2006-09-13 18:27:39

by Mark Fasheh

[permalink] [raw]
Subject: Re: - r-o-bind-mount-clean-up-ocfs2-nlink-handling.patch removed from -mm tree

On Tue, Sep 12, 2006 at 10:06:30PM -0700, [email protected] wrote:
> The patch titled
>
> r/o bind mounts: clean up OCFS2 nlink handling
>
> has been removed from the -mm tree. Its filename is
>
> r-o-bind-mount-clean-up-ocfs2-nlink-handling.patch
>
> This patch was dropped because git-ocfs2 changes broke it. New patch, please.
Yep, that was very likely due to my dentry vote removal changes.

Dave, how's this one look? I guess I'll leave the same description message
below...


Subject: r/o bind mounts: clean up OCFS2 nlink handling
From: Dave Hansen <[email protected]>

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.

Cleanups to apply against current git-ocfs2 changes by Mark Fasheh.

Cc: Dave Hansen <[email protected]>
Signed-off-by: Mark Fasheh <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Andrew Morton <[email protected]>

diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 4cfc061..4f74cd9 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -797,11 +797,23 @@ static int ocfs2_remote_dentry_delete(st
return ret;
}

+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;
@@ -813,6 +825,7 @@ 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);
@@ -876,15 +889,10 @@ 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--;
+ future_nlink = inode->i_nlink - 1;

status = ocfs2_remote_dentry_delete(dentry);
if (status < 0) {
@@ -894,7 +902,7 @@ 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);
@@ -921,7 +929,7 @@ 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) {
@@ -937,10 +945,10 @@ 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) {
@@ -949,7 +957,7 @@ 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) {
@@ -959,9 +967,6 @@ static int ocfs2_unlink(struct inode *di
}

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


2006-09-13 18:37:17

by Dave Hansen

[permalink] [raw]
Subject: Re: - r-o-bind-mount-clean-up-ocfs2-nlink-handling.patch removed from -mm tree

On Wed, 2006-09-13 at 11:27 -0700, Mark Fasheh wrote:
> On Tue, Sep 12, 2006 at 10:06:30PM -0700, [email protected] wrote:
> > The patch titled
> >
> > r/o bind mounts: clean up OCFS2 nlink handling
> >
> > has been removed from the -mm tree. Its filename is
> >
> > r-o-bind-mount-clean-up-ocfs2-nlink-handling.patch
> >
> > This patch was dropped because git-ocfs2 changes broke it. New patch, please.
> Yep, that was very likely due to my dentry vote removal changes.
>
> Dave, how's this one look? I guess I'll leave the same description message
> below...

I was _just_ fighting with your git tree to see what was conflicting!
You have impeccable timing.

> 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;
> @@ -813,6 +825,7 @@ 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);
> @@ -876,15 +889,10 @@ 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--;
> + future_nlink = inode->i_nlink - 1;

Now that the vote call is gone, I don't think we even use future_nlink.
Can we just kill this entire section?

-- Dave

2006-09-13 19:12:39

by Mark Fasheh

[permalink] [raw]
Subject: Re: - r-o-bind-mount-clean-up-ocfs2-nlink-handling.patch removed from -mm tree

On Wed, Sep 13, 2006 at 11:36:36AM -0700, Dave Hansen wrote:
> I was _just_ fighting with your git tree to see what was conflicting!
> You have impeccable timing.
Heh, glad that the timing worked out :)


> > - /* 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--;
> > + future_nlink = inode->i_nlink - 1;
>
> Now that the vote call is gone, I don't think we even use future_nlink.
> Can we just kill this entire section?
Yeah, good catch. Lets try this one again...


Subject: r/o bind mounts: clean up OCFS2 nlink handling
From: Dave Hansen <[email protected]>

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.

Cc: Dave Hansen <[email protected]>
Signed-off-by: Mark Fasheh <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Al Viro <[email protected]>
Cc: Andrew Morton <[email protected]>

diff --git a/fs/ocfs2/namei.c b/fs/ocfs2/namei.c
index 4cfc061..1c3d296 100644
--- a/fs/ocfs2/namei.c
+++ b/fs/ocfs2/namei.c
@@ -797,11 +797,23 @@ static int ocfs2_remote_dentry_delete(st
return ret;
}

+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;
@@ -876,16 +888,6 @@ 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;
- else
- inode->i_nlink--;
-
status = ocfs2_remote_dentry_delete(dentry);
if (status < 0) {
/* This vote should succeed under all normal
@@ -894,7 +896,7 @@ 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);
@@ -921,7 +923,7 @@ 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) {
@@ -937,10 +939,10 @@ 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) {
@@ -949,7 +951,7 @@ 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) {
@@ -959,9 +961,6 @@ static int ocfs2_unlink(struct inode *di
}

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

2006-09-13 19:19:45

by Dave Hansen

[permalink] [raw]
Subject: Re: - r-o-bind-mount-clean-up-ocfs2-nlink-handling.patch removed from -mm tree

On Wed, 2006-09-13 at 12:12 -0700, Mark Fasheh wrote:
> > Now that the vote call is gone, I don't think we even use future_nlink.
> > Can we just kill this entire section?
> Yeah, good catch. Lets try this one again...

Looks good to me. Thanks a bunch for updating this one.

Signed-off-by: Dave Hansen <[email protected]>

-- Dave