ext4: use truncate_setsize() unconditionally

In commit c8d46e41 (ext4: Add flag to files with blocks intentionally
past EOF), if the EOFBLOCKS_FL flag is set, we call ext4_truncate()
before calling vmtruncate().  This caused any allocated but unwritten
blocks created by calling fallocate() with the FALLOC_FL_KEEP_SIZE
flag to be dropped.  This was done to make to make sure that
EOFBLOCKS_FL would not be cleared while still leaving blocks past
i_size allocated.  This was not necessary, since ext4_truncate()
guarantees that blocks past i_size will be dropped, even in the case
where truncate() has increased i_size before calling ext4_truncate().

So fix this by removing the EOFBLOCKS_FL special case treatment in
ext4_setattr().  In addition, use truncate_setsize() followed by a
call to ext4_truncate() instead of using vmtruncate().  This is more
efficient since it skips the call to inode_newsize_ok(), which has
been checked already by inode_change_ok().  This is also in a win in
the case where EOFBLOCKS_FL is set since it avoids calling
ext4_truncate() twice.

Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>

diff --git a/fs/ext4/inode.c b/fs/ext4/inode.c
index 6348c1f..d98b033 100644 (file)
--- a/fs/ext4/inode.c
+++ b/fs/ext4/inode.c
@@ -5309,8 +5309,7 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
 
        if (S_ISREG(inode->i_mode) &&
            attr->ia_valid & ATTR_SIZE &&
-           (attr->ia_size < inode->i_size ||
-            (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))) {
+           (attr->ia_size < inode->i_size)) {
                handle_t *handle;
 
                handle = ext4_journal_start(inode, 3);
@@ -5344,14 +5343,15 @@ int ext4_setattr(struct dentry *dentry, struct iattr *attr)
                                goto err_out;
                        }
                }
-               /* ext4_truncate will clear the flag */
-               if ((ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS)))
-                       ext4_truncate(inode);
        }
 
-       if ((attr->ia_valid & ATTR_SIZE) &&
-           attr->ia_size != i_size_read(inode))
-               rc = vmtruncate(inode, attr->ia_size);
+       if (attr->ia_valid & ATTR_SIZE) {
+               if (attr->ia_size != i_size_read(inode)) {
+                       truncate_setsize(inode, attr->ia_size);
+                       ext4_truncate(inode);
+               } else if (ext4_test_inode_flag(inode, EXT4_INODE_EOFBLOCKS))
+                       ext4_truncate(inode);
+       }
 
        if (!rc) {
                setattr_copy(inode, attr);