If an inode has been copied up metadata only, then we need to query the
number of blocks from lower and fill up the stat->st_blocks.
We need to be careful about races where we are doing stat on one cpu and
data copy up is taking place on other cpu. We want to return
stat->st_blocks either from lower or stable upper and not something in
between. Hence, ovl_has_upperdata() is called first to figure out whether
block reporting will take place from lower or upper.
Reviewed-by: Amir Goldstein <amir73il@xxxxxxxxx>
Signed-off-by: Vivek Goyal <vgoyal@xxxxxxxxxx>
---
fs/overlayfs/inode.c | 17 ++++++++++++++++-
fs/overlayfs/overlayfs.h | 1 +
fs/overlayfs/util.c | 16 ++++++++++++++++
3 files changed, 33 insertions(+), 1 deletion(-)
diff --git a/fs/overlayfs/inode.c b/fs/overlayfs/inode.c
index 165e1b52f619..150929a1fcdf 100644
--- a/fs/overlayfs/inode.c
+++ b/fs/overlayfs/inode.c
@@ -76,6 +76,9 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
bool is_dir = S_ISDIR(dentry->d_inode->i_mode);
bool samefs = ovl_same_sb(dentry->d_sb);
int err;
+ bool metacopy = false;
+
+ metacopy = ovl_is_metacopy_dentry(dentry);
type = ovl_path_real(dentry, &realpath);
old_cred = ovl_override_creds(dentry->d_sb);
@@ -93,7 +96,8 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
if (!is_dir || samefs) {
if (OVL_TYPE_ORIGIN(type)) {
struct kstat lowerstat;
- u32 lowermask = STATX_INO | (!is_dir ? STATX_NLINK : 0);
+ u32 lowermask = STATX_INO | STATX_BLOCKS |
+ (!is_dir ? STATX_NLINK : 0);
ovl_path_lower(dentry, &realpath);
err = vfs_getattr(&realpath, &lowerstat,
@@ -126,6 +130,17 @@ int ovl_getattr(const struct path *path, struct kstat *stat,
else
stat->dev = ovl_get_pseudo_dev(dentry);
}
+ if (metacopy) {
+ struct kstat lowerdatastat;
+ u32 lowermask = STATX_BLOCKS;
+
+ ovl_path_lowerdata(dentry, &realpath);
+ err = vfs_getattr(&realpath, &lowerdatastat,
+ lowermask, flags);
+ if (err)
+ goto out;
+ stat->blocks = lowerdatastat.blocks;
+ }
if (samefs) {
/*
* When all layers are on the same fs, all real inode
diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h
index d999813f9aeb..2d682923252e 100644
--- a/fs/overlayfs/overlayfs.h
+++ b/fs/overlayfs/overlayfs.h
@@ -272,6 +272,7 @@ bool ovl_need_index(struct dentry *dentry);
int ovl_nlink_start(struct dentry *dentry, bool *locked);
void ovl_nlink_end(struct dentry *dentry, bool locked);
int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir);
+bool ovl_is_metacopy_dentry(struct dentry *dentry);
static inline bool ovl_is_impuredir(struct dentry *dentry)
{
diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c
index 22df74cb1def..274bbfc855e0 100644
--- a/fs/overlayfs/util.c
+++ b/fs/overlayfs/util.c
@@ -754,3 +754,19 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir)
pr_err("overlayfs: failed to lock workdir+upperdir\n");
return -EIO;
}
+
+bool ovl_is_metacopy_dentry(struct dentry *dentry)
+{
+ struct ovl_entry *oe = dentry->d_fsdata;
+
+ if (!d_is_reg(dentry))
+ return false;
+
+ if (ovl_dentry_upper(dentry)) {
+ if (!ovl_has_upperdata(dentry))
+ return true;
+ return false;
+ }
+
+ return (oe->numlower > 1);
+}
--
2.13.6
--
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