diff options
| author | Brian Behlendorf <[email protected]> | 2014-12-19 12:57:54 -0800 |
|---|---|---|
| committer | Brian Behlendorf <[email protected]> | 2014-12-22 09:31:56 -0800 |
| commit | 74328ee18f94d27f9c802d29fdd311018dab2adf (patch) | |
| tree | e1c45efc24bf65c579832175d193d5c4c18df2d8 /module/zfs | |
| parent | 2d9d57b0fbe17b56a1bdd09505400144778cb189 (diff) | |
Fix zfs_putpage() lock inversion
There exists a lock inversions involving the zfs range lock and the
individual page writeback bits which can result in a deadlock. To
prevent this we must always manipulate the writeback bit while
holding the range lock. The exact deadlock is as follows:
------ Process A ------ ------ Process B ------
zpl_writepages zpl_fallocate
write_cache_pages zpl_fallocate_common
zpl_putpage zfs_space
zfs_putpage (set bit) zfs_freesp
zfs_range_lock (wait on lock) zfs_free_range (take lock)
[has not yet initiated I/O, truncate_inode_pages_range
the bit will not be cleared] wait_on_page_writeback (wait on bit)
Signed-off-by: Brian Behlendorf <[email protected]>
Signed-off-by: Tim Chase <[email protected]>
Signed-off-by: Richard Yao <[email protected]>
Issue #2976
Diffstat (limited to 'module/zfs')
| -rw-r--r-- | module/zfs/zfs_vnops.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/module/zfs/zfs_vnops.c b/module/zfs/zfs_vnops.c index d05ccef39..a048aeb36 100644 --- a/module/zfs/zfs_vnops.c +++ b/module/zfs/zfs_vnops.c @@ -3899,14 +3899,13 @@ zfs_putpage(struct inode *ip, struct page *pp, struct writeback_control *wbc) } #endif + rl = zfs_range_lock(zp, pgoff, pglen, RL_WRITER); + set_page_writeback(pp); unlock_page(pp); - rl = zfs_range_lock(zp, pgoff, pglen, RL_WRITER); tx = dmu_tx_create(zsb->z_os); - dmu_tx_hold_write(tx, zp->z_id, pgoff, pglen); - dmu_tx_hold_sa(tx, zp->z_sa_hdl, B_FALSE); zfs_sa_upgrade_txholds(tx, zp); err = dmu_tx_assign(tx, TXG_NOWAIT); |