linux-ext4 - Re: [PATCH 5 3/4] nfsd_open(): rename 'int access' to 'int may_flags' in nfsd

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Message-ID: <4F60AC0D.9020204@itwm.fraunhofer.de>
Date:	Wed, 14 Mar 2012 15:32:45 +0100
From:	Bernd Schubert <bernd.schubert@...m.fraunhofer.de>
To:	"J. Bruce Fields" <bfields@...hat.com>
CC:	Bernd Schubert <bernd.schubert@...tmail.fm>,
	"J. Bruce Fields" <bfields@...ldses.org>, Ted Ts'o <tytso@....edu>,
	linux-nfs@...r.kernel.org, linux-ext4@...r.kernel.org,
	linux-fsdevel@...r.kernel.org, yong.fan@...mcloud.com,
	sandeen@...hat.com, adilger@...mcloud.com
Subject: Re: [PATCH 5 3/4] nfsd_open(): rename 'int access' to 'int may_flags'
 in nfsd_open()

On 03/13/2012 10:29 PM, J. Bruce Fields wrote:
> On Tue, Mar 13, 2012 at 10:09:05PM +0100, Bernd Schubert wrote:
>> Hmm, there must have gone something wrong on merging,
>
> In that case one approach would be to rebase your last-sent patches on
> to the same base as Ted's versions, confirm that one still works and the
> other doesn't, and do a diff....
>
>> my own test
>> also fails
>>
>> http://www.pci.uni-heidelberg.de/tc/usr/bernd/downloads/test_seekdir/
>>
>> (Sorry, it does not say 'failure', but one needs to compare the file
>> names and telldir-offset numbers)
>>
>> I think I will continue in the morning as its already 1 a.m. here.
>
> OK, thanks for following up!

Took me some time to figure out what is going on and in the end I previously forgot 
another test case - I always tested directories being sufficiently large, so that 
they got the EXT4_INODE_INDEX flag. However, the cython tests failed on a small 
directory, which doesn't have that flag. But then ext4_readdir() always uses the 
dx version, I guess in order to always return the same offset values 
(in the sense of converting a non-dx dir to dx). In ext4_dir_llseek() I only 
tested for the EXT4_INODE_INDEX flag, which is not correct in any case.
So here is the patch, shall I sent an updated version of the previous ext4 patch 
or is this patch sufficient?

Signed-off-by: Bernd Schubert <bernd.schubert@...m.fraunhofer.de>

diff --git a/fs/ext4/dir.c b/fs/ext4/dir.c
index 71a66ff..6a19a35 100644
--- a/fs/ext4/dir.c
+++ b/fs/ext4/dir.c
@@ -44,6 +44,24 @@ static unsigned char get_dtype(struct super_block *sb, int filetype)
 	return (ext4_filetype_table[filetype]);
 }
 
+/**
+ * Check if the given dir-inode refers to an htree indexed directory
+ *
+ * Return 1 if it is a dx dir, 0 if not
+ */
+static int is_dx_dir(struct inode *inode)
+{
+	struct super_block *sb = inode->i_sb;
+
+	if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
+		     EXT4_FEATURE_COMPAT_DIR_INDEX) &&
+	    ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
+	     ((inode->i_size >> sb->s_blocksize_bits) == 1)))
+		return 1;
+
+	return 0;
+}
+
 /*
  * Return 0 if the directory entry is OK, and 1 if there is a problem
  *
@@ -99,18 +117,13 @@ static int ext4_readdir(struct file *filp,
 	unsigned int offset;
 	int i, stored;
 	struct ext4_dir_entry_2 *de;
-	struct super_block *sb;
 	int err;
 	struct inode *inode = filp->f_path.dentry->d_inode;
+	struct super_block *sb = inode->i_sb;
 	int ret = 0;
 	int dir_has_error = 0;
 
-	sb = inode->i_sb;
-
-	if (EXT4_HAS_COMPAT_FEATURE(inode->i_sb,
-				    EXT4_FEATURE_COMPAT_DIR_INDEX) &&
-	    ((ext4_test_inode_flag(inode, EXT4_INODE_INDEX)) ||
-	     ((inode->i_size >> sb->s_blocksize_bits) == 1))) {
+	if (is_dx_dir(inode)) {
 		err = ext4_dx_readdir(filp, dirent, filldir);
 		if (err != ERR_BAD_DX_DIR) {
 			ret = err;
@@ -308,7 +321,7 @@ loff_t ext4_dir_llseek(struct file *file, loff_t offset, int origin)
 {
 	struct inode *inode = file->f_mapping->host;
 	loff_t ret = -EINVAL;
-	int is_dx_dir = ext4_test_inode_flag(inode, EXT4_INODE_INDEX);
+	int dx_dir = is_dx_dir(inode);
 
 	mutex_lock(&inode->i_mutex);
 
@@ -323,7 +336,7 @@ loff_t ext4_dir_llseek(struct file *file, loff_t offset, int origin)
 
 		/* so only negative offsets are left, does that have a
 		 * meaning for directories at all? */
-		if (is_dx_dir)
+		if (dx_dir)
 			offset += ext4_get_htree_eof(file);
 		else
 			offset += inode->i_size;
@@ -347,7 +360,7 @@ loff_t ext4_dir_llseek(struct file *file, loff_t offset, int origin)
 	if (unlikely(offset < 0))
 		goto out_err;
 
-	if (!is_dx_dir) {
+	if (!dx_dir) {
 		if (offset > inode->i_sb->s_maxbytes)
 			goto out_err;
 	} else if (offset > ext4_get_htree_eof(file))




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