path: root/Documentation
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authorLinus Torvalds <torvalds@linux-foundation.org>2015-02-22 17:42:14 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2015-02-22 17:42:14 -0800
commitbe5e6616dd74e17fdd8e16ca015cfef94d49b467 (patch)
treea18826e557f0d6636f1e05a4ec30d584ed981a2b /Documentation
parent90c453ca2214394eec602d98e6cb92d151908493 (diff)
parent0a280962dc6e117e0e4baa668453f753579265d9 (diff)
Merge branch 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull more vfs updates from Al Viro: "Assorted stuff from this cycle. The big ones here are multilayer overlayfs from Miklos and beginning of sorting ->d_inode accesses out from David" * 'for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (51 commits) autofs4 copy_dev_ioctl(): keep the value of ->size we'd used for allocation procfs: fix race between symlink removals and traversals debugfs: leave freeing a symlink body until inode eviction Documentation/filesystems/Locking: ->get_sb() is long gone trylock_super(): replacement for grab_super_passive() fanotify: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions Cachefiles: Fix up scripted S_ISDIR/S_ISREG/S_ISLNK conversions VFS: (Scripted) Convert S_ISLNK/DIR/REG(dentry->d_inode) to d_is_*(dentry) SELinux: Use d_is_positive() rather than testing dentry->d_inode Smack: Use d_is_positive() rather than testing dentry->d_inode TOMOYO: Use d_is_dir() rather than d_inode and S_ISDIR() Apparmor: Use d_is_positive/negative() rather than testing dentry->d_inode Apparmor: mediated_filesystem() should use dentry->d_sb not inode->i_sb VFS: Split DCACHE_FILE_TYPE into regular and special types VFS: Add a fallthrough flag for marking virtual dentries VFS: Add a whiteout dentry type VFS: Introduce inode-getting helpers for layered/unioned fs environments Infiniband: Fix potential NULL d_inode dereference posix_acl: fix reference leaks in posix_acl_create autofs4: Wrong format for printing dentry ...
Diffstat (limited to 'Documentation')
2 files changed, 28 insertions, 2 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 2ca3d17eee56..f91926f2f482 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -164,8 +164,6 @@ the block device inode. See there for more details.
--------------------------- file_system_type ---------------------------
- int (*get_sb) (struct file_system_type *, int,
- const char *, void *, struct vfsmount *);
struct dentry *(*mount) (struct file_system_type *, int,
const char *, void *);
void (*kill_sb) (struct super_block *);
diff --git a/Documentation/filesystems/overlayfs.txt b/Documentation/filesystems/overlayfs.txt
index a27c950ece61..6db0e5d1da07 100644
--- a/Documentation/filesystems/overlayfs.txt
+++ b/Documentation/filesystems/overlayfs.txt
@@ -159,6 +159,22 @@ overlay filesystem (though an operation on the name of the file such as
rename or unlink will of course be noticed and handled).
+Multiple lower layers
+Multiple lower layers can now be given using the the colon (":") as a
+separator character between the directory names. For example:
+ mount -t overlay overlay -olowerdir=/lower1:/lower2:/lower3 /merged
+As the example shows, "upperdir=" and "workdir=" may be omitted. In
+that case the overlay will be read-only.
+The specified lower directories will be stacked beginning from the
+rightmost one and going left. In the above example lower1 will be the
+top, lower2 the middle and lower3 the bottom layer.
Non-standard behavior
@@ -196,3 +212,15 @@ Changes to the underlying filesystems while part of a mounted overlay
filesystem are not allowed. If the underlying filesystem is changed,
the behavior of the overlay is undefined, though it will not result in
a crash or deadlock.
+There's testsuite developed by David Howells at:
+ git://git.infradead.org/users/dhowells/unionmount-testsuite.git
+Run as root:
+ # cd unionmount-testsuite
+ # ./run --ov

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