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path: root/fs/iomap/swapfile.c
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2025-07-14iomap: header dietChristoph Hellwig
Drop various unused #include statements. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/20250710133343.399917-2-hch@lst.de Reviewed-by: Joanne Koong <joannelkoong@gmail.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-26iomap: introduce a full map advance helperBrian Foster
Various iomap_iter_advance() calls advance by the full mapping length and thus have no need for the current length input or post-advance remaining length output from the standard advance function. Add an iomap_iter_advance_full() helper to clean up these cases. Signed-off-by: Brian Foster <bfoster@redhat.com> Link: https://lore.kernel.org/r/20250224144757.237706-13-bfoster@redhat.com Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-26iomap: rename iomap_iter processed field to statusBrian Foster
The iter.processed field name is no longer appropriate now that iomap operations do not return the number of bytes processed. Rename the field to iter.status to reflect that a success or error code is expected. Also change the type to int as there is no longer a need for an s64. This reduces the size of iomap_iter by 8 bytes due to a combination of smaller type and reduction in structure padding. While here, fix up the return types of various _iter() helpers to reflect the type change. Signed-off-by: Brian Foster <bfoster@redhat.com> Link: https://lore.kernel.org/r/20250224144757.237706-12-bfoster@redhat.com Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-02-26iomap: convert misc simple ops to incremental advanceBrian Foster
Update several of the remaining iomap operations to advance the iter directly rather than via return value. This includes page faults, fiemap, seek data/hole and swapfile activation. Signed-off-by: Brian Foster <bfoster@redhat.com> Link: https://lore.kernel.org/r/20250224144757.237706-4-bfoster@redhat.com Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Christian Brauner <brauner@kernel.org>
2025-01-25mm, swap: clean up device availability checkKairui Song
Remove highest_bit and lowest_bit. After the HDD allocation path has been removed, the only purpose of these two fields is to determine whether the device is full or not, which can instead be determined by checking the inuse_pages. Link: https://lkml.kernel.org/r/20250113175732.48099-6-ryncsn@gmail.com Signed-off-by: Kairui Song <kasong@tencent.com> Reviewed-by: Baoquan He <bhe@redhat.com> Cc: Barry Song <v-songbaohua@oppo.com> Cc: Chis Li <chrisl@kernel.org> Cc: "Huang, Ying" <ying.huang@linux.alibaba.com> Cc: Hugh Dickens <hughd@google.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Kalesh Singh <kaleshsingh@google.com> Cc: Nhat Pham <nphamcs@gmail.com> Cc: Ryan Roberts <ryan.roberts@arm.com> Cc: Yosry Ahmed <yosryahmed@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2021-08-18mm/swap: consider max pages in iomap_swapfile_add_extentXu Yu
When the max pages (last_page in the swap header + 1) is smaller than the total pages (inode size) of the swapfile, iomap_swapfile_activate overwrites sis->max with total pages. However, frontswap_map is a swap page state bitmap allocated using the initial sis->max page count read from the swap header. If swapfile activation increases sis->max, it's possible for the frontswap code to walk off the end of the bitmap, thereby corrupting kernel memory. [djwong: modify the description a bit; the original paragraph reads: "However, frontswap_map is allocated using max pages. When test and clear the sis offset, which is larger than max pages, of frontswap_map in __frontswap_invalidate_page(), neighbors of frontswap_map may be overwritten, i.e., slab is polluted." Note also that this bug resulted in a behavioral change: activating a swap file that was formatted and later extended results in all pages being activated, not the number of pages recorded in the swap header.] This fixes the issue by considering the limitation of max pages of swap info in iomap_swapfile_add_extent(). To reproduce the case, compile kernel with slub RED ZONE, then run test: $ sudo stress-ng -a 1 -x softlockup,resources -t 72h --metrics --times \ --verify -v -Y /root/tmpdir/stress-ng/stress-statistic-12.yaml \ --log-file /root/tmpdir/stress-ng/stress-logfile-12.txt \ --temp-path /root/tmpdir/stress-ng/ We'll get the error log as below: [ 1151.015141] ============================================================================= [ 1151.016489] BUG kmalloc-16 (Not tainted): Right Redzone overwritten [ 1151.017486] ----------------------------------------------------------------------------- [ 1151.017486] [ 1151.018997] Disabling lock debugging due to kernel taint [ 1151.019873] INFO: 0x0000000084e43932-0x0000000098d17cae @offset=7392. First byte 0x0 instead of 0xcc [ 1151.021303] INFO: Allocated in __do_sys_swapon+0xcf6/0x1170 age=43417 cpu=9 pid=3816 [ 1151.022538] __slab_alloc+0xe/0x20 [ 1151.023069] __kmalloc_node+0xfd/0x4b0 [ 1151.023704] __do_sys_swapon+0xcf6/0x1170 [ 1151.024346] do_syscall_64+0x33/0x40 [ 1151.024925] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1151.025749] INFO: Freed in put_cred_rcu+0xa1/0xc0 age=43424 cpu=3 pid=2041 [ 1151.026889] kfree+0x276/0x2b0 [ 1151.027405] put_cred_rcu+0xa1/0xc0 [ 1151.027949] rcu_do_batch+0x17d/0x410 [ 1151.028566] rcu_core+0x14e/0x2b0 [ 1151.029084] __do_softirq+0x101/0x29e [ 1151.029645] asm_call_irq_on_stack+0x12/0x20 [ 1151.030381] do_softirq_own_stack+0x37/0x40 [ 1151.031037] do_softirq.part.15+0x2b/0x30 [ 1151.031710] __local_bh_enable_ip+0x4b/0x50 [ 1151.032412] copy_fpstate_to_sigframe+0x111/0x360 [ 1151.033197] __setup_rt_frame+0xce/0x480 [ 1151.033809] arch_do_signal+0x1a3/0x250 [ 1151.034463] exit_to_user_mode_prepare+0xcf/0x110 [ 1151.035242] syscall_exit_to_user_mode+0x27/0x190 [ 1151.035970] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1151.036795] INFO: Slab 0x000000003b9de4dc objects=44 used=9 fp=0x00000000539e349e flags=0xfffffc0010201 [ 1151.038323] INFO: Object 0x000000004855ba01 @offset=7376 fp=0x0000000000000000 [ 1151.038323] [ 1151.039683] Redzone 000000008d0afd3d: cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc cc ................ [ 1151.041180] Object 000000004855ba01: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ [ 1151.042714] Redzone 0000000084e43932: 00 00 00 c0 cc cc cc cc ........ [ 1151.044120] Padding 000000000864c042: 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a 5a ZZZZZZZZZZZZZZZZ [ 1151.045615] CPU: 5 PID: 3816 Comm: stress-ng Tainted: G B 5.10.50+ #7 [ 1151.046846] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014 [ 1151.048633] Call Trace: [ 1151.049072] dump_stack+0x57/0x6a [ 1151.049585] check_bytes_and_report+0xed/0x110 [ 1151.050320] check_object+0x1eb/0x290 [ 1151.050924] ? __x64_sys_swapoff+0x39a/0x540 [ 1151.051646] free_debug_processing+0x151/0x350 [ 1151.052333] __slab_free+0x21a/0x3a0 [ 1151.052938] ? _cond_resched+0x2d/0x40 [ 1151.053529] ? __vunmap+0x1de/0x220 [ 1151.054139] ? __x64_sys_swapoff+0x39a/0x540 [ 1151.054796] ? kfree+0x276/0x2b0 [ 1151.055307] kfree+0x276/0x2b0 [ 1151.055832] __x64_sys_swapoff+0x39a/0x540 [ 1151.056466] do_syscall_64+0x33/0x40 [ 1151.057084] entry_SYSCALL_64_after_hwframe+0x44/0xa9 [ 1151.057866] RIP: 0033:0x150340b0ffb7 [ 1151.058481] Code: Unable to access opcode bytes at RIP 0x150340b0ff8d. [ 1151.059537] RSP: 002b:00007fff7f4ee238 EFLAGS: 00000246 ORIG_RAX: 00000000000000a8 [ 1151.060768] RAX: ffffffffffffffda RBX: 00007fff7f4ee66c RCX: 0000150340b0ffb7 [ 1151.061904] RDX: 000000000000000a RSI: 0000000000018094 RDI: 00007fff7f4ee860 [ 1151.063033] RBP: 00007fff7f4ef980 R08: 0000000000000000 R09: 0000150340a672bd [ 1151.064135] R10: 00007fff7f4edca0 R11: 0000000000000246 R12: 0000000000018094 [ 1151.065253] R13: 0000000000000005 R14: 000000000160d930 R15: 00007fff7f4ee66c [ 1151.066413] FIX kmalloc-16: Restoring 0x0000000084e43932-0x0000000098d17cae=0xcc [ 1151.066413] [ 1151.067890] FIX kmalloc-16: Object at 0x000000004855ba01 not freed Fixes: 67482129cdab ("iomap: add a swapfile activation function") Fixes: a45c0eccc564 ("iomap: move the swapfile code into a separate file") Signed-off-by: Gang Deng <gavin.dg@linux.alibaba.com> Signed-off-by: Xu Yu <xuyu@linux.alibaba.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-08-16iomap: switch iomap_swapfile_activate to use iomap_iterChristoph Hellwig
Switch iomap_swapfile_activate to use iomap_iter. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-03-26iomap: improve the warnings from iomap_swapfile_activateChristoph Hellwig
Print the path name of the swapfile that failed to active to ease debugging the problem and to avoid a scare if xfstests hits these cases. Also reword one warning a bit, as the error is not about a file being on multiple devices, but one that has at least an extent outside the main device known to the VFS and swap code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-03-09iomap: Fix negative assignment to unsigned sis->pages in iomap_swapfile_activateRitesh Harjani
In case if isi.nr_pages is 0, we are making sis->pages (which is unsigned int) a huge value in iomap_swapfile_activate() by assigning -1. This could cause a kernel crash in kernel v4.18 (with below signature). Or could lead to unknown issues on latest kernel if the fake big swap gets used. Fix this issue by returning -EINVAL in case of nr_pages is 0, since it is anyway a invalid swapfile. Looks like this issue will be hit when we have pagesize < blocksize type of configuration. I was able to hit the issue in case of a tiny swap file with below test script. https://raw.githubusercontent.com/riteshharjani/LinuxStudy/master/scripts/swap-issue.sh kernel crash analysis on v4.18 ============================== On v4.18 kernel, it causes a kernel panic, since sis->pages becomes a huge value and isi.nr_extents is 0. When 0 is returned it is considered as a swapfile over NFS and SWP_FILE is set (sis->flags |= SWP_FILE). Then when swapoff was getting called it was calling a_ops->swap_deactivate() if (sis->flags & SWP_FILE) is true. Since a_ops->swap_deactivate() is NULL in case of XFS, it causes below panic. Panic signature on v4.18 kernel: ======================================= root@qemu:/home/qemu# [ 8291.723351] XFS (loop2): Unmounting Filesystem [ 8292.123104] XFS (loop2): Mounting V5 Filesystem [ 8292.132451] XFS (loop2): Ending clean mount [ 8292.263362] Adding 4294967232k swap on /mnt1/test/swapfile. Priority:-2 extents:1 across:274877906880k [ 8292.277834] Unable to handle kernel paging request for instruction fetch [ 8292.278677] Faulting instruction address: 0x00000000 cpu 0x19: Vector: 400 (Instruction Access) at [c0000009dd5b7ad0] pc: 0000000000000000 lr: c0000000003eb9dc: destroy_swap_extents+0xfc/0x120 sp: c0000009dd5b7d50 msr: 8000000040009033 current = 0xc0000009b6710080 paca = 0xc00000003ffcb280 irqmask: 0x03 irq_happened: 0x01 pid = 5604, comm = swapoff Linux version 4.18.0 (riteshh@xxxxxxx) (gcc version 8.4.0 (Ubuntu 8.4.0-1ubuntu1~18.04)) #57 SMP Wed Mar 3 01:33:04 CST 2021 enter ? for help [link register ] c0000000003eb9dc destroy_swap_extents+0xfc/0x120 [c0000009dd5b7d50] c0000000025a7058 proc_poll_event+0x0/0x4 (unreliable) [c0000009dd5b7da0] c0000000003f0498 sys_swapoff+0x3f8/0x910 [c0000009dd5b7e30] c00000000000bbe4 system_call+0x5c/0x70 Exception: c01 (System Call) at 00007ffff7d208d8 Signed-off-by: Ritesh Harjani <riteshh@linux.ibm.com> [djwong: rework the comment to provide more details] Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2019-10-21iomap: use a srcmap for a read-modify-write I/OGoldwyn Rodrigues
The srcmap is used to identify where the read is to be performed from. It is passed to ->iomap_begin, which can fill it in if we need to read data for partially written blocks from a different location than the write target. The srcmap is only supported for buffered writes so far. Signed-off-by: Goldwyn Rodrigues <rgoldwyn@suse.com> [hch: merged two patches, removed the IOMAP_F_COW flag, use iomap as srcmap if not set, adjust length down to srcmap end as well] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Acked-by: Goldwyn Rodrigues <rgoldwyn@suse.com>
2019-07-17iomap: move internal declarations into fs/iomap/Darrick J. Wong
Move internal function declarations out of fs/internal.h into include/linux/iomap.h so that our transition is complete. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2019-07-17iomap: move the swapfile code into a separate fileDarrick J. Wong
Move the swapfile activation code into a separate file so that we can group related functions in a single file instead of having a single enormous source file. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>