From: Christoph Hellwig <hch@lst.de>
To: viro@zeniv.linux.org.uk
Cc: linux-fsdevel@vger.kernel.org
Subject: [PATCH] update Documentation/filesystems/Locking
Date: Fri, 19 Jun 2009 20:22:37 +0200 [thread overview]
Message-ID: <20090619182237.GA11086@lst.de> (raw)
The rules for locking in many superblock operations has changed
significantly, so update the documentation for it. Also correct some
older updates and ommissions.
Signed-off-by: Christoph Hellwig <hch@lst.de>
Index: linux-2.6/Documentation/filesystems/Locking
===================================================================
--- linux-2.6.orig/Documentation/filesystems/Locking 2009-06-13 17:41:07.606841805 +0200
+++ linux-2.6/Documentation/filesystems/Locking 2009-06-13 17:47:42.400814653 +0200
@@ -109,27 +109,28 @@ prototypes:
locking rules:
All may block.
- BKL s_lock s_umount
-alloc_inode: no no no
-destroy_inode: no
-dirty_inode: no (must not sleep)
-write_inode: no
-drop_inode: no !!!inode_lock!!!
-delete_inode: no
-put_super: yes yes no
-write_super: no yes read
-sync_fs: no no read
-freeze_fs: ?
-unfreeze_fs: ?
-statfs: no no no
-remount_fs: yes yes maybe (see below)
-clear_inode: no
-umount_begin: yes no no
-show_options: no (vfsmount->sem)
-quota_read: no no no (see below)
-quota_write: no no no (see below)
+ None have BKL
+ s_umount
+alloc_inode:
+destroy_inode:
+dirty_inode: (must not sleep)
+write_inode:
+drop_inode: !!!inode_lock!!!
+delete_inode:
+put_super: write
+write_super: read
+sync_fs: read
+freeze_fs: read
+unfreeze_fs: read
+statfs: no
+remount_fs: maybe (see below)
+clear_inode:
+umount_begin: no
+show_options: no (namespace_sem)
+quota_read: no (see below)
+quota_write: no (see below)
-->remount_fs() will have the s_umount lock if it's already mounted.
+->remount_fs() will have the s_umount exclusive lock if it's already mounted.
When called from get_sb_single, it does NOT have the s_umount lock.
->quota_read() and ->quota_write() functions are both guaranteed to
be the only ones operating on the quota file by the quota code (via
next reply other threads:[~2009-06-19 18:22 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2009-06-19 18:22 Christoph Hellwig [this message]
-- strict thread matches above, loose matches on Subject: below --
2003-07-18 21:07 [PATCH] Update Documentation/filesystems/Locking Matthew Wilcox
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