[PATCH 08/25] sysfs: Implement __sysfs_get_dentry

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From: Eric W. Biederman
Date: Tuesday, August 7, 2007 - 2:16 pm

This function is similar but much simpler to sysfs_get_dentry
returns a sysfs dentry if one currently exists.

Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
---
 fs/sysfs/dir.c |   38 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 38 insertions(+), 0 deletions(-)

diff --git a/fs/sysfs/dir.c b/fs/sysfs/dir.c
index 6ca4382..2caa5e0 100644
--- a/fs/sysfs/dir.c
+++ b/fs/sysfs/dir.c
@@ -848,6 +848,44 @@ void sysfs_remove_dir(struct kobject * kobj)
 	__sysfs_remove_dir(sd);
 }
 
+/**
+ *	__sysfs_get_dentry - get dentry for the given sysfs_dirent
+ *	@sb: superblock of the dentry to return
+ *	@sd: sysfs_dirent of interest
+ *
+ *	Get dentry for @sd.  Only return a dentry if one currently
+ *	exists.
+ *
+ *	LOCKING:
+ *	Kernel thread context (may sleep)
+ *
+ *	RETURNS:
+ *	Pointer to found dentry on success, NULL on failure.
+ */
+static struct dentry *__sysfs_get_dentry(struct super_block *sb, struct sysfs_dirent *sd)
+{
+	struct inode *inode;
+	struct dentry *dentry = NULL;
+
+	inode = ilookup5_nowait(sysfs_sb, sd->s_ino, sysfs_ilookup_test, sd);
+	if (inode && !(inode->i_state & I_NEW)) {
+		struct dentry *alias;
+		spin_lock(&dcache_lock);
+		list_for_each_entry(alias, &inode->i_dentry, d_alias) {
+			if (!IS_ROOT(alias) && d_unhashed(alias))
+				continue;
+			if (alias->d_sb != sb)
+				continue;
+			dentry = alias;
+			dget_locked(dentry);
+			break;
+		}
+		spin_unlock(&dcache_lock);
+	}
+	iput(inode);
+	return dentry;
+}
+
 int sysfs_rename_dir(struct kobject * kobj, const char *new_name)
 {
 	struct sysfs_dirent *sd;
-- 
1.5.1.1.181.g2de0

-
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Messages in current thread:
[PATCH 2/5] sysfs: simplify sysfs_rename_dir(), Tejun Heo, (Thu Aug 2, 5:38 am)
[PATCH 0/25] Sysfs cleanups &amp; tagged directory support, Eric W. Biederman, (Tue Aug 7, 2:06 pm)
[PATCH 02/25] sysfs: Remove sysfs_instantiate, Eric W. Biederman, (Tue Aug 7, 2:08 pm)
[PATCH 03/25] sysfs: Use kill_anon_super, Eric W. Biederman, (Tue Aug 7, 2:10 pm)
[PATCH 04/25] sysfs: Make sysfs_mount static, Eric W. Biederman, (Tue Aug 7, 2:11 pm)
[PATCH 06/25] sysfs: Simplify readdir., Eric W. Biederman, (Tue Aug 7, 2:13 pm)
[PATCH 07/25] sysfs: Rewrite sysfs_drop_dentry., Eric W. Biederman, (Tue Aug 7, 2:14 pm)
[PATCH 08/25] sysfs: Implement __sysfs_get_dentry, Eric W. Biederman, (Tue Aug 7, 2:16 pm)
[PATCH 10/25] sysfs: Rewrite sysfs_get_dentry in terms of ..., Eric W. Biederman, (Tue Aug 7, 2:18 pm)
[PATCH 11/25] sysfs: Remove s_dentry, Eric W. Biederman, (Tue Aug 7, 2:19 pm)
[PATCH 12/25] sysfs: Introduce sysfs_rename_mutex, Eric W. Biederman, (Tue Aug 7, 2:21 pm)
[PATCH 13/25] sysfs: Simply sysfs_get_dentry, Eric W. Biederman, (Tue Aug 7, 2:22 pm)
[PATCH 14/25] sysfs: Don't use lookup_one_len_kern, Eric W. Biederman, (Tue Aug 7, 2:23 pm)
[PATCH 15/25] vfs: Remove lookup_one_len_kern, Eric W. Biederman, (Tue Aug 7, 2:25 pm)
[PATCH 16/25] sysfs: Support for preventing unmounts., Eric W. Biederman, (Tue Aug 7, 2:26 pm)
[PATCH 17/25] sysfs: Rewrite rename in terms of sysfs dirents, Eric W. Biederman, (Tue Aug 7, 2:27 pm)
[PATCH 19/25] sysfs: sysfs_get_dentry add a sb parameter, Eric W. Biederman, (Tue Aug 7, 2:29 pm)
[PATCH 20/25] sysfs: Rename Support multiple superblocks, Eric W. Biederman, (Tue Aug 7, 2:31 pm)
Re: [PATCH 02/25] sysfs: Remove sysfs_instantiate, Tejun Heo, (Tue Aug 7, 11:37 pm)
Re: [PATCH 03/25] sysfs: Use kill_anon_super, Tejun Heo, (Tue Aug 7, 11:50 pm)
Re: [PATCH 04/25] sysfs: Make sysfs_mount static, Tejun Heo, (Tue Aug 7, 11:51 pm)
Re: [PATCH 06/25] sysfs: Simplify readdir., Tejun Heo, (Wed Aug 8, 12:12 am)
Re: [PATCH 07/25] sysfs: Rewrite sysfs_drop_dentry., Tejun Heo, (Wed Aug 8, 12:35 am)
Re: [PATCH 11/25] sysfs: Remove s_dentry, Tejun Heo, (Wed Aug 8, 12:46 am)
Re: [PATCH 0/25] Sysfs cleanups &amp; tagged directory support, Eric W. Biederman, (Wed Aug 8, 12:47 am)
Re: [PATCH 0/25] Sysfs cleanups &amp; tagged directory support, Eric W. Biederman, (Wed Aug 8, 12:57 am)
Re: [PATCH 13/25] sysfs: Simply sysfs_get_dentry, Tejun Heo, (Wed Aug 8, 1:24 am)
Re: [PATCH 12/25] sysfs: Introduce sysfs_rename_mutex, Eric W. Biederman, (Wed Aug 8, 1:28 am)
Re: [PATCH 15/25] vfs: Remove lookup_one_len_kern, Tejun Heo, (Wed Aug 8, 1:39 am)
Re: [PATCH 14/25] sysfs: Don't use lookup_one_len_kern, Eric W. Biederman, (Wed Aug 8, 8:26 am)
Re: [PATCH 17/25] sysfs: Rewrite rename in terms of sysfs ..., Eric W. Biederman, (Wed Aug 8, 8:32 am)
Re: [PATCH 19/25] sysfs: sysfs_get_dentry add a sb parameter, Eric W. Biederman, (Wed Aug 8, 8:34 am)
Re: [PATCH 20/25] sysfs: Rename Support multiple superblocks, Eric W. Biederman, (Wed Aug 8, 8:45 am)
Re: alternative approached at tagged nodes, Tejun Heo, (Wed Aug 8, 9:31 am)
Re: [PATCH 20/25] sysfs: Rename Support multiple superblocks, Eric W. Biederman, (Wed Aug 8, 9:35 am)
Re: [PATCH 20/25] sysfs: Rename Support multiple superblocks, Eric W. Biederman, (Wed Aug 8, 9:55 am)