kernel/linux.git/fs/nfs/callback_proc.c, branch v7.2-rc2

NFSv4/pnfs: defer return_range callbacks until after inode unlock

2026-06-08T14:21:56+00:00

Sometimes unmounting an NFS filesystem mounted with pNFS SCSI layouts triggers the following warning: BUG: scheduling while atomic: umount.nfs4/... __schedule_bug+0xbd/0x100 schedule_debug.constprop.0+0x19f/0x220 __schedule+0x10d/0x10a0 schedule+0x74/0x190 schedule_timeout+0xf5/0x220 io_schedule_timeout+0xd5/0x160 __wait_for_common+0x186/0x4b0 blk_execute_rq+0x2ef/0x3a0 scsi_execute_cmd+0x1ff/0x700 sd_pr_out_command.isra.0+0x242/0x380 [sd_mod] bl_unregister_scsi.constprop.0+0x109/0x3c0 [blocklayoutdriver] bl_unregister_dev+0x175/0x1c0 [blocklayoutdriver] bl_free_device+0x1f/0x1b0 [blocklayoutdriver] bl_free_deviceid_node+0x12/0x30 [blocklayoutdriver] nfs4_put_deviceid_node+0x171/0x360 [nfsv4] ext_tree_remove+0x11c/0x1d0 [blocklayoutdriver] _pnfs_return_layout+0x416/0x900 [nfsv4] nfs4_evict_inode+0x108/0x130 [nfsv4] evict+0x316/0x750 dispose_list+0xf1/0x1a0 evict_inodes+0x33f/0x440 generic_shutdown_super+0xc9/0x4e0 kill_anon_super+0x3a/0x90 nfs_kill_super+0x44/0x60 [nfs] deactivate_locked_super+0xb8/0x1b0 cleanup_mnt+0x25a/0x380 task_work_run+0x13e/0x210 exit_to_user_mode_loop+0x169/0x400 do_syscall_64+0x467/0x1550 entry_SYSCALL_64_after_hwframe+0x76/0x7e The warning occurs because the block layout driver unregisters the SCSI device while the inode lock is still held. Device unregistration issues a SCSI PR command, which may sleep, resulting in a "scheduling while atomic" warning. During layout return, ext_tree_remove() invokes the layout driver's return_range callback while holding the inode lock. For block layouts, this callback eventually calls bl_unregister_scsi(), which may block in scsi_execute_cmd() while issuing PR commands to the device. Fix this by deferring the return_range callbacks until after the inode lock has been released. The layout header reference count is incremented before invoking return_range(), ensuring that the layout header remains valid while the layout driver removes extents from the extent tree. Fixes: c88953d87f5c8 ("pnfs: add return_range method") Signed-off-by: Dai Ngo Signed-off-by: Anna Schumaker

Convert 'alloc_obj' family to use the new default GFP_KERNEL argument

2026-02-22T01:09:51+00:00

This was done entirely with mindless brute force, using git grep -l '\

treewide: Replace kmalloc with kmalloc_obj for non-scalar types

2026-02-21T09:02:28+00:00

This is the result of running the Coccinelle script from scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to avoid scalar types (which need careful case-by-case checking), and instead replace kmalloc-family calls that allocate struct or union object instances: Single allocations: kmalloc(sizeof(TYPE), ...) are replaced with: kmalloc_obj(TYPE, ...) Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...) are replaced with: kmalloc_objs(TYPE, COUNT, ...) Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...) are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...) (where TYPE may also be *VAR) The resulting allocations no longer return "void *", instead returning "TYPE *". Signed-off-by: Kees Cook

NFS: Merge CONFIG_NFS_V4_1 with CONFIG_NFS_V4

2026-01-30T16:42:21+00:00

Compiling the NFSv4 module without any minorversion support doesn't make much sense, so this patch sets NFS v4.1 as the default, always enabled NFS version allowing us to replace all the CONFIG_NFS_V4_1s scattered throughout the code with CONFIG_NFS_V4. Signed-off-by: Anna Schumaker

NFS: take a delegation reference in nfs4_get_valid_delegation

2026-01-20T19:49:46+00:00

Currently most work on struct nfs_delegation happens directly under RCU protection. This is generally fine, despite that long RCU sections are not good for performance. But for operations later taking a reference to the delegation to perform blocking work, refcount_inc is used, which can be racy against dropping the last reference and thus lead to use after frees in extremely rare cases. Fix this by taking a reference in nfs4_get_valid_delegation using refcount_inc_not_zero so that the callers have a stabilized reference they can work with and can be moved outside the RCU critical section. Signed-off-by: Christoph Hellwig Signed-off-by: Anna Schumaker

NFS: CB_OFFLOAD can return NFS4ERR_DELAY

2025-01-21T16:34:50+00:00

RFC 7862 permits the callback service to respond to a CB_OFFLOAD operation with NFS4ERR_DELAY. Use that instead of NFS4ERR_SERVERFAULT for temporary memory allocation failure, as that is more consistent with how other operations report memory allocation failure. Reviewed-by: Jeff Layton Signed-off-by: Chuck Lever Reviewed-by: Benjamin Coddington Signed-off-by: Anna Schumaker

pNFS: Add a flag argument to pnfs_destroy_layouts_byclid()

2024-07-08T17:47:26+00:00

Change the bool argument to a flag so that we can add different modes for doing bulk destroy of a layout. In particular, we will want the ability to schedule return of all the layouts associated with a given NFS server when it reboots. Signed-off-by: Trond Myklebust Reviewed-by: Jeff Layton Signed-off-by: Anna Schumaker

NFSv4: Add CB_GETATTR support for delegated attributes

2024-07-08T17:47:25+00:00

When the client holds an attribute delegation, the server may retrieve all the timestamps through a CB_GETATTR callback. Signed-off-by: Trond Myklebust Signed-off-by: Lance Shelton Reviewed-by: Jeff Layton Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker

NFSv4.1: if referring calls are complete, trust the stateid argument

2024-01-04T15:47:56+00:00

If the server is recalling a layout, and sends us a list of referring calls that we can see are complete, then we should just trust that the stateid argument is correct, even if the sequence id doesn't match the one we hold. Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker

NFSv4: Track the number of referring calls in struct cb_process_state

2024-01-04T15:47:56+00:00

When the server gives us a set of referring calls, to tell us that the NFSv4.1 callback needs to be ordered with respect to those calls, then we may want to make that information available to the operations. In certain cases, it may allow them to optimise their behaviour due to the extra knowledge. Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker