There is a regular need in the kernel to provide a way to declare having a dynamically sized set of trailing elements in a structure. Kernel code should always use “flexible array members”[1] for these cases. The older style of one-element or zero-length arrays should no longer be used[2]. Refactor the code according to the use of flexible-array members in multiple structures, instead of one-element arrays. Also, make use of the new struct_size() helper to properly calculate the size of multiple structures that contain flexible-array members. Below are the results of running xfstests for groups shutdown and log with the following configuration in local.config: export TEST_DEV=/dev/sda3 export TEST_DIR=/mnt/test export SCRATCH_DEV=/dev/sda4 export SCRATCH_MNT=/mnt/scratch The size for both partitions /dev/sda3 and /dev/sda4 is 25GB. These are the results of running ./check -g shutdown and ./check -g log, respectively, on 5.11.0-next-20210301 kernel _without_ this patch applied: gustavo@beefy:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-no-patch.out FSTYP -- xfs (debug) PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021 MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4 MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch generic/042 2s ... 2s generic/043 13s ... 13s generic/044 14s ... 14s generic/045 18s ... 18s generic/046 14s ... 14s generic/047 20s ... 22s generic/048 51s ... 50s generic/049 9s ... 8s generic/050 2s ... 1s generic/051 76s ... 75s generic/052 1s ... 2s generic/054 31s ... 30s generic/055 16s ... 21s generic/388 89s ... 75s generic/392 5s ... 5s generic/417 11s ... 11s generic/461 21s ... 22s generic/468 3s ... 3s generic/474 1s ... 1s generic/475 86s ... 93s generic/505 2s ... 2s generic/506 2s ... 2s generic/507 [not run] file system doesn't support chattr +AsSu generic/508 1s ... 1s generic/530 10s ... 10s generic/536 3s ... 2s generic/599 1s ... 1s generic/622 23s ... 24s xfs/051 18s ... 18s xfs/079 15s ... 14s xfs/121 6s ... 16s xfs/181 12s ... 15s xfs/212 1s ... 3s Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212 Not run: generic/507 Passed all 33 tests gustavo@beefy:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-no-patch.out FSTYP -- xfs (debug) PLATFORM -- Linux/x86_64 beefy 5.11.0-next-20210301 #4 SMP Mon Mar 1 05:42:06 CST 2021 MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4 MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch generic/034 1s ... 1s generic/039 1s ... 1s generic/040 5s ... 5s generic/041 7s ... 7s generic/043 13s ... 13s generic/044 14s ... 14s generic/045 18s ... 18s generic/046 14s ... 14s generic/051 76s ... 76s generic/052 1s ... 2s generic/054 30s ... 48s generic/055 23s ... 15s generic/056 1s ... 1s generic/057 1s ... 1s generic/059 2s ... 2s generic/065 1s ... 1s generic/066 1s ... 2s generic/073 1s ... 1s generic/090 1s ... 1s generic/101 1s ... 1s generic/104 1s ... 1s generic/106 1s ... 1s generic/107 1s ... 1s generic/177 1s ... 1s generic/311 67s ... 67s generic/321 2s ... 2s generic/322 1s ... 2s generic/325 1s ... 1s generic/335 1s ... 1s generic/336 2s ... 1s generic/341 1s ... 1s generic/342 1s ... 1s generic/343 1s ... 1s generic/376 1s ... 1s generic/388 75s ... 97s generic/417 15s ... 12s generic/455 [not run] This test requires a valid $LOGWRITES_DEV generic/457 [not run] This test requires a valid $LOGWRITES_DEV generic/475 88s ... 89s generic/479 2s ... 2s generic/480 1s ... 1s generic/481 1s ... 1s generic/483 7s ... 6s generic/489 1s ... 1s generic/498 1s ... 1s generic/501 61s ... 63s generic/502 1s ... 1s generic/509 1s ... 1s generic/510 1s ... 1s generic/512 1s ... 1s generic/520 16s ... 17s generic/526 2s ... 1s generic/527 0s ... 1s generic/534 0s ... 1s generic/535 2s ... 1s generic/546 3s ... 3s generic/547 2s ... 2s generic/552 1s ... 1s generic/557 1s ... 2s generic/588 2s ... 1s shared/002 9s ... 9s xfs/011 18s ... 18s xfs/029 1s ... 1s xfs/051 18s ... 18s xfs/057 23s ... 23s xfs/079 14s ... 14s xfs/095 1s ... 1s xfs/119 3s ... 3s xfs/121 6s ... 6s xfs/141 14s ... 26s xfs/181 14s ... 14s xfs/216 3s ... 2s xfs/217 2s ... 2s xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439 Not run: generic/455 generic/457 xfs/439 Passed all 74 tests These are the results of running ./check -g shutdown and ./check -g log, respectively, on 5.11.0-xfstests-patched-next-20210301+ kernel _with_ this patch applied on top: gustavo@beefy:~/git/xfstests$ time sudo ./check -g shutdown 2>&1 | tee xfs-shutdown-patched.out FSTYP -- xfs (debug) PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021 MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4 MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch generic/042 2s ... 3s generic/043 13s ... 12s generic/044 14s ... 15s generic/045 18s ... 18s generic/046 14s ... 15s generic/047 21s ... 21s generic/048 51s ... 51s generic/049 9s ... 8s generic/050 1s ... 2s generic/051 76s ... 77s generic/052 6s ... 2s generic/054 35s ... 48s generic/055 16s ... 17s generic/388 77s ... 73s generic/392 7s ... 5s generic/417 13s ... 11s generic/461 22s ... 21s generic/468 2s ... 3s generic/474 2s ... 1s generic/475 90s ... 96s generic/505 3s ... 3s generic/506 1s ... 2s generic/507 [not run] file system doesn't support chattr +AsSu generic/508 2s ... 10s generic/530 9s ... 13s generic/536 2s ... 1s generic/599 1s ... 1s generic/622 24s ... 25s xfs/051 18s ... 18s xfs/079 14s ... 13s xfs/121 6s ... 8s xfs/181 11s ... 14s xfs/212 2s ... 1s Ran: generic/042 generic/043 generic/044 generic/045 generic/046 generic/047 generic/048 generic/049 generic/050 generic/051 generic/052 generic/054 generic/055 generic/388 generic/392 generic/417 generic/461 generic/468 generic/474 generic/475 generic/505 generic/506 generic/507 generic/508 generic/530 generic/536 generic/599 generic/622 xfs/051 xfs/079 xfs/121 xfs/181 xfs/212 Not run: generic/507 Passed all 33 tests gustavo@beefy:~/git/xfstests$ time sudo ./check -g log 2>&1 | tee xfs-log-patched.out FSTYP -- xfs (debug) PLATFORM -- Linux/x86_64 beefy 5.11.0-xfstests-patched-next-20210301+ #10 SMP Mon Mar 1 17:36:20 CST 2021 MKFS_OPTIONS -- -f -bsize=4096 /dev/sda4 MOUNT_OPTIONS -- /dev/sda4 /mnt/scratch generic/034 1s ... 1s generic/039 1s ... 1s generic/040 5s ... 5s generic/041 7s ... 7s generic/043 12s ... 13s generic/044 15s ... 15s generic/045 18s ... 18s generic/046 15s ... 14s generic/051 77s ... 76s generic/052 2s ... 1s generic/054 48s ... 29s generic/055 17s ... 16s generic/056 1s ... 1s generic/057 1s ... 1s generic/059 2s ... 2s generic/065 1s ... 1s generic/066 1s ... 1s generic/073 1s ... 1s generic/090 1s ... 1s generic/101 1s ... 1s generic/104 1s ... 1s generic/106 1s ... 1s generic/107 1s ... 1s generic/177 1s ... 1s generic/311 68s ... 68s generic/321 2s ... 2s generic/322 1s ... 1s generic/325 2s ... 1s generic/335 1s ... 1s generic/336 1s ... 1s generic/341 1s ... 1s generic/342 1s ... 1s generic/343 1s ... 1s generic/376 1s ... 1s generic/388 73s ... 83s generic/417 11s ... 11s generic/455 [not run] This test requires a valid $LOGWRITES_DEV generic/457 [not run] This test requires a valid $LOGWRITES_DEV generic/475 96s ... 83s generic/479 2s generic/480 2s ... 1s generic/481 0s ... 1s generic/483 7s ... 7s generic/489 1s ... 1s generic/498 1s ... 1s generic/501 63s ... 61s generic/502 1s ... 1s generic/509 1s ... 1s generic/510 1s ... 1s generic/512 1s ... 1s generic/520 16s ... 16s generic/526 1s ... 1s generic/527 1s ... 1s generic/534 1s ... 1s generic/535 1s ... 1s generic/546 4s ... 4s generic/547 2s ... 2s generic/552 1s ... 1s generic/557 1s ... 1s generic/588 2s ... 1s shared/002 8s ... 9s xfs/011 18s ... 18s xfs/029 1s ... 1s xfs/051 18s ... 18s xfs/057 23s ... 24s xfs/079 13s ... 14s xfs/095 2s ... 1s xfs/119 3s ... 3s xfs/121 8s ... 6s xfs/141 18s ... 12s xfs/181 14s ... 12s xfs/216 3s ... 2s xfs/217 2s ... 2s xfs/439 [not run] test requires XFS bug_on_assert to be off, turn it off to run the test Ran: generic/034 generic/039 generic/040 generic/041 generic/043 generic/044 generic/045 generic/046 generic/051 generic/052 generic/054 generic/055 generic/056 generic/057 generic/059 generic/065 generic/066 generic/073 generic/090 generic/101 generic/104 generic/106 generic/107 generic/177 generic/311 generic/321 generic/322 generic/325 generic/335 generic/336 generic/341 generic/342 generic/343 generic/376 generic/388 generic/417 generic/455 generic/457 generic/475 generic/479 generic/480 generic/481 generic/483 generic/489 generic/498 generic/501 generic/502 generic/509 generic/510 generic/512 generic/520 generic/526 generic/527 generic/534 generic/535 generic/546 generic/547 generic/552 generic/557 generic/588 shared/002 xfs/011 xfs/029 xfs/051 xfs/057 xfs/079 xfs/095 xfs/119 xfs/121 xfs/141 xfs/181 xfs/216 xfs/217 xfs/439 Not run: generic/455 generic/457 xfs/439 Passed all 74 tests Notice that the test results before and after this patch is applied are identical and successful. Other tests might need to be run in order to verify everything is working as expected. For such tests, the intervention of the maintainers might be needed. [1] https://en.wikipedia.org/wiki/Flexible_array_member [2] https://www.kernel.org/doc/html/v5.9/process/deprecated.html#zero-length-and-one-element-arrays Link: https://github.com/KSPP/linux/issues/79 Build-tested-by: kernel test robot <lkp@xxxxxxxxx> Link: https://lore.kernel.org/lkml/603e3177.WsvTXRpcLn5wdYW6%25lkp@xxxxxxxxx/ Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx> --- fs/xfs/libxfs/xfs_log_format.h | 12 +++++------ fs/xfs/xfs_extfree_item.c | 39 +++++++++++++++------------------- fs/xfs/xfs_ondisk.h | 8 +++---- 3 files changed, 27 insertions(+), 32 deletions(-) diff --git a/fs/xfs/libxfs/xfs_log_format.h b/fs/xfs/libxfs/xfs_log_format.h index 8bd00da6d2a4..9934a465b441 100644 --- a/fs/xfs/libxfs/xfs_log_format.h +++ b/fs/xfs/libxfs/xfs_log_format.h @@ -574,7 +574,7 @@ typedef struct xfs_efi_log_format { uint16_t efi_size; /* size of this item */ uint32_t efi_nextents; /* # extents to free */ uint64_t efi_id; /* efi identifier */ - xfs_extent_t efi_extents[1]; /* array of extents to free */ + xfs_extent_t efi_extents[]; /* array of extents to free */ } xfs_efi_log_format_t; typedef struct xfs_efi_log_format_32 { @@ -582,7 +582,7 @@ typedef struct xfs_efi_log_format_32 { uint16_t efi_size; /* size of this item */ uint32_t efi_nextents; /* # extents to free */ uint64_t efi_id; /* efi identifier */ - xfs_extent_32_t efi_extents[1]; /* array of extents to free */ + xfs_extent_32_t efi_extents[]; /* array of extents to free */ } __attribute__((packed)) xfs_efi_log_format_32_t; typedef struct xfs_efi_log_format_64 { @@ -590,7 +590,7 @@ typedef struct xfs_efi_log_format_64 { uint16_t efi_size; /* size of this item */ uint32_t efi_nextents; /* # extents to free */ uint64_t efi_id; /* efi identifier */ - xfs_extent_64_t efi_extents[1]; /* array of extents to free */ + xfs_extent_64_t efi_extents[]; /* array of extents to free */ } xfs_efi_log_format_64_t; /* @@ -603,7 +603,7 @@ typedef struct xfs_efd_log_format { uint16_t efd_size; /* size of this item */ uint32_t efd_nextents; /* # of extents freed */ uint64_t efd_efi_id; /* id of corresponding efi */ - xfs_extent_t efd_extents[1]; /* array of extents freed */ + xfs_extent_t efd_extents[]; /* array of extents freed */ } xfs_efd_log_format_t; typedef struct xfs_efd_log_format_32 { @@ -611,7 +611,7 @@ typedef struct xfs_efd_log_format_32 { uint16_t efd_size; /* size of this item */ uint32_t efd_nextents; /* # of extents freed */ uint64_t efd_efi_id; /* id of corresponding efi */ - xfs_extent_32_t efd_extents[1]; /* array of extents freed */ + xfs_extent_32_t efd_extents[]; /* array of extents freed */ } __attribute__((packed)) xfs_efd_log_format_32_t; typedef struct xfs_efd_log_format_64 { @@ -619,7 +619,7 @@ typedef struct xfs_efd_log_format_64 { uint16_t efd_size; /* size of this item */ uint32_t efd_nextents; /* # of extents freed */ uint64_t efd_efi_id; /* id of corresponding efi */ - xfs_extent_64_t efd_extents[1]; /* array of extents freed */ + xfs_extent_64_t efd_extents[]; /* array of extents freed */ } xfs_efd_log_format_64_t; /* diff --git a/fs/xfs/xfs_extfree_item.c b/fs/xfs/xfs_extfree_item.c index 93223ebb3372..5ed3ea93071c 100644 --- a/fs/xfs/xfs_extfree_item.c +++ b/fs/xfs/xfs_extfree_item.c @@ -73,8 +73,8 @@ static inline int xfs_efi_item_sizeof( struct xfs_efi_log_item *efip) { - return sizeof(struct xfs_efi_log_format) + - (efip->efi_format.efi_nextents - 1) * sizeof(xfs_extent_t); + return struct_size(&efip->efi_format, efi_extents, + efip->efi_format.efi_nextents); } STATIC void @@ -153,17 +153,14 @@ xfs_efi_init( { struct xfs_efi_log_item *efip; - uint size; ASSERT(nextents > 0); - if (nextents > XFS_EFI_MAX_FAST_EXTENTS) { - size = (uint)(sizeof(struct xfs_efi_log_item) + - ((nextents - 1) * sizeof(xfs_extent_t))); - efip = kmem_zalloc(size, 0); - } else { + if (nextents > XFS_EFI_MAX_FAST_EXTENTS) + efip = kmem_zalloc(struct_size(efip, efi_format.efi_extents, + nextents), 0); + else efip = kmem_cache_zalloc(xfs_efi_zone, GFP_KERNEL | __GFP_NOFAIL); - } xfs_log_item_init(mp, &efip->efi_item, XFS_LI_EFI, &xfs_efi_item_ops); efip->efi_format.efi_nextents = nextents; @@ -186,12 +183,12 @@ xfs_efi_copy_format(xfs_log_iovec_t *buf, xfs_efi_log_format_t *dst_efi_fmt) { xfs_efi_log_format_t *src_efi_fmt = buf->i_addr; uint i; - uint len = sizeof(xfs_efi_log_format_t) + - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_t); + size_t len = struct_size(src_efi_fmt, efi_extents, + src_efi_fmt->efi_nextents); uint len32 = sizeof(xfs_efi_log_format_32_t) + - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_32_t); + src_efi_fmt->efi_nextents * sizeof(xfs_extent_32_t); uint len64 = sizeof(xfs_efi_log_format_64_t) + - (src_efi_fmt->efi_nextents - 1) * sizeof(xfs_extent_64_t); + src_efi_fmt->efi_nextents * sizeof(xfs_extent_64_t); if (buf->i_len == len) { memcpy((char *)dst_efi_fmt, (char*)src_efi_fmt, len); @@ -254,7 +251,7 @@ xfs_efd_item_sizeof( struct xfs_efd_log_item *efdp) { return sizeof(xfs_efd_log_format_t) + - (efdp->efd_format.efd_nextents - 1) * sizeof(xfs_extent_t); + efdp->efd_format.efd_nextents * sizeof(xfs_extent_t); } STATIC void @@ -328,14 +325,12 @@ xfs_trans_get_efd( ASSERT(nextents > 0); - if (nextents > XFS_EFD_MAX_FAST_EXTENTS) { - efdp = kmem_zalloc(sizeof(struct xfs_efd_log_item) + - (nextents - 1) * sizeof(struct xfs_extent), - 0); - } else { + if (nextents > XFS_EFD_MAX_FAST_EXTENTS) + efdp = kmem_zalloc(struct_size(efip, efi_format.efi_extents, + nextents), 0); + else efdp = kmem_cache_zalloc(xfs_efd_zone, GFP_KERNEL | __GFP_NOFAIL); - } xfs_log_item_init(tp->t_mountp, &efdp->efd_item, XFS_LI_EFD, &xfs_efd_item_ops); @@ -747,9 +742,9 @@ xlog_recover_efd_commit_pass2( efd_formatp = item->ri_buf[0].i_addr; ASSERT((item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_32_t) + - ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_32_t)))) || + (efd_formatp->efd_nextents * sizeof(xfs_extent_32_t)))) || (item->ri_buf[0].i_len == (sizeof(xfs_efd_log_format_64_t) + - ((efd_formatp->efd_nextents - 1) * sizeof(xfs_extent_64_t))))); + (efd_formatp->efd_nextents * sizeof(xfs_extent_64_t))))); xlog_recover_release_intent(log, XFS_LI_EFI, efd_formatp->efd_efi_id); return 0; diff --git a/fs/xfs/xfs_ondisk.h b/fs/xfs/xfs_ondisk.h index 0aa87c210104..f58e0510385a 100644 --- a/fs/xfs/xfs_ondisk.h +++ b/fs/xfs/xfs_ondisk.h @@ -118,10 +118,10 @@ xfs_check_ondisk_structs(void) /* log structures */ XFS_CHECK_STRUCT_SIZE(struct xfs_buf_log_format, 88); XFS_CHECK_STRUCT_SIZE(struct xfs_dq_logformat, 24); - XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 28); - XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 32); - XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 28); - XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 32); + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_32, 16); + XFS_CHECK_STRUCT_SIZE(struct xfs_efd_log_format_64, 16); + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_32, 16); + XFS_CHECK_STRUCT_SIZE(struct xfs_efi_log_format_64, 16); XFS_CHECK_STRUCT_SIZE(struct xfs_extent_32, 12); XFS_CHECK_STRUCT_SIZE(struct xfs_extent_64, 16); XFS_CHECK_STRUCT_SIZE(struct xfs_log_dinode, 176); -- 2.27.0
