2016-02-22 22:51:29

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH 1/2] NFSv4.x/pnfs: Fix a race between layoutget and pnfs_destroy_layout

If the server reboots while there is a layoutget outstanding, then
the call to pnfs_choose_layoutget_stateid() will fail with an EAGAIN
error, which causes an infinite loop in send_layoutget(). The reason
why we never break out of the loop is that the layout 'plh_block_lgets'
field is never cleared.

Fix is to replace plh_block_lgets with NFS_LAYOUT_INVALID_STID, which
can be reset after a new layoutget.

Fixes: ab7d763e477c5 ("pNFS: Ensure nfs4_layoutget_prepare returns...")
Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/pnfs.c | 24 ++++++++++++++++++++++--
1 file changed, 22 insertions(+), 2 deletions(-)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 5064f23ca8cc..8a41538f1155 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -252,6 +252,27 @@ pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
}
}

+/*
+ * Mark a pnfs_layout_hdr and all associated layout segments as invalid
+ *
+ * In order to continue using the pnfs_layout_hdr, a full recovery
+ * is required.
+ * Note that caller must hold inode->i_lock.
+ */
+static void
+pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
+ struct list_head *lseg_list)
+{
+ struct pnfs_layout_range range = {
+ .iomode = IOMODE_ANY,
+ .offset = 0,
+ .length = NFS4_MAX_UINT64,
+ };
+
+ set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
+ pnfs_mark_matching_lsegs_invalid(lo, lseg_list, &range);
+}
+
static int
pnfs_iomode_to_fail_bit(u32 iomode)
{
@@ -554,9 +575,8 @@ pnfs_destroy_layout(struct nfs_inode *nfsi)
spin_lock(&nfsi->vfs_inode.i_lock);
lo = nfsi->layout;
if (lo) {
- lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
- pnfs_mark_matching_lsegs_invalid(lo, &tmp_list, NULL);
pnfs_get_layout_hdr(lo);
+ pnfs_mark_layout_stateid_invalid(lo, &tmp_list);
pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RO_FAILED);
pnfs_layout_clear_fail_bit(lo, NFS_LAYOUT_RW_FAILED);
spin_unlock(&nfsi->vfs_inode.i_lock);
--
2.5.0



2016-02-22 22:51:30

by Trond Myklebust

[permalink] [raw]
Subject: [PATCH 2/2] NFSv4.x/pnfs: Fix a race between layoutget and bulk recalls

Replace another case where the layout 'plh_block_lgets' can trigger
infinite loops in send_layoutget().

Signed-off-by: Trond Myklebust <[email protected]>
---
fs/nfs/pnfs.c | 17 ++++++-----------
1 file changed, 6 insertions(+), 11 deletions(-)

diff --git a/fs/nfs/pnfs.c b/fs/nfs/pnfs.c
index 8a41538f1155..2fa483e6dbe2 100644
--- a/fs/nfs/pnfs.c
+++ b/fs/nfs/pnfs.c
@@ -259,7 +259,7 @@ pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
* is required.
* Note that caller must hold inode->i_lock.
*/
-static void
+static int
pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
struct list_head *lseg_list)
{
@@ -270,7 +270,7 @@ pnfs_mark_layout_stateid_invalid(struct pnfs_layout_hdr *lo,
};

set_bit(NFS_LAYOUT_INVALID_STID, &lo->plh_flags);
- pnfs_mark_matching_lsegs_invalid(lo, lseg_list, &range);
+ return pnfs_mark_matching_lsegs_invalid(lo, lseg_list, &range);
}

static int
@@ -637,11 +637,6 @@ pnfs_layout_free_bulk_destroy_list(struct list_head *layout_list,
{
struct pnfs_layout_hdr *lo;
struct inode *inode;
- struct pnfs_layout_range range = {
- .iomode = IOMODE_ANY,
- .offset = 0,
- .length = NFS4_MAX_UINT64,
- };
LIST_HEAD(lseg_list);
int ret = 0;

@@ -656,11 +651,11 @@ pnfs_layout_free_bulk_destroy_list(struct list_head *layout_list,

spin_lock(&inode->i_lock);
list_del_init(&lo->plh_bulk_destroy);
- lo->plh_block_lgets++; /* permanently block new LAYOUTGETs */
- if (is_bulk_recall)
- set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
- if (pnfs_mark_matching_lsegs_invalid(lo, &lseg_list, &range))
+ if (pnfs_mark_layout_stateid_invalid(lo, &lseg_list)) {
+ if (is_bulk_recall)
+ set_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags);
ret = -EAGAIN;
+ }
spin_unlock(&inode->i_lock);
pnfs_free_lseg_list(&lseg_list);
/* Free all lsegs that are attached to commit buckets */
--
2.5.0