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9p: fix readdir corner cases

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The patch below also addresses a couple of other corner cases in readdir
seen with a large (e.g. 64k) msize.  I'm not sure what people think of
my co-opting of fid->aux here.  I'd be happy to rework if there's a better
way.

When the size of the user supplied buffer passed to readdir is smaller
than the data returned in one go by the 9P read request, v9fs_dir_readdir()
currently discards extra data so that, on the next call, a 9P read
request will be issued with offset < previous offset + bytes returned,
which voilates the constraint described in paragraph 3 of read(5) description.
This patch preseves the leftover data in fid->aux for use in the next call.

Signed-off-by: Jim Garlick <garlick@llnl.gov>
Signed-off-by: Eric Van Hensbergen <ericvh@gmail.com>
This commit is contained in:
Eric Van Hensbergen
2009-11-02 08:39:28 -06:00
parent 2511cd0b3b
commit 3e2796a90c
3 changed files with 70 additions and 32 deletions
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5
net/9p/client.c
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@@ -582,11 +582,9 @@ static struct p9_fid *p9_fid_create(struct p9_client *clnt)
memset(&fid->qid, 0, sizeof(struct p9_qid));
fid->mode = -1;
fid->rdir_fpos = 0;
fid->uid = current_fsuid();
fid->clnt = clnt;
fid->aux = NULL;
fid->rdir = NULL;
spin_lock_irqsave(&clnt->lock, flags);
list_add(&fid->flist, &clnt->fidlist);
spin_unlock_irqrestore(&clnt->lock, flags);
@@ -609,6 +607,7 @@ static void p9_fid_destroy(struct p9_fid *fid)
spin_lock_irqsave(&clnt->lock, flags);
list_del(&fid->flist);
spin_unlock_irqrestore(&clnt->lock, flags);
kfree(fid->rdir);
kfree(fid);
}