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pNFS: Prevent the layout header refcount going to zero in pnfs_roc()

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Ensure that we hold a reference to the layout header when processing
the pNFS return-on-close so that the refcount value does not inadvertently
go to zero.

Reported-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Cc: stable@vger.kernel.org # v4.10+
Tested-by: Tigran Mkrtchyan <tigran.mkrtchyan@desy.de>
This commit is contained in:
Trond Myklebust 2018-03-07 14:49:06 -05:00
parent d9ee65539d
commit 9c6376ebdd
1 changed files with 10 additions and 3 deletions
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13
fs/nfs/pnfs.c
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@ -292,8 +292,11 @@ pnfs_detach_layout_hdr(struct pnfs_layout_hdr *lo)
void void
pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo) pnfs_put_layout_hdr(struct pnfs_layout_hdr *lo)
{ {
struct inode *inode = lo->plh_inode; struct inode *inode;
if (!lo)
return;
inode = lo->plh_inode;
pnfs_layoutreturn_before_put_layout_hdr(lo); pnfs_layoutreturn_before_put_layout_hdr(lo);
if (refcount_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) { if (refcount_dec_and_lock(&lo->plh_refcount, &inode->i_lock)) {
@ -1241,10 +1244,12 @@ bool pnfs_roc(struct inode *ino,
spin_lock(&ino->i_lock); spin_lock(&ino->i_lock);
lo = nfsi->layout; lo = nfsi->layout;
if (!lo || !pnfs_layout_is_valid(lo) || if (!lo || !pnfs_layout_is_valid(lo) ||
test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) test_bit(NFS_LAYOUT_BULK_RECALL, &lo->plh_flags)) {
lo = NULL;
goto out_noroc; goto out_noroc;
}
pnfs_get_layout_hdr(lo);
if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) { if (test_bit(NFS_LAYOUT_RETURN_LOCK, &lo->plh_flags)) {
pnfs_get_layout_hdr(lo);
spin_unlock(&ino->i_lock); spin_unlock(&ino->i_lock);
wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN, wait_on_bit(&lo->plh_flags, NFS_LAYOUT_RETURN,
TASK_UNINTERRUPTIBLE); TASK_UNINTERRUPTIBLE);
@ -1312,10 +1317,12 @@ bool pnfs_roc(struct inode *ino,
struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld; struct pnfs_layoutdriver_type *ld = NFS_SERVER(ino)->pnfs_curr_ld;
if (ld->prepare_layoutreturn) if (ld->prepare_layoutreturn)
ld->prepare_layoutreturn(args); ld->prepare_layoutreturn(args);
pnfs_put_layout_hdr(lo);
return true; return true;
} }
if (layoutreturn) if (layoutreturn)
pnfs_send_layoutreturn(lo, &stateid, iomode, true); pnfs_send_layoutreturn(lo, &stateid, iomode, true);
pnfs_put_layout_hdr(lo);
return false; return false;
} }