Re: + cifs-remove-unneeded-checks.patch added to -mm tree

Re: + cifs-remove-unneeded-checks.patch added to -mm tree

[Steve French]

[-- Attachment #1: Type: text/plain, Size: 915 bytes --]

On Mon, 2007-04-02 at 13:51 -0500, Steven French wrote:
> akpm@linux-foundation.org wrote on 03/11/2007 03:57:40 AM:
> 
> > 
> > The patch titled
> >      cifs: remove unneeded checks
> > has been added to the -mm tree.  Its filename is
> >      cifs-remove-unneeded-checks.patch
> > 
> > ------------------------------------------------------
> > Subject: cifs: remove unneeded checks
> > From: Christoph Hellwig <hch@lst.de>
> > 
> > file->f_path.dentry or file->f_path.dentry.d_inode can't be NULL since at
> > least ten years, similar for all but very few arguments passed in from the
> > VFS.

I merged most of Christoph's cifs-remove-unneeded-checks patch into the
cifs-2.6 development tree. The part I did not merge was a little harder
to verify and vaguely reminded me of the old bug report.  The part I
left out is attached (I don't mind leaving that part in mm a little
longer to make sure it is safe).



[-- Attachment #2: cifs-remove-unneeded-checks-part2.patch --]
[-- Type: text/x-patch, Size: 3704 bytes --]

diff -Nau /home/stevef/linux-2.6/fs/cifs/file.c /home/stevef/virtfs-2.6/fs/cifs/file.c
--- /home/stevef/linux-2.6/fs/cifs/file.c	2007-04-02 13:55:36.000000000 -0500
+++ /home/stevef/virtfs-2.6/fs/cifs/file.c	2007-04-02 13:48:29.000000000 -0500
@@ -352,8 +352,6 @@
 	int disposition = FILE_OPEN;
 	__u16 netfid;
 
-	if (inode == NULL)
-		return -EBADF;
 	if (file->private_data) {
 		pCifsFile = (struct cifsFileInfo *)file->private_data;
 	} else
@@ -367,12 +365,6 @@
 		return 0;
 	}
 
-	if (file->f_path.dentry == NULL) {
-		up(&pCifsFile->fh_sem);
-		cFYI(1, ("failed file reopen, no valid name if dentry freed"));
-		FreeXid(xid);
-		return -EBADF;
-	}
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
 /* can not grab rename sem here because various ops, including
@@ -784,6 +776,7 @@
 ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 	size_t write_size, loff_t *poffset)
 {
+	struct inode *inode = file->f_path.dentry->d_inode;
 	int rc = 0;
 	unsigned int bytes_written = 0;
 	unsigned int total_written;
@@ -831,11 +824,6 @@
 					return -EBADF;
 			}
 			if (open_file->invalidHandle) {
-				if ((file->f_path.dentry == NULL) ||
-				    (file->f_path.dentry->d_inode == NULL)) {
-					FreeXid(xid);
-					return total_written;
-				}
 				/* we could deadlock if we called
 				   filemap_fdatawait from here so tell
 				   reopen_file not to flush data to server
@@ -868,21 +856,18 @@
 
 	cifs_stats_bytes_written(pTcon, total_written);
 
-	/* since the write may have blocked check these pointers again */
-	if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
-		struct inode *inode = file->f_path.dentry->d_inode;
 /* Do not update local mtime - server will set its actual value on write		
  *		inode->i_ctime = inode->i_mtime = 
  * 			current_fs_time(inode->i_sb);*/
-		if (total_written > 0) {
-			spin_lock(&inode->i_lock);
-			if (*poffset > file->f_path.dentry->d_inode->i_size)
-				i_size_write(file->f_path.dentry->d_inode,
-					*poffset);
-			spin_unlock(&inode->i_lock);
-		}
-		mark_inode_dirty_sync(file->f_path.dentry->d_inode);	
+	if (total_written > 0) {
+		spin_lock(&inode->i_lock);
+		if (*poffset > file->f_path.dentry->d_inode->i_size)
+			i_size_write(file->f_path.dentry->d_inode,
+				*poffset);
+		spin_unlock(&inode->i_lock);
 	}
+	mark_inode_dirty_sync(file->f_path.dentry->d_inode);
+
 	FreeXid(xid);
 	return total_written;
 }
@@ -988,19 +973,17 @@
 	cifs_stats_bytes_written(pTcon, total_written);
 
 	/* since the write may have blocked check these pointers again */
-	if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
 /*BB We could make this contingent on superblock ATIME flag too */
-/*		file->f_path.dentry->d_inode->i_ctime =
-		file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
-		if (total_written > 0) {
-			spin_lock(&file->f_path.dentry->d_inode->i_lock);
-			if (*poffset > file->f_path.dentry->d_inode->i_size)
-				i_size_write(file->f_path.dentry->d_inode,
-					     *poffset);
-			spin_unlock(&file->f_path.dentry->d_inode->i_lock);
-		}
-		mark_inode_dirty_sync(file->f_path.dentry->d_inode);
+/*	file->f_path.dentry->d_inode->i_ctime =
+	file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
+	if (total_written > 0) {
+		spin_lock(&file->f_path.dentry->d_inode->i_lock);
+		if (*poffset > file->f_path.dentry->d_inode->i_size)
+			i_size_write(file->f_path.dentry->d_inode,
+				     *poffset);
+		spin_unlock(&file->f_path.dentry->d_inode->i_lock);
 	}
+	mark_inode_dirty_sync(file->f_path.dentry->d_inode);
 	FreeXid(xid);
 	return total_written;
 }
Common subdirectories: /home/stevef/linux-2.6/fs/cifs/.tmp_versions and /home/stevef/virtfs-2.6/fs/cifs/.tmp_versions

Re: + cifs-remove-unneeded-checks.patch added to -mm tree

[Christoph Hellwig]

On Mon, Apr 02, 2007 at 03:36:01PM -0500, Steve French wrote:
> I merged most of Christoph's cifs-remove-unneeded-checks patch into the
> cifs-2.6 development tree. The part I did not merge was a little harder
> to verify and vaguely reminded me of the old bug report.  The part I
> left out is attached (I don't mind leaving that part in mm a little
> longer to make sure it is safe).


diff -Nau /home/stevef/linux-2.6/fs/cifs/file.c /home/stevef/virtfs-2.6/fs/cifs/file.c
--- /home/stevef/linux-2.6/fs/cifs/file.c	2007-04-02 13:55:36.000000000 -0500
+++ /home/stevef/virtfs-2.6/fs/cifs/file.c	2007-04-02 13:48:29.000000000 -0500
@@ -352,8 +352,6 @@
 	int disposition = FILE_OPEN;
 	__u16 netfid;
 
-	if (inode == NULL)
-		return -EBADF;

This is cifs_reopen_file.  One of the callers (find_writable_file) calls
this with the &cifs_inode->vfs_inode as inode argument, which can't be
NULL per definition.  All other callers pass
file->f_path.dentry->d_inode as inode argument, which per definition is
not never zero, because there are not file structs arount that don't
point to an inode.

Note that you could nicely simplify the find_writable_file calling
conventions by not passing the inode argument explicitly at all, but
rather always deriving it from file->f_path.dentry->d_inode inside
the function body.

 	if (file->private_data) {
 		pCifsFile = (struct cifsFileInfo *)file->private_data;
 	} else
@@ -367,12 +365,6 @@
 		return 0;
 	}
 
-	if (file->f_path.dentry == NULL) {
-		up(&pCifsFile->fh_sem);
-		cFYI(1, ("failed file reopen, no valid name if dentry freed"));
-		FreeXid(xid);
-		return -EBADF;
-	}

@@ -784,6 +776,7 @@
 ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 	size_t write_size, loff_t *poffset)
 {
+	struct inode *inode = file->f_path.dentry->d_inode;
 	int rc = 0;
 	unsigned int bytes_written = 0;
 	unsigned int total_written;
@@ -831,11 +824,6 @@
 					return -EBADF;
 			}
 			if (open_file->invalidHandle) {
-				if ((file->f_path.dentry == NULL) ||
-				    (file->f_path.dentry->d_inode == NULL)) {
-					FreeXid(xid);
-					return total_written;
-				}

Same again here, there's no fscking chance read/write could ever work
without a dentry or inode.

+ cifs-remove-unneeded-checks.patch added to -mm tree

[akpm]

The patch titled
     cifs: remove unneeded checks
has been added to the -mm tree.  Its filename is
     cifs-remove-unneeded-checks.patch

*** Remember to use Documentation/SubmitChecklist when testing your code ***

See http://www.zip.com.au/~akpm/linux/patches/stuff/added-to-mm.txt to find
out what to do about this

------------------------------------------------------
Subject: cifs: remove unneeded checks
From: Christoph Hellwig <hch@lst.de>

file->f_path.dentry or file->f_path.dentry.d_inode can't be NULL since at
least ten years, similar for all but very few arguments passed in from the
VFS.

Cc: Steven French <sfrench@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 fs/cifs/cifsfs.c  |    3 -
 fs/cifs/file.c    |   82 ++++++++++----------------------------------
 fs/cifs/readdir.c |   27 +-------------
 3 files changed, 24 insertions(+), 88 deletions(-)

diff -puN fs/cifs/cifsfs.c~cifs-remove-unneeded-checks fs/cifs/cifsfs.c
--- a/fs/cifs/cifsfs.c~cifs-remove-unneeded-checks
+++ a/fs/cifs/cifsfs.c
@@ -529,8 +529,7 @@ static loff_t cifs_llseek(struct file *f
 		/* some applications poll for the file length in this strange
 		   way so we must seek to end on non-oplocked files by
 		   setting the revalidate time to zero */
-		if(file->f_path.dentry->d_inode)		
-			CIFS_I(file->f_path.dentry->d_inode)->time = 0;
+		CIFS_I(file->f_path.dentry->d_inode)->time = 0;
 
 		retval = cifs_revalidate(file->f_path.dentry);
 		if (retval < 0)
diff -puN fs/cifs/file.c~cifs-remove-unneeded-checks fs/cifs/file.c
--- a/fs/cifs/file.c~cifs-remove-unneeded-checks
+++ a/fs/cifs/file.c
@@ -352,8 +352,6 @@ static int cifs_reopen_file(struct inode
 	int disposition = FILE_OPEN;
 	__u16 netfid;
 
-	if (inode == NULL)
-		return -EBADF;
 	if (file->private_data) {
 		pCifsFile = (struct cifsFileInfo *)file->private_data;
 	} else
@@ -367,12 +365,6 @@ static int cifs_reopen_file(struct inode
 		return 0;
 	}
 
-	if (file->f_path.dentry == NULL) {
-		up(&pCifsFile->fh_sem);
-		cFYI(1, ("failed file reopen, no valid name if dentry freed"));
-		FreeXid(xid);
-		return -EBADF;
-	}
 	cifs_sb = CIFS_SB(inode->i_sb);
 	pTcon = cifs_sb->tcon;
 /* can not grab rename sem here because various ops, including
@@ -784,6 +776,7 @@ int cifs_lock(struct file *file, int cmd
 ssize_t cifs_user_write(struct file *file, const char __user *write_data,
 	size_t write_size, loff_t *poffset)
 {
+	struct inode *inode = file->f_path.dentry->d_inode;
 	int rc = 0;
 	unsigned int bytes_written = 0;
 	unsigned int total_written;
@@ -792,12 +785,7 @@ ssize_t cifs_user_write(struct file *fil
 	int xid, long_op;
 	struct cifsFileInfo *open_file;
 
-	if (file->f_path.dentry == NULL)
-		return -EBADF;
-
 	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
-	if (cifs_sb == NULL)
-		return -EBADF;
 
 	pTcon = cifs_sb->tcon;
 
@@ -807,14 +795,9 @@ ssize_t cifs_user_write(struct file *fil
 
 	if (file->private_data == NULL)
 		return -EBADF;
-	else
-		open_file = (struct cifsFileInfo *) file->private_data;
+	open_file = (struct cifsFileInfo *) file->private_data;
 	
 	xid = GetXid();
-	if (file->f_path.dentry->d_inode == NULL) {
-		FreeXid(xid);
-		return -EBADF;
-	}
 
 	if (*poffset > file->f_path.dentry->d_inode->i_size)
 		long_op = 2; /* writes past end of file can take a long time */
@@ -841,11 +824,6 @@ ssize_t cifs_user_write(struct file *fil
 					return -EBADF;
 			}
 			if (open_file->invalidHandle) {
-				if ((file->f_path.dentry == NULL) ||
-				    (file->f_path.dentry->d_inode == NULL)) {
-					FreeXid(xid);
-					return total_written;
-				}
 				/* we could deadlock if we called
 				   filemap_fdatawait from here so tell
 				   reopen_file not to flush data to server
@@ -878,21 +856,18 @@ ssize_t cifs_user_write(struct file *fil
 
 	cifs_stats_bytes_written(pTcon, total_written);
 
-	/* since the write may have blocked check these pointers again */
-	if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
-		struct inode *inode = file->f_path.dentry->d_inode;
 /* Do not update local mtime - server will set its actual value on write		
  *		inode->i_ctime = inode->i_mtime = 
  * 			current_fs_time(inode->i_sb);*/
-		if (total_written > 0) {
-			spin_lock(&inode->i_lock);
-			if (*poffset > file->f_path.dentry->d_inode->i_size)
-				i_size_write(file->f_path.dentry->d_inode,
-					*poffset);
-			spin_unlock(&inode->i_lock);
-		}
-		mark_inode_dirty_sync(file->f_path.dentry->d_inode);	
+	if (total_written > 0) {
+		spin_lock(&inode->i_lock);
+		if (*poffset > file->f_path.dentry->d_inode->i_size)
+			i_size_write(file->f_path.dentry->d_inode,
+				*poffset);
+		spin_unlock(&inode->i_lock);
 	}
+	mark_inode_dirty_sync(file->f_path.dentry->d_inode);
+
 	FreeXid(xid);
 	return total_written;
 }
@@ -908,12 +883,7 @@ static ssize_t cifs_write(struct file *f
 	int xid, long_op;
 	struct cifsFileInfo *open_file;
 
-	if (file->f_path.dentry == NULL)
-		return -EBADF;
-
 	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
-	if (cifs_sb == NULL)
-		return -EBADF;
 
 	pTcon = cifs_sb->tcon;
 
@@ -922,14 +892,9 @@ static ssize_t cifs_write(struct file *f
 
 	if (file->private_data == NULL)
 		return -EBADF;
-	else
-		open_file = (struct cifsFileInfo *)file->private_data;
+	open_file = (struct cifsFileInfo *)file->private_data;
 	
 	xid = GetXid();
-	if (file->f_path.dentry->d_inode == NULL) {
-		FreeXid(xid);
-		return -EBADF;
-	}
 
 	if (*poffset > file->f_path.dentry->d_inode->i_size)
 		long_op = 2; /* writes past end of file can take a long time */
@@ -957,11 +922,6 @@ static ssize_t cifs_write(struct file *f
 					return -EBADF;
 			}
 			if (open_file->invalidHandle) {
-				if ((file->f_path.dentry == NULL) ||
-				   (file->f_path.dentry->d_inode == NULL)) {
-					FreeXid(xid);
-					return total_written;
-				}
 				/* we could deadlock if we called
 				   filemap_fdatawait from here so tell
 				   reopen_file not to flush data to 
@@ -1013,19 +973,17 @@ static ssize_t cifs_write(struct file *f
 	cifs_stats_bytes_written(pTcon, total_written);
 
 	/* since the write may have blocked check these pointers again */
-	if ((file->f_path.dentry) && (file->f_path.dentry->d_inode)) {
 /*BB We could make this contingent on superblock ATIME flag too */
-/*		file->f_path.dentry->d_inode->i_ctime =
-		file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
-		if (total_written > 0) {
-			spin_lock(&file->f_path.dentry->d_inode->i_lock);
-			if (*poffset > file->f_path.dentry->d_inode->i_size)
-				i_size_write(file->f_path.dentry->d_inode,
-					     *poffset);
-			spin_unlock(&file->f_path.dentry->d_inode->i_lock);
-		}
-		mark_inode_dirty_sync(file->f_path.dentry->d_inode);
+/*	file->f_path.dentry->d_inode->i_ctime =
+	file->f_path.dentry->d_inode->i_mtime = CURRENT_TIME;*/
+	if (total_written > 0) {
+		spin_lock(&file->f_path.dentry->d_inode->i_lock);
+		if (*poffset > file->f_path.dentry->d_inode->i_size)
+			i_size_write(file->f_path.dentry->d_inode,
+				     *poffset);
+		spin_unlock(&file->f_path.dentry->d_inode->i_lock);
 	}
+	mark_inode_dirty_sync(file->f_path.dentry->d_inode);
 	FreeXid(xid);
 	return total_written;
 }
diff -puN fs/cifs/readdir.c~cifs-remove-unneeded-checks fs/cifs/readdir.c
--- a/fs/cifs/readdir.c~cifs-remove-unneeded-checks
+++ a/fs/cifs/readdir.c
@@ -440,9 +440,6 @@ static int initiate_cifs_search(const in
 	cifsFile->invalidHandle = TRUE;
 	cifsFile->srch_inf.endOfSearch = FALSE;
 
-	if(file->f_path.dentry == NULL)
-		return -ENOENT;
-
 	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 	if(cifs_sb == NULL)
 		return -EINVAL;
@@ -614,20 +611,10 @@ static int cifs_entry_is_dot(char *curre
    whether we can use the cached search results from the previous search */
 static int is_dir_changed(struct file * file)
 {
-	struct inode * inode;
-	struct cifsInodeInfo *cifsInfo;
-
-	if(file->f_path.dentry == NULL)
-		return 0;
-
-	inode = file->f_path.dentry->d_inode;
-
-	if(inode == NULL)
-		return 0;
-
-	cifsInfo = CIFS_I(inode);
+	struct inode *inode = file->f_path.dentry->d_inode;
+	struct cifsInodeInfo *cifsInfo = CIFS_I(inode);
 
-	if(cifsInfo->time == 0)
+	if (cifsInfo->time == 0)
 		return 1; /* directory was changed, perhaps due to unlink */
 	else
 		return 0;
@@ -847,9 +834,6 @@ static int cifs_filldir(char *pfindEntry
 	if((scratch_buf == NULL) || (pfindEntry == NULL) || (pCifsF == NULL))
 		return -ENOENT;
 
-	if(file->f_path.dentry == NULL)
-		return -ENOENT;
-
 	rc = cifs_entry_is_dot(pfindEntry,pCifsF);
 	/* skip . and .. since we added them first */
 	if(rc != 0) 
@@ -993,11 +977,6 @@ int cifs_readdir(struct file *file, void
 
 	xid = GetXid();
 
-	if(file->f_path.dentry == NULL) {
-		FreeXid(xid);
-		return -EIO;
-	}
-
 	cifs_sb = CIFS_SB(file->f_path.dentry->d_sb);
 	pTcon = cifs_sb->tcon;
 	if(pTcon == NULL)
_

Patches currently in -mm which might be from hch@lst.de are

ufs2-tindirect-truncate-fix.patch
cifs-remove-unneeded-checks.patch
xfs-use-xfs_get_buf_noaddr-for-iclogs.patch
xfs-stop-using-kmalloc-in-xfs_buf_get_noaddr.patch
xfs-stop-using-kmalloc-in-xfs_buf_get_noaddr-fix.patch
simplify-the-stacktrace-code.patch
allow-access-to-proc-pid-fd-after-setuid.patch
fix-quadratic-behavior-of-shrink_dcache_parent.patch
freevxfs-possible-null-pointer-dereference-fix.patch
vfs-remove-superflous-sb-==-null-checks.patch
nameic-remove-utterly-outdated-comment.patch
make-static-counters-in-new_inode-and-iunique-be-32-bits.patch
change-libfs-sb-creation-routines-to-avoid-collisions-with-their-root-inodes.patch
aio-is-unlikely.patch
ps3fb-thread-updates.patch
ps3av-thread-updates.patch
ps3fb-kill-superfluous-zero-initializations.patch
ps3av-misc-updates.patch