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>

1 files changed, 56 insertions, 34 deletions

diff --git a/fs/nfs/dir.c b/fs/nfs/dir.c
index 635ff65d309..c6ce8af266e 100644
--- 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);