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Diffstat (limited to 'fs/overlayfs/copy_up.c')
-rw-r--r--fs/overlayfs/copy_up.c53
1 files changed, 25 insertions, 28 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index b801c6353100..6220642fe113 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -227,13 +227,17 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
{
struct ovl_fh *fh;
- int fh_type, fh_len, dwords;
- void *buf;
+ int fh_type, dwords;
int buflen = MAX_HANDLE_SZ;
uuid_t *uuid = &real->d_sb->s_uuid;
+ int err;
- buf = kmalloc(buflen, GFP_KERNEL);
- if (!buf)
+ /* Make sure the real fid stays 32bit aligned */
+ BUILD_BUG_ON(OVL_FH_FID_OFFSET % 4);
+ BUILD_BUG_ON(MAX_HANDLE_SZ + OVL_FH_FID_OFFSET > 255);
+
+ fh = kzalloc(buflen + OVL_FH_FID_OFFSET, GFP_KERNEL);
+ if (!fh)
return ERR_PTR(-ENOMEM);
/*
@@ -242,27 +246,19 @@ struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
* the price or reconnecting the dentry.
*/
dwords = buflen >> 2;
- fh_type = exportfs_encode_fh(real, buf, &dwords, 0);
+ fh_type = exportfs_encode_fh(real, (void *)fh->fb.fid, &dwords, 0);
buflen = (dwords << 2);
- fh = ERR_PTR(-EIO);
+ err = -EIO;
if (WARN_ON(fh_type < 0) ||
WARN_ON(buflen > MAX_HANDLE_SZ) ||
WARN_ON(fh_type == FILEID_INVALID))
- goto out;
+ goto out_err;
- BUILD_BUG_ON(MAX_HANDLE_SZ + offsetof(struct ovl_fh, fid) > 255);
- fh_len = offsetof(struct ovl_fh, fid) + buflen;
- fh = kmalloc(fh_len, GFP_KERNEL);
- if (!fh) {
- fh = ERR_PTR(-ENOMEM);
- goto out;
- }
-
- fh->version = OVL_FH_VERSION;
- fh->magic = OVL_FH_MAGIC;
- fh->type = fh_type;
- fh->flags = OVL_FH_FLAG_CPU_ENDIAN;
+ fh->fb.version = OVL_FH_VERSION;
+ fh->fb.magic = OVL_FH_MAGIC;
+ fh->fb.type = fh_type;
+ fh->fb.flags = OVL_FH_FLAG_CPU_ENDIAN;
/*
* When we will want to decode an overlay dentry from this handle
* and all layers are on the same fs, if we get a disconncted real
@@ -270,14 +266,15 @@ struct ovl_fh *ovl_encode_real_fh(struct dentry *real, bool is_upper)
* it to upperdentry or to lowerstack is by checking this flag.
*/
if (is_upper)
- fh->flags |= OVL_FH_FLAG_PATH_UPPER;
- fh->len = fh_len;
- fh->uuid = *uuid;
- memcpy(fh->fid, buf, buflen);
+ fh->fb.flags |= OVL_FH_FLAG_PATH_UPPER;
+ fh->fb.len = sizeof(fh->fb) + buflen;
+ fh->fb.uuid = *uuid;
-out:
- kfree(buf);
return fh;
+
+out_err:
+ kfree(fh);
+ return ERR_PTR(err);
}
int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
@@ -300,8 +297,8 @@ int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
/*
* Do not fail when upper doesn't support xattrs.
*/
- err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh,
- fh ? fh->len : 0, 0);
+ err = ovl_check_setxattr(dentry, upper, OVL_XATTR_ORIGIN, fh->buf,
+ fh ? fh->fb.len : 0, 0);
kfree(fh);
return err;
@@ -317,7 +314,7 @@ static int ovl_set_upper_fh(struct dentry *upper, struct dentry *index)
if (IS_ERR(fh))
return PTR_ERR(fh);
- err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh, fh->len, 0);
+ err = ovl_do_setxattr(index, OVL_XATTR_UPPER, fh->buf, fh->fb.len, 0);
kfree(fh);
return err;