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path: root/fs/overlayfs/copy_up.c
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Diffstat (limited to 'fs/overlayfs/copy_up.c')
-rw-r--r--fs/overlayfs/copy_up.c125
1 files changed, 97 insertions, 28 deletions
diff --git a/fs/overlayfs/copy_up.c b/fs/overlayfs/copy_up.c
index 0d9de353f42b..9f5a47338e59 100644
--- a/fs/overlayfs/copy_up.c
+++ b/fs/overlayfs/copy_up.c
@@ -316,6 +316,29 @@ static int ovl_set_origin(struct dentry *dentry, struct dentry *lower,
return err;
}
+static int ovl_link_up(struct dentry *parent, struct dentry *dentry)
+{
+ int err;
+ struct dentry *upper;
+ struct dentry *upperdir = ovl_dentry_upper(parent);
+ struct inode *udir = d_inode(upperdir);
+
+ inode_lock_nested(udir, I_MUTEX_PARENT);
+ upper = lookup_one_len(dentry->d_name.name, upperdir,
+ dentry->d_name.len);
+ err = PTR_ERR(upper);
+ if (!IS_ERR(upper)) {
+ err = ovl_do_link(ovl_dentry_upper(dentry), udir, upper, true);
+ dput(upper);
+
+ if (!err)
+ ovl_dentry_set_upper_alias(dentry);
+ }
+ inode_unlock(udir);
+
+ return err;
+}
+
struct ovl_copy_up_ctx {
struct dentry *parent;
struct dentry *dentry;
@@ -323,9 +346,11 @@ struct ovl_copy_up_ctx {
struct kstat stat;
struct kstat pstat;
const char *link;
- struct dentry *upperdir;
+ struct dentry *destdir;
+ struct qstr destname;
struct dentry *workdir;
bool tmpfile;
+ bool origin;
};
static int ovl_install_temp(struct ovl_copy_up_ctx *c, struct dentry *temp,
@@ -333,10 +358,9 @@ static int ovl_install_temp(struct ovl_copy_up_ctx *c, struct dentry *temp,
{
int err;
struct dentry *upper;
- struct inode *udir = d_inode(c->upperdir);
+ struct inode *udir = d_inode(c->destdir);
- upper = lookup_one_len(c->dentry->d_name.name, c->upperdir,
- c->dentry->d_name.len);
+ upper = lookup_one_len(c->destname.name, c->destdir, c->destname.len);
if (IS_ERR(upper))
return PTR_ERR(upper);
@@ -345,11 +369,8 @@ static int ovl_install_temp(struct ovl_copy_up_ctx *c, struct dentry *temp,
else
err = ovl_do_rename(d_inode(c->workdir), temp, udir, upper, 0);
- /* Restore timestamps on parent (best effort) */
- if (!err) {
- ovl_set_timestamps(c->upperdir, &c->pstat);
+ if (!err)
*newdentry = dget(c->tmpfile ? upper : temp);
- }
dput(upper);
return err;
@@ -439,7 +460,7 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
* Don't set origin when we are breaking the association with a lower
* hard link.
*/
- if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1) {
+ if (c->origin) {
err = ovl_set_origin(c->dentry, c->lowerpath.dentry, temp);
if (err)
return err;
@@ -450,7 +471,7 @@ static int ovl_copy_up_inode(struct ovl_copy_up_ctx *c, struct dentry *temp)
static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
{
- struct inode *udir = c->upperdir->d_inode;
+ struct inode *udir = c->destdir->d_inode;
struct dentry *newdentry = NULL;
struct dentry *temp = NULL;
int err;
@@ -473,7 +494,6 @@ static int ovl_copy_up_locked(struct ovl_copy_up_ctx *c)
if (err)
goto out_cleanup;
- ovl_dentry_set_upper_alias(c->dentry);
ovl_inode_update(d_inode(c->dentry), newdentry);
out:
dput(temp);
@@ -498,24 +518,57 @@ static int ovl_do_copy_up(struct ovl_copy_up_ctx *c)
{
int err;
struct ovl_fs *ofs = c->dentry->d_sb->s_fs_info;
+ bool indexed = false;
- /* Mark parent "impure" because it may now contain non-pure upper */
- err = ovl_set_impure(c->parent, c->upperdir);
- if (err)
- return err;
+ if (ovl_indexdir(c->dentry->d_sb) && !S_ISDIR(c->stat.mode) &&
+ c->stat.nlink > 1)
+ indexed = true;
+
+ if (S_ISDIR(c->stat.mode) || c->stat.nlink == 1 || indexed)
+ c->origin = true;
+
+ if (indexed) {
+ c->destdir = ovl_indexdir(c->dentry->d_sb);
+ err = ovl_get_index_name(c->lowerpath.dentry, &c->destname);
+ if (err)
+ return err;
+ } else {
+ /*
+ * Mark parent "impure" because it may now contain non-pure
+ * upper
+ */
+ err = ovl_set_impure(c->parent, c->destdir);
+ if (err)
+ return err;
+ }
/* Should we copyup with O_TMPFILE or with workdir? */
if (S_ISREG(c->stat.mode) && ofs->tmpfile) {
c->tmpfile = true;
- return ovl_copy_up_locked(c);
+ err = ovl_copy_up_locked(c);
+ } else {
+ err = -EIO;
+ if (lock_rename(c->workdir, c->destdir) != NULL) {
+ pr_err("overlayfs: failed to lock workdir+upperdir\n");
+ } else {
+ err = ovl_copy_up_locked(c);
+ unlock_rename(c->workdir, c->destdir);
+ }
}
- err = -EIO;
- if (lock_rename(c->workdir, c->upperdir) != NULL) {
- pr_err("overlayfs: failed to lock workdir+upperdir\n");
- } else {
- err = ovl_copy_up_locked(c);
- unlock_rename(c->workdir, c->upperdir);
+ if (indexed) {
+ if (!err)
+ ovl_set_flag(OVL_INDEX, d_inode(c->dentry));
+ kfree(c->destname.name);
+ } else if (!err) {
+ struct inode *udir = d_inode(c->destdir);
+
+ /* Restore timestamps on parent (best effort) */
+ inode_lock(udir);
+ ovl_set_timestamps(c->destdir, &c->pstat);
+ inode_unlock(udir);
+
+ ovl_dentry_set_upper_alias(c->dentry);
}
return err;
@@ -543,7 +596,8 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
return err;
ovl_path_upper(parent, &parentpath);
- ctx.upperdir = parentpath.dentry;
+ ctx.destdir = parentpath.dentry;
+ ctx.destname = dentry->d_name;
err = vfs_getattr(&parentpath, &ctx.pstat,
STATX_ATIME | STATX_MTIME, AT_STATX_SYNC_AS_STAT);
@@ -567,7 +621,10 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
if (err > 0)
err = 0;
} else {
- err = ovl_do_copy_up(&ctx);
+ if (!ovl_dentry_upper(dentry))
+ err = ovl_do_copy_up(&ctx);
+ if (!err && !ovl_dentry_has_upper_alias(dentry))
+ err = ovl_link_up(parent, dentry);
ovl_copy_up_end(dentry);
}
do_delayed_call(&done);
@@ -583,9 +640,22 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
while (!err) {
struct dentry *next;
struct dentry *parent;
- enum ovl_path_type type = ovl_path_type(dentry);
- if (OVL_TYPE_UPPER(type))
+ /*
+ * Check if copy-up has happened as well as for upper alias (in
+ * case of hard links) is there.
+ *
+ * Both checks are lockless:
+ * - false negatives: will recheck under oi->lock
+ * - false positives:
+ * + ovl_dentry_upper() uses memory barriers to ensure the
+ * upper dentry is up-to-date
+ * + ovl_dentry_has_upper_alias() relies on locking of
+ * upper parent i_rwsem to prevent reordering copy-up
+ * with rename.
+ */
+ if (ovl_dentry_upper(dentry) &&
+ ovl_dentry_has_upper_alias(dentry))
break;
next = dget(dentry);
@@ -593,8 +663,7 @@ int ovl_copy_up_flags(struct dentry *dentry, int flags)
for (;;) {
parent = dget_parent(next);
- type = ovl_path_type(parent);
- if (OVL_TYPE_UPPER(type))
+ if (ovl_dentry_upper(parent))
break;
dput(next);
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-19 03:56:56 +0000