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authorLinus Torvalds <torvalds@linux-foundation.org>2019-12-14 11:13:54 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2019-12-14 11:13:54 -0800
commit81c64b0bd0900405b4e55f3d48a2fc7dd5e1676c (patch)
treea4cdfebf4e3e39bd80b1685c389ffea04baaf8dd
parente31736d9fae841e8a1612f263136454af10f476a (diff)
parent35c6cb41686c4de03d738fd95617a0cf7441bbe1 (diff)
downloadlinux-stericsson-81c64b0bd0900405b4e55f3d48a2fc7dd5e1676c.tar.gz
Merge tag 'ovl-fixes-5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs fixes from Miklos Szeredi: "Fix some bugs and documentation" * tag 'ovl-fixes-5.5-rc2' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: docs: filesystems: overlayfs: Fix restview warnings docs: filesystems: overlayfs: Rename overlayfs.txt to .rst ovl: relax WARN_ON() on rename to self ovl: fix corner case of non-unique st_dev;st_ino ovl: don't use a temp buf for encoding real fh ovl: make sure that real fid is 32bit aligned in memory ovl: fix lookup failure on multi lower squashfs
-rw-r--r--Documentation/filesystems/overlayfs.rst (renamed from Documentation/filesystems/overlayfs.txt)10
-rw-r--r--MAINTAINERS2
-rw-r--r--fs/overlayfs/copy_up.c53
-rw-r--r--fs/overlayfs/dir.c2
-rw-r--r--fs/overlayfs/export.c80
-rw-r--r--fs/overlayfs/inode.c8
-rw-r--r--fs/overlayfs/namei.c52
-rw-r--r--fs/overlayfs/overlayfs.h34
-rw-r--r--fs/overlayfs/ovl_entry.h2
-rw-r--r--fs/overlayfs/super.c24
10 files changed, 166 insertions, 101 deletions
diff --git a/Documentation/filesystems/overlayfs.txt b/Documentation/filesystems/overlayfs.rst
index 845d689e0fd7..e443be7928db 100644
--- a/Documentation/filesystems/overlayfs.txt
+++ b/Documentation/filesystems/overlayfs.rst
@@ -1,3 +1,5 @@
+.. SPDX-License-Identifier: GPL-2.0
+
Written by: Neil Brown
Please see MAINTAINERS file for where to send questions.
@@ -181,7 +183,7 @@ Kernel config options:
worried about backward compatibility with kernels that have the redirect_dir
feature and follow redirects even if turned off.
-Module options (can also be changed through /sys/module/overlay/parameters/*):
+Module options (can also be changed through /sys/module/overlay/parameters/):
- "redirect_dir=BOOL":
See OVERLAY_FS_REDIRECT_DIR kernel config option above.
@@ -263,7 +265,7 @@ top, lower2 the middle and lower3 the bottom layer.
Metadata only copy up
---------------------
+---------------------
When metadata only copy up feature is enabled, overlayfs will only copy
up metadata (as opposed to whole file), when a metadata specific operation
@@ -286,10 +288,10 @@ pointed by REDIRECT. This should not be possible on local system as setting
"trusted." xattrs will require CAP_SYS_ADMIN. But it should be possible
for untrusted layers like from a pen drive.
-Note: redirect_dir={off|nofollow|follow(*)} conflicts with metacopy=on, and
+Note: redirect_dir={off|nofollow|follow[*]} conflicts with metacopy=on, and
results in an error.
-(*) redirect_dir=follow only conflicts with metacopy=on if upperdir=... is
+[*] redirect_dir=follow only conflicts with metacopy=on if upperdir=... is
given.
Sharing and copying layers
diff --git a/MAINTAINERS b/MAINTAINERS
index b540ecc4e2a3..cc0a4a8ae06a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -12394,7 +12394,7 @@ L: linux-unionfs@vger.kernel.org
T: git git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs.git
S: Supported
F: fs/overlayfs/
-F: Documentation/filesystems/overlayfs.txt
+F: Documentation/filesystems/overlayfs.rst
P54 WIRELESS DRIVER
M: Christian Lamparter <chunkeey@googlemail.com>
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;
diff --git a/fs/overlayfs/dir.c b/fs/overlayfs/dir.c
index 702aa63f6774..29abdb1d3b5c 100644
--- a/fs/overlayfs/dir.c
+++ b/fs/overlayfs/dir.c
@@ -1170,7 +1170,7 @@ static int ovl_rename(struct inode *olddir, struct dentry *old,
if (newdentry == trap)
goto out_dput;
- if (WARN_ON(olddentry->d_inode == newdentry->d_inode))
+ if (olddentry->d_inode == newdentry->d_inode)
goto out_dput;
err = 0;
diff --git a/fs/overlayfs/export.c b/fs/overlayfs/export.c
index 73c9775215b3..70e55588aedc 100644
--- a/fs/overlayfs/export.c
+++ b/fs/overlayfs/export.c
@@ -211,10 +211,11 @@ static int ovl_check_encode_origin(struct dentry *dentry)
return 1;
}
-static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen)
+static int ovl_dentry_to_fid(struct dentry *dentry, u32 *fid, int buflen)
{
struct ovl_fh *fh = NULL;
int err, enc_lower;
+ int len;
/*
* Check if we should encode a lower or upper file handle and maybe
@@ -231,11 +232,12 @@ static int ovl_d_to_fh(struct dentry *dentry, char *buf, int buflen)
return PTR_ERR(fh);
err = -EOVERFLOW;
- if (fh->len > buflen)
+ len = OVL_FH_LEN(fh);
+ if (len > buflen)
goto fail;
- memcpy(buf, (char *)fh, fh->len);
- err = fh->len;
+ memcpy(fid, fh, len);
+ err = len;
out:
kfree(fh);
@@ -243,31 +245,16 @@ out:
fail:
pr_warn_ratelimited("overlayfs: failed to encode file handle (%pd2, err=%i, buflen=%d, len=%d, type=%d)\n",
- dentry, err, buflen, fh ? (int)fh->len : 0,
- fh ? fh->type : 0);
+ dentry, err, buflen, fh ? (int)fh->fb.len : 0,
+ fh ? fh->fb.type : 0);
goto out;
}
-static int ovl_dentry_to_fh(struct dentry *dentry, u32 *fid, int *max_len)
-{
- int res, len = *max_len << 2;
-
- res = ovl_d_to_fh(dentry, (char *)fid, len);
- if (res <= 0)
- return FILEID_INVALID;
-
- len = res;
-
- /* Round up to dwords */
- *max_len = (len + 3) >> 2;
- return OVL_FILEID;
-}
-
static int ovl_encode_fh(struct inode *inode, u32 *fid, int *max_len,
struct inode *parent)
{
struct dentry *dentry;
- int type;
+ int bytes = *max_len << 2;
/* TODO: encode connectable file handles */
if (parent)
@@ -277,10 +264,14 @@ static int ovl_encode_fh(struct inode *inode, u32 *fid, int *max_len,
if (WARN_ON(!dentry))
return FILEID_INVALID;
- type = ovl_dentry_to_fh(dentry, fid, max_len);
-
+ bytes = ovl_dentry_to_fid(dentry, fid, bytes);
dput(dentry);
- return type;
+ if (bytes <= 0)
+ return FILEID_INVALID;
+
+ *max_len = bytes >> 2;
+
+ return OVL_FILEID_V1;
}
/*
@@ -777,24 +768,45 @@ out_err:
goto out;
}
+static struct ovl_fh *ovl_fid_to_fh(struct fid *fid, int buflen, int fh_type)
+{
+ struct ovl_fh *fh;
+
+ /* If on-wire inner fid is aligned - nothing to do */
+ if (fh_type == OVL_FILEID_V1)
+ return (struct ovl_fh *)fid;
+
+ if (fh_type != OVL_FILEID_V0)
+ return ERR_PTR(-EINVAL);
+
+ fh = kzalloc(buflen, GFP_KERNEL);
+ if (!fh)
+ return ERR_PTR(-ENOMEM);
+
+ /* Copy unaligned inner fh into aligned buffer */
+ memcpy(&fh->fb, fid, buflen - OVL_FH_WIRE_OFFSET);
+ return fh;
+}
+
static struct dentry *ovl_fh_to_dentry(struct super_block *sb, struct fid *fid,
int fh_len, int fh_type)
{
struct dentry *dentry = NULL;
- struct ovl_fh *fh = (struct ovl_fh *) fid;
+ struct ovl_fh *fh = NULL;
int len = fh_len << 2;
unsigned int flags = 0;
int err;
- err = -EINVAL;
- if (fh_type != OVL_FILEID)
+ fh = ovl_fid_to_fh(fid, len, fh_type);
+ err = PTR_ERR(fh);
+ if (IS_ERR(fh))
goto out_err;
err = ovl_check_fh_len(fh, len);
if (err)
goto out_err;
- flags = fh->flags;
+ flags = fh->fb.flags;
dentry = (flags & OVL_FH_FLAG_PATH_UPPER) ?
ovl_upper_fh_to_d(sb, fh) :
ovl_lower_fh_to_d(sb, fh);
@@ -802,12 +814,18 @@ static struct dentry *ovl_fh_to_dentry(struct super_block *sb, struct fid *fid,
if (IS_ERR(dentry) && err != -ESTALE)
goto out_err;
+out:
+ /* We may have needed to re-align OVL_FILEID_V0 */
+ if (!IS_ERR_OR_NULL(fh) && fh != (void *)fid)
+ kfree(fh);
+
return dentry;
out_err:
pr_warn_ratelimited("overlayfs: failed to decode file handle (len=%d, type=%d, flags=%x, err=%i)\n",
- len, fh_type, flags, err);
- return ERR_PTR(err);
+ fh_len, fh_type, flags, err);
+ dentry = ERR_PTR(err);
+ goto out;
}
static struct dentry *ovl_fh_to_parent(struct super_block *sb, struct fid *fid,
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index bc14781886bf..b045cf1826fc 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -200,8 +200,14 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
if (ovl_test_flag(OVL_INDEX, d_inode(dentry)) ||
(!ovl_verify_lower(dentry->d_sb) &&
(is_dir || lowerstat.nlink == 1))) {
- stat->ino = lowerstat.ino;
lower_layer = ovl_layer_lower(dentry);
+ /*
+ * Cannot use origin st_dev;st_ino because
+ * origin inode content may differ from overlay
+ * inode content.
+ */
+ if (samefs || lower_layer->fsid)
+ stat->ino = lowerstat.ino;
}
/*
diff --git a/fs/overlayfs/namei.c b/fs/overlayfs/namei.c
index c269d6033525..76ff66339173 100644
--- a/fs/overlayfs/namei.c
+++ b/fs/overlayfs/namei.c
@@ -84,21 +84,21 @@ static int ovl_acceptable(void *ctx, struct dentry *dentry)
* Return -ENODATA for "origin unknown".
* Return <0 for an invalid file handle.
*/
-int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
+int ovl_check_fb_len(struct ovl_fb *fb, int fb_len)
{
- if (fh_len < sizeof(struct ovl_fh) || fh_len < fh->len)
+ if (fb_len < sizeof(struct ovl_fb) || fb_len < fb->len)
return -EINVAL;
- if (fh->magic != OVL_FH_MAGIC)
+ if (fb->magic != OVL_FH_MAGIC)
return -EINVAL;
/* Treat larger version and unknown flags as "origin unknown" */
- if (fh->version > OVL_FH_VERSION || fh->flags & ~OVL_FH_FLAG_ALL)
+ if (fb->version > OVL_FH_VERSION || fb->flags & ~OVL_FH_FLAG_ALL)
return -ENODATA;
/* Treat endianness mismatch as "origin unknown" */
- if (!(fh->flags & OVL_FH_FLAG_ANY_ENDIAN) &&
- (fh->flags & OVL_FH_FLAG_BIG_ENDIAN) != OVL_FH_FLAG_CPU_ENDIAN)
+ if (!(fb->flags & OVL_FH_FLAG_ANY_ENDIAN) &&
+ (fb->flags & OVL_FH_FLAG_BIG_ENDIAN) != OVL_FH_FLAG_CPU_ENDIAN)
return -ENODATA;
return 0;
@@ -119,15 +119,15 @@ static struct ovl_fh *ovl_get_fh(struct dentry *dentry, const char *name)
if (res == 0)
return NULL;
- fh = kzalloc(res, GFP_KERNEL);
+ fh = kzalloc(res + OVL_FH_WIRE_OFFSET, GFP_KERNEL);
if (!fh)
return ERR_PTR(-ENOMEM);
- res = vfs_getxattr(dentry, name, fh, res);
+ res = vfs_getxattr(dentry, name, fh->buf, res);
if (res < 0)
goto fail;
- err = ovl_check_fh_len(fh, res);
+ err = ovl_check_fb_len(&fh->fb, res);
if (err < 0) {
if (err == -ENODATA)
goto out;
@@ -158,12 +158,12 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
* Make sure that the stored uuid matches the uuid of the lower
* layer where file handle will be decoded.
*/
- if (!uuid_equal(&fh->uuid, &mnt->mnt_sb->s_uuid))
+ if (!uuid_equal(&fh->fb.uuid, &mnt->mnt_sb->s_uuid))
return NULL;
- bytes = (fh->len - offsetof(struct ovl_fh, fid));
- real = exportfs_decode_fh(mnt, (struct fid *)fh->fid,
- bytes >> 2, (int)fh->type,
+ bytes = (fh->fb.len - offsetof(struct ovl_fb, fid));
+ real = exportfs_decode_fh(mnt, (struct fid *)fh->fb.fid,
+ bytes >> 2, (int)fh->fb.type,
connected ? ovl_acceptable : NULL, mnt);
if (IS_ERR(real)) {
/*
@@ -173,7 +173,7 @@ struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
* index entries correctly.
*/
if (real == ERR_PTR(-ESTALE) &&
- !(fh->flags & OVL_FH_FLAG_PATH_UPPER))
+ !(fh->fb.flags & OVL_FH_FLAG_PATH_UPPER))
real = NULL;
return real;
}
@@ -323,6 +323,14 @@ int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
int i;
for (i = 0; i < ofs->numlower; i++) {
+ /*
+ * If lower fs uuid is not unique among lower fs we cannot match
+ * fh->uuid to layer.
+ */
+ if (ofs->lower_layers[i].fsid &&
+ ofs->lower_layers[i].fs->bad_uuid)
+ continue;
+
origin = ovl_decode_real_fh(fh, ofs->lower_layers[i].mnt,
connected);
if (origin)
@@ -400,7 +408,7 @@ static int ovl_verify_fh(struct dentry *dentry, const char *name,
if (IS_ERR(ofh))
return PTR_ERR(ofh);
- if (fh->len != ofh->len || memcmp(fh, ofh, fh->len))
+ if (fh->fb.len != ofh->fb.len || memcmp(&fh->fb, &ofh->fb, fh->fb.len))
err = -ESTALE;
kfree(ofh);
@@ -431,7 +439,7 @@ int ovl_verify_set_fh(struct dentry *dentry, const char *name,
err = ovl_verify_fh(dentry, name, fh);
if (set && err == -ENODATA)
- err = ovl_do_setxattr(dentry, name, fh, fh->len, 0);
+ err = ovl_do_setxattr(dentry, name, fh->buf, fh->fb.len, 0);
if (err)
goto fail;
@@ -505,20 +513,20 @@ int ovl_verify_index(struct ovl_fs *ofs, struct dentry *index)
goto fail;
err = -EINVAL;
- if (index->d_name.len < sizeof(struct ovl_fh)*2)
+ if (index->d_name.len < sizeof(struct ovl_fb)*2)
goto fail;
err = -ENOMEM;
len = index->d_name.len / 2;
- fh = kzalloc(len, GFP_KERNEL);
+ fh = kzalloc(len + OVL_FH_WIRE_OFFSET, GFP_KERNEL);
if (!fh)
goto fail;
err = -EINVAL;
- if (hex2bin((u8 *)fh, index->d_name.name, len))
+ if (hex2bin(fh->buf, index->d_name.name, len))
goto fail;
- err = ovl_check_fh_len(fh, len);
+ err = ovl_check_fb_len(&fh->fb, len);
if (err)
goto fail;
@@ -597,11 +605,11 @@ static int ovl_get_index_name_fh(struct ovl_fh *fh, struct qstr *name)
{
char *n, *s;
- n = kcalloc(fh->len, 2, GFP_KERNEL);
+ n = kcalloc(fh->fb.len, 2, GFP_KERNEL);
if (!n)
return -ENOMEM;
- s = bin2hex(n, fh, fh->len);
+ s = bin2hex(n, fh->buf, fh->fb.len);
*name = (struct qstr) QSTR_INIT(n, s - n);
return 0;
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index 6934bcf030f0..f283b1d69a9e 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -71,20 +71,36 @@ enum ovl_entry_flag {
#error Endianness not defined
#endif
-/* The type returned by overlay exportfs ops when encoding an ovl_fh handle */
-#define OVL_FILEID 0xfb
+/* The type used to be returned by overlay exportfs for misaligned fid */
+#define OVL_FILEID_V0 0xfb
+/* The type returned by overlay exportfs for 32bit aligned fid */
+#define OVL_FILEID_V1 0xf8
-/* On-disk and in-memeory format for redirect by file handle */
-struct ovl_fh {
+/* On-disk format for "origin" file handle */
+struct ovl_fb {
u8 version; /* 0 */
u8 magic; /* 0xfb */
u8 len; /* size of this header + size of fid */
u8 flags; /* OVL_FH_FLAG_* */
u8 type; /* fid_type of fid */
uuid_t uuid; /* uuid of filesystem */
- u8 fid[0]; /* file identifier */
+ u32 fid[0]; /* file identifier should be 32bit aligned in-memory */
} __packed;
+/* In-memory and on-wire format for overlay file handle */
+struct ovl_fh {
+ u8 padding[3]; /* make sure fb.fid is 32bit aligned */
+ union {
+ struct ovl_fb fb;
+ u8 buf[0];
+ };
+} __packed;
+
+#define OVL_FH_WIRE_OFFSET offsetof(struct ovl_fh, fb)
+#define OVL_FH_LEN(fh) (OVL_FH_WIRE_OFFSET + (fh)->fb.len)
+#define OVL_FH_FID_OFFSET (OVL_FH_WIRE_OFFSET + \
+ offsetof(struct ovl_fb, fid))
+
static inline int ovl_do_rmdir(struct inode *dir, struct dentry *dentry)
{
int err = vfs_rmdir(dir, dentry);
@@ -302,7 +318,13 @@ static inline void ovl_inode_unlock(struct inode *inode)
/* namei.c */
-int ovl_check_fh_len(struct ovl_fh *fh, int fh_len);
+int ovl_check_fb_len(struct ovl_fb *fb, int fb_len);
+
+static inline int ovl_check_fh_len(struct ovl_fh *fh, int fh_len)
+{
+ return ovl_check_fb_len(&fh->fb, fh_len - OVL_FH_WIRE_OFFSET);
+}
+
struct dentry *ovl_decode_real_fh(struct ovl_fh *fh, struct vfsmount *mnt,
bool connected);
int ovl_check_origin_fh(struct ovl_fs *ofs, struct ovl_fh *fh, bool connected,
diff --git a/fs/overlayfs/ovl_entry.h b/fs/overlayfs/ovl_entry.h
index a8279280e88d..28348c44ea5b 100644
--- a/fs/overlayfs/ovl_entry.h
+++ b/fs/overlayfs/ovl_entry.h
@@ -22,6 +22,8 @@ struct ovl_config {
struct ovl_sb {
struct super_block *sb;
dev_t pseudo_dev;
+ /* Unusable (conflicting) uuid */
+ bool bad_uuid;
};
struct ovl_layer {
diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c
index afbcb116a7f1..7621ff176d15 100644
--- a/fs/overlayfs/super.c
+++ b/fs/overlayfs/super.c
@@ -1255,7 +1255,7 @@ static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid)
{
unsigned int i;
- if (!ofs->config.nfs_export && !(ofs->config.index && ofs->upper_mnt))
+ if (!ofs->config.nfs_export && !ofs->upper_mnt)
return true;
for (i = 0; i < ofs->numlowerfs; i++) {
@@ -1263,9 +1263,13 @@ static bool ovl_lower_uuid_ok(struct ovl_fs *ofs, const uuid_t *uuid)
* We use uuid to associate an overlay lower file handle with a
* lower layer, so we can accept lower fs with null uuid as long
* as all lower layers with null uuid are on the same fs.
+ * if we detect multiple lower fs with the same uuid, we
+ * disable lower file handle decoding on all of them.
*/
- if (uuid_equal(&ofs->lower_fs[i].sb->s_uuid, uuid))
+ if (uuid_equal(&ofs->lower_fs[i].sb->s_uuid, uuid)) {
+ ofs->lower_fs[i].bad_uuid = true;
return false;
+ }
}
return true;
}
@@ -1277,6 +1281,7 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path)
unsigned int i;
dev_t dev;
int err;
+ bool bad_uuid = false;
/* fsid 0 is reserved for upper fs even with non upper overlay */
if (ofs->upper_mnt && ofs->upper_mnt->mnt_sb == sb)
@@ -1288,11 +1293,15 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path)
}
if (!ovl_lower_uuid_ok(ofs, &sb->s_uuid)) {
- ofs->config.index = false;
- ofs->config.nfs_export = false;
- pr_warn("overlayfs: %s uuid detected in lower fs '%pd2', falling back to index=off,nfs_export=off.\n",
- uuid_is_null(&sb->s_uuid) ? "null" : "conflicting",
- path->dentry);
+ bad_uuid = true;
+ if (ofs->config.index || ofs->config.nfs_export) {
+ ofs->config.index = false;
+ ofs->config.nfs_export = false;
+ pr_warn("overlayfs: %s uuid detected in lower fs '%pd2', falling back to index=off,nfs_export=off.\n",
+ uuid_is_null(&sb->s_uuid) ? "null" :
+ "conflicting",
+ path->dentry);
+ }
}
err = get_anon_bdev(&dev);
@@ -1303,6 +1312,7 @@ static int ovl_get_fsid(struct ovl_fs *ofs, const struct path *path)
ofs->lower_fs[ofs->numlowerfs].sb = sb;
ofs->lower_fs[ofs->numlowerfs].pseudo_dev = dev;
+ ofs->lower_fs[ofs->numlowerfs].bad_uuid = bad_uuid;
ofs->numlowerfs++;
return ofs->numlowerfs;