entry, pages_ptr, page, array_size * PAGE_SIZE);
-       } while (array->eof_index < 0 && array->size < MAX_READDIR_ARRAY);
+               status = nfs_readdir_page_filler(desc, &entry, pages_ptr, page, array_size * PAGE_SIZE);
+               if (status < 0) {
+                       if (status == -ENOSPC)
+                               status = 0;
+                       break;
+               }
+       } while (array->eof_index < 0);
 
        nfs_readdir_free_large_page(pages_ptr, pages, array_size);
 out_release_array:
@@ -582,8 +604,10 @@ static
 int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page)
 {
        struct inode    *inode = desc->file->f_path.dentry->d_inode;
+       int ret;
 
-       if (nfs_readdir_xdr_to_array(desc, page, inode) < 0)
+       ret = nfs_readdir_xdr_to_array(desc, page, inode);
+       if (ret < 0)
                goto error;
        SetPageUptodate(page);
 
@@ -595,7 +619,7 @@ int nfs_readdir_filler(nfs_readdir_descriptor_t *desc, struct page* page)
        return 0;
  error:
        unlock_page(page);
-       return -EIO;
+       return ret;
 }
 
 static
@@ -608,12 +632,8 @@ void cache_page_release(nfs_readdir_descriptor_t *desc)
 static
 struct page *get_cache_page(nfs_readdir_descriptor_t *desc)
 {
-       struct page *page;
-       page = read_cache_page(desc->file->f_path.dentry->d_inode->i_mapping,
+       return read_cache_page(desc->file->f_path.dentry->d_inode->i_mapping,
                        desc->page_index, (filler_t *)nfs_readdir_filler, desc);
-       if (IS_ERR(page))
-               desc->eof = 1;
-       return page;
 }
 
 /*
@@ -639,8 +659,10 @@ int find_cache_page(nfs_readdir_descriptor_t *desc)
 static inline
 int readdir_search_pagecache(nfs_readdir_descriptor_t *desc)
 {
-       int res = -EAGAIN;
+       int res;
 
+       if (desc->page_index == 0)
+               desc->current_index = 0;
        while (1) {
                res = find_cache_page(desc);
                if (res != -EAGAIN)
@@ -670,6 +692,8 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
        struct dentry *dentry = NULL;
 
        array = nfs_readdir_get_array(desc->page);
+       if (IS_ERR(array))
+               return PTR_ERR(array);
 
        for (i = desc->cache_entry_index; i < array->size; i++) {
                d_type = DT_UNKNOWN;
@@ -685,11 +709,9 @@ int nfs_do_filldir(nfs_readdir_descriptor_t *desc, void *dirent,
                        *desc->dir_cookie = array->array[i+1].cookie;
                else
                        *desc->dir_cookie = array->last_cookie;
-               if (i == array->eof_index) {
-                       desc->eof = 1;
-                       break;
-               }
        }
+       if (i == array->eof_index)
+               desc->eof = 1;
 
        nfs_readdir_release_array(desc->page);
        cache_page_release(desc);