В линуксе mount --bind /dev /mnt/dev ЕМНИП
On Sat, Jun 30, 2018 at 1:46 PM, Slawa Olhovchenkov firstname.lastname@example.org wrote:
On Fri, Jun 29, 2018 at 05:59:00PM +0300, Gena Makhomed wrote:
Т.е. директории должны быть как бы зеркалами друг друга.
Это возможно сделать?
Теоретически - наверное возможно, если написать свой модуль ядра, который будет реализовывать эту логику на уровне файловой системы.
кажется в лялихе тоже такое было.
MOUNT_UNIONFS(8) FreeBSD System Manager's Manual MOUNT_UNIONFS(8)
NAME mount_unionfs — mount union file systems
SYNOPSIS mount_unionfs [-b] [-o options] directory uniondir
DESCRIPTION The mount_unionfs utility attaches directory above uniondir in such a way that the contents of both directory trees remain visible. By default, directory becomes the upper layer and uniondir becomes the lower layer.
The options are as follows: -b Deprecated. Use -o below instead. -o Options are specified with the -o flag followed by an option. The following options are available: below Inverts the default position, so that directory
becomes the lower layer and uniondir becomes the upper layer. However, uniondir remains the mount point.
copymode = traditional | transparent | masquerade Specifies the way to create a file or a directory in
the upper layer automatically when needed. The traditional mode uses the same way as the old unionfs for backward compatibility, and transparent duplicates the file and directory mode bits and the ownership in the lower layer to the created file in the upper layer. For behavior of the masquerade mode, see MASQUERADE MODE below.
whiteout = always | whenneeded Specifies whether whiteouts should always be made in
the upper layer when removing a file or directory or only when it already exists in the lower layer.
udir=mode Specifies directory mode bits in octal for masquerade mode. ufile=mode Specifies file mode bits in octal for masquerade mode. gid=gid Specifies group for masquerade mode. uid=uid Specifies user for masquerade mode. To enforce file system security, the user mounting a file system must
be superuser or else have write permission on the mounted-on directory. In addition, the vfs.usermount sysctl(8) variable must be set to 1 to permit file system mounting by ordinary users. However, note that transparent and masquerade modes require vfs.usermount to be set to 0 because this functionality can only be used by superusers.
Filenames are looked up in the upper layer and then in the lower
layer. If a directory is found in the lower layer, and there is no entry in the upper layer, then a shadow directory will be created in the upper layer. The ownership and the mode bits are set depending on the copymode option. In traditional mode, it will be owned by the user who originally did the union mount, with mode 0777 (“rwxrwxrwx”) modified by the umask in effect at that time.
If a file exists in the upper layer then there is no way to access a
file with the same name in the lower layer. If necessary, a combination of loopback and union mounts can be made which will still allow the lower files to be accessed by a different pathname.
Except in the case of a directory, access to an object is granted via
the normal file system access checks. For directories, the current user must have access to both the upper and lower directories (should they both exist).
Requests to create or modify objects in uniondir are passed to the
upper layer with the exception of a few special cases. An attempt to open for writing a file which exists in the lower layer causes a copy of the entire file to be made to the upper layer, and then for the upper layer copy to be opened. Similarly, an attempt to truncate a lower layer file to zero length causes an empty file to be created in the upper layer. Any other operation which would ultimately require modification to the lower layer fails with EROFS.
The union file system manipulates the namespace, rather than
individual file systems. The union operation applies recursively down the directory tree now rooted at uniondir. Thus any file systems which are mounted under uniondir will take part in the union operation. This differs from the union option to mount(8) which only applies the union operation to the mount point itself, and then only for lookups.
nginx-ru mailing list email@example.com http://mailman.nginx.org/mailman/listinfo/nginx-ru