linux/fs
David Howells c636ebdb18 [PATCH] VFS: Destroy the dentries contributed by a superblock on unmounting
The attached patch destroys all the dentries attached to a superblock in one go
by:

 (1) Destroying the tree rooted at s_root.

 (2) Destroying every entry in the anon list, one at a time.

 (3) Each entry in the anon list has its subtree consumed from the leaves
     inwards.

This reduces the amount of work generic_shutdown_super() does, and avoids
iterating through the dentry_unused list.

Note that locking is almost entirely absent in the shrink_dcache_for_umount*()
functions added by this patch.  This is because:

 (1) at the point the filesystem calls generic_shutdown_super(), it is not
     permitted to further touch the superblock's set of dentries, and nor may
     it remove aliases from inodes;

 (2) the dcache memory shrinker now skips dentries that are being unmounted;
     and

 (3) the superblock no longer has any external references through which the VFS
     can reach it.

Given these points, the only locking we need to do is when we remove dentries
from the unused list and the name hashes, which we do a directory's worth at a
time.

We also don't need to guard against reference counts going to zero unexpectedly
and removing bits of the tree we're working on as nothing else can call dput().

A cut down version of dentry_iput() has been folded into
shrink_dcache_for_umount_subtree() function.  Apart from not needing to unlock
things, it also doesn't need to check for inotify watches.

In this version of the patch, the complaint about a dentry still being in use
has been expanded from a single BUG_ON() and now gives much more information.

Signed-off-by: David Howells <dhowells@redhat.com>
Acked-by: NeilBrown <neilb@suse.de>
Acked-by: Ian Kent <raven@themaw.net>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
2006-10-11 11:14:25 -07:00
..
9p [PATCH] r/o bind mount prepwork: inc_nlink() helper 2006-10-01 00:39:30 -07:00
adfs [PATCH] Streamline generic_file_* interfaces and filemap cleanups 2006-10-01 00:39:28 -07:00
affs [PATCH] Streamline generic_file_* interfaces and filemap cleanups 2006-10-01 00:39:28 -07:00
afs [PATCH] fs/*: use BUILD_BUG_ON 2006-10-11 11:14:23 -07:00
autofs [PATCH] r/o bind mount prepwork: inc_nlink() helper 2006-10-01 00:39:30 -07:00
autofs4 [PATCH] AUTOFS: Make sure all dentries refs are released before calling kill_anon_super() 2006-10-11 11:14:25 -07:00
befs [PATCH] befs: endianness annotations 2006-10-10 16:15:33 -07:00
bfs [PATCH] r/o bind mount prepwork: inc_nlink() helper 2006-10-01 00:39:30 -07:00
cifs Still more typo fixes 2006-10-03 22:36:44 +02:00
coda [PATCH] r/o bind mount prepwork: inc_nlink() helper 2006-10-01 00:39:30 -07:00
configfs Merge git://git.kernel.org/pub/scm/linux/kernel/git/steve/gfs2-2.6 2006-10-04 09:06:16 -07:00
cramfs [PATCH] cramfs: make cramfs_uncompress_exit() return void 2006-09-29 09:18:20 -07:00
debugfs debugfs: spelling fix 2006-10-03 23:28:36 +02:00
devpts [PATCH] inode-diet: Eliminate i_blksize from the inode structure 2006-09-27 08:26:18 -07:00
dlm [PATCH] dlm gfp_t annotations 2006-10-09 14:19:08 -07:00
ecryptfs [PATCH] ecryptfs: fs/Makefile and fs/Kconfig 2006-10-04 07:55:24 -07:00
efs [PATCH] Really ignore kmem_cache_destroy return value 2006-09-27 08:26:10 -07:00
exportfs [PATCH] VFS: Make filldir_t and struct kstat deal in 64-bit inode numbers 2006-10-03 08:03:40 -07:00
ext2 [PATCH] ext2: errors behaviour fix 2006-10-11 11:14:21 -07:00
ext3 [PATCH] ext3: errors behaviour fix 2006-10-11 11:14:21 -07:00
ext4 [PATCH] ext4 whitespace cleanups 2006-10-11 11:14:19 -07:00
fat [PATCH] Remove unnecessary check in fs/fat/inode.c 2006-10-11 11:14:23 -07:00
freevxfs [PATCH] freevxfs: fix leak on error path 2006-09-29 09:18:20 -07:00
fuse [PATCH] r/o bind mounts: monitor zeroing of i_nlink 2006-10-01 00:39:30 -07:00
gfs2 [GFS2] Fix endian bug for de_type 2006-10-03 21:03:35 -04:00
hfs [PATCH] r/o bind mounts: monitor zeroing of i_nlink 2006-10-01 00:39:30 -07:00
hfsplus fix file specification in comments 2006-10-03 23:01:26 +02:00
hostfs [PATCH] Streamline generic_file_* interfaces and filemap cleanups 2006-10-01 00:39:28 -07:00
hpfs [PATCH] hpfs endianness annotations 2006-10-10 16:15:34 -07:00
hppfs [PATCH] hppfs: readdir callback missed in prototype change 2006-10-09 14:19:08 -07:00
hugetlbfs [PATCH] hugetlb: fix linked list corruption in unmap_hugepage_range() 2006-10-11 11:14:15 -07:00
isofs [PATCH] isofs endianness annotations 2006-10-10 16:15:34 -07:00
jbd [PATCH] null dereference in fs/jbd/journal.c 2006-10-11 11:14:14 -07:00
jbd2 [PATCH] jbd2: switch blks_type from sector_t to ull 2006-10-11 11:14:18 -07:00
jffs [PATCH] r/o bind mounts: unlink: monitor i_nlink 2006-10-01 00:39:30 -07:00
jffs2 [PATCH] fs/*: use BUILD_BUG_ON 2006-10-11 11:14:23 -07:00
jfs JFS: White space cleanup 2006-10-02 09:55:27 -05:00
lockd [PATCH] knfsd: lockd: fix refount on nsm 2006-10-04 07:55:20 -07:00
minix [PATCH] fs/*: use BUILD_BUG_ON 2006-10-11 11:14:23 -07:00
msdos [PATCH] r/o bind mounts: monitor zeroing of i_nlink 2006-10-01 00:39:30 -07:00
ncpfs [PATCH] wrong order of arguments in copy_to_user() in ncpfs 2006-10-09 14:19:08 -07:00
nfs Fix extraneous '&' in recent NFS client cleanup 2006-10-08 17:28:25 -07:00
nfs_common
nfsd [PATCH] knfsd: tidy up up meaning of 'buffer size' in nfsd/sunrpc 2006-10-06 08:53:41 -07:00
nls fix file specification in comments 2006-10-03 23:01:26 +02:00
ntfs [PATCH] Streamline generic_file_* interfaces and filemap cleanups 2006-10-01 00:39:28 -07:00
ocfs2 [PATCH] fs/*: use BUILD_BUG_ON 2006-10-11 11:14:23 -07:00
openpromfs Move several *_SUPER_MAGIC symbols to include/linux/magic.h. 2006-09-24 11:13:19 -04:00
partitions [PATCH] fs/partitions endianness annotations 2006-10-10 16:15:34 -07:00
proc IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 2006-10-05 15:10:12 +01:00
qnx4 [PATCH] r/o bind mounts: monitor zeroing of i_nlink 2006-10-01 00:39:30 -07:00
ramfs [PATCH] r/o bind mount prepwork: inc_nlink() helper 2006-10-01 00:39:30 -07:00
reiserfs [PATCH] ReiserFS: Make sure all dentries refs are released before calling kill_block_super() 2006-10-11 11:14:25 -07:00
romfs [PATCH] Really ignore kmem_cache_destroy return value 2006-09-27 08:26:10 -07:00
smbfs [PATCH] Streamline generic_file_* interfaces and filemap cleanups 2006-10-01 00:39:28 -07:00
sysfs [PATCH] pr_debug: sysfs: use size_t length modifier in pr_debug format arguments 2006-10-03 08:04:19 -07:00
sysv [PATCH] fs/*: use BUILD_BUG_ON 2006-10-11 11:14:23 -07:00
udf [PATCH] UDF: Fix mounting read-write 2006-10-05 16:18:55 -07:00
ufs [PATCH] ufs endianness annotations 2006-10-10 16:15:34 -07:00
vfat [PATCH] r/o bind mounts: monitor zeroing of i_nlink 2006-10-01 00:39:30 -07:00
xfs BUG_ON conversion for fs/xfs/ 2006-10-03 23:37:55 +02:00
aio.c [PATCH] pr_debug: aio: use size_t length modifier in pr_debug format arguments 2006-10-03 08:04:19 -07:00
attr.c [PATCH] capable/capability.h (fs/) 2006-01-11 18:42:13 -08:00
bad_inode.c [PATCH] Remove readv/writev methods and use aio_read/aio_write instead 2006-10-01 00:39:28 -07:00
binfmt_aout.c [PATCH] Require mmap handler for a.out executables 2006-09-29 09:18:08 -07:00
binfmt_elf_fdpic.c [PATCH] elf_fdpic_core_dump: don't take tasklist_lock 2006-09-29 09:18:14 -07:00
binfmt_elf.c [PATCH] Support piping into commands in /proc/sys/kernel/core_pattern 2006-10-01 00:39:33 -07:00
binfmt_em86.c
binfmt_flat.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
binfmt_misc.c [PATCH] Fix unserialized task->files changing 2006-09-29 09:18:12 -07:00
binfmt_script.c
binfmt_som.c [PARISC] Fix fs/binfmt_som.c 2006-10-04 06:51:26 -06:00
bio.c [PATCH] Update axboe@suse.de email address 2006-09-30 20:52:34 +02:00
block_dev.c [PATCH] Streamline generic_file_* interfaces and filemap cleanups 2006-10-01 00:39:28 -07:00
buffer.c [PATCH] D-cache aliasing issue in __block_prepare_write 2006-10-11 11:14:23 -07:00
char_dev.c [PATCH] BLOCK: Move extern declarations out of fs/*.c into header files [try #6] 2006-09-30 20:52:18 +02:00
compat_ioctl.c [PATCH] 32-bit compatibility HDIO IOCTLs 2006-10-11 11:14:22 -07:00
compat.c [PATCH] more fs/compat.c __user annotations 2006-10-10 15:37:20 -07:00
dcache.c [PATCH] VFS: Destroy the dentries contributed by a superblock on unmounting 2006-10-11 11:14:25 -07:00
dcookies.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
direct-io.c [PATCH] lockdep: annotate direct io 2006-07-03 15:27:06 -07:00
dnotify.c [PATCH] file: modify struct fown_struct to use a struct pid 2006-10-02 07:57:14 -07:00
dquot.c [PATCH] dquot: add proper locking when using current->signal->tty 2006-09-29 09:18:14 -07:00
drop_caches.c
eventpoll.c [PATCH] epoll_pwait() 2006-10-11 11:14:21 -07:00
exec.c [PATCH] namespaces: utsname: switch to using uts namespaces 2006-10-02 07:57:21 -07:00
fcntl.c [PATCH] file: Add locking to f_getown 2006-10-02 07:57:15 -07:00
fifo.c [PATCH] pipe.c/fifo.c code cleanups 2006-04-11 13:53:33 +02:00
file_table.c [PATCH] file: modify struct fown_struct to use a struct pid 2006-10-02 07:57:14 -07:00
file.c [PATCH] expand_fdtable(): remove pointless unlock+lock 2006-09-29 09:18:25 -07:00
filesystems.c [PATCH] Ban register_filesystem(NULL); 2006-09-29 09:18:20 -07:00
fs-writeback.c [PATCH] BLOCK: Remove dependence on existence of blockdev_superblock [try #6] 2006-09-30 20:52:26 +02:00
generic_acl.c [PATCH] Generic infrastructure for acls 2006-09-29 09:18:24 -07:00
inode.c [PATCH] fs/inode.c NULL noise removal 2006-10-10 15:37:23 -07:00
inotify_user.c [PATCH] inotify: fix deadlock found by lockdep 2006-07-31 13:28:41 -07:00
inotify.c [PATCH] inotify (4/5): allow watch removal from event handler 2006-06-20 05:25:19 -04:00
internal.h [PATCH] CONFIG_BLOCK internal.h cleanups 2006-09-30 20:52:32 +02:00
ioctl.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
ioprio.c [PATCH] Update axboe@suse.de email address 2006-09-30 20:52:34 +02:00
Kconfig [PATCH] jbd2: enable building of jbd2 and have ext4 use it rather than jbd 2006-10-11 11:14:16 -07:00
Kconfig.binfmt
libfs.c [PATCH] r/o bind mount prepwork: inc_nlink() helper 2006-10-01 00:39:30 -07:00
locks.c [PATCH] file: modify struct fown_struct to use a struct pid 2006-10-02 07:57:14 -07:00
Makefile [PATCH] jbd2: enable building of jbd2 and have ext4 use it rather than jbd 2006-10-11 11:14:16 -07:00
mbcache.c [PATCH] mbcache: add lock annotation for __mb_cache_entry_release_unlock() 2006-09-29 09:18:07 -07:00
mpage.c [PATCH] BLOCK: Dissociate generic_writepages() from mpage stuff [try #6] 2006-09-30 20:52:26 +02:00
namei.c [PATCH] r/o bind mount prepwork: move open_namei()'s vfs_create() 2006-10-01 00:39:30 -07:00
namespace.c [PATCH] namespaces: incorporate fs namespace into nsproxy 2006-10-02 07:57:20 -07:00
nfsctl.c Remove obsolete #include <linux/config.h> 2006-06-30 19:25:36 +02:00
no-block.c [PATCH] BLOCK: Make it possible to disable the block layer [try #6] 2006-09-30 20:52:31 +02:00
open.c [PATCH] r/o bind mounts: prepare for write access checks: collapse if() 2006-10-01 00:39:30 -07:00
pipe.c [PATCH] Some cleanup in the pipe code 2006-10-01 00:39:33 -07:00
pnode.c [PATCH] core: use list_move() 2006-06-26 09:58:17 -07:00
pnode.h
posix_acl.c [PATCH] kmemdup: some users 2006-10-01 00:39:19 -07:00
quota_v1.c
quota_v2.c [PATCH] sem2mutex: quota 2006-03-23 07:38:11 -08:00
quota.c [PATCH] BLOCK: Make it possible to disable the block layer [try #6] 2006-09-30 20:52:31 +02:00
read_write.c [PATCH] Add vector AIO support 2006-10-01 00:39:29 -07:00
read_write.h [PATCH] Remove readv/writev methods and use aio_read/aio_write instead 2006-10-01 00:39:28 -07:00
readdir.c [PATCH] VFS: Make filldir_t and struct kstat deal in 64-bit inode numbers 2006-10-03 08:03:40 -07:00
select.c [PATCH] enforce RLIMIT_NOFILE in poll() 2006-09-29 09:18:23 -07:00
seq_file.c [PATCH] sem2mutex: fs/seq_file.c 2006-03-23 07:38:12 -08:00
splice.c [PATCH] Update axboe@suse.de email address 2006-09-30 20:52:34 +02:00
stat.c [PATCH] VFS: Make filldir_t and struct kstat deal in 64-bit inode numbers 2006-10-03 08:03:40 -07:00
super.c [PATCH] VFS: Destroy the dentries contributed by a superblock on unmounting 2006-10-11 11:14:25 -07:00
sync.c [PATCH] BLOCK: Move functions out of buffer code [try #6] 2006-09-30 20:31:19 +02:00
utimes.c [PATCH] Create fs/utimes.c 2006-10-01 00:39:19 -07:00
xattr_acl.c
xattr.c [PATCH] Introduce vfs_listxattr 2006-10-09 14:20:38 -07:00