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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-17 01:29:46 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2020-10-17 01:29:46 +0300 |
| commit | 071a0578b0ce0b0e543d1e38ee6926b9cc21c198 (patch) | |
| tree | 4e6bf57dc1b26ea7107237e6dcf8c70d12a9c1fb /Documentation/filesystems | |
| parent | fad70111d57e0b728b587eabc6f9f9b5240faa17 (diff) | |
| parent | be4df0cea08a8b59eb38d73de988b7ba8022df41 (diff) | |
| download | linux-071a0578b0ce0b0e543d1e38ee6926b9cc21c198.tar.xz | |
Merge tag 'ovl-update-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:
- Improve performance for certain container setups by introducing a
"volatile" mode
- ioctl improvements
- continue preparation for unprivileged overlay mounts
* tag 'ovl-update-5.10' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs:
ovl: use generic vfs_ioc_setflags_prepare() helper
ovl: support [S|G]ETFLAGS and FS[S|G]ETXATTR ioctls for directories
ovl: rearrange ovl_can_list()
ovl: enumerate private xattrs
ovl: pass ovl_fs down to functions accessing private xattrs
ovl: drop flags argument from ovl_do_setxattr()
ovl: adhere to the vfs_ vs. ovl_do_ conventions for xattrs
ovl: use ovl_do_getxattr() for private xattr
ovl: fold ovl_getxattr() into ovl_get_redirect_xattr()
ovl: clean up ovl_getxattr() in copy_up.c
duplicate ovl_getxattr()
ovl: provide a mount option "volatile"
ovl: check for incompatible features in work dir
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/overlayfs.rst | 19 |
1 files changed, 19 insertions, 0 deletions
diff --git a/Documentation/filesystems/overlayfs.rst b/Documentation/filesystems/overlayfs.rst index 8ea83a51c266..580ab9a0fe31 100644 --- a/Documentation/filesystems/overlayfs.rst +++ b/Documentation/filesystems/overlayfs.rst @@ -564,6 +564,25 @@ Note: the mount options index=off,nfs_export=on are conflicting for a read-write mount and will result in an error. +Volatile mount +-------------- + +This is enabled with the "volatile" mount option. Volatile mounts are not +guaranteed to survive a crash. It is strongly recommended that volatile +mounts are only used if data written to the overlay can be recreated +without significant effort. + +The advantage of mounting with the "volatile" option is that all forms of +sync calls to the upper filesystem are omitted. + +When overlay is mounted with "volatile" option, the directory +"$workdir/work/incompat/volatile" is created. During next mount, overlay +checks for this directory and refuses to mount if present. This is a strong +indicator that user should throw away upper and work directories and create +fresh one. In very limited cases where the user knows that the system has +not crashed and contents of upperdir are intact, The "volatile" directory +can be removed. + Testsuite --------- |