From: Erez Zadok <ezk@cs.sunysb.edu>
To: akpm@linux-foundation.org
Cc: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org,
viro@ftp.linux.org.uk, hch@infradead.org,
Erez Zadok <ezk@cs.sunysb.edu>
Subject: [PATCH 2/3] Unionfs: locking fixes
Date: Thu, 3 Jan 2008 00:57:39 -0500 [thread overview]
Message-ID: <119933986346-git-send-email-ezk@cs.sunysb.edu> (raw)
In-Reply-To: <11993398601-git-send-email-ezk@cs.sunysb.edu>
Lock parent dentries during revalidation.
Reduce total number of lockdep classes used.
Signed-off-by: Erez Zadok <ezk@cs.sunysb.edu>
---
fs/unionfs/dentry.c | 13 ++++++++++++-
fs/unionfs/fanout.h | 3 ++-
2 files changed, 14 insertions(+), 2 deletions(-)
diff --git a/fs/unionfs/dentry.c b/fs/unionfs/dentry.c
index 0369d93..7646828 100644
--- a/fs/unionfs/dentry.c
+++ b/fs/unionfs/dentry.c
@@ -42,6 +42,7 @@ static bool __unionfs_d_revalidate_one(struct dentry *dentry,
memset(&lowernd, 0, sizeof(struct nameidata));
verify_locked(dentry);
+ verify_locked(dentry->d_parent);
/* if the dentry is unhashed, do NOT revalidate */
if (d_deleted(dentry))
@@ -351,7 +352,10 @@ bool __unionfs_d_revalidate_chain(struct dentry *dentry, struct nameidata *nd,
* to child order.
*/
for (i = 0; i < chain_len; i++) {
- unionfs_lock_dentry(chain[i], UNIONFS_DMUTEX_REVAL+i);
+ unionfs_lock_dentry(chain[i], UNIONFS_DMUTEX_REVAL_CHILD);
+ if (chain[i] != chain[i]->d_parent)
+ unionfs_lock_dentry(chain[i]->d_parent,
+ UNIONFS_DMUTEX_REVAL_PARENT);
saved_bstart = dbstart(chain[i]);
saved_bend = dbend(chain[i]);
sbgen = atomic_read(&UNIONFS_SB(dentry->d_sb)->generation);
@@ -366,6 +370,8 @@ bool __unionfs_d_revalidate_chain(struct dentry *dentry, struct nameidata *nd,
bindex++)
unionfs_mntput(chain[i], bindex);
}
+ if (chain[i] != chain[i]->d_parent)
+ unionfs_unlock_dentry(chain[i]->d_parent);
unionfs_unlock_dentry(chain[i]);
if (unlikely(!valid))
@@ -376,6 +382,9 @@ bool __unionfs_d_revalidate_chain(struct dentry *dentry, struct nameidata *nd,
out_this:
/* finally, lock this dentry and revalidate it */
verify_locked(dentry);
+ if (dentry != dentry->d_parent)
+ unionfs_lock_dentry(dentry->d_parent,
+ UNIONFS_DMUTEX_REVAL_PARENT);
dgen = atomic_read(&UNIONFS_D(dentry)->generation);
if (unlikely(is_newer_lower(dentry))) {
@@ -394,6 +403,8 @@ out_this:
purge_inode_data(dentry->d_inode);
}
valid = __unionfs_d_revalidate_one(dentry, nd);
+ if (dentry != dentry->d_parent)
+ unionfs_unlock_dentry(dentry->d_parent);
/*
* If __unionfs_d_revalidate_one() succeeded above, then it will
diff --git a/fs/unionfs/fanout.h b/fs/unionfs/fanout.h
index 5f31015..4d9a45f 100644
--- a/fs/unionfs/fanout.h
+++ b/fs/unionfs/fanout.h
@@ -290,7 +290,8 @@ enum unionfs_dentry_lock_class {
UNIONFS_DMUTEX_PARENT,
UNIONFS_DMUTEX_CHILD,
UNIONFS_DMUTEX_WHITEOUT,
- UNIONFS_DMUTEX_REVAL, /* for file/dentry revalidate */
+ UNIONFS_DMUTEX_REVAL_PARENT, /* for file/dentry revalidate */
+ UNIONFS_DMUTEX_REVAL_CHILD, /* for file/dentry revalidate */
};
static inline void unionfs_lock_dentry(struct dentry *d,
--
1.5.2.2
next prev parent reply other threads:[~2008-01-03 5:58 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-01-03 5:57 [GIT PULL -mm] 0/3 Unionfs updates/fixes/cleanups Erez Zadok
2008-01-03 5:57 ` [PATCH 1/3] Unionfs: use printk KERN_CONT for debugging messages Erez Zadok
2008-01-03 6:26 ` Joe Perches
2008-01-03 18:36 ` Erez Zadok
2008-01-03 5:57 ` Erez Zadok [this message]
2008-01-03 5:57 ` [PATCH 3/3] Unionfs: use VFS helpers to manipulate i_nlink Erez Zadok
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=119933986346-git-send-email-ezk@cs.sunysb.edu \
--to=ezk@cs.sunysb.edu \
--cc=akpm@linux-foundation.org \
--cc=hch@infradead.org \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=viro@ftp.linux.org.uk \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox
Powered by JetHome