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checkout: Support a "pure addition" mode

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I plan to use this for `rpm-ostree livefs`.
https://github.com/projectatomic/rpm-ostree/issues/639

Closes: #714
Approved by: jlebon
This commit is contained in:
Colin Walters authored and Atomic Bot committed 2017-03-06 20:58:04 +00:00
1 parent ff34810097
commit 94948e3522
5 files changed
+94 -31
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src/libostree/ostree-repo-checkout.c
+49 -25
View File
@@ -201,8 +201,16 @@ checkout_file_from_input_at (OstreeRepo *self,
while (G_UNLIKELY (res == -1 && errno == EINTR));
if (res == -1)
{
glnx_set_error_from_errno (error);
goto out;
if (errno == EEXIST && options->overwrite_mode == OSTREE_REPO_CHECKOUT_OVERWRITE_ADD_FILES)
{
ret = TRUE;
goto out;
}
else
{
glnx_set_error_from_errno (error);
goto out;
}
}
if (options->mode != OSTREE_REPO_CHECKOUT_MODE_USER)
@@ -240,6 +248,11 @@ checkout_file_from_input_at (OstreeRepo *self,
while (G_UNLIKELY (fd == -1 && errno == EINTR));
if (fd == -1)
{
if (errno == EEXIST && options->overwrite_mode == OSTREE_REPO_CHECKOUT_OVERWRITE_ADD_FILES)
{
ret = TRUE;
goto out;
}
glnx_set_error_from_errno (error);
goto out;
}
@@ -332,6 +345,12 @@ checkout_file_unioning_from_input_at (OstreeRepo *repo,
return ret;
}
typedef enum {
HARDLINK_RESULT_NOT_SUPPORTED,
HARDLINK_RESULT_SKIP_EXISTED,
HARDLINK_RESULT_LINKED
} HardlinkResult;
static gboolean
checkout_file_hardlink (OstreeRepo *self,
OstreeRepoCheckoutAtOptions *options,
@@ -339,28 +358,32 @@ checkout_file_hardlink (OstreeRepo *self,
int destination_dfd,
const char *destination_name,
gboolean allow_noent,
gboolean *out_was_supported,
HardlinkResult *out_result,
GCancellable *cancellable,
GError **error)
{
gboolean ret = FALSE;
gboolean ret_was_supported = FALSE;
HardlinkResult ret_result = HARDLINK_RESULT_NOT_SUPPORTED;
int srcfd = (self->mode == OSTREE_REPO_MODE_BARE || self->mode == OSTREE_REPO_MODE_BARE_USER) ?
self->objects_dir_fd : self->uncompressed_objects_dir_fd;
again:
if (linkat (srcfd, loose_path, destination_dfd, destination_name, 0) != -1)
ret_was_supported = TRUE;
if (linkat (srcfd, loose_path, destination_dfd, destination_name, 0) == 0)
ret_result = HARDLINK_RESULT_LINKED;
else if (!options->no_copy_fallback && (errno == EMLINK || errno == EXDEV || errno == EPERM))
{
/* EMLINK, EXDEV and EPERM shouldn't be fatal; we just can't do the
* optimization of hardlinking instead of copying.
*/
ret_was_supported = FALSE;
}
else if (allow_noent && errno == ENOENT)
{
ret_was_supported = FALSE;
}
else if (errno == EEXIST && options->overwrite_mode == OSTREE_REPO_CHECKOUT_OVERWRITE_ADD_FILES)
{
/* In this mode, we keep existing content. Distinguish this case though to
* avoid inserting into the devino cache.
*/
ret_result = HARDLINK_RESULT_SKIP_EXISTED;
}
else if (errno == EEXIST && options->overwrite_mode == OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES)
{
@@ -370,7 +393,7 @@ checkout_file_hardlink (OstreeRepo *self,
* the same file, then rename() does nothing, and returns a
* success status."
*
* So we can't make this atomic.
* So we can't make this atomic.
*/
(void) unlinkat (destination_dfd, destination_name, 0);
goto again;
@@ -379,14 +402,12 @@ checkout_file_hardlink (OstreeRepo *self,
{
g_prefix_error (error, "Hardlinking %s to %s: ", loose_path, destination_name);
glnx_set_error_from_errno (error);
goto out;
return FALSE;
}
ret = TRUE;
if (out_was_supported)
*out_was_supported = ret_was_supported;
out:
return ret;
if (out_result)
*out_result = ret_result;
return TRUE;
}
static gboolean
@@ -439,7 +460,7 @@ checkout_one_file_at (OstreeRepo *repo,
}
else
{
gboolean did_hardlink = FALSE;
HardlinkResult hardlink_res = HARDLINK_RESULT_NOT_SUPPORTED;
/* Try to do a hardlink first, if it's a regular file. This also
* traverses all parent repos.
*/
@@ -469,11 +490,11 @@ checkout_one_file_at (OstreeRepo *repo,
options,
loose_path_buf,
destination_dfd, destination_name,
TRUE, &did_hardlink,
TRUE, &hardlink_res,
cancellable, error))
goto out;
if (did_hardlink && options->devino_to_csum_cache)
if (hardlink_res == HARDLINK_RESULT_LINKED && options->devino_to_csum_cache)
{
struct stat stbuf;
OstreeDevIno *key;
@@ -492,13 +513,13 @@ checkout_one_file_at (OstreeRepo *repo,
g_hash_table_add ((GHashTable*)options->devino_to_csum_cache, key);
}
if (did_hardlink)
if (hardlink_res != HARDLINK_RESULT_NOT_SUPPORTED)
break;
}
current_repo = current_repo->parent_repo;
}
need_copy = !did_hardlink;
need_copy = (hardlink_res == HARDLINK_RESULT_NOT_SUPPORTED);
}
can_cache = (options->enable_uncompressed_cache
@@ -514,7 +535,7 @@ checkout_one_file_at (OstreeRepo *repo,
&& repo->mode == OSTREE_REPO_MODE_ARCHIVE_Z2
&& options->mode == OSTREE_REPO_CHECKOUT_MODE_USER)
{
gboolean did_hardlink;
HardlinkResult hardlink_res = HARDLINK_RESULT_NOT_SUPPORTED;
if (!ostree_repo_load_file (repo, checksum, &input, NULL, NULL,
cancellable, error))
@@ -560,19 +581,20 @@ checkout_one_file_at (OstreeRepo *repo,
if (!checkout_file_hardlink (repo, options, loose_path_buf,
destination_dfd, destination_name,
FALSE, &did_hardlink,
FALSE, &hardlink_res,
cancellable, error))
{
g_prefix_error (error, "Using new cached uncompressed hardlink of %s to %s: ", checksum, destination_name);
goto out;
}
need_copy = !did_hardlink;
need_copy = (hardlink_res == HARDLINK_RESULT_NOT_SUPPORTED);
}
/* Fall back to copy if we couldn't hardlink */
if (need_copy)
{
g_assert (!options->no_copy_fallback);
if (!ostree_repo_load_file (repo, checksum, &input, NULL, &xattrs,
cancellable, error))
goto out;
@@ -655,7 +677,9 @@ checkout_tree_at (OstreeRepo *self,
while (G_UNLIKELY (res == -1 && errno == EINTR));
if (res == -1)
{
if (errno == EEXIST && options->overwrite_mode == OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES)
if (errno == EEXIST &&
(options->overwrite_mode == OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES
|| options->overwrite_mode == OSTREE_REPO_CHECKOUT_OVERWRITE_ADD_FILES))
did_exist = TRUE;
else
{
src/libostree/ostree-repo.h
+4 -2
View File
@@ -722,11 +722,13 @@ typedef enum {
/**
* OstreeRepoCheckoutOverwriteMode:
* @OSTREE_REPO_CHECKOUT_OVERWRITE_NONE: No special options
* @OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES: When layering checkouts, overwrite earlier files, but keep earlier directories
* @OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES: When layering checkouts, unlink() and replace existing files, but do not modify existing directories
* @OSTREE_REPO_CHECKOUT_OVERWRITE_ADD_FILES: Only add new files/directories
*/
typedef enum {
OSTREE_REPO_CHECKOUT_OVERWRITE_NONE = 0,
OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES = 1
OSTREE_REPO_CHECKOUT_OVERWRITE_UNION_FILES = 1,
OSTREE_REPO_CHECKOUT_OVERWRITE_ADD_FILES = 2, /* Since: 2017.3 */
} OstreeRepoCheckoutOverwriteMode;
_OSTREE_PUBLIC