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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: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
This commit is contained in:
OGAWA Hirofumi 2010-01-12 03:32:24 +09:00
parent 3c8ad49b01
commit 8045e29850
1 changed files with 16 additions and 5 deletions
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21
fs/fat/namei_vfat.c
View File

@ -701,6 +701,15 @@ static int vfat_find(struct inode *dir, struct qstr *qname,
return fat_search_long(dir, qname->name, len, sinfo); 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, static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
struct nameidata *nd) struct nameidata *nd)
{ {
@ -729,11 +738,11 @@ static struct dentry *vfat_lookup(struct inode *dir, struct dentry *dentry,
} }
alias = d_find_alias(inode); 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 * This inode has non anonymous-DCACHE_DISCONNECTED
* means, the user did ->lookup() by an another name * dentry. This means, the user did ->lookup() by an
* (longname vs 8.3 alias of it) in past. * another name (longname vs 8.3 alias of it) in past.
* *
* Switch to new one for reason of locality if possible. * 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); iput(inode);
unlock_super(sb); unlock_super(sb);
return alias; return alias;
} } else
dput(alias);
out: out:
unlock_super(sb); unlock_super(sb);
dentry->d_op = sb->s_root->d_op; dentry->d_op = sb->s_root->d_op;