Patchwork [v2] ext3: Convert ext3 to new truncate calling convention

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Submitter Jan Kara
Date May 25, 2011, 10:43 a.m.
Message ID <1306320216-19368-1-git-send-email-jack@suse.cz>
Download mbox | patch
Permalink /patch/97325/
State Not Applicable
Headers show

Comments

Jan Kara - May 25, 2011, 10:43 a.m.
Mostly trivial conversion. We fix a bug that IS_IMMUTABLE and IS_APPEND
files could not be truncated during failed writes as we change the code.
In fact we remove the test altogether because do_sys_[f]truncate() and
may_open() do necessary checks anyway.

Signed-off-by: Jan Kara <jack@suse.cz>
---
 fs/ext3/file.c          |    1 -
 fs/ext3/inode.c         |   25 ++++++++++---------------
 include/linux/ext3_fs.h |    2 +-
 3 files changed, 11 insertions(+), 17 deletions(-)

 - updated patch to match ext4 version:
    - use truncate_setsize() instead of opencoding it
    - remove IS_APPEND & IS_IMMUTABLE check altogether
    - remove duplicate inode_newsize_ok() check
Christoph Hellwig - May 25, 2011, 11:48 a.m.
On Wed, May 25, 2011 at 12:43:36PM +0200, Jan Kara wrote:
> Mostly trivial conversion. We fix a bug that IS_IMMUTABLE and IS_APPEND
> files could not be truncated during failed writes as we change the code.
> In fact we remove the test altogether because do_sys_[f]truncate() and
> may_open() do necessary checks anyway.

This doesn't look quite correct me.  One of the major points of the
new truncate sequence is to to *_truncate_page before updating i_size,
so that we can properly handle an error there.  With your patch it's
still called too late.

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Theodore Ts'o - May 25, 2011, 9:41 p.m.
On Wed, May 25, 2011 at 12:43:36PM +0200, Jan Kara wrote:
> Mostly trivial conversion. We fix a bug that IS_IMMUTABLE and IS_APPEND
> files could not be truncated during failed writes as we change the code.
> In fact we remove the test altogether because do_sys_[f]truncate() and
> may_open() do necessary checks anyway.
> 
> Signed-off-by: Jan Kara <jack@suse.cz>

Thanks, added to the ext4 tree.

						- Ted
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Theodore Ts'o - May 25, 2011, 9:42 p.m.
On Wed, May 25, 2011 at 05:41:10PM -0400, Ted Ts'o wrote:
> On Wed, May 25, 2011 at 12:43:36PM +0200, Jan Kara wrote:
> > Mostly trivial conversion. We fix a bug that IS_IMMUTABLE and IS_APPEND
> > files could not be truncated during failed writes as we change the code.
> > In fact we remove the test altogether because do_sys_[f]truncate() and
> > may_open() do necessary checks anyway.
> > 
> > Signed-off-by: Jan Kara <jack@suse.cz>
> 
> Thanks, added to the ext4 tree.

Oops, replied to the wrong message.  I pulled in the ext4 v2 version
of your patch, obviously...

					- Ted
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Jan Kara - May 26, 2011, 2:23 p.m.
On Wed 25-05-11 07:48:23, Christoph Hellwig wrote:
> On Wed, May 25, 2011 at 12:43:36PM +0200, Jan Kara wrote:
> > Mostly trivial conversion. We fix a bug that IS_IMMUTABLE and IS_APPEND
> > files could not be truncated during failed writes as we change the code.
> > In fact we remove the test altogether because do_sys_[f]truncate() and
> > may_open() do necessary checks anyway.
> 
> This doesn't look quite correct me.  One of the major points of the
> new truncate sequence is to to *_truncate_page before updating i_size,
> so that we can properly handle an error there.  With your patch it's
> still called too late.
  OK, I missed this point (frankly, handling of error from
ext3_block_truncate_page() does not seem like a huge win when we cannot
handle error anywhere else during truncate but it's an improvement I
agree). I'll move ext3_block_truncate_page() before the setting of i_size.
Thanks for having a look at the patch.

								Honza
Christoph Hellwig - May 27, 2011, 7:16 a.m.
On Thu, May 26, 2011 at 04:23:37PM +0200, Jan Kara wrote:
> > This doesn't look quite correct me.  One of the major points of the
> > new truncate sequence is to to *_truncate_page before updating i_size,
> > so that we can properly handle an error there.  With your patch it's
> > still called too late.
>   OK, I missed this point (frankly, handling of error from
> ext3_block_truncate_page() does not seem like a huge win when we cannot
> handle error anywhere else during truncate but it's an improvement I
> agree). I'll move ext3_block_truncate_page() before the setting of i_size.
> Thanks for having a look at the patch.

Btw, I think ext4 has the same issue.

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Patch

diff --git a/fs/ext3/file.c b/fs/ext3/file.c
index f55df0e..86c8ab3 100644
--- a/fs/ext3/file.c
+++ b/fs/ext3/file.c
@@ -71,7 +71,6 @@  const struct file_operations ext3_file_operations = {
 };
 
 const struct inode_operations ext3_file_inode_operations = {
-	.truncate	= ext3_truncate,
 	.setattr	= ext3_setattr,
 #ifdef CONFIG_EXT3_FS_XATTR
 	.setxattr	= generic_setxattr,
diff --git a/fs/ext3/inode.c b/fs/ext3/inode.c
index 4d327a5..d78da39 100644
--- a/fs/ext3/inode.c
+++ b/fs/ext3/inode.c
@@ -234,12 +234,10 @@  void ext3_evict_inode (struct inode *inode)
 	if (inode->i_blocks)
 		ext3_truncate(inode);
 	/*
-	 * Kill off the orphan record which ext3_truncate created.
-	 * AKPM: I think this can be inside the above `if'.
-	 * Note that ext3_orphan_del() has to be able to cope with the
-	 * deletion of a non-existent orphan - this is because we don't
-	 * know if ext3_truncate() actually created an orphan record.
-	 * (Well, we could do this if we need to, but heck - it works)
+	 * Kill off the orphan record created when the inode lost the last
+	 * link.  Note that ext3_orphan_del() has to be able to cope with the
+	 * deletion of a non-existent orphan - ext3_truncate() could
+	 * have removed the record.
 	 */
 	ext3_orphan_del(handle, inode);
 	EXT3_I(inode)->i_dtime	= get_seconds();
@@ -890,6 +888,9 @@  int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
 	if (!create || err == -EIO)
 		goto cleanup;
 
+	/*
+	 * Block out ext3_truncate while we alter the tree
+	 */
 	mutex_lock(&ei->truncate_mutex);
 
 	/*
@@ -938,9 +939,6 @@  int ext3_get_blocks_handle(handle_t *handle, struct inode *inode,
 	 */
 	count = ext3_blks_to_allocate(partial, indirect_blks,
 					maxblocks, blocks_to_boundary);
-	/*
-	 * Block out ext3_truncate while we alter the tree
-	 */
 	err = ext3_alloc_branch(handle, inode, indirect_blks, &count, goal,
 				offsets + (partial - chain), partial);
 
@@ -1863,7 +1861,7 @@  retry:
 			/* This is really bad luck. We've written the data
 			 * but cannot extend i_size. Truncate allocated blocks
 			 * and pretend the write failed... */
-			ext3_truncate(inode);
+			ext3_truncate_failed_write(inode);
 			ret = PTR_ERR(handle);
 			goto out;
 		}
@@ -2414,8 +2412,6 @@  static void ext3_free_branches(handle_t *handle, struct inode *inode,
 
 int ext3_can_truncate(struct inode *inode)
 {
-	if (IS_APPEND(inode) || IS_IMMUTABLE(inode))
-		return 0;
 	if (S_ISREG(inode->i_mode))
 		return 1;
 	if (S_ISDIR(inode->i_mode))
@@ -3264,9 +3260,8 @@  int ext3_setattr(struct dentry *dentry, struct iattr *attr)
 
 	if ((attr->ia_valid & ATTR_SIZE) &&
 	    attr->ia_size != i_size_read(inode)) {
-		rc = vmtruncate(inode, attr->ia_size);
-		if (rc)
-			goto err_out;
+		truncate_setsize(inode, attr->ia_size);
+		ext3_truncate(inode);
 	}
 
 	setattr_copy(inode, attr);
diff --git a/include/linux/ext3_fs.h b/include/linux/ext3_fs.h
index 85c1d30..d7511b4 100644
--- a/include/linux/ext3_fs.h
+++ b/include/linux/ext3_fs.h
@@ -913,7 +913,7 @@  extern void ext3_dirty_inode(struct inode *);
 extern int ext3_change_inode_journal_flag(struct inode *, int);
 extern int ext3_get_inode_loc(struct inode *, struct ext3_iloc *);
 extern int ext3_can_truncate(struct inode *inode);
-extern void ext3_truncate (struct inode *);
+extern void ext3_truncate(struct inode *inode);
 extern void ext3_set_inode_flags(struct inode *);
 extern void ext3_get_inode_flags(struct ext3_inode_info *);
 extern void ext3_set_aops(struct inode *inode);