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author | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-12 09:28:55 -0700 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-07-12 09:28:55 -0700 |
commit | 6b1c776d3efbda31085b6a9f3bc7f774511fafd9 (patch) | |
tree | d306d6c2841b88b0a78ccdaf3532bb1e1f8260a0 /fs/overlayfs/Kconfig | |
parent | 58c7ffc0747a3a9145629d4966291f0586703767 (diff) | |
parent | f4439de118283159ff165e52036134a278ebf990 (diff) |
Merge branch 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs
Pull overlayfs updates from Miklos Szeredi:
"This work from Amir introduces the inodes index feature, which
provides:
- hardlinks are not broken on copy up
- infrastructure for overlayfs NFS export
This also fixes constant st_ino for samefs case for lower hardlinks"
* 'overlayfs-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/mszeredi/vfs: (33 commits)
ovl: mark parent impure and restore timestamp on ovl_link_up()
ovl: document copying layers restrictions with inodes index
ovl: cleanup orphan index entries
ovl: persistent overlay inode nlink for indexed inodes
ovl: implement index dir copy up
ovl: move copy up lock out
ovl: rearrange copy up
ovl: add flag for upper in ovl_entry
ovl: use struct copy_up_ctx as function argument
ovl: base tmpfile in workdir too
ovl: factor out ovl_copy_up_inode() helper
ovl: extract helper to get temp file in copy up
ovl: defer upper dir lock to tempfile link
ovl: hash overlay non-dir inodes by copy up origin
ovl: cleanup bad and stale index entries on mount
ovl: lookup index entry for copy up origin
ovl: verify index dir matches upper dir
ovl: verify upper root dir matches lower root dir
ovl: introduce the inodes index dir feature
ovl: generalize ovl_create_workdir()
...
Diffstat (limited to 'fs/overlayfs/Kconfig')
-rw-r--r-- | fs/overlayfs/Kconfig | 20 |
1 files changed, 20 insertions, 0 deletions
diff --git a/fs/overlayfs/Kconfig b/fs/overlayfs/Kconfig index c0c9683934b7..cbfc196e5dc5 100644 --- a/fs/overlayfs/Kconfig +++ b/fs/overlayfs/Kconfig @@ -23,3 +23,23 @@ config OVERLAY_FS_REDIRECT_DIR Note, that redirects are not backward compatible. That is, mounting an overlay which has redirects on a kernel that doesn't support this feature will have unexpected results. + +config OVERLAY_FS_INDEX + bool "Overlayfs: turn on inodes index feature by default" + depends on OVERLAY_FS + help + If this config option is enabled then overlay filesystems will use + the inodes index dir to map lower inodes to upper inodes by default. + In this case it is still possible to turn off index globally with the + "index=off" module option or on a filesystem instance basis with the + "index=off" mount option. + + The inodes index feature prevents breaking of lower hardlinks on copy + up. + + Note, that the inodes index feature is read-only backward compatible. + That is, mounting an overlay which has an index dir on a kernel that + doesn't support this feature read-only, will not have any negative + outcomes. However, mounting the same overlay with an old kernel + read-write and then mounting it again with a new kernel, will have + unexpected results. |