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ovl: factor out ovl_get_index_fh() helper 

The helper is needed to lookup an index by file handle for NFS export.

Signed-off-by: Amir Goldstein <amir73il@gmail.com>
Signed-off-by: Miklos Szeredi <mszeredi@redhat.com>
This commit is contained in:
Amir Goldstein 2017-12-28 20:23:05 +02:00 committed by Miklos Szeredi
parent 24f0b17203
commit 91ffe7beb3
2 changed files with 50 additions and 10 deletions
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59
fs/overlayfs/namei.c
View File

@ -585,6 +585,21 @@ orphan:
goto out;
}
static int ovl_get_index_name_fh(struct ovl_fh *fh, struct qstr *name)
{
char *n, *s;
n = kzalloc(fh->len * 2, GFP_KERNEL);
if (!n)
return -ENOMEM;
s = bin2hex(n, fh, fh->len);
*name = (struct qstr) QSTR_INIT(n, s - n);
return 0;
}
/*
* Lookup in indexdir for the index entry of a lower real inode or a copy up
* origin inode. The index entry name is the hex representation of the lower
@ -602,25 +617,49 @@ orphan:
*/
int ovl_get_index_name(struct dentry *origin, struct qstr *name)
{
int err;
struct ovl_fh *fh;
char *n, *s;
int err;
fh = ovl_encode_fh(origin, false);
if (IS_ERR(fh))
return PTR_ERR(fh);
err = -ENOMEM;
n = kzalloc(fh->len * 2, GFP_KERNEL);
if (n) {
s = bin2hex(n, fh, fh->len);
*name = (struct qstr) QSTR_INIT(n, s - n);
err = 0;
}
err = ovl_get_index_name_fh(fh, name);
kfree(fh);
return err;
}
/* Lookup index by file handle for NFS export */
struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh)
{
struct dentry *index;
struct qstr name;
int err;
err = ovl_get_index_name_fh(fh, &name);
if (err)
return ERR_PTR(err);
index = lookup_one_len_unlocked(name.name, ofs->indexdir, name.len);
kfree(name.name);
if (IS_ERR(index)) {
if (PTR_ERR(index) == -ENOENT)
index = NULL;
return index;
}
if (d_is_negative(index))
err = 0;
else if (ovl_is_whiteout(index))
err = -ESTALE;
else if (ovl_dentry_weird(index))
err = -EIO;
else
return index;
dput(index);
return ERR_PTR(err);
}
static struct dentry *ovl_lookup_index(struct dentry *dentry,

1
fs/overlayfs/overlayfs.h
View File

@ -257,6 +257,7 @@ int ovl_verify_set_fh(struct dentry *dentry, const char *name,
struct dentry *real, bool is_upper, bool set);
int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index);
int ovl_get_index_name(struct dentry *origin, struct qstr *name);
struct dentry *ovl_get_index_fh(struct ovl_fs *ofs, struct ovl_fh *fh);
int ovl_path_next(int idx, struct dentry *dentry, struct path *path);
struct dentry *ovl_lookup(struct inode *dir, struct dentry *dentry,
unsigned int flags);