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fs: increase d_name lock coverage

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Cover d_name with d_lock in more cases, where there may be concurrent
modification to it.

Signed-off-by: Nick Piggin <npiggin@kernel.dk>
This commit is contained in:
Nick Piggin 2011-01-07 17:49:36 +11:00
parent b23fb0a603
commit 9abca36087
1 changed files with 12 additions and 2 deletions
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14
fs/dcache.c
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@ -1350,6 +1350,11 @@ static struct dentry *__d_instantiate_unique(struct dentry *entry,
list_for_each_entry(alias, &inode->i_dentry, d_alias) { list_for_each_entry(alias, &inode->i_dentry, d_alias) {
struct qstr *qstr = &alias->d_name; struct qstr *qstr = &alias->d_name;
/*
* Don't need alias->d_lock here, because aliases with
* d_parent == entry->d_parent are not subject to name or
* parent changes, because the parent inode i_mutex is held.
*/
if (qstr->hash != hash) if (qstr->hash != hash)
continue; continue;
if (alias->d_parent != entry->d_parent) if (alias->d_parent != entry->d_parent)
@ -2313,7 +2318,9 @@ static int prepend_path(const struct path *path, struct path *root,
} }
parent = dentry->d_parent; parent = dentry->d_parent;
prefetch(parent); prefetch(parent);
spin_lock(&dentry->d_lock);
error = prepend_name(buffer, buflen, &dentry->d_name); error = prepend_name(buffer, buflen, &dentry->d_name);
spin_unlock(&dentry->d_lock);
if (!error) if (!error)
error = prepend(buffer, buflen, "/", 1); error = prepend(buffer, buflen, "/", 1);
if (error) if (error)
@ -2515,10 +2522,13 @@ static char *__dentry_path(struct dentry *dentry, char *buf, int buflen)
while (!IS_ROOT(dentry)) { while (!IS_ROOT(dentry)) {
struct dentry *parent = dentry->d_parent; struct dentry *parent = dentry->d_parent;
int error;
prefetch(parent); prefetch(parent);
if ((prepend_name(&end, &buflen, &dentry->d_name) != 0) || spin_lock(&dentry->d_lock);
(prepend(&end, &buflen, "/", 1) != 0)) error = prepend_name(&end, &buflen, &dentry->d_name);
spin_unlock(&dentry->d_lock);
if (error != 0 || prepend(&end, &buflen, "/", 1) != 0)
goto Elong; goto Elong;
retval = end; retval = end;