[PATCH 5/6] clean up OCFS2 nlink handling

Dave Hansen
2006-08-09T16:59:18Z

OCFS2 does some operations on i_nlink, then reverts them if some
of its operations fail to complete. This does not fit in well
with the drop_nlink() logic where we expect i_nlink to stay at
zero once it gets there.

So, delay all of the nlink operations until we're sure that the
operations have completed. Also, introduce a small helper to
check whether an inode has proper "unlinkable" i_nlink counts
no matter whether it is a directory or regular inode.

This patch is broken out from the others because it does contain
some logical changes.

Signed-off-by: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: Mark Fasheh <mark.fasheh@oracle.com>
---

arch/i386/kernel/setup.c | 0
lxc-dave/fs/ocfs2/namei.c | 45 ++++++++++++++++++++++++---------------------
2 files changed, 24 insertions(+), 21 deletions(-)

diff -puN fs/ocfs2/namei.c~B5-clean_up_OCFS2_nlink_handling fs/ocfs2/namei.c
--- lxc/fs/ocfs2/namei.c~B5-clean_up_OCFS2_nlink_handling 2006-08-08 09:18:54.000000000 -0700
+++ lxc-dave/fs/ocfs2/namei.c 2006-08-08 09:18:56.000000000 -0700
@@ -744,11 +744,23 @@ bail:
return err;
}

+static inline int inode_is_unlinkable(struct inode *inode)
+{
+ if (S_ISDIR(inode->i_mode)) {
+ if (inode->i_nlink == 2)
+ return 1;
+ return 0;
+ }
+
+ if (inode->i_nlink == 1)
+ return 1;
+ return 0;
+}
+
static int ocfs2_unlink(struct inode *dir,
struct dentry *dentry)
{
int status;
- unsigned int saved_nlink = 0;
struct inode *inode = dentry->d_inode;
struct ocfs2_super *osb = OCFS2_SB(dir->i_sb);
u64 blkno;
@@ -760,6 +772,7 @@ static int ocfs2_unlink(struct inode *di
struct buffer_head *dirent_bh = NULL;
char orphan_name[OCFS2_ORPHAN_NAMELEN + 1];
struct buffer_head *orphan_entry_bh = NULL;
+ unsigned int future_nlink;

mlog_entry("(0x%p, 0x%p, '%.*s')\n", dir, dentry,
dentry->d_name.len, dentry->d_name.name);
@@ -823,18 +836,11 @@ static int ocfs2_unlink(struct inode *di
}
}

- /* There are still a few steps left until we can consider the
- * unlink to have succeeded. Save off nlink here before
- * modification so we can set it back in case we hit an issue
- * before commit. */
- saved_nlink = inode->i_nlink;
- if (S_ISDIR(inode->i_mode))
- inode->i_nlink = 0;
+ if (S_ISDIR(inode->i_mode) && (inode->i_nlink == 2))
+ future_nlink = 0;
else
- inode->i_nlink--;
-
- status = ocfs2_request_unlink_vote(inode, dentry,
- (unsigned int) inode->i_nlink);
+ future_nlink = inode->i_nlink - 1;
+ status = ocfs2_request_unlink_vote(inode, dentry, future_nlink);
if (status < 0) {
/* This vote should succeed under all normal
* circumstances. */
@@ -842,7 +848,7 @@ static int ocfs2_unlink(struct inode *di
goto leave;
}

- if (!inode->i_nlink) {
+ if (inode_is_unlinkable(inode)) {
status = ocfs2_prepare_orphan_dir(osb, handle, inode,
orphan_name,
&orphan_entry_bh);
@@ -869,7 +875,7 @@ static int ocfs2_unlink(struct inode *di

fe = (struct ocfs2_dinode *) fe_bh->b_data;

- if (!inode->i_nlink) {
+ if (inode_is_unlinkable(inode)) {
status = ocfs2_orphan_add(osb, handle, inode, fe, orphan_name,
orphan_entry_bh);
if (status < 0) {
@@ -885,10 +891,10 @@ static int ocfs2_unlink(struct inode *di
goto leave;
}

- /* We can set nlink on the dinode now. clear the saved version
- * so that it doesn't get set later. */
+ if (S_ISDIR(inode->i_mode))
+ drop_nlink(inode);
+ drop_nlink(inode);
fe->i_links_count = cpu_to_le16(inode->i_nlink);
- saved_nlink = 0;

status = ocfs2_journal_dirty(handle, fe_bh);
if (status < 0) {
@@ -897,7 +903,7 @@ static int ocfs2_unlink(struct inode *di
}

if (S_ISDIR(inode->i_mode)) {
- dir->i_nlink--;
+ drop_nlink(dir);
status = ocfs2_mark_inode_dirty(handle, dir,
parent_node_bh);
if (status < 0) {
@@ -907,9 +913,6 @@ static int ocfs2_unlink(struct inode *di
}

leave:
- if (status < 0 && saved_nlink)
- inode->i_nlink = saved_nlink;
-
if (handle)
ocfs2_commit_trans(handle);

diff -puN arch/i386/kernel/setup.c~B5-clean_up_OCFS2_nlink_handling arch/i386/kernel/setup.c
_