Add the rt linux 4.1.3-rt3 as base

[kvmfornfv.git] / kernel / fs / ext4 / truncate.h

diff --git a/kernel/fs/ext4/truncate.h b/kernel/fs/ext4/truncate.h
new file mode 100644 (file)
index 0000000..011ba66
--- /dev/null
+++ b/kernel/fs/ext4/truncate.h
@@ -0,0 +1,43 @@
+/*
+ * linux/fs/ext4/truncate.h
+ *
+ * Common inline functions needed for truncate support
+ */
+
+/*
+ * Truncate blocks that were not used by write. We have to truncate the
+ * pagecache as well so that corresponding buffers get properly unmapped.
+ */
+static inline void ext4_truncate_failed_write(struct inode *inode)
+{
+       truncate_inode_pages(inode->i_mapping, inode->i_size);
+       ext4_truncate(inode);
+}
+
+/*
+ * Work out how many blocks we need to proceed with the next chunk of a
+ * truncate transaction.
+ */
+static inline unsigned long ext4_blocks_for_truncate(struct inode *inode)
+{
+       ext4_lblk_t needed;
+
+       needed = inode->i_blocks >> (inode->i_sb->s_blocksize_bits - 9);
+
+       /* Give ourselves just enough room to cope with inodes in which
+        * i_blocks is corrupt: we've seen disk corruptions in the past
+        * which resulted in random data in an inode which looked enough
+        * like a regular file for ext4 to try to delete it.  Things
+        * will go a bit crazy if that happens, but at least we should
+        * try not to panic the whole kernel. */
+       if (needed < 2)
+               needed = 2;
+
+       /* But we need to bound the transaction so we don't overflow the
+        * journal. */
+       if (needed > EXT4_MAX_TRANS_DATA)
+               needed = EXT4_MAX_TRANS_DATA;
+
+       return EXT4_DATA_TRANS_BLOCKS(inode->i_sb) + needed;
+}
+