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nfs/blocklayout: Fix premature PR key unregistration

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During generic/069 runs with pNFS SCSI layouts, the NFS client emits
the following in the system journal:

kernel: pNFS: failed to open device /dev/disk/by-id/dm-uuid-mpath-0x6001405e3366f045b7949eb8e4540b51 (-2)
kernel: pNFS: using block device sdb (reservation key 0x666b60901e7b26b3)
kernel: pNFS: failed to open device /dev/disk/by-id/dm-uuid-mpath-0x6001405e3366f045b7949eb8e4540b51 (-2)
kernel: pNFS: using block device sdb (reservation key 0x666b60901e7b26b3)
kernel: sd 6:0:0:1: reservation conflict
kernel: sd 6:0:0:1: [sdb] tag#16 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s
kernel: sd 6:0:0:1: [sdb] tag#16 CDB: Write(10) 2a 00 00 00 00 50 00 00 08 00
kernel: reservation conflict error, dev sdb, sector 80 op 0x1:(WRITE) flags 0x0 phys_seg 1 prio class 2
kernel: sd 6:0:0:1: reservation conflict
kernel: sd 6:0:0:1: reservation conflict
kernel: sd 6:0:0:1: [sdb] tag#18 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s
kernel: sd 6:0:0:1: [sdb] tag#17 FAILED Result: hostbyte=DID_OK driverbyte=DRIVER_OK cmd_age=0s
kernel: sd 6:0:0:1: [sdb] tag#18 CDB: Write(10) 2a 00 00 00 00 60 00 00 08 00
kernel: sd 6:0:0:1: [sdb] tag#17 CDB: Write(10) 2a 00 00 00 00 58 00 00 08 00
kernel: reservation conflict error, dev sdb, sector 96 op 0x1:(WRITE) flags 0x0 phys_seg 1 prio class 0
kernel: reservation conflict error, dev sdb, sector 88 op 0x1:(WRITE) flags 0x0 phys_seg 1 prio class 0
systemd[1]: fstests-generic-069.scope: Deactivated successfully.
systemd[1]: fstests-generic-069.scope: Consumed 5.092s CPU time.
systemd[1]: media-test.mount: Deactivated successfully.
systemd[1]: media-scratch.mount: Deactivated successfully.
kernel: sd 6:0:0:1: reservation conflict
kernel: failed to unregister PR key.

This appears to be due to a race. bl_alloc_lseg() calls this:

561 static struct nfs4_deviceid_node *
562 bl_find_get_deviceid(struct nfs_server *server,
563                 const struct nfs4_deviceid *id, const struct cred *cred,
564                 gfp_t gfp_mask)
565 {
566         struct nfs4_deviceid_node *node;
567         unsigned long start, end;
568
569 retry:
570         node = nfs4_find_get_deviceid(server, id, cred, gfp_mask);
571         if (!node)
572                 return ERR_PTR(-ENODEV);

nfs4_find_get_deviceid() does a lookup without the spin lock first.
If it can't find a matching deviceid, it creates a new device_info
(which calls bl_alloc_deviceid_node, and that registers the device's
PR key).

Then it takes the nfs4_deviceid_lock and looks up the deviceid again.
If it finds it this time, bl_find_get_deviceid() frees the spare
(new) device_info, which unregisters the PR key for the same device.

Any subsequent I/O from this client on that device gets EBADE.

The umount later unregisters the device's PR key again.

To prevent this problem, register the PR key after the deviceid_node
lookup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Benjamin Coddington <bcodding@redhat.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever 2024-06-25 16:02:06 -04:00 committed by Anna Schumaker
parent 5468fc8298
commit d869da91cc
3 changed files with 94 additions and 31 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

19
fs/nfs/blocklayout/blocklayout.c
View File

@ -564,25 +564,32 @@ bl_find_get_deviceid(struct nfs_server *server,
gfp_t gfp_mask)
{
struct nfs4_deviceid_node *node;
unsigned long start, end;
int err = -ENODEV;
retry:
node = nfs4_find_get_deviceid(server, id, cred, gfp_mask);
if (!node)
return ERR_PTR(-ENODEV);
if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags) == 0)
return node;
if (test_bit(NFS_DEVICEID_UNAVAILABLE, &node->flags)) {
unsigned long end = jiffies;
unsigned long start = end - PNFS_DEVICE_RETRY_TIMEOUT;
end = jiffies;
start = end - PNFS_DEVICE_RETRY_TIMEOUT;
if (!time_in_range(node->timestamp_unavailable, start, end)) {
nfs4_delete_deviceid(node->ld, node->nfs_client, id);
goto retry;
}
goto out_put;
}
if (!bl_register_dev(container_of(node, struct pnfs_block_dev, node)))
goto out_put;
return node;
out_put:
nfs4_put_deviceid_node(node);
return ERR_PTR(-ENODEV);
return ERR_PTR(err);
}
static int

9
fs/nfs/blocklayout/blocklayout.h
View File

@ -104,20 +104,26 @@ struct pnfs_block_dev {
u64 start;
u64 len;
enum pnfs_block_volume_type type;
u32 nr_children;
struct pnfs_block_dev *children;
u64 chunk_size;
struct file *bdev_file;
u64 disk_offset;
unsigned long flags;
u64 pr_key;
bool pr_registered;
bool (*map)(struct pnfs_block_dev *dev, u64 offset,
struct pnfs_block_dev_map *map);
};
/* pnfs_block_dev flag bits */
enum {
PNFS_BDEV_REGISTERED = 0,
};
/* sector_t fields are all in 512-byte sectors */
struct pnfs_block_extent {
union {
@ -172,6 +178,7 @@ struct bl_msg_hdr {
#define BL_DEVICE_REQUEST_ERR 0x2 /* User level process fails */
/* dev.c */
bool bl_register_dev(struct pnfs_block_dev *d);
struct nfs4_deviceid_node *bl_alloc_deviceid_node(struct nfs_server *server,
struct pnfs_device *pdev, gfp_t gfp_mask);
void bl_free_deviceid_node(struct nfs4_deviceid_node *d);

91
fs/nfs/blocklayout/dev.c
View File

@ -13,9 +13,75 @@
#define NFSDBG_FACILITY NFSDBG_PNFS_LD
static void bl_unregister_scsi(struct pnfs_block_dev *dev)
{
struct block_device *bdev = file_bdev(dev->bdev_file);
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
if (!test_and_clear_bit(PNFS_BDEV_REGISTERED, &dev->flags))
return;
if (ops->pr_register(bdev, dev->pr_key, 0, false))
pr_err("failed to unregister PR key.\n");
}
static bool bl_register_scsi(struct pnfs_block_dev *dev)
{
struct block_device *bdev = file_bdev(dev->bdev_file);
const struct pr_ops *ops = bdev->bd_disk->fops->pr_ops;
int status;
if (test_and_set_bit(PNFS_BDEV_REGISTERED, &dev->flags))
return true;
status = ops->pr_register(bdev, 0, dev->pr_key, true);
if (status) {
pr_err("pNFS: failed to register key for block device %s.",
bdev->bd_disk->disk_name);
return false;
}
return true;
}
static void bl_unregister_dev(struct pnfs_block_dev *dev)
{
u32 i;
if (dev->nr_children) {
for (i = 0; i < dev->nr_children; i++)
bl_unregister_dev(&dev->children[i]);
return;
}
if (dev->type == PNFS_BLOCK_VOLUME_SCSI)
bl_unregister_scsi(dev);
}
bool bl_register_dev(struct pnfs_block_dev *dev)
{
u32 i;
if (dev->nr_children) {
for (i = 0; i < dev->nr_children; i++) {
if (!bl_register_dev(&dev->children[i])) {
while (i > 0)
bl_unregister_dev(&dev->children[--i]);
return false;
}
}
return true;
}
if (dev->type == PNFS_BLOCK_VOLUME_SCSI)
return bl_register_scsi(dev);
return true;
}
static void
bl_free_device(struct pnfs_block_dev *dev)
{
bl_unregister_dev(dev);
if (dev->nr_children) {
int i;
@ -23,17 +89,6 @@ bl_free_device(struct pnfs_block_dev *dev)
bl_free_device(&dev->children[i]);
kfree(dev->children);
} else {
if (dev->pr_registered) {
const struct pr_ops *ops =
file_bdev(dev->bdev_file)->bd_disk->fops->pr_ops;
int error;
error = ops->pr_register(file_bdev(dev->bdev_file),
dev->pr_key, 0, false);
if (error)
pr_err("failed to unregister PR key.\n");
}
if (dev->bdev_file)
fput(dev->bdev_file);
}
@ -365,14 +420,6 @@ bl_parse_scsi(struct nfs_server *server, struct pnfs_block_dev *d,
goto out_blkdev_put;
}
error = ops->pr_register(file_bdev(d->bdev_file), 0, d->pr_key, true);
if (error) {
pr_err("pNFS: failed to register key for block device %s.",
file_bdev(d->bdev_file)->bd_disk->disk_name);
goto out_blkdev_put;
}
d->pr_registered = true;
return 0;
out_blkdev_put:
@ -458,7 +505,9 @@ static int
bl_parse_deviceid(struct nfs_server *server, struct pnfs_block_dev *d,
struct pnfs_block_volume *volumes, int idx, gfp_t gfp_mask)
{
switch (volumes[idx].type) {
d->type = volumes[idx].type;
switch (d->type) {
case PNFS_BLOCK_VOLUME_SIMPLE:
return bl_parse_simple(server, d, volumes, idx, gfp_mask);
case PNFS_BLOCK_VOLUME_SLICE:
@ -470,7 +519,7 @@ bl_parse_deviceid(struct nfs_server *server, struct pnfs_block_dev *d,
case PNFS_BLOCK_VOLUME_SCSI:
return bl_parse_scsi(server, d, volumes, idx, gfp_mask);
default:
dprintk("unsupported volume type: %d\n", volumes[idx].type);
dprintk("unsupported volume type: %d\n", d->type);
return -EIO;
}
}