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authorJosef Bacik <jbacik@fusionio.com>2012-06-27 17:18:41 -0400
committerChris Mason <chris.mason@fusionio.com>2012-07-02 15:39:18 -0400
commit7fd1a3f73f3743b4ffd520effe288a70b0ec47c9 (patch)
tree176c81896d74f9662d6ebc91b902804921551db7 /fs/btrfs/extent_io.c
parentbdb7d303b33c1648514c9f9461d7513a4c05ce48 (diff)
downloadblackbird-op-linux-7fd1a3f73f3743b4ffd520effe288a70b0ec47c9.tar.gz
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Btrfs: hold a ref on the inode during writepages
We can race with unlink and not actually be able to do our igrab in btrfs_add_ordered_extent. This will result in all sorts of problems. Instead of doing the complicated work to try and handle returning an error properly from btrfs_add_ordered_extent, just hold a ref to the inode during writepages. If we cannot grab a ref we know we're freeing this inode anyway and can just drop the dirty pages on the floor, because screw them we're going to invalidate them anyway. Thanks, Signed-off-by: Josef Bacik <jbacik@fusionio.com>
Diffstat (limited to 'fs/btrfs/extent_io.c')
-rw-r--r--fs/btrfs/extent_io.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/fs/btrfs/extent_io.c b/fs/btrfs/extent_io.c
index aaa12c1eb348..01c21b6c6d43 100644
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c
@@ -3324,6 +3324,7 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
writepage_t writepage, void *data,
void (*flush_fn)(void *))
{
+ struct inode *inode = mapping->host;
int ret = 0;
int done = 0;
int nr_to_write_done = 0;
@@ -3334,6 +3335,18 @@ static int extent_write_cache_pages(struct extent_io_tree *tree,
int scanned = 0;
int tag;
+ /*
+ * We have to hold onto the inode so that ordered extents can do their
+ * work when the IO finishes. The alternative to this is failing to add
+ * an ordered extent if the igrab() fails there and that is a huge pain
+ * to deal with, so instead just hold onto the inode throughout the
+ * writepages operation. If it fails here we are freeing up the inode
+ * anyway and we'd rather not waste our time writing out stuff that is
+ * going to be truncated anyway.
+ */
+ if (!igrab(inode))
+ return 0;
+
pagevec_init(&pvec, 0);
if (wbc->range_cyclic) {
index = mapping->writeback_index; /* Start from prev offset */
@@ -3428,6 +3441,7 @@ retry:
index = 0;
goto retry;
}
+ btrfs_add_delayed_iput(inode);
return ret;
}
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