Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszer...
[sfrench/cifs-2.6.git] / fs / overlayfs / copy_up.c
index 2d4985018fdbe58e204bf60a988726ed9633cbe7..906ea6c93260179c9c4947abe97c35750162c3e3 100644 (file)
@@ -21,6 +21,7 @@
 #include <linux/fdtable.h>
 #include <linux/ratelimit.h>
 #include "overlayfs.h"
+#include "ovl_entry.h"
 
 #define OVL_COPY_UP_CHUNK_SIZE (1 << 20)
 
@@ -233,12 +234,14 @@ int ovl_set_attr(struct dentry *upperdentry, struct kstat *stat)
 
 static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
                              struct dentry *dentry, struct path *lowerpath,
-                             struct kstat *stat, const char *link)
+                             struct kstat *stat, const char *link,
+                             struct kstat *pstat, bool tmpfile)
 {
        struct inode *wdir = workdir->d_inode;
        struct inode *udir = upperdir->d_inode;
        struct dentry *newdentry = NULL;
        struct dentry *upper = NULL;
+       struct dentry *temp = NULL;
        int err;
        const struct cred *old_creds = NULL;
        struct cred *new_creds = NULL;
@@ -249,25 +252,30 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
                .link = link
        };
 
-       newdentry = ovl_lookup_temp(workdir, dentry);
-       err = PTR_ERR(newdentry);
-       if (IS_ERR(newdentry))
-               goto out;
-
        upper = lookup_one_len(dentry->d_name.name, upperdir,
                               dentry->d_name.len);
        err = PTR_ERR(upper);
        if (IS_ERR(upper))
-               goto out1;
+               goto out;
 
        err = security_inode_copy_up(dentry, &new_creds);
        if (err < 0)
-               goto out2;
+               goto out1;
 
        if (new_creds)
                old_creds = override_creds(new_creds);
 
-       err = ovl_create_real(wdir, newdentry, &cattr, NULL, true);
+       if (tmpfile)
+               temp = ovl_do_tmpfile(upperdir, stat->mode);
+       else
+               temp = ovl_lookup_temp(workdir, dentry);
+       err = PTR_ERR(temp);
+       if (IS_ERR(temp))
+               goto out1;
+
+       err = 0;
+       if (!tmpfile)
+               err = ovl_create_real(wdir, temp, &cattr, NULL, true);
 
        if (new_creds) {
                revert_creds(old_creds);
@@ -282,39 +290,55 @@ static int ovl_copy_up_locked(struct dentry *workdir, struct dentry *upperdir,
 
                ovl_path_upper(dentry, &upperpath);
                BUG_ON(upperpath.dentry != NULL);
-               upperpath.dentry = newdentry;
+               upperpath.dentry = temp;
+
+               if (tmpfile) {
+                       inode_unlock(udir);
+                       err = ovl_copy_up_data(lowerpath, &upperpath,
+                                              stat->size);
+                       inode_lock_nested(udir, I_MUTEX_PARENT);
+               } else {
+                       err = ovl_copy_up_data(lowerpath, &upperpath,
+                                              stat->size);
+               }
 
-               err = ovl_copy_up_data(lowerpath, &upperpath, stat->size);
                if (err)
                        goto out_cleanup;
        }
 
-       err = ovl_copy_xattr(lowerpath->dentry, newdentry);
+       err = ovl_copy_xattr(lowerpath->dentry, temp);
        if (err)
                goto out_cleanup;
 
-       inode_lock(newdentry->d_inode);
-       err = ovl_set_attr(newdentry, stat);
-       inode_unlock(newdentry->d_inode);
+       inode_lock(temp->d_inode);
+       err = ovl_set_attr(temp, stat);
+       inode_unlock(temp->d_inode);
        if (err)
                goto out_cleanup;
 
-       err = ovl_do_rename(wdir, newdentry, udir, upper, 0);
+       if (tmpfile)
+               err = ovl_do_link(temp, udir, upper, true);
+       else
+               err = ovl_do_rename(wdir, temp, udir, upper, 0);
        if (err)
                goto out_cleanup;
 
+       newdentry = dget(tmpfile ? upper : temp);
        ovl_dentry_update(dentry, newdentry);
        ovl_inode_update(d_inode(dentry), d_inode(newdentry));
-       newdentry = NULL;
+
+       /* Restore timestamps on parent (best effort) */
+       ovl_set_timestamps(upperdir, pstat);
 out2:
-       dput(upper);
+       dput(temp);
 out1:
-       dput(newdentry);
+       dput(upper);
 out:
        return err;
 
 out_cleanup:
-       ovl_cleanup(wdir, newdentry);
+       if (!tmpfile)
+               ovl_cleanup(wdir, temp);
        goto out2;
 }
 
@@ -338,6 +362,7 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
        struct dentry *lowerdentry = lowerpath->dentry;
        struct dentry *upperdir;
        const char *link = NULL;
+       struct ovl_fs *ofs = dentry->d_sb->s_fs_info;
 
        if (WARN_ON(!workdir))
                return -EROFS;
@@ -358,6 +383,25 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
                        return PTR_ERR(link);
        }
 
+       /* Should we copyup with O_TMPFILE or with workdir? */
+       if (S_ISREG(stat->mode) && ofs->tmpfile) {
+               err = ovl_copy_up_start(dentry);
+               /* err < 0: interrupted, err > 0: raced with another copy-up */
+               if (unlikely(err)) {
+                       pr_debug("ovl_copy_up_start(%pd2) = %i\n", dentry, err);
+                       if (err > 0)
+                               err = 0;
+                       goto out_done;
+               }
+
+               inode_lock_nested(upperdir->d_inode, I_MUTEX_PARENT);
+               err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
+                                        stat, link, &pstat, true);
+               inode_unlock(upperdir->d_inode);
+               ovl_copy_up_end(dentry);
+               goto out_done;
+       }
+
        err = -EIO;
        if (lock_rename(workdir, upperdir) != NULL) {
                pr_err("overlayfs: failed to lock workdir+upperdir\n");
@@ -370,13 +414,10 @@ static int ovl_copy_up_one(struct dentry *parent, struct dentry *dentry,
        }
 
        err = ovl_copy_up_locked(workdir, upperdir, dentry, lowerpath,
-                                stat, link);
-       if (!err) {
-               /* Restore timestamps on parent (best effort) */
-               ovl_set_timestamps(upperdir, &pstat);
-       }
+                                stat, link, &pstat, false);
 out_unlock:
        unlock_rename(workdir, upperdir);
+out_done:
        do_delayed_call(&done);
 
        return err;