kernel/fs/nfs/file.c, branch linux-rolling-stable

NFS: Fix a deadlock involving nfs_release_folio()

2026-01-23T10:21:13Z

[ Upstream commit cce0be6eb4971456b703aaeafd571650d314bcca ] Wang Zhaolong reports a deadlock involving NFSv4.1 state recovery waiting on kthreadd, which is attempting to reclaim memory by calling nfs_release_folio(). The latter cannot make progress due to state recovery being needed. It seems that the only safe thing to do here is to kick off a writeback of the folio, without waiting for completion, or else kicking off an asynchronous commit. Reported-by: Wang Zhaolong Fixes: 96780ca55e3c ("NFS: fix up nfs_release_folio() to try to release the page") Signed-off-by: Trond Myklebust Signed-off-by: Sasha Levin

NFS: Enable use of the RWF_DONTCACHE flag on the NFS client

2025-09-23T17:29:50Z

The NFS client needs to defer dropbehind until after any writes to the folio have been persisted on the server. Since this may be a 2 step process, use folio_end_writeback_no_dropbehind() to allow release of the writeback flag, and then call folio_end_dropbehind() once the COMMIT is done. Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker

nfs: new tracepoints around write handling

2025-09-23T17:28:19Z

New start and done tracepoints for: nfs_update_folio() nfs_write_begin() nfs_write_end() nfs_try_to_update_request() Signed-off-by: Jeff Layton Reviewed-by: Benjamin Coddington Signed-off-by: Anna Schumaker

nfs: add tracepoints to nfs_file_read() and nfs_file_write()

2025-09-23T17:28:19Z

Add some tracepoints to the I/O submission codepaths. Signed-off-by: Jeff Layton Reviewed-by: Benjamin Coddington Signed-off-by: Anna Schumaker

NFS: nfs_invalidate_folio() must observe the offset and size arguments

2025-09-06T20:51:26Z

If we're truncating part of the folio, then we need to write out the data on the part that is not covered by the cancellation. Fixes: d47992f86b30 ("mm: change invalidatepage prototype to accept length") Signed-off-by: Trond Myklebust

NFS: Protect against 'eof page pollution'

2025-09-06T20:51:25Z

This commit fixes the failing xfstest 'generic/363'. When the user mmaps() an area that extends beyond the end of file, and proceeds to write data into the folio that straddles that eof, we're required to discard that folio data if the user calls some function that extends the file length. Signed-off-by: Trond Myklebust

Merge tag 'vfs-6.17-rc1.mmap_prepare' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs

2025-07-28T20:43:25Z

Pull mmap_prepare updates from Christian Brauner: "Last cycle we introduce f_op->mmap_prepare() in c84bf6dd2b83 ("mm: introduce new .mmap_prepare() file callback"). This is preferred to the existing f_op->mmap() hook as it does require a VMA to be established yet, thus allowing the mmap logic to invoke this hook far, far earlier, prior to inserting a VMA into the virtual address space, or performing any other heavy handed operations. This allows for much simpler unwinding on error, and for there to be a single attempt at merging a VMA rather than having to possibly reattempt a merge based on potentially altered VMA state. Far more importantly, it prevents inappropriate manipulation of incompletely initialised VMA state, which is something that has been the cause of bugs and complexity in the past. The intent is to gradually deprecate f_op->mmap, and in that vein this series coverts the majority of file systems to using f_op->mmap_prepare. Prerequisite steps are taken - firstly ensuring all checks for mmap capabilities use the file_has_valid_mmap_hooks() helper rather than directly checking for f_op->mmap (which is now not a valid check) and secondly updating daxdev_mapping_supported() to not require a VMA parameter to allow ext4 and xfs to be converted. Commit bb666b7c2707 ("mm: add mmap_prepare() compatibility layer for nested file systems") handles the nasty edge-case of nested file systems like overlayfs, which introduces a compatibility shim to allow f_op->mmap_prepare() to be invoked from an f_op->mmap() callback. This allows for nested filesystems to continue to function correctly with all file systems regardless of which callback is used. Once we finally convert all file systems, this shim can be removed. As a result, ecryptfs, fuse, and overlayfs remain unaltered so they can nest all other file systems. We additionally do not update resctl - as this requires an update to remap_pfn_range() (or an alternative to it) which we defer to a later series, equally we do not update cramfs which needs a mixed mapping insertion with the same issue, nor do we update procfs, hugetlbfs, syfs or kernfs all of which require VMAs for internal state and hooks. We shall return to all of these later" * tag 'vfs-6.17-rc1.mmap_prepare' of git://git.kernel.org/pub/scm/linux/kernel/git/vfs/vfs: doc: update porting, vfs documentation to describe mmap_prepare() fs: replace mmap hook with .mmap_prepare for simple mappings fs: convert most other generic_file_*mmap() users to .mmap_prepare() fs: convert simple use of generic_file_*_mmap() to .mmap_prepare() mm/filemap: introduce generic_file_*_mmap_prepare() helpers fs/xfs: transition from deprecated .mmap hook to .mmap_prepare fs/ext4: transition from deprecated .mmap hook to .mmap_prepare fs/dax: make it possible to check dev dax support without a VMA fs: consistently use can_mmap_file() helper mm/nommu: use file_has_valid_mmap_hooks() helper mm: rename call_mmap/mmap_prepare to vfs_mmap/mmap_prepare

fs: change write_begin/write_end interface to take struct kiocb *

2025-07-16T12:48:18Z

Change the address_space_operations callbacks write_begin() and write_end() to take struct kiocb * as the first argument instead of struct file *. Update all affected function prototypes, implementations, call sites, and related documentation across VFS, filesystems, and block layer. Part of a series refactoring address_space_operations write_begin and write_end callbacks to use struct kiocb for passing write context and flags. Signed-off-by: Taotao Chen Link: https://lore.kernel.org/20250716093559.217344-4-chentaotao@didiglobal.com Signed-off-by: Christian Brauner

fs: convert most other generic_file_*mmap() users to .mmap_prepare()

2025-06-19T11:56:57Z

Update nearly all generic_file_mmap() and generic_file_readonly_mmap() callers to use generic_file_mmap_prepare() and generic_file_readonly_mmap_prepare() respectively. We update blkdev, 9p, afs, erofs, ext2, nfs, ntfs3, smb, ubifs and vboxsf file systems this way. Remaining users we cannot yet update are ecryptfs, fuse and cramfs. The former two are nested file systems that must support any underlying file ssytem, and cramfs inserts a mixed mapping which currently requires a VMA. Once all file systems have been converted to mmap_prepare(), we can then update nested file systems. Signed-off-by: Lorenzo Stoakes Link: https://lore.kernel.org/08db85970d89b17a995d2cffae96fb4cc462377f.1750099179.git.lorenzo.stoakes@oracle.com Signed-off-by: Christian Brauner

NFS: fix nfs_release_folio() to not deadlock via kcompactd writeback

2025-03-06T05:36:15Z

Add PF_KCOMPACTD flag and current_is_kcompactd() helper to check for it so nfs_release_folio() can skip calling nfs_wb_folio() from kcompactd. Otherwise NFS can deadlock waiting for kcompactd enduced writeback which recurses back to NFS (which triggers writeback to NFSD via NFS loopback mount on the same host, NFSD blocks waiting for XFS's call to __filemap_get_folio): 6070.550357] INFO: task kcompactd0:58 blocked for more than 4435 seconds. {--- [58] "kcompactd0" [<0>] folio_wait_bit+0xe8/0x200 [<0>] folio_wait_writeback+0x2b/0x80 [<0>] nfs_wb_folio+0x80/0x1b0 [nfs] [<0>] nfs_release_folio+0x68/0x130 [nfs] [<0>] split_huge_page_to_list_to_order+0x362/0x840 [<0>] migrate_pages_batch+0x43d/0xb90 [<0>] migrate_pages_sync+0x9a/0x240 [<0>] migrate_pages+0x93c/0x9f0 [<0>] compact_zone+0x8e2/0x1030 [<0>] compact_node+0xdb/0x120 [<0>] kcompactd+0x121/0x2e0 [<0>] kthread+0xcf/0x100 [<0>] ret_from_fork+0x31/0x40 [<0>] ret_from_fork_asm+0x1a/0x30 ---} [akpm@linux-foundation.org: fix build] Link: https://lkml.kernel.org/r/20250225022002.26141-1-snitzer@kernel.org Fixes: 96780ca55e3c ("NFS: fix up nfs_release_folio() to try to release the page") Signed-off-by: Mike Snitzer Cc: Anna Schumaker Cc: Trond Myklebust Cc: Signed-off-by: Andrew Morton