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Message-Id: <1243893048-17031-23-git-send-email-ebiederm@xmission.com>
Date: Mon, 1 Jun 2009 14:50:48 -0700
From: "Eric W. Biederman" <ebiederm@...ssion.com>
To: Al Viro <viro@...IV.linux.org.uk>
Cc: <linux-kernel@...r.kernel.org>, <linux-pci@...r.kernel.org>,
<linux-mm@...ck.org>, <linux-fsdevel@...r.kernel.org>,
Hugh Dickins <hugh@...itas.com>, Tejun Heo <tj@...nel.org>,
Alexey Dobriyan <adobriyan@...il.com>,
Linus Torvalds <torvalds@...ux-foundation.org>,
Alan Cox <alan@...rguk.ukuu.org.uk>,
Greg Kroah-Hartman <gregkh@...e.de>,
Nick Piggin <npiggin@...e.de>,
Andrew Morton <akpm@...ux-foundation.org>,
Christoph Hellwig <hch@...radead.org>,
"Eric W. Biederman" <ebiederm@...well.aristanetworks.com>,
"Eric W. Biederman" <ebiederm@...stanetworks.com>
Subject: [PATCH 23/23] vfs: Teach readahead to use the file_hotplug_lock
From: Eric W. Biederman <ebiederm@...well.aristanetworks.com>
Signed-off-by: Eric W. Biederman <ebiederm@...stanetworks.com>
---
mm/filemap.c | 25 ++++++++++++++++---------
1 files changed, 16 insertions(+), 9 deletions(-)
diff --git a/mm/filemap.c b/mm/filemap.c
index 379ff0b..5016aa5 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1402,16 +1402,23 @@ SYSCALL_DEFINE(readahead)(int fd, loff_t offset, size_t count)
ret = -EBADF;
file = fget(fd);
- if (file) {
- if (file->f_mode & FMODE_READ) {
- struct address_space *mapping = file->f_mapping;
- pgoff_t start = offset >> PAGE_CACHE_SHIFT;
- pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
- unsigned long len = end - start + 1;
- ret = do_readahead(mapping, file, start, len);
- }
- fput(file);
+ if (!file)
+ goto out;
+
+ if (!(file->f_mode & FMODE_READ))
+ goto out_fput;
+
+ if (file_hotplug_read_trylock(file)) {
+ struct address_space *mapping = file->f_mapping;
+ pgoff_t start = offset >> PAGE_CACHE_SHIFT;
+ pgoff_t end = (offset + count - 1) >> PAGE_CACHE_SHIFT;
+ unsigned long len = end - start + 1;
+ ret = do_readahead(mapping, file, start, len);
+ file_hotplug_read_unlock(file);
}
+out_fput:
+ fput(file);
+out:
return ret;
}
#ifdef CONFIG_HAVE_SYSCALL_WRAPPERS
--
1.6.3.1.54.g99dd.dirty
--
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