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| author | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-03-08 21:21:04 +0100 |
|---|---|---|
| committer | Russell King <rmk+kernel@arm.linux.org.uk> | 2010-03-08 21:21:04 +0100 |
| commit | 988addf82e4c03739375279de73929580a2d4a6a (patch) | |
| tree | 989ae1cd4e264bbad80c65f04480486246e7b9f3 /Documentation/filesystems/sharedsubtree.txt | |
| parent | Merge branch 'for-rmk/samsung6' of git://git.fluff.org/bjdooks/linux into dev... (diff) | |
| parent | Merge git://git.kernel.org/pub/scm/linux/kernel/git/amit/virtio-console (diff) | |
| download | linux-988addf82e4c03739375279de73929580a2d4a6a.tar.xz linux-988addf82e4c03739375279de73929580a2d4a6a.zip | |
Merge branch 'origin' into devel-stable
Conflicts:
arch/arm/mach-mx2/devices.c
arch/arm/mach-mx2/devices.h
sound/soc/pxa/pxa-ssp.c
Diffstat (limited to 'Documentation/filesystems/sharedsubtree.txt')
| -rw-r--r-- | Documentation/filesystems/sharedsubtree.txt | 16 |
1 files changed, 15 insertions, 1 deletions
diff --git a/Documentation/filesystems/sharedsubtree.txt b/Documentation/filesystems/sharedsubtree.txt index 23a181074f94..fc0e39af43c3 100644 --- a/Documentation/filesystems/sharedsubtree.txt +++ b/Documentation/filesystems/sharedsubtree.txt @@ -837,6 +837,9 @@ replicas continue to be exactly same. individual lists does not affect propagation or the way propagation tree is modified by operations. + All vfsmounts in a peer group have the same ->mnt_master. If it is + non-NULL, they form a contiguous (ordered) segment of slave list. + A example propagation tree looks as shown in the figure below. [ NOTE: Though it looks like a forest, if we consider all the shared mounts as a conceptual entity called 'pnode', it becomes a tree] @@ -874,8 +877,19 @@ replicas continue to be exactly same. NOTE: The propagation tree is orthogonal to the mount tree. +8B Locking: + + ->mnt_share, ->mnt_slave, ->mnt_slave_list, ->mnt_master are protected + by namespace_sem (exclusive for modifications, shared for reading). + + Normally we have ->mnt_flags modifications serialized by vfsmount_lock. + There are two exceptions: do_add_mount() and clone_mnt(). + The former modifies a vfsmount that has not been visible in any shared + data structures yet. + The latter holds namespace_sem and the only references to vfsmount + are in lists that can't be traversed without namespace_sem. -8B Algorithm: +8C Algorithm: The crux of the implementation resides in rbind/move operation. |