Messages in this thread Patch in this message | | | From | Sage Weil <> | Subject | [PATCH] vfs: clean up real_lookup | Date | Thu, 24 Sep 2009 09:11:00 -0700 |
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Get rid of the goto by flipping the if (!result) over. Make the comments a bit more descriptive. Fix a few kernel style problems. No functional changes.
CC: Ian Kent <raven@themaw.net> CC: Christoph Hellwig <hch@infradead.org> Signed-off-by: Yehuda Sadeh <yehuda@newdream.net> Signed-off-by: Sage Weil <sage@newdream.net> --- fs/namei.c | 65 +++++++++++++++++++++++++++++++---------------------------- 1 files changed, 34 insertions(+), 31 deletions(-)
diff --git a/fs/namei.c b/fs/namei.c index f74ddb3..6770dde 100644 --- a/fs/namei.c +++ b/fs/namei.c @@ -469,19 +469,20 @@ ok: * This is called when everything else fails, and we actually have * to go to the low-level filesystem to find out what we should do.. * - * We get the directory semaphore, and after getting that we also + * We get the directory mutex, and after getting that we also * make sure that nobody added the entry to the dcache in the meantime.. * SMP-safe */ -static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, struct nameidata *nd) +static struct dentry *real_lookup(struct dentry *parent, struct qstr *name, + struct nameidata *nd) { - struct dentry * result; + struct dentry *result, *dentry; struct inode *dir = parent->d_inode; mutex_lock(&dir->i_mutex); /* * First re-do the cached lookup just in case it was created - * while we waited for the directory semaphore.. + * while we waited for the directory mutex. * * FIXME! This could use version numbering or similar to * avoid unnecessary cache lookups. @@ -494,38 +495,40 @@ static struct dentry * real_lookup(struct dentry * parent, struct qstr * name, s * so doing d_lookup() (with seqlock), instead of lockfree __d_lookup */ result = d_lookup(parent, name); - if (!result) { - struct dentry *dentry; - -do_the_lookup: - /* Don't create child dentry for a dead directory. */ - result = ERR_PTR(-ENOENT); - if (IS_DEADDIR(dir)) - goto out_unlock; - - dentry = d_alloc(parent, name); - result = ERR_PTR(-ENOMEM); - if (dentry) { - result = dir->i_op->lookup(dir, dentry, nd); + if (result) { + /* + * The cache was re-populated while we waited on the + * mutex. We need to revalidate, this time while + * holding i_mutex (to avoid another race). + */ + if (result->d_op && result->d_op->d_revalidate) { + result = do_revalidate(result, nd); if (result) - dput(dentry); - else - result = dentry; + goto out_unlock; + /* + * The dentry was left behind invalid. Just + * do the lookup. + */ + } else { + goto out_unlock; } -out_unlock: - mutex_unlock(&dir->i_mutex); - return result; } - /* - * Uhhuh! Nasty case: the cache was re-populated while - * we waited on the semaphore. Need to revalidate. - */ - if (result->d_op && result->d_op->d_revalidate) { - result = do_revalidate(result, nd); - if (!result) - goto do_the_lookup; + /* Don't create child dentry for a dead directory. */ + result = ERR_PTR(-ENOENT); + if (IS_DEADDIR(dir)) + goto out_unlock; + + dentry = d_alloc(parent, name); + result = ERR_PTR(-ENOMEM); + if (dentry) { + result = dir->i_op->lookup(dir, dentry, nd); + if (result) + dput(dentry); + else + result = dentry; } +out_unlock: mutex_unlock(&dir->i_mutex); return result; } -- 1.5.6.5
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