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introduce a parallel variant of ->iterate()

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New method: ->iterate_shared().  Same arguments as in ->iterate(),
called with the directory locked only shared.  Once all filesystems
switch, the old one will be gone.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
This commit is contained in:
Al Viro
2016-04-20 23:08:32 -04:00
parent 63b6df1413
commit 6192269444
5 changed files with 48 additions and 11 deletions
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20
fs/readdir.c
View File

@@ -24,15 +24,21 @@
int iterate_dir(struct file *file, struct dir_context *ctx)
{
struct inode *inode = file_inode(file);
bool shared = false;
int res = -ENOTDIR;
if (!file->f_op->iterate)
if (file->f_op->iterate_shared)
shared = true;
else if (!file->f_op->iterate)
goto out;
res = security_file_permission(file, MAY_READ);
if (res)
goto out;
inode_lock(inode);
if (shared)
inode_lock_shared(inode);
else
inode_lock(inode);
// res = mutex_lock_killable(&inode->i_mutex);
// if (res)
// goto out;
@@ -40,12 +46,18 @@ int iterate_dir(struct file *file, struct dir_context *ctx)
res = -ENOENT;
if (!IS_DEADDIR(inode)) {
ctx->pos = file->f_pos;
res = file->f_op->iterate(file, ctx);
if (shared)
res = file->f_op->iterate_shared(file, ctx);
else
res = file->f_op->iterate(file, ctx);
file->f_pos = ctx->pos;
fsnotify_access(file);
file_accessed(file);
}
inode_unlock(inode);
if (shared)
inode_unlock_shared(inode);
else
inode_unlock(inode);
out:
return res;
}