fs: remove some AOP_TRUNCATED_PAGE

prepare/commit_write no longer returns AOP_TRUNCATED_PAGE since OCFS2 and
GFS2 were converted to the new aops, so we can make some simplifications
for that.

[michal.k.k.piotrowski@gmail.com: fix warning]
Signed-off-by: Nick Piggin <npiggin@suse.de>
Cc: Michael Halcrow <mhalcrow@us.ibm.com>
Cc: Mark Fasheh <mark.fasheh@oracle.com>
Cc: Steven Whitehouse <swhiteho@redhat.com>
Signed-off-by: Michal Piotrowski <michal.k.k.piotrowski@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

4 files changed, 16 insertions, 48 deletions

diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 281c19ff7f45..6f8e16e3d6c0 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -621,11 +621,7 @@ struct address_space_operations {
         any basic-blocks on storage, then those blocks should be
         pre-read (if they haven't been read already) so that the
         updated blocks can be written out properly.
-        The page will be locked.  If prepare_write wants to unlock the
-        page it, like readpage, may do so and return
-        AOP_TRUNCATED_PAGE.
-        In this case the prepare_write will be retried one the lock is
-        regained.
+        The page will be locked.
 
         Note: the page _must not_ be marked uptodate in this function
         (or anywhere else) unless it actually is uptodate right now. As
diff --git a/fs/ecryptfs/mmap.c b/fs/ecryptfs/mmap.c
index fd3f94d4a668..aaea55a61ea1 100644
--- a/fs/ecryptfs/mmap.c
+++ b/fs/ecryptfs/mmap.c
@@ -446,11 +446,9 @@ out:
         return rc;
 }
 
-static
-void ecryptfs_release_lower_page(struct page *lower_page, int page_locked)
+static void ecryptfs_release_lower_page(struct page *lower_page)
 {
-        if (page_locked)
-                unlock_page(lower_page);
+        unlock_page(lower_page);
         page_cache_release(lower_page);
 }
 
@@ -471,7 +469,6 @@ static int ecryptfs_write_inode_size_to_header(struct file *lower_file,
         const struct address_space_operations *lower_a_ops;
         u64 file_size;
 
-retry:
         header_page = grab_cache_page(lower_inode->i_mapping, 0);
         if (!header_page) {
                 ecryptfs_printk(KERN_ERR, "grab_cache_page for "
@@ -482,11 +479,7 @@ retry:
         lower_a_ops = lower_inode->i_mapping->a_ops;
         rc = lower_a_ops->prepare_write(lower_file, header_page, 0, 8);
         if (rc) {
-                if (rc == AOP_TRUNCATED_PAGE) {
-                        ecryptfs_release_lower_page(header_page, 0);
-                        goto retry;
-                } else
-                        ecryptfs_release_lower_page(header_page, 1);
+                ecryptfs_release_lower_page(header_page);
                 goto out;
         }
         file_size = (u64)i_size_read(inode);
@@ -500,11 +493,7 @@ retry:
         if (rc < 0)
                 ecryptfs_printk(KERN_ERR, "Error commiting header page "
                                 "write\n");
-        if (rc == AOP_TRUNCATED_PAGE) {
-                ecryptfs_release_lower_page(header_page, 0);
-                goto retry;
-        } else
-                ecryptfs_release_lower_page(header_page, 1);
+        ecryptfs_release_lower_page(header_page);
         lower_inode->i_mtime = lower_inode->i_ctime = CURRENT_TIME;
         mark_inode_dirty_sync(inode);
 out:
@@ -593,7 +582,6 @@ int ecryptfs_get_lower_page(struct page **lower_page, struct inode *lower_inode,
 {
         int rc = 0;
 
-retry:
         *lower_page = grab_cache_page(lower_inode->i_mapping, lower_page_index);
         if (!(*lower_page)) {
                 rc = -EINVAL;
@@ -607,16 +595,11 @@ retry:
                                                           byte_offset,
                                                           region_bytes);
         if (rc) {
-                if (rc == AOP_TRUNCATED_PAGE) {
-                        ecryptfs_release_lower_page(*lower_page, 0);
-                        goto retry;
-                } else {
-                        ecryptfs_printk(KERN_ERR, "prepare_write for "
-                                "lower_page_index = [0x%.16x] failed; rc = "
-                                "[%d]\n", lower_page_index, rc);
-                        ecryptfs_release_lower_page(*lower_page, 1);
-                        (*lower_page) = NULL;
-                }
+                ecryptfs_printk(KERN_ERR, "prepare_write for "
+                        "lower_page_index = [0x%.16x] failed; rc = "
+                        "[%d]\n", lower_page_index, rc);
+                ecryptfs_release_lower_page(*lower_page);
+                (*lower_page) = NULL;
         }
 out:
         return rc;
@@ -632,19 +615,16 @@ ecryptfs_commit_lower_page(struct page *lower_page, struct inode *lower_inode,
                            struct file *lower_file, int byte_offset,
                            int region_size)
 {
-        int page_locked = 1;
         int rc = 0;
 
         rc = lower_inode->i_mapping->a_ops->commit_write(
                 lower_file, lower_page, byte_offset, region_size);
-        if (rc == AOP_TRUNCATED_PAGE)
-                page_locked = 0;
         if (rc < 0) {
                 ecryptfs_printk(KERN_ERR,
                                 "Error committing write; rc = [%d]\n", rc);
         } else
                 rc = 0;
-        ecryptfs_release_lower_page(lower_page, page_locked);
+        ecryptfs_release_lower_page(lower_page);
         return rc;
 }
 
diff --git a/include/linux/fs.h b/include/linux/fs.h
index a40557eae2ed..f70d52c46617 100644
--- a/include/linux/fs.h
+++ b/include/linux/fs.h
@@ -381,7 +381,7 @@ struct iattr {
  *                      trying again.  The aop will be taking reasonable
  *                      precautions not to livelock.  If the caller held a page
  *                      reference, it should drop it before retrying.  Returned
- *                      by readpage(), prepare_write(), and commit_write().
+ *                      by readpage().
  *
  * address_space_operation functions return these large constants to indicate
  * special semantics to the caller.  These are much larger than the bytes in a
diff --git a/mm/filemap.c b/mm/filemap.c
index 195339b27e9a..c6049e947cd9 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1898,13 +1898,10 @@ again:
 
                 ret = aops->prepare_write(file, page, offset, offset+len);
                 if (ret) {
-                        if (ret != AOP_TRUNCATED_PAGE)
-                                unlock_page(page);
+                        unlock_page(page);
                         page_cache_release(page);
                         if (pos + len > inode->i_size)
                                 vmtruncate(inode, inode->i_size);
-                        if (ret == AOP_TRUNCATED_PAGE)
-                                goto again;
                 }
                 return ret;
         }
@@ -1931,7 +1928,6 @@ int pagecache_write_end(struct file *file, struct address_space *mapping,
                 unlock_page(page);
                 mark_page_accessed(page);
                 page_cache_release(page);
-                BUG_ON(ret == AOP_TRUNCATED_PAGE); /* can't deal with */
 
                 if (ret < 0) {
                         if (pos + len > inode->i_size)
@@ -2142,7 +2138,7 @@ static ssize_t generic_perform_write_2copy(struct file *file,
                 flush_dcache_page(page);
 
                 status = a_ops->commit_write(file, page, offset, offset+bytes);
-                if (unlikely(status < 0 || status == AOP_TRUNCATED_PAGE))
+                if (unlikely(status < 0))
                         goto fs_write_aop_error;
                 if (unlikely(status > 0)) /* filesystem did partial write */
                         copied = min_t(size_t, copied, status);
@@ -2162,8 +2158,7 @@ static ssize_t generic_perform_write_2copy(struct file *file,
                 continue;
 
 fs_write_aop_error:
-                if (status != AOP_TRUNCATED_PAGE)
-                        unlock_page(page);
+                unlock_page(page);
                 page_cache_release(page);
                 if (src_page)
                         page_cache_release(src_page);
@@ -2175,10 +2170,7 @@ fs_write_aop_error:
                  */
                 if (pos + bytes > inode->i_size)
                         vmtruncate(inode, inode->i_size);
-                if (status == AOP_TRUNCATED_PAGE)
-                        continue;
-                else
-                        break;
+                break;
         } while (iov_iter_count(i));
 
         return written ? written : status;