Decoding an indexed non-dir file handle is similar to decoding a lower
non-dir file handle, but additionally, we lookup the file handle in index
dir by name to find the real upper inode.
Signed-off-by: Amir Goldstein <amir73il@xxxxxxxxx>
---
fs/overlayfs/export.c | 72 +++++++++++++++++++++++++++++++++------------------
1 file changed, 47 insertions(+), 25 deletions(-)
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 6b359f968c01..602bada474ba 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -168,22 +168,24 @@ static int ovl_encode_inode_fh(struct inode *inode, u32 *fid, int *max_len,
}
/*
- * Find or instantiate an overlay dentry from real dentries.
+ * Find or instantiate an overlay dentry from real dentries and index.
*/
static struct dentry *ovl_obtain_alias(struct super_block *sb,
- struct dentry *upper,
- struct ovl_path *lowerpath)
+ struct dentry *upper_alias,
+ struct ovl_path *lowerpath,
+ struct dentry *index)
{
struct dentry *lower = lowerpath ? lowerpath->dentry : NULL;
+ struct dentry *upper = upper_alias ?: index;
struct dentry *dentry;
struct inode *inode;
struct ovl_entry *oe;
- /* TODO: obtain an indexed non-dir upper with origin */
- if (lower && (upper || d_is_dir(lower)))
+ /* We get overlay directory dentries with ovl_lookup_real() */
+ if (d_is_dir(upper ?: lower))
return ERR_PTR(-EIO);
- inode = ovl_get_inode(sb, dget(upper), lower, NULL, !!lower);
+ inode = ovl_get_inode(sb, dget(upper), lower, index, !!lower);
if (IS_ERR(inode)) {
dput(upper);
return ERR_CAST(inode);
@@ -200,13 +202,16 @@ static struct dentry *ovl_obtain_alias(struct super_block *sb,
}
dentry->d_fsdata = oe;
- if (upper)
+ if (upper_alias)
ovl_dentry_set_upper_alias(dentry);
if (lower) {
oe->lowerstack->dentry = dget(lower);
oe->lowerstack->layer = lowerpath->layer;
}
+ if (index)
+ ovl_set_flag(OVL_INDEX, inode);
+
return dentry;
}
@@ -321,30 +326,26 @@ static struct dentry *ovl_lookup_real(struct super_block *sb,
}
/*
- * Get an overlay dentry from upper/lower real dentries.
+ * Get an overlay dentry from upper/lower real dentries and index.
*/
static struct dentry *ovl_get_dentry(struct super_block *sb,
struct dentry *upper,
- struct ovl_path *lowerpath)
+ struct ovl_path *lowerpath,
+ struct dentry *index)
{
+ struct dentry *real = upper ?: (index ?: lowerpath->dentry);
+
/*
- * Obtain a disconnected overlay dentry from a disconnected non-dir
- * real lower dentry.
+ * Obtain a disconnected overlay dentry from a non-dir real dentry
+ * and index.
*/
- if (!upper && !d_is_dir(lowerpath->dentry))
- return ovl_obtain_alias(sb, NULL, lowerpath);
+ if (!d_is_dir(real))
+ return ovl_obtain_alias(sb, upper, lowerpath, index);
/* TODO: lookup connected dir from real lower dir */
if (!upper)
return ERR_PTR(-EACCES);
- /*
- * Obtain a disconnected overlay dentry from a non-dir real upper
- * dentry.
- */
- if (!d_is_dir(upper))
- return ovl_obtain_alias(sb, upper, NULL);
-
/* Removed empty directory? */
if ((upper->d_flags & DCACHE_DISCONNECTED) || d_unhashed(upper))
return ERR_PTR(-ENOENT);
@@ -370,7 +371,7 @@ static struct dentry *ovl_upper_fh_to_d(struct super_block *sb,
if (IS_ERR_OR_NULL(upper))
return upper;
- dentry = ovl_get_dentry(sb, upper, NULL);
+ dentry = ovl_get_dentry(sb, upper, NULL, NULL);
dput(upper);
return dentry;
@@ -383,17 +384,38 @@ static struct dentry *ovl_lower_fh_to_d(struct super_block *sb,
struct ovl_path origin = { };
struct ovl_path *stack = &origin;
struct dentry *dentry = NULL;
+ struct dentry *index = NULL;
int err;
+ /* First lookup indexed upper by fh */
+ index = ovl_get_index_fh(ofs, fh);
+ err = PTR_ERR(index);
+ if (IS_ERR(index))
+ return ERR_PTR(err);
+
+ /* Then lookup origin by fh */
err = ovl_check_origin_fh(fh, NULL, ofs->lower_layers, ofs->numlower,
&stack);
- if (err)
- return ERR_PTR(err);
+ if (err) {
+ goto out_err;
+ } else if (!index && !origin.dentry) {
+ return NULL;
+ } else if (index && origin.dentry) {
+ err = ovl_verify_origin(index, origin.dentry, false, false);
+ if (err)
+ goto out_err;
+ }
- dentry = ovl_get_dentry(sb, NULL, &origin);
- dput(origin.dentry);
+ dentry = ovl_get_dentry(sb, NULL, &origin, index);
+out:
+ dput(origin.dentry);
+ dput(index);
return dentry;
+
+out_err:
+ dentry = ERR_PTR(err);
+ goto out;
}
static struct dentry *ovl_fh_to_dentry(struct super_block *sb, struct fid *fid,
--
2.7.4
--
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