Lines Matching refs:lower

26 non-directory objects may report an st_dev from the lower filesystem or
87 and a 'lower' filesystem.  When a name exists in both filesystems, the
89 'lower' filesystem is either hidden or, in the case of directories,
92 It would be more correct to refer to an upper and lower 'directory
96 lower.
98 A wide range of filesystems supported by Linux can be the lower filesystem,
100 needed for OverlayFS to work.  The lower filesystem does not need to be
101 writable.  The lower filesystem can even be another overlayfs.  The upper
113 upper and lower filesystems and refers to a non-directory in either,
114 then the lower object is hidden - the name refers only to the upper
117 Where both upper and lower objects are directories, a merged directory
123   mount -t overlay overlay -olowerdir=/lower,upperdir=/upper,\
134 exists, else the lower.
138 directory only.  These attributes of the lower directory are hidden.
143 In order to support rm and rmdir without changing the lower
150 matching name in the lower level is ignored, and the whiteout itself
155 directory in the lower filesystem with the same name is ignored.
161 lower directories are each read and the name lists merged in the
162 obvious way (upper is read first, then lower - entries that already
187 underlying directory (upper or lower).
192 When renaming a directory that is on the lower layer or merged (i.e. the
241 indexed by the file handle of the lower inode and a file handle of the
246 lower directory.  In that case, lookup returns an error and warns about
249 Because lower layer redirects cannot be verified with the index, enabling
258 files etc.) are presented either from the upper or lower filesystem as
259 appropriate.  When a file in the lower filesystem is accessed in a way
261 some metadata etc., the file is first copied from the lower filesystem
273 data is copied from the lower to the upper filesystem.  Finally any
293  compared to direct access on underlying lower or upper filesystems
300  b) check if mounting task would be allowed real operation on lower or
316   mount -t overlay overlay -olowerdir=/lower,upperdir=/upper,... /merged
320   cp -a /lower /upper
327 Multiple lower layers
330 Multiple lower layers can now be given using the colon (":") as a
338 The specified lower directories will be stacked beginning from the
342 Note: directory names containing colons can be provided as lower layer by
345   mount -t overlay overlay -olowerdir=/a\:lower\:\:dir /merged
348 be provided as lower layer using the fsconfig syscall from new mount api:
350   fsconfig(fs_fd, FSCONFIG_SET_STRING, "lowerdir", "/a:lower::dir", 0);
352 In the latter case, colons in lower layer directory names will be escaped
372 Do not use metacopy=on with untrusted upper/lower directories. Otherwise
374 appropriate REDIRECT and METACOPY xattrs, and gain access to file on lower
386 Data-only lower layers
394  2) st_ino and st_dev object identifier from a file in a lower layer
396  3) data from a file in another lower layer (further below)
398 The "lower data" file can be on any lower layer, except from the top most
399 lower layer.
401 Below the top most lower layer, any number of lower most layers may be defined
402 as "data-only" lower layers, using double colon ("::") separators.
403 A normal lower layer is not allowed to be below a data-only layer, so single
411 The paths of files in the "data-only" lower layers are not visible in the
413 in the "data-only" lower layers are not visible in overlayfs inodes.
415 Only the data of the files in the "data-only" lower layers may be visible
416 when a "metacopy" file in one of the lower layers above it, has a "redirect"
417 to the absolute path of the "lower data" file in the "data-only" lower layer.
423 During metadata copy up of a lower file, if the source file has
425 digest of the lower file is added to the "trusted.overlay.metacopy"
426 xattr. This is then used to verify the content of the lower file
431 that was in the lower at the time of the copy-up. If at any time
432 (during a mount, after a remount, etc) such a file in the lower is
444 an untrusted lower layer can be used to supply validated file content
445 for all metacopy files.  If additionally the untrusted lower
471 a very common practice.  An overlay mount may use the same lower layer
472 path as another overlay mount and it may use a lower layer path that is
473 beneath or above the path of another overlay lower layer path.
484 different lower layer path, is allowed, unless the "inodes index" feature
488 handle of the lower layer root directory, along with the UUID of the lower
491 the lower root directory file handle and lower filesystem UUID are compared
493 lower root origin, mount will fail with ESTALE.  An overlayfs mount with
494 "inodes index" enabled will fail with EOPNOTSUPP if the lower filesystem
495 does not support NFS export, lower filesystem does not have a valid UUID or
499 mount time. So if same upper is mounted with different set of lower, mount
505 the copied layers will fail the verification of the lower root file handle.
517 done in the case when the file resides on a lower layer.
519 b) If a file residing on a lower layer is opened for read-only and then
523 c) If a file residing on a lower layer is being executed, then opening that
534 If this feature is disabled, then rename(2) on a lower or merged directory
572 upper tree.  Offline changes to the lower tree are only allowed if the
574 have not been used.  If the lower tree is modified and any of these
579 behavior on offline changes of the underlying lower layer is different
582 On every copy_up, an NFS file handle of the lower inode, along with the
583 UUID of the lower filesystem, are encoded and stored in an extended
587 that found a lower directory at the lookup path or at the path pointed
589 that the found lower directory file handle and lower filesystem UUID
591 found lower directory does not match the stored origin, that directory
602 With the "nfs_export" feature, on copy_up of any lower object, an index
613 1. For a non-upper object, encode a lower file handle from lower inode
614 2. For an indexed object, encode a lower file handle from copy_up origin
619  - Header including path type information (e.g. lower/upper)
630 3. For a lower file handle, lookup the handle in index directory by name.
642 When overlay filesystem has multiple lower layers, a middle layer
643 directory may have a "redirect" to lower directory.  Because middle layer
644 "redirects" are not indexed, a lower file handle that was encoded from the
646 layer directory.  Similarly, a lower file handle that was encoded from a
649 directories that cannot be decoded from a lower file handle, these
669 is changed. This is only applicable if all lower/upper/work directories are on