| Message ID | 20200603165813.13629-3-alexander.mikhalitsyn@virtuozzo.com |
|---|---|
| State | New |
| Series | "overlayfs: add dynamic path resolving in mount options" |
| Headers | show |
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig index 27a3f05..2a76e28 100644 --- a/fs/overlayfs/Kconfig +++ b/fs/overlayfs/Kconfig @@ -133,4 +133,30 @@ config OVERLAY_FS_DYNAMIC_RESOLVE_PATH_OPTIONS For more information, see Documentation/filesystems/overlayfs.txt + If unsure, say N. + +config OVERLAY_FS_PATH_OPTIONS_MNT_ID + bool "Overlayfs: show mnt_id for all mount paths options" + default y + depends on OVERLAY_FS + help + This option helps checkpoint/restore of overlayfs mounts. + If N selected, old behavior is saved. + + If this config option is enabled then in overlay filesystems mount + options you will be able to see additional parameters lowerdir_mnt_id/ + upperdir_mnt_id with corresponding mnt_ids. + + It's also possible to change this behavior on overlayfs module loading or + through sysfs (mnt_id_path_opts parameter). + + Disable this to get a backward compatible with previous kernels configuration, + but in this case checkpoint/restore functionality for overlayfs mounts + may not fully work. + + If backward compatibility is not an issue, then it is safe and + recommended to say Y here. + + For more information, see Documentation/filesystems/overlayfs.txt + If unsure, say N. \ No newline at end of file diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h index f508cd2..6440be5 100644 --- a/fs/overlayfs/overlayfs.h +++ b/fs/overlayfs/overlayfs.h @@ -256,6 +256,9 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); void print_path_option(struct seq_file *m, const char *name, struct path *path); void print_paths_option(struct seq_file *m, const char *name, struct path *paths, unsigned int num); +void print_mnt_id_option(struct seq_file *m, const char *name, struct path *path); +void print_mnt_ids_option(struct seq_file *m, const char *name, + struct path *paths, unsigned int num); static inline bool ovl_is_impuredir(struct dentry *dentry) { diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c index 138c6ac..be01553 100644 --- a/fs/overlayfs/super.c +++ b/fs/overlayfs/super.c @@ -61,6 +61,10 @@ static bool ovl_dyn_path_opts = IS_ENABLED(CONFIG_OVERLAY_FS_DYNAMIC_RESOLVE_PAT module_param_named(dyn_path_opts, ovl_dyn_path_opts, bool, 0644); MODULE_PARM_DESC(dyn_path_opts, "dyn_path_opts feature enabled"); +static bool ovl_mnt_id_path_opts = IS_ENABLED(OVERLAY_FS_PATH_OPTIONS_MNT_ID); +module_param_named(mnt_id_path_opts, ovl_mnt_id_path_opts, bool, 0644); +MODULE_PARM_DESC(mnt_id_path_opts, "mnt_id_path_opts feature enabled"); + static void ovl_entry_stack_free(struct ovl_entry *oe) { unsigned int i; @@ -390,6 +394,16 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) } } + if (ovl_mnt_id_path_opts) { + print_mnt_ids_option(m, "lowerdir_mnt_id", ofs->lowerpaths, ofs->numlower); + /* + * We don't need to show mnt_id for workdir because it + * on the same mount as upperdir. + */ + if (ofs->config.upperdir) + print_mnt_id_option(m, "upperdir_mnt_id", &ofs->upperpath); + } + if (ofs->config.default_permissions) seq_puts(m, ",default_permissions"); if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c index bb670ee..0425c49 100644 --- a/fs/overlayfs/util.c +++ b/fs/overlayfs/util.c @@ -18,6 +18,7 @@ #include <linux/namei.h> #include <linux/ratelimit.h> #include <linux/seq_file.h> +#include "../mount.h" #include "overlayfs.h" int ovl_want_write(struct dentry *dentry) @@ -699,3 +700,23 @@ void print_paths_option(struct seq_file *m, const char *name, seq_path(m, &paths[i], ", \t\n\\"); } } + +void print_mnt_id_option(struct seq_file *m, const char *name, struct path *path) +{ + seq_show_option(m, name, ""); + seq_printf(m, "%i", real_mount(path->mnt)->mnt_id); +} + +void print_mnt_ids_option(struct seq_file *m, const char *name, + struct path *paths, unsigned int num) +{ + int i; + + seq_show_option(m, name, ""); + + for (i = 0; i < num; i++) { + if (i) + seq_putc(m, ':'); + seq_printf(m, "%i", real_mount(paths[i].mnt)->mnt_id); + } +}
On 6/3/20 7:58 PM, Alexander Mikhalitsyn wrote: > This patch adds config OVERLAY_FS_PATH_OPTIONS_MNT_ID > compile-time option, and "mnt_id_path_opts" runtime module option. > If enabled, user may see mnt_ids for lowerdir, upperdir paths > in mountinfo in separate lowerdir_mnt_id/upperdir_mnt_id options. > > This patch is very helpful to checkpoint/restore functionality > of overlayfs mounts in case when we have overmounts on > lowerdir, workdir, upperdir paths. > > https://jira.sw.ru/browse/PSBM-58614 > Reviewed-by: Pavel Tikhomirov <ptikhomirov@virtuozzo.com> > Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com > --- > fs/overlayfs/Kconfig | 26 ++++++++++++++++++++++++++ > fs/overlayfs/overlayfs.h | 3 +++ > fs/overlayfs/super.c | 14 ++++++++++++++ > fs/overlayfs/util.c | 21 +++++++++++++++++++++ > 4 files changed, 64 insertions(+) > > diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig > index 27a3f05..2a76e28 100644 > --- a/fs/overlayfs/Kconfig > +++ b/fs/overlayfs/Kconfig > @@ -133,4 +133,30 @@ config OVERLAY_FS_DYNAMIC_RESOLVE_PATH_OPTIONS > > For more information, see Documentation/filesystems/overlayfs.txt > > + If unsure, say N. > + > +config OVERLAY_FS_PATH_OPTIONS_MNT_ID > + bool "Overlayfs: show mnt_id for all mount paths options" > + default y > + depends on OVERLAY_FS > + help > + This option helps checkpoint/restore of overlayfs mounts. > + If N selected, old behavior is saved. > + > + If this config option is enabled then in overlay filesystems mount > + options you will be able to see additional parameters lowerdir_mnt_id/ > + upperdir_mnt_id with corresponding mnt_ids. > + > + It's also possible to change this behavior on overlayfs module loading or > + through sysfs (mnt_id_path_opts parameter). > + > + Disable this to get a backward compatible with previous kernels configuration, > + but in this case checkpoint/restore functionality for overlayfs mounts > + may not fully work. > + > + If backward compatibility is not an issue, then it is safe and > + recommended to say Y here. > + > + For more information, see Documentation/filesystems/overlayfs.txt > + > If unsure, say N. > \ No newline at end of file > diff --git a/fs/overlayfs/overlayfs.h b/fs/overlayfs/overlayfs.h > index f508cd2..6440be5 100644 > --- a/fs/overlayfs/overlayfs.h > +++ b/fs/overlayfs/overlayfs.h > @@ -256,6 +256,9 @@ int ovl_lock_rename_workdir(struct dentry *workdir, struct dentry *upperdir); > void print_path_option(struct seq_file *m, const char *name, struct path *path); > void print_paths_option(struct seq_file *m, const char *name, > struct path *paths, unsigned int num); > +void print_mnt_id_option(struct seq_file *m, const char *name, struct path *path); > +void print_mnt_ids_option(struct seq_file *m, const char *name, > + struct path *paths, unsigned int num); > > static inline bool ovl_is_impuredir(struct dentry *dentry) > { > diff --git a/fs/overlayfs/super.c b/fs/overlayfs/super.c > index 138c6ac..be01553 100644 > --- a/fs/overlayfs/super.c > +++ b/fs/overlayfs/super.c > @@ -61,6 +61,10 @@ static bool ovl_dyn_path_opts = IS_ENABLED(CONFIG_OVERLAY_FS_DYNAMIC_RESOLVE_PAT > module_param_named(dyn_path_opts, ovl_dyn_path_opts, bool, 0644); > MODULE_PARM_DESC(dyn_path_opts, "dyn_path_opts feature enabled"); > > +static bool ovl_mnt_id_path_opts = IS_ENABLED(OVERLAY_FS_PATH_OPTIONS_MNT_ID); > +module_param_named(mnt_id_path_opts, ovl_mnt_id_path_opts, bool, 0644); > +MODULE_PARM_DESC(mnt_id_path_opts, "mnt_id_path_opts feature enabled"); > + > static void ovl_entry_stack_free(struct ovl_entry *oe) > { > unsigned int i; > @@ -390,6 +394,16 @@ static int ovl_show_options(struct seq_file *m, struct dentry *dentry) > } > } > > + if (ovl_mnt_id_path_opts) { > + print_mnt_ids_option(m, "lowerdir_mnt_id", ofs->lowerpaths, ofs->numlower); > + /* > + * We don't need to show mnt_id for workdir because it > + * on the same mount as upperdir. > + */ > + if (ofs->config.upperdir) > + print_mnt_id_option(m, "upperdir_mnt_id", &ofs->upperpath); > + } > + > if (ofs->config.default_permissions) > seq_puts(m, ",default_permissions"); > if (strcmp(ofs->config.redirect_mode, ovl_redirect_mode_def()) != 0) > diff --git a/fs/overlayfs/util.c b/fs/overlayfs/util.c > index bb670ee..0425c49 100644 > --- a/fs/overlayfs/util.c > +++ b/fs/overlayfs/util.c > @@ -18,6 +18,7 @@ > #include <linux/namei.h> > #include <linux/ratelimit.h> > #include <linux/seq_file.h> > +#include "../mount.h" > #include "overlayfs.h" > > int ovl_want_write(struct dentry *dentry) > @@ -699,3 +700,23 @@ void print_paths_option(struct seq_file *m, const char *name, > seq_path(m, &paths[i], ", \t\n\\"); > } > } > + > +void print_mnt_id_option(struct seq_file *m, const char *name, struct path *path) > +{ > + seq_show_option(m, name, ""); > + seq_printf(m, "%i", real_mount(path->mnt)->mnt_id); > +} > + > +void print_mnt_ids_option(struct seq_file *m, const char *name, > + struct path *paths, unsigned int num) > +{ > + int i; > + > + seq_show_option(m, name, ""); > + > + for (i = 0; i < num; i++) { > + if (i) > + seq_putc(m, ':'); > + seq_printf(m, "%i", real_mount(paths[i].mnt)->mnt_id); > + } > +} >
This patch adds config OVERLAY_FS_PATH_OPTIONS_MNT_ID compile-time option, and "mnt_id_path_opts" runtime module option. If enabled, user may see mnt_ids for lowerdir, upperdir paths in mountinfo in separate lowerdir_mnt_id/upperdir_mnt_id options. This patch is very helpful to checkpoint/restore functionality of overlayfs mounts in case when we have overmounts on lowerdir, workdir, upperdir paths. https://jira.sw.ru/browse/PSBM-58614 Signed-off-by: Alexander Mikhalitsyn <alexander.mikhalitsyn@virtuozzo.com> --- fs/overlayfs/Kconfig | 26 ++++++++++++++++++++++++++ fs/overlayfs/overlayfs.h | 3 +++ fs/overlayfs/super.c | 14 ++++++++++++++ fs/overlayfs/util.c | 21 +++++++++++++++++++++ 4 files changed, 64 insertions(+)