Commit 2454dfea authored by Trond Myklebust's avatar Trond Myklebust
Browse files

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: ab7d763e ("pNFS: Ensure nfs4_layoutget_prepare returns...")
Signed-off-by: default avatarTrond Myklebust <trond.myklebust@primarydata.com>
parent d07fbb8f

fs/nfs/pnfs.c

+22 −2
Original line number Diff line number Diff line
@@ -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);

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