ext4: only call ext4_truncate when size <= isize

At LSF we decided that if we truncate up from isize we shouldn't trim
fallocated blocks that were fallocated with KEEP_SIZE and are past the
new i_size.  This patch fixes ext4 to do this.

[ Completely reworked patch so that i_disksize would actually get set
  when truncating up.  Also reworked the code for handling truncate so
  that it's easier to handle. -- tytso ]

Signed-off-by: Josef Bacik <jbacik@fb.com>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Reviewed-by: Lukas Czerner <lczerner@redhat.com>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index ae93f0b..e057c6f 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -4681,8 +4681,10 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
                ext4_journal_stop(handle);
        }
 
-       if (attr->ia_valid & ATTR_SIZE && attr->ia_size != inode->i_size) {
+       if (attr->ia_valid & ATTR_SIZE) {
                handle_t *handle;
+               loff_t oldsize = inode->i_size;
+               int shrink = (attr->ia_size <= inode->i_size);
 
                if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
                        struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
@@ -4690,24 +4692,26 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
                        if (attr->ia_size > sbi->s_bitmap_maxbytes)
                                return -EFBIG;
                }
+               if (!S_ISREG(inode->i_mode))
+                       return -EINVAL;
 
                if (IS_I_VERSION(inode) && attr->ia_size != inode->i_size)
                        inode_inc_iversion(inode);
 
-               if (S_ISREG(inode->i_mode) &&
+               if (ext4_should_order_data(inode) &&
                    (attr->ia_size < inode->i_size)) {
-                       if (ext4_should_order_data(inode)) {
-                               error = ext4_begin_ordered_truncate(inode,
+                       error = ext4_begin_ordered_truncate(inode,
                                                            attr->ia_size);
-                               if (error)
-                                       goto err_out;
-                       }
+                       if (error)
+                               goto err_out;
+               }
+               if (attr->ia_size != inode->i_size) {
                        handle = ext4_journal_start(inode, EXT4_HT_INODE, 3);
                        if (IS_ERR(handle)) {
                                error = PTR_ERR(handle);
                                goto err_out;
                        }
-                       if (ext4_handle_valid(handle)) {
+                       if (ext4_handle_valid(handle) && shrink) {
                                error = ext4_orphan_add(handle, inode);
                                orphan = 1;
                        }
@@ -4726,15 +4730,13 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
                        up_write(&EXT4_I(inode)->i_data_sem);
                        ext4_journal_stop(handle);
                        if (error) {
-                               ext4_orphan_del(NULL, inode);
+                               if (orphan)
+                                       ext4_orphan_del(NULL, inode);
                                goto err_out;
                        }
-               } else {
-                       loff_t oldsize = inode->i_size;
-
-                       i_size_write(inode, attr->ia_size);
-                       pagecache_isize_extended(inode, oldsize, inode->i_size);
                }
+               if (!shrink)
+                       pagecache_isize_extended(inode, oldsize, inode->i_size);
 
                /*
                 * Blocks are going to be removed from the inode. Wait
@@ -4754,13 +4756,9 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
                 * in data=journal mode to make pages freeable.
                 */
                truncate_pagecache(inode, inode->i_size);
+               if (shrink)
+                       ext4_truncate(inode);
        }
-       /*
-        * We want to call ext4_truncate() even if attr->ia_size ==
-        * inode->i_size for cases like truncation of fallocated space
-        */
-       if (attr->ia_valid & ATTR_SIZE)
-               ext4_truncate(inode);
 
        if (!rc) {
                setattr_copy(inode, attr);