udf: Don't write integrity descriptor too often

We update information in logical volume integrity descriptor after each
allocation (as LVID contains free space, number of directories and files on
disk etc.). If the filesystem is on some phase change media, this leads to its
quick degradation as such media is able to handle only 10000 overwrites or so.
We solve the problem by writing new information into LVID only on umount,
remount-ro and sync. This solves the problem at the price of longer media
inconsistency (previously media became consistent after pdflush flushed dirty
LVID buffer) but that should be acceptable.

Report by and patch written in cooperation with
Rich Coe <Richard.Coe@med.ge.com>.

Signed-off-by: Jan Kara <jack@suse.cz>

1 files changed, 11 insertions, 0 deletions

diff --git a/fs/udf/udfdecl.h b/fs/udf/udfdecl.h
index 9a2a9b61413e..cac51b77a5d1 100644
--- a/fs/udf/udfdecl.h
+++ b/fs/udf/udfdecl.h
@@ -111,6 +111,17 @@ struct extent_position {
 
 /* super.c */
 extern void udf_warning(struct super_block *, const char *, const char *, ...);
+static inline void udf_updated_lvid(struct super_block *sb)
+{
+        struct buffer_head *bh = UDF_SB(sb)->s_lvid_bh;
+
+        BUG_ON(!bh);
+        WARN_ON_ONCE(((struct logicalVolIntegrityDesc *)
+                     bh->b_data)->integrityType !=
+                     cpu_to_le32(LVID_INTEGRITY_TYPE_OPEN));
+        sb->s_dirt = 1;
+        UDF_SB(sb)->s_lvid_dirty = 1;
+}
 
 /* namei.c */
 extern int udf_write_fi(struct inode *inode, struct fileIdentDesc *,