overlayfs fixes for 6.6-rc6
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This commit is contained in:
Linus Torvalds
commit
19fd4a91dd
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@ -339,6 +339,18 @@ The specified lower directories will be stacked beginning from the
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rightmost one and going left. In the above example lower1 will be the
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top, lower2 the middle and lower3 the bottom layer.
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Note: directory names containing colons can be provided as lower layer by
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escaping the colons with a single backslash. For example:
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mount -t overlay overlay -olowerdir=/a\:lower\:\:dir /merged
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Since kernel version v6.5, directory names containing colons can also
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be provided as lower layer using the fsconfig syscall from new mount api:
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fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir", "/a:lower::dir", 0);
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In the latter case, colons in lower layer directory names will be escaped
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as an octal characters (\072) when displayed in /proc/self/mountinfo.
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Metadata only copy up
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---------------------
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@ -192,17 +192,19 @@ int vfs_parse_fs_string(struct fs_context *fc, const char *key,
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EXPORT_SYMBOL(vfs_parse_fs_string);
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/**
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* generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
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* vfs_parse_monolithic_sep - Parse key[=val][,key[=val]]* mount data
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* @fc: The superblock configuration to fill in.
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* @data: The data to parse
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* @sep: callback for separating next option
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*
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* Parse a blob of data that's in key[=val][,key[=val]]* form. This can be
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* called from the ->monolithic_mount_data() fs_context operation.
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* Parse a blob of data that's in key[=val][,key[=val]]* form with a custom
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* option separator callback.
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*
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* Returns 0 on success or the error returned by the ->parse_option() fs_context
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* operation on failure.
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*/
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int generic_parse_monolithic(struct fs_context *fc, void *data)
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int vfs_parse_monolithic_sep(struct fs_context *fc, void *data,
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char *(*sep)(char **))
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{
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char *options = data, *key;
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int ret = 0;
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@ -214,7 +216,7 @@ int generic_parse_monolithic(struct fs_context *fc, void *data)
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if (ret)
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return ret;
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while ((key = strsep(&options, ",")) != NULL) {
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while ((key = sep(&options)) != NULL) {
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if (*key) {
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size_t v_len = 0;
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char *value = strchr(key, '=');
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@ -233,6 +235,28 @@ int generic_parse_monolithic(struct fs_context *fc, void *data)
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return ret;
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}
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EXPORT_SYMBOL(vfs_parse_monolithic_sep);
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static char *vfs_parse_comma_sep(char **s)
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{
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return strsep(s, ",");
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}
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/**
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* generic_parse_monolithic - Parse key[=val][,key[=val]]* mount data
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* @fc: The superblock configuration to fill in.
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* @data: The data to parse
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*
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* Parse a blob of data that's in key[=val][,key[=val]]* form. This can be
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* called from the ->monolithic_mount_data() fs_context operation.
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*
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* Returns 0 on success or the error returned by the ->parse_option() fs_context
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* operation on failure.
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*/
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int generic_parse_monolithic(struct fs_context *fc, void *data)
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{
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return vfs_parse_monolithic_sep(fc, data, vfs_parse_comma_sep);
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}
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EXPORT_SYMBOL(generic_parse_monolithic);
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/**
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@ -157,6 +157,34 @@ const struct fs_parameter_spec ovl_parameter_spec[] = {
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{}
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};
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static char *ovl_next_opt(char **s)
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{
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char *sbegin = *s;
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char *p;
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if (sbegin == NULL)
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return NULL;
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for (p = sbegin; *p; p++) {
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if (*p == '\\') {
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p++;
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if (!*p)
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break;
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} else if (*p == ',') {
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*p = '\0';
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*s = p + 1;
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return sbegin;
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}
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}
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*s = NULL;
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return sbegin;
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}
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static int ovl_parse_monolithic(struct fs_context *fc, void *data)
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{
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return vfs_parse_monolithic_sep(fc, data, ovl_next_opt);
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}
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static ssize_t ovl_parse_param_split_lowerdirs(char *str)
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{
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ssize_t nr_layers = 1, nr_colons = 0;
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@ -164,7 +192,8 @@ static ssize_t ovl_parse_param_split_lowerdirs(char *str)
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for (s = d = str;; s++, d++) {
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if (*s == '\\') {
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s++;
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/* keep esc chars in split lowerdir */
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*d++ = *s++;
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} else if (*s == ':') {
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bool next_colon = (*(s + 1) == ':');
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@ -239,7 +268,7 @@ static void ovl_unescape(char *s)
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}
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}
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static int ovl_mount_dir(const char *name, struct path *path)
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static int ovl_mount_dir(const char *name, struct path *path, bool upper)
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{
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int err = -ENOMEM;
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char *tmp = kstrdup(name, GFP_KERNEL);
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@ -248,7 +277,7 @@ static int ovl_mount_dir(const char *name, struct path *path)
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ovl_unescape(tmp);
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err = ovl_mount_dir_noesc(tmp, path);
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if (!err && path->dentry->d_flags & DCACHE_OP_REAL) {
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if (!err && upper && path->dentry->d_flags & DCACHE_OP_REAL) {
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pr_err("filesystem on '%s' not supported as upperdir\n",
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tmp);
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path_put_init(path);
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@ -269,7 +298,7 @@ static int ovl_parse_param_upperdir(const char *name, struct fs_context *fc,
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struct path path;
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char *dup;
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err = ovl_mount_dir(name, &path);
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err = ovl_mount_dir(name, &path, true);
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if (err)
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return err;
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@ -321,12 +350,6 @@ static void ovl_parse_param_drop_lowerdir(struct ovl_fs_context *ctx)
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* Set "/lower1", "/lower2", and "/lower3" as lower layers and
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* "/data1" and "/data2" as data lower layers. Any existing lower
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* layers are replaced.
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* (2) lowerdir=:/lower4
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* Append "/lower4" to current stack of lower layers. This requires
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* that there already is at least one lower layer configured.
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* (3) lowerdir=::/lower5
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* Append data "/lower5" as data lower layer. This requires that
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* there's at least one regular lower layer present.
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*/
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static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
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{
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@ -348,49 +371,9 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
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return 0;
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}
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if (strncmp(name, "::", 2) == 0) {
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/*
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* This is a data layer.
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* There must be at least one regular lower layer
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* specified.
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*/
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if (ctx->nr == 0) {
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pr_err("data lower layers without regular lower layers not allowed");
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return -EINVAL;
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}
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/* Skip the leading "::". */
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name += 2;
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data_layer = true;
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/*
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* A data layer is automatically an append as there
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* must've been at least one regular lower layer.
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*/
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append = true;
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} else if (*name == ':') {
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/*
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* This is a regular lower layer.
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* If users want to append a layer enforce that they
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* have already specified a first layer before. It's
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* better to be strict.
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*/
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if (ctx->nr == 0) {
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pr_err("cannot append layer if no previous layer has been specified");
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return -EINVAL;
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}
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/*
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* Once a sequence of data layers has started regular
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* lower layers are forbidden.
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*/
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if (ctx->nr_data > 0) {
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pr_err("regular lower layers cannot follow data lower layers");
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return -EINVAL;
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}
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/* Skip the leading ":". */
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name++;
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append = true;
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if (*name == ':') {
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pr_err("cannot append lower layer");
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return -EINVAL;
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}
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dup = kstrdup(name, GFP_KERNEL);
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@ -472,7 +455,7 @@ static int ovl_parse_param_lowerdir(const char *name, struct fs_context *fc)
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l = &ctx->lower[nr];
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memset(l, 0, sizeof(*l));
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err = ovl_mount_dir_noesc(dup_iter, &l->path);
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err = ovl_mount_dir(dup_iter, &l->path, false);
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if (err)
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goto out_put;
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@ -682,6 +665,7 @@ static int ovl_reconfigure(struct fs_context *fc)
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}
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static const struct fs_context_operations ovl_context_ops = {
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.parse_monolithic = ovl_parse_monolithic,
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.parse_param = ovl_parse_param,
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.get_tree = ovl_get_tree,
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.reconfigure = ovl_reconfigure,
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@ -950,16 +934,23 @@ int ovl_show_options(struct seq_file *m, struct dentry *dentry)
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struct super_block *sb = dentry->d_sb;
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struct ovl_fs *ofs = OVL_FS(sb);
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size_t nr, nr_merged_lower = ofs->numlayer - ofs->numdatalayer;
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char **lowerdatadirs = &ofs->config.lowerdirs[nr_merged_lower];
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/* lowerdirs[] starts from offset 1 */
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seq_printf(m, ",lowerdir=%s", ofs->config.lowerdirs[1]);
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/* dump regular lower layers */
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for (nr = 2; nr < nr_merged_lower; nr++)
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seq_printf(m, ":%s", ofs->config.lowerdirs[nr]);
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/* dump data lower layers */
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for (nr = 0; nr < ofs->numdatalayer; nr++)
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seq_printf(m, "::%s", lowerdatadirs[nr]);
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/*
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* lowerdirs[] starts from offset 1, then
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* >= 0 regular lower layers prefixed with : and
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* >= 0 data-only lower layers prefixed with ::
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*
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* we need to escase comma and space like seq_show_option() does and
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* we also need to escape the colon separator from lowerdir paths.
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*/
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seq_puts(m, ",lowerdir=");
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for (nr = 1; nr < ofs->numlayer; nr++) {
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if (nr > 1)
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seq_putc(m, ':');
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if (nr >= nr_merged_lower)
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seq_putc(m, ':');
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seq_escape(m, ofs->config.lowerdirs[nr], ":, \t\n\\");
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}
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if (ofs->config.upperdir) {
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seq_show_option(m, "upperdir", ofs->config.upperdir);
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seq_show_option(m, "workdir", ofs->config.workdir);
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@ -136,6 +136,8 @@ extern struct fs_context *vfs_dup_fs_context(struct fs_context *fc);
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extern int vfs_parse_fs_param(struct fs_context *fc, struct fs_parameter *param);
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extern int vfs_parse_fs_string(struct fs_context *fc, const char *key,
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const char *value, size_t v_size);
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int vfs_parse_monolithic_sep(struct fs_context *fc, void *data,
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char *(*sep)(char **));
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extern int generic_parse_monolithic(struct fs_context *fc, void *data);
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extern int vfs_get_tree(struct fs_context *fc);
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extern void put_fs_context(struct fs_context *fc);
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