repart: Keep existing directory timestamps intact when copying

Otherwise, when merging multiple directory trees, the output becomes
unreproducible as the directory timestamps will be changed to the current
time when copying identical directories from the second tree.

We introduce a new copy flag to achieve this behavior.

diff --git a/src/partition/repart.c b/src/partition/repart.c
index bca9f28372ea3ff29a32c3eaa3b5bd35f4bec294..e14c9a4750b018bac1d05c82d9337d2a2f4c49d3 100644 (file)
--- a/src/partition/repart.c
+++ b/src/partition/repart.c
@@ -4961,14 +4961,14 @@ static int do_copy_files(Context *context, Partition *p, const char *root) {
                                                 sfd, ".",
                                                 pfd, fn,
                                                 UID_INVALID, GID_INVALID,
-                                                COPY_REFLINK|COPY_HOLES|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS|COPY_ALL_XATTRS|COPY_GRACEFUL_WARN|COPY_TRUNCATE,
+                                                COPY_REFLINK|COPY_HOLES|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS|COPY_ALL_XATTRS|COPY_GRACEFUL_WARN|COPY_TRUNCATE|COPY_RESTORE_DIRECTORY_TIMESTAMPS,
                                                 denylist, subvolumes_by_source_inode);
                         } else
                                 r = copy_tree_at(
                                                 sfd, ".",
                                                 tfd, ".",
                                                 UID_INVALID, GID_INVALID,
-                                                COPY_REFLINK|COPY_HOLES|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS|COPY_ALL_XATTRS|COPY_GRACEFUL_WARN|COPY_TRUNCATE,
+                                                COPY_REFLINK|COPY_HOLES|COPY_MERGE|COPY_REPLACE|COPY_SIGINT|COPY_HARDLINKS|COPY_ALL_XATTRS|COPY_GRACEFUL_WARN|COPY_TRUNCATE|COPY_RESTORE_DIRECTORY_TIMESTAMPS,
                                                 denylist, subvolumes_by_source_inode);
                         if (r < 0)
                                 return log_error_errno(r, "Failed to copy '%s%s' to '%s%s': %m",

diff --git a/src/shared/copy.c b/src/shared/copy.c
index c5c5cf083d0233cc23e744f2053a91191f8f1c2b..8e240dc434f933295aabb52142bbf534c0a543e8 100644 (file)
--- a/src/shared/copy.c
+++ b/src/shared/copy.c
@@ -1009,6 +1009,7 @@ static int fd_copy_directory(
 
         _cleanup_close_ int fdf = -EBADF, fdt = -EBADF;
         _cleanup_closedir_ DIR *d = NULL;
+        struct stat dt_st;
         bool exists;
         int r;
 
@@ -1053,6 +1054,9 @@ static int fd_copy_directory(
         if (fdt < 0)
                 return fdt;
 
+        if (exists && FLAGS_SET(copy_flags, COPY_RESTORE_DIRECTORY_TIMESTAMPS) && fstat(fdt, &dt_st) < 0)
+                return -errno;
+
         r = 0;
 
         if (PTR_TO_INT(hashmap_get(denylist, st)) == DENY_CONTENTS) {
@@ -1152,7 +1156,9 @@ finish:
 
                 (void) copy_xattr(dirfd(d), NULL, fdt, NULL, copy_flags);
                 (void) futimens(fdt, (struct timespec[]) { st->st_atim, st->st_mtim });
-        }
+        } else if (FLAGS_SET(copy_flags, COPY_RESTORE_DIRECTORY_TIMESTAMPS))
+                /* If the directory already exists, make sure the timestamps stay the same as before. */
+                (void) futimens(fdt, (struct timespec[]) { dt_st.st_atim, dt_st.st_mtim });
 
         if (copy_flags & COPY_FSYNC_FULL) {
                 if (fsync(fdt) < 0)

diff --git a/src/shared/copy.h b/src/shared/copy.h
index b8fb28a09e48983b810aacc57429cb8e8d9f91fa..db95738b8056147abcbf05e3aafee45209d4f797 100644 (file)
--- a/src/shared/copy.h
+++ b/src/shared/copy.h
@@ -12,25 +12,26 @@
 #include "set.h"
 
 typedef enum CopyFlags {
-        COPY_REFLINK       = 1 << 0,  /* Try to reflink */
-        COPY_MERGE         = 1 << 1,  /* Merge existing trees with our new one to copy */
-        COPY_REPLACE       = 1 << 2,  /* Replace an existing file if there's one */
-        COPY_SAME_MOUNT    = 1 << 3,  /* Don't descend recursively into other file systems, across mount point boundaries */
-        COPY_MERGE_EMPTY   = 1 << 4,  /* Merge an existing, empty directory with our new tree to copy */
-        COPY_CRTIME        = 1 << 5,  /* Generate a user.crtime_usec xattr off the source crtime if there is one, on copying */
-        COPY_SIGINT        = 1 << 6,  /* Check for SIGINT regularly and return EINTR if seen (caller needs to block SIGINT) */
-        COPY_SIGTERM       = 1 << 7,  /* ditto, but for SIGTERM */
-        COPY_MAC_CREATE    = 1 << 8,  /* Create files with the correct MAC label (currently SELinux only) */
-        COPY_HARDLINKS     = 1 << 9,  /* Try to reproduce hard links */
-        COPY_FSYNC         = 1 << 10, /* fsync() after we are done */
-        COPY_FSYNC_FULL    = 1 << 11, /* fsync_full() after we are done */
-        COPY_SYNCFS        = 1 << 12, /* syncfs() the *top-level* dir after we are done */
-        COPY_ALL_XATTRS    = 1 << 13, /* Preserve all xattrs when copying, not just those in the user namespace */
-        COPY_HOLES         = 1 << 14, /* Copy holes */
-        COPY_GRACEFUL_WARN = 1 << 15, /* Skip copying file types that aren't supported by the target filesystem */
-        COPY_TRUNCATE      = 1 << 16, /* Truncate to current file offset after copying */
-        COPY_LOCK_BSD      = 1 << 17, /* Return a BSD exclusively locked file descriptor referring to the copied image/directory. */
-        COPY_VERIFY_LINKED = 1 << 18, /* Check the source file is still linked after copying. */
+        COPY_REFLINK                      = 1 << 0,  /* Try to reflink */
+        COPY_MERGE                        = 1 << 1,  /* Merge existing trees with our new one to copy */
+        COPY_REPLACE                      = 1 << 2,  /* Replace an existing file if there's one */
+        COPY_SAME_MOUNT                   = 1 << 3,  /* Don't descend recursively into other file systems, across mount point boundaries */
+        COPY_MERGE_EMPTY                  = 1 << 4,  /* Merge an existing, empty directory with our new tree to copy */
+        COPY_CRTIME                       = 1 << 5,  /* Generate a user.crtime_usec xattr off the source crtime if there is one, on copying */
+        COPY_SIGINT                       = 1 << 6,  /* Check for SIGINT regularly and return EINTR if seen (caller needs to block SIGINT) */
+        COPY_SIGTERM                      = 1 << 7,  /* ditto, but for SIGTERM */
+        COPY_MAC_CREATE                   = 1 << 8,  /* Create files with the correct MAC label (currently SELinux only) */
+        COPY_HARDLINKS                    = 1 << 9,  /* Try to reproduce hard links */
+        COPY_FSYNC                        = 1 << 10, /* fsync() after we are done */
+        COPY_FSYNC_FULL                   = 1 << 11, /* fsync_full() after we are done */
+        COPY_SYNCFS                       = 1 << 12, /* syncfs() the *top-level* dir after we are done */
+        COPY_ALL_XATTRS                   = 1 << 13, /* Preserve all xattrs when copying, not just those in the user namespace */
+        COPY_HOLES                        = 1 << 14, /* Copy holes */
+        COPY_GRACEFUL_WARN                = 1 << 15, /* Skip copying file types that aren't supported by the target filesystem */
+        COPY_TRUNCATE                     = 1 << 16, /* Truncate to current file offset after copying */
+        COPY_LOCK_BSD                     = 1 << 17, /* Return a BSD exclusively locked file descriptor referring to the copied image/directory. */
+        COPY_VERIFY_LINKED                = 1 << 18, /* Check the source file is still linked after copying. */
+        COPY_RESTORE_DIRECTORY_TIMESTAMPS = 1 << 19, /* Make sure existing directory timestamps don't change during copying. */
 } CopyFlags;
 
 typedef enum DenyType {