2011-04-13 14:54:12

by Weston Andros Adamson

[permalink] [raw]
Subject: [PATCH] Don't mark_inode_dirty_sync() while holding lock

mark_inode_dirty_sync() grabs the same inode lock!

race conditions between holding the lock in pnfs_set_layoutcommit() and in
mark_inode_dirty_sync() can result in a second call to pnfs_layoutcommit_inode(), but
this will be a noop as NFS_INO_LAYOUTCOMMIT won't be set in the second call

Signed-off-by: Weston Andros Adamson <[email protected]>
---
fs/nfs/pnfs.c | 8 +++++++-
1 files changed, 7 insertions(+), 1 deletions(-)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index d9ab972..ff681ab 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -1004,6 +1004,7 @@ pnfs_set_layoutcommit(struct nfs_write_data *wdata)
{
struct nfs_inode *nfsi = NFS_I(wdata->inode);
loff_t end_pos = wdata->args.offset + wdata->res.count;
+ bool mark_as_dirty = false;

spin_lock(&nfsi->vfs_inode.i_lock);
if (!test_and_set_bit(NFS_INO_LAYOUTCOMMIT, &nfsi->flags)) {
@@ -1011,13 +1012,18 @@ pnfs_set_layoutcommit(struct nfs_write_data *wdata)
get_lseg(wdata->lseg);
wdata->lseg->pls_lc_cred =
get_rpccred(wdata->args.context->state->owner->so_cred);
- mark_inode_dirty_sync(wdata->inode);
+ mark_as_dirty = true;
dprintk("%s: Set layoutcommit for inode %lu ",
__func__, wdata->inode->i_ino);
}
if (end_pos > wdata->lseg->pls_end_pos)
wdata->lseg->pls_end_pos = end_pos;
spin_unlock(&nfsi->vfs_inode.i_lock);
+
+ /* if pnfs_layoutcommit_inode() runs between inode locks, the next one
+ * will be a noop because NFS_INO_LAYOUTCOMMIT will not be set */
+ if (mark_as_dirty)
+ mark_inode_dirty_sync(wdata->inode);
}
EXPORT_SYMBOL_GPL(pnfs_set_layoutcommit);

--
1.7.4.2