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Commit 8045e298 authored by OGAWA Hirofumi's avatar OGAWA Hirofumi
Browse files

fat: Fix vfat_lookup() 



After d_find_alias(), vfat_lookup() checks !(->d_flags & DCACHE_DISCONNECTED)
without IS_ROOT().  This means it hits non-anonymous but disconnected
dentry. (NOTE: d_splice_alias() doesn't clear DCACHE_DISCONNECTED)

But, vfat_lookup() has interest to alias if it was non-anonymous. So,
this adds vfat_d_anon_disconn() helper to check it correctly.

Another bug is refcnt leak. It needs dput() for uninterested alias.

Signed-off-by: default avatarOGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
parent 3c8ad49b

fs/fat/namei_vfat.c

+16 −5
Original line number Diff line number Diff line
@@ -701,6 +701,15 @@ static int vfat_find(struct inode *dir, struct qstr *qname, 
	return fat_search_long(dir, qname->name, len, sinfo);

}



/*

 * (nfsd's) anonymous disconnected dentry?

 * NOTE: !IS_ROOT() is not anonymous (I.e. d_splice_alias() did the job).

 */

static int vfat_d_anon_disconn(struct dentry *dentry)

{

	return IS_ROOT(dentry) && (dentry->d_flags & DCACHE_DISCONNECTED);

}



static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,

				  struct nameidata *nd)

{
@@ -729,11 +738,11 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 
	}



	alias = d_find_alias(inode);

	if (alias && !(alias->d_flags & DCACHE_DISCONNECTED)) {

	if (alias && !vfat_d_anon_disconn(alias)) {

		/*

		 * This inode has non DCACHE_DISCONNECTED dentry. This

		 * means, the user did ->lookup() by an another name

		 * (longname vs 8.3 alias of it) in past.

		 * This inode has non anonymous-DCACHE_DISCONNECTED

		 * dentry. This means, the user did ->lookup() by an

		 * another name (longname vs 8.3 alias of it) in past.

		 *

		 * Switch to new one for reason of locality if possible.

		 */
@@ -743,7 +752,9 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry, 
		iput(inode);

		unlock_super(sb);

		return alias;

	}

	} else

		dput(alias);



out:

	unlock_super(sb);

	dentry->d_op = sb->s_root->d_op;