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authorTheodore Ts'o <tytso@mit.edu>2011-06-28 03:16:04 +0400
committerTheodore Ts'o <tytso@mit.edu>2011-06-28 03:16:04 +0400
commit9f125d641beb898f5bf2fe69583192c18043517a (patch)
tree02259a4f538fbca0cbd6a9f0c4a9f96c82d738d6 /fs/ext4/truncate.h
parent1f7d1e77419050831a905353683807fa69a26625 (diff)
downloadlinux-9f125d641beb898f5bf2fe69583192c18043517a.tar.xz
ext4: move common truncate functions to header file
Move two functions that will be needed by the indirect functions to be moved to indirect.c as well as inode.c to truncate.h as inline functions, so that we can avoid having duplicate copies of the function (which can be a maintenance problem) without having to expose them as globally functions. Signed-off-by: "Theodore Ts'o" <tytso@mit.edu>
Diffstat (limited to 'fs/ext4/truncate.h')
-rw-r--r--fs/ext4/truncate.h43
1 files changed, 43 insertions, 0 deletions
diff --git a/fs/ext4/truncate.h b/fs/ext4/truncate.h
new file mode 100644
index 000000000000..011ba6670d99
--- /dev/null
+++ b/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;
+}
+