kernel/git/next/linux-next.git/fs/smb/client, branch fs-current

smb/client: flush dirty data before punching a hole

2026-07-15T02:51:52+00:00

Punching a hole after a large buffered write may leave the range reported as data. Reproduce it with: xfs_io -f \ -c "pwrite -b 3m -S 0x61 0 3m" \ -c "fpunch 1m 1m" \ -c "seek -h 0" \ -c "seek -d 1m" \ /mnt/test/repro Punching 1 MiB at offset 1 MiB should produce: 0 1 MiB 2 MiB 3 MiB | DATA | HOLE | DATA | EOF Instead, the entire file is reported as data. SEEK_HOLE(0) returns EOF, and SEEK_DATA(1M) returns 1M. This happens because a dirty folio spanning the punched range can be written back after the punch and refill the hole. Fix this by flushing and waiting for dirty data in the punched range before invalidating the page cache and issuing FSCTL_SET_ZERO_DATA. The xfstests generic/539 pass against Samba/ksmbd with this change. Signed-off-by: Huiwen He Reviewed-by: ChenXiaoSong Signed-off-by: Steve French

smb/client: Use EXPORT_SYMBOL_IF_KUNIT() to export symbols in SMB2

2026-07-15T02:51:19+00:00

Replace EXPORT_SYMBOL_FOR_MODULES() with EXPORT_SYMBOL_IF_KUNIT() to mark the symbols as visible only if CONFIG_KUNIT is enabled. Kunit test should import the namespace EXPORTED_FOR_KUNIT_TESTING to use these marked symbols. This is the standard way for all KUnit tests. Signed-off-by: Andy Shevchenko Reviewed-by: ChenXiaoSong Signed-off-by: Steve French

smb/client: Use EXPORT_SYMBOL_IF_KUNIT() to export symbols

2026-07-15T02:48:00+00:00

smb: client: reject overlapping data areas in SMB2 responses

2026-07-13T15:37:55+00:00

Commit 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") restricted the implied bcc[0] length exception to responses without a data area. However, the overlap handling in __smb2_calc_size() clears data_length, which can make an invalid response appear to have no data area and so qualify for the exception. Track data area overlap separately and reject such responses before applying the length compatibility exceptions. Fixes: 53b7c271f06b ("smb: client: restrict implied bcc[0] exemption to responses without data area") Cc: stable@vger.kernel.org Signed-off-by: Shoichiro Miyamoto Signed-off-by: Steve French

smb/client: refresh allocation after EOF-extending fallocate

2026-07-13T15:37:55+00:00

Before this change, xfstests generic/496 was not supported on ksmbd: generic/496 ... [not run] fallocated swap not supported here ksmbd handles SetEOF as truncate, so EOF extension alone does not allocate backing blocks. A fallocated swapfile can therefore still look sparse to swapon. Request allocation for EOF-extending fallocate ranges that can be represented by FILE_ALLOCATION_INFORMATION, and refresh the allocation state afterwards. With this change, xfstests generic/496 and generic/701 pass on ksmbd. However, Samba "strict allocate = no" now exposes the real generic/701 failure: the old pass came from inflated local i_blocks, not from server allocation. generic/213 also fails in that case because an oversized allocation request may not return ENOSPC. Signed-off-by: Huiwen He Reviewed-by: ChenXiaoSong Signed-off-by: Steve French

smb/client: emulate small EOF-extending mode 0 fallocate ranges

2026-07-13T15:37:55+00:00

When a mode 0 fallocate extends EOF from 1G to 2G + 1M, the client currently sends SetEOF for 2G + 1M. This can make fallocate return success without allocating the requested range, or allocate extra space before that range. For example, on a fresh file: xfs_io -f \ -c "falloc 0 1G" \ -c "falloc 2G 1M" \ -c "truncate 3G" test The second fallocate should allocate [2G, 2G + 1M), leaving [1G, 2G) as a hole. Before this change, the result depended on the server allocation policy. With Samba "strict allocate = no", SetEOF could return success without allocating [2G, 2G + 1M). With "strict allocate = yes": # filefrag -v test [0, 1G) allocated [1G, 2G) allocated unexpectedly [2G, 2G + 1M) allocated SMB cannot allocate that arbitrary range, so write zeroes to small EOF-extending ranges instead. Limit this to 1 MiB to bound the client-side I/O cost. With "strict allocate = no", the requested range [2G, 2G + 1M) is allocated by the writes. With "strict allocate = yes": # filefrag -v test [0, 1G) allocated [1G, 2G) hole [2G, 2G + 1M) allocated This fixes the small EOF-extending range case exercised by generic/213. Signed-off-by: Huiwen He Reviewed-by: ChenXiaoSong Signed-off-by: Steve French

smb/client: reduce fallocate zero buffer allocation

2026-07-13T15:37:55+00:00

The fallocate emulation allocates a 1 MiB zero-filled buffer even though each SMB2_write request is limited to SMB2_MAX_BUFFER_SIZE, which is 64 KiB. A high-order 1 MiB allocation is more likely to fail on a fragmented system. Allocate only the smaller of the requested range and SMB2_MAX_BUFFER_SIZE, and reuse that zero-filled buffer for every write request. Also reject a successful write that makes no progress to avoid looping indefinitely. This reduces the contiguous allocation required by fallocate emulation without changing the written data or range semantics. Signed-off-by: Huiwen He Reviewed-by: ChenXiaoSong Signed-off-by: Steve French

smb/client: handle overlapping allocated ranges in fallocate

2026-07-13T15:37:54+00:00

smb3_simple_fallocate_range() can skip holes when an allocated range returned by the server starts before the current fallocate offset. The skipped hole is not zero-filled, but fallocate still returns success. A later write to that hole may therefore fail with ENOSPC. The function queries allocated ranges so that it can preserve existing contents and write zeroes only into holes. However, the server may return a range that starts before the current fallocate offset. For example, assume the fallocate request is [100, 400) and the only allocated range returned by the server is [0, 200): Request: [100, 400) Server range: [ 0, 200) allocated Correct: [100, 200) allocated data, skip [200, 400) hole, zero-fill Current: [100, 300) skipped [300, 400) zero-filled afterwards The current code adds the full server range length, 200, to the current offset 100 and moves to 300. As a result, the hole in [200, 300) is skipped without being zero-filled. Fix this by advancing only over the part of the allocated range that overlaps the current fallocate offset. Ignore ranges that end before the current offset and reject ranges whose end offset overflows. This also prevents a malformed range length from causing an out-of-bounds zero-buffer read. Fixes: 966a3cb7c7db ("cifs: improve fallocate emulation") Signed-off-by: Huiwen He Reviewed-by: ChenXiaoSong Signed-off-by: Steve French

smb/client: refresh allocation size after duplicate extents

2026-07-13T15:37:54+00:00

FSCTL_DUPLICATE_EXTENTS_TO_FILE changes the target file extents on the server, but the client does not refresh the target AllocationSize/i_blocks. Callers can observe or use the wrong st_blocks value immediately after the clone, before a later attribute revalidation corrects it. For example, create a reflinked file with a leading hole: xfs_io -f -c "pwrite -S 0x61 0 64k" src touch dst chmod 600 dst xfs_io -c "reflink src 0 1m 64k" dst mkswap dst swapon dst The file still has a hole after mkswap: /mnt/scratch/dst: [0..7]: allocated [8..2047]: hole [2048..2175]: allocated The server also reports only the allocated ranges: server dst size=1114112 blocks=144 but the client reported EOF-derived blocks: client dst size=1114112 blocks=2176 and swapon succeeded: swapon_result=success /mnt/scratch/dst 1.1M 0B -1 So EOF-derived i_blocks can let a sparse reflinked file pass the CIFS swapfile hole check. Fix this by querying FILE_ALL_INFORMATION on the target handle after a successful duplicate extents request. Update i_blocks from AllocationSize and keep the refreshed target inode attributes valid so a following stat does not immediately revalidate again. If the query fails, mark the cached inode attributes stale so a later getattr can refresh them. This also fixes the xfstests generic/370 regression introduced by the i_blocks accounting change, as tested on a Samba "vfs objects = btrfs" share. Fixes: 99cd0a6eeb6c ("smb/client: do not account EOF extension as allocation") Signed-off-by: Huiwen He Reviewed-by: ChenXiaoSong Signed-off-by: Steve French

smb: client: use kvzalloc() for megabyte buffer in simple fallocate

2026-07-13T15:33:56+00:00

Currently in smb3_simple_fallocate_range(), a 1 MB buffer is allocated using kzalloc(). Under heavy memory fragmentation, a contiguous 1 MB block of physical memory (an order-8 allocation) may not be available, causing the allocation to fail. This failure was observed during xfstests generic/013 on a 4GB RAM test machine running fsstress: fsstress: page allocation failure: order:8, mode:0x40dc0(GFP_KERNEL|__GFP_ZERO|__GFP_COMP), nodemask=(null),cpuset=/,mems_allowed=0 Call Trace: dump_stack_lvl+0x5d/0x80 warn_alloc+0x163/0x190 __alloc_pages_slowpath.constprop.0+0x71b/0x12f0 __alloc_frozen_pages_noprof+0x2f6/0x340 alloc_pages_mpol+0xb6/0x170 ___kmalloc_large_node+0xb3/0xd0 __kmalloc_large_noprof+0x1e/0xc0 smb3_simple_falloc.isra.0+0x62b/0x960 cifs_fallocate+0xed/0x180 vfs_fallocate+0x165/0x3c0 __x64_sys_fallocate+0x48/0xa0 do_syscall_64+0xe1/0x640 entry_SYSCALL_64_after_hwframe+0x76/0x7e Node 0 Normal: 3375*4kB ... 7*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB Since this scratch buffer does not require physically contiguous memory, switch the allocation to kvzalloc(). This retains the performance benefits of kmalloc() under normal conditions, while gracefully falling back to virtually contiguous memory when physical allocation fails. Fixes: 966a3cb7c7db ("cifs: improve fallocate emulation") Cc: stable@vger.kernel.org Signed-off-by: Fredric Cover Tested-by: Fredric Cover Signed-off-by: Steve French