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authorMiklos Szeredi <mszeredi@suse.cz>2008-07-04 09:35:17 +0200
committerJens Axboe <jens.axboe@oracle.com>2008-07-04 09:52:14 +0200
commit32502b8413a77b54b9e19809404109590c32dfb7 (patch)
treec84b87396be32d529b9902a7261b772b1d919e8b
parent8b3d3567f72aa61d5d6f4ce89d289b154e1ea866 (diff)
splice: fix generic_file_splice_read() race with page invalidation
If a page was invalidated during splicing from file to a pipe, then generic_file_splice_read() could return a short or zero count. This manifested itself in rare I/O errors seen on nfs exported fuse filesystems. This is because nfsd uses splice_direct_to_actor() to read files, and fuse uses invalidate_inode_pages2() to invalidate stale data on open. Fix by redoing the page find/create if it was found to be truncated (invalidated). Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
-rw-r--r--fs/splice.c17
1 files changed, 13 insertions, 4 deletions
diff --git a/fs/splice.c b/fs/splice.c
index aa5f6f60b30..399442179d8 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -379,13 +379,22 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
lock_page(page);
/*
- * page was truncated, stop here. if this isn't the
- * first page, we'll just complete what we already
- * added
+ * Page was truncated, or invalidated by the
+ * filesystem. Redo the find/create, but this time the
+ * page is kept locked, so there's no chance of another
+ * race with truncate/invalidate.
*/
if (!page->mapping) {
unlock_page(page);
- break;
+ page = find_or_create_page(mapping, index,
+ mapping_gfp_mask(mapping));
+
+ if (!page) {
+ error = -ENOMEM;
+ break;
+ }
+ page_cache_release(pages[page_nr]);
+ pages[page_nr] = page;
}
/*
* page was already under io and is now done, great