[PATCH] Ext2/3 noatime and dirsync fixes

Patch from "Theodore Ts'o" <tytso@mit.edu>

I recently noticed a bug in ext2/3; newly created inodes which inherit
the noatime flag from their containing directory do not respect noatime
until the inode is flushed from the inode cache and then re-read later.
This is because the code which checks the ext2 no-atime attribute and
then sets the S_NOATIME in inode->i_flags is present in
ext2_read_inode(), but not in ext2_new_inode().

I fixed this in 2.4, and then found an even worse bug in the 2.5 code;
the DIRSYNC flag is completely ignored *except* in the case where a
directory is newly created using mkdir and its parent directory has the
DIRSYNC flag.  S_DIRSYNC doesn't get set in the ext2_new_inode() or the
ext2_ioctl() paths (which is used by chattr).

This patch centralizes the code which translates the ext2 flags in the
raw ext2 inode to the appropriate flag values in inode->i_flags in a
single location.  This fixes the bug, makes things cleaner, and also
removes 30 lines of code and 128 bytes of compiled x86 text in the
bargain.

4 files changed, 21 insertions, 28 deletions

diff --git a/fs/ext2/ext2.h b/fs/ext2/ext2.h
index 7850dcbe7bf1..610695289845 100644
--- a/fs/ext2/ext2.h
+++ b/fs/ext2/ext2.h
@@ -112,6 +112,7 @@ extern int ext2_sync_inode (struct inode *);
 extern void ext2_discard_prealloc (struct inode *);
 extern void ext2_truncate (struct inode *);
 extern int ext2_setattr (struct dentry *, struct iattr *);
+extern void ext2_set_inode_flags(struct inode *inode);
 
 /* ioctl.c */
 extern int ext2_ioctl (struct inode *, struct file *, unsigned int,
diff --git a/fs/ext2/ialloc.c b/fs/ext2/ialloc.c
index 345e7495176d..87b2d99f4a7c 100644
--- a/fs/ext2/ialloc.c
+++ b/fs/ext2/ialloc.c
@@ -545,10 +545,7 @@ repeat:
 	ei->i_prealloc_count = 0;
 	ei->i_dir_start_lookup = 0;
 	ei->i_state = EXT2_STATE_NEW;
-	if (ei->i_flags & EXT2_SYNC_FL)
-		inode->i_flags |= S_SYNC;
-	if (ei->i_flags & EXT2_DIRSYNC_FL)
-		inode->i_flags |= S_DIRSYNC;
+	ext2_set_inode_flags(inode);
 	inode->i_generation = EXT2_SB(sb)->s_next_generation++;
 	insert_inode_hash(inode);
 
diff --git a/fs/ext2/inode.c b/fs/ext2/inode.c
index e47f84e305cd..c2fbefdd3613 100644
--- a/fs/ext2/inode.c
+++ b/fs/ext2/inode.c
@@ -1011,6 +1011,23 @@ Egdp:
 	return ERR_PTR(-EIO);
 }
 
+void ext2_set_inode_flags(struct inode *inode)
+{
+	unsigned int flags = EXT2_I(inode)->i_flags;
+
+	inode->i_flags &= ~(S_SYNC|S_APPEND|S_IMMUTABLE|S_NOATIME|S_DIRSYNC);
+	if (flags & EXT2_SYNC_FL)
+		inode->i_flags |= S_SYNC;
+	if (flags & EXT2_APPEND_FL)
+		inode->i_flags |= S_APPEND;
+	if (flags & EXT2_IMMUTABLE_FL)
+		inode->i_flags |= S_IMMUTABLE;
+	if (flags & EXT2_NOATIME_FL)
+		inode->i_flags |= S_NOATIME;
+	if (flags & EXT2_DIRSYNC_FL)
+		inode->i_flags |= S_DIRSYNC;
+}
+
 void ext2_read_inode (struct inode * inode)
 {
 	struct ext2_inode_info *ei = EXT2_I(inode);
@@ -1108,14 +1125,7 @@ void ext2_read_inode (struct inode * inode)
 				   le32_to_cpu(raw_inode->i_block[0]));
 	}
 	brelse (bh);
-	if (ei->i_flags & EXT2_SYNC_FL)
-		inode->i_flags |= S_SYNC;
-	if (ei->i_flags & EXT2_APPEND_FL)
-		inode->i_flags |= S_APPEND;
-	if (ei->i_flags & EXT2_IMMUTABLE_FL)
-		inode->i_flags |= S_IMMUTABLE;
-	if (ei->i_flags & EXT2_NOATIME_FL)
-		inode->i_flags |= S_NOATIME;
+	ext2_set_inode_flags(inode);
 	return;
 	
 bad_inode:
diff --git a/fs/ext2/ioctl.c b/fs/ext2/ioctl.c
index afff8566f3b6..101055bbf519 100644
--- a/fs/ext2/ioctl.c
+++ b/fs/ext2/ioctl.c
@@ -58,22 +58,7 @@ int ext2_ioctl (struct inode * inode, struct file * filp, unsigned int cmd,
 		flags |= oldflags & ~EXT2_FL_USER_MODIFIABLE;
 		ei->i_flags = flags;
 
-		if (flags & EXT2_SYNC_FL)
-			inode->i_flags |= S_SYNC;
-		else
-			inode->i_flags &= ~S_SYNC;
-		if (flags & EXT2_APPEND_FL)
-			inode->i_flags |= S_APPEND;
-		else
-			inode->i_flags &= ~S_APPEND;
-		if (flags & EXT2_IMMUTABLE_FL)
-			inode->i_flags |= S_IMMUTABLE;
-		else
-			inode->i_flags &= ~S_IMMUTABLE;
-		if (flags & EXT2_NOATIME_FL)
-			inode->i_flags |= S_NOATIME;
-		else
-			inode->i_flags &= ~S_NOATIME;
+		ext2_set_inode_flags(inode);
 		inode->i_ctime = CURRENT_TIME;
 		mark_inode_dirty(inode);
 		return 0;