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path: root/fs/xfs/libxfs/xfs_inode_fork.c
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2024-09-01xfs: standardize the btree maxrecs function parametersDarrick J. Wong1-2/+2
Standardize the parameters in xfs_{alloc,bm,ino,rmap,refcount}bt_maxrecs so that we have consistent calling conventions. This doesn't affect the kernel that much, but enables us to clean up userspace a bit. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-09-01xfs: replace shouty XFS_BM{BT,DR} macrosDarrick J. Wong1-15/+15
Replace all the shouty bmap btree and bmap disk root macros with actual functions. sed \ -e 's/XFS_BMBT_BLOCK_LEN/xfs_bmbt_block_len/g' \ -e 's/XFS_BMBT_REC_ADDR/xfs_bmbt_rec_addr/g' \ -e 's/XFS_BMBT_KEY_ADDR/xfs_bmbt_key_addr/g' \ -e 's/XFS_BMBT_PTR_ADDR/xfs_bmbt_ptr_addr/g' \ -e 's/XFS_BMDR_REC_ADDR/xfs_bmdr_rec_addr/g' \ -e 's/XFS_BMDR_KEY_ADDR/xfs_bmdr_key_addr/g' \ -e 's/XFS_BMDR_PTR_ADDR/xfs_bmdr_ptr_addr/g' \ -e 's/XFS_BMAP_BROOT_PTR_ADDR/xfs_bmap_broot_ptr_addr/g' \ -e 's/XFS_BMAP_BROOT_SPACE_CALC/xfs_bmap_broot_space_calc/g' \ -e 's/XFS_BMAP_BROOT_SPACE/xfs_bmap_broot_space/g' \ -e 's/XFS_BMDR_SPACE_CALC/xfs_bmdr_space_calc/g' \ -e 's/XFS_BMAP_BMDR_SPACE/xfs_bmap_bmdr_space/g' \ -i $(git ls-files fs/xfs/*.[ch] fs/xfs/libxfs/*.[ch] fs/xfs/scrub/*.[ch]) Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-09-01xfs: fix a sloppy memory handling bug in xfs_iroot_reallocDarrick J. Wong1-5/+5
While refactoring code, I noticed that when xfs_iroot_realloc tries to shrink a bmbt root block, it allocates a smaller new block and then copies "records" and pointers to the new block. However, bmbt root blocks cannot ever be leaves, which means that it's not technically correct to copy records. We /should/ be copying keys. Note that this has never resulted in actual memory corruption because sizeof(bmbt_rec) == (sizeof(bmbt_key) + sizeof(bmbt_ptr)). However, this will no longer be true when we start adding realtime rmap stuff, so fix this now. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-05-03xfs: simplify iext overflow checking and upgradeChristoph Hellwig1-32/+25
Currently the calls to xfs_iext_count_may_overflow and xfs_iext_count_upgrade are always paired. Merge them into a single function to simplify the callers and the actual check and upgrade logic itself. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-22xfs: move xfs_symlink_remote.c declarations to xfs_symlink_remote.hDarrick J. Wong1-0/+1
Move declarations for libxfs symlink functions into a separate header file like we do for most everything else. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: create a helper to decide if a file mapping targets the rt volumeDarrick J. Wong1-0/+9
Create a helper so that we can stop open-coding this decision everywhere. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-22xfs: report inode corruption errors to the health systemDarrick J. Wong1-0/+8
Whenever we encounter corrupt inode records, we should report that to the health monitoring system for later reporting. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2024-02-19xfs: Replace xfs_isilocked with xfs_assert_ilockedMatthew Wilcox (Oracle)1-1/+1
To use the new rwsem_assert_held()/rwsem_assert_held_write(), we can't use the existing ASSERT macro. Add a new xfs_assert_ilocked() and convert all the callers. Fix an apparent bug in xfs_isilocked(): If the caller specifies XFS_IOLOCK_EXCL | XFS_ILOCK_EXCL, xfs_assert_ilocked() will check both the IOLOCK and the ILOCK are held for write. xfs_isilocked() only checked that the ILOCK was held for write. xfs_assert_ilocked() is always on, even if DEBUG or XFS_WARN aren't defined. It's a cheap check, so I don't think it's worth defining it away. Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: "Matthew Wilcox (Oracle)" <willy@infradead.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: use GFP_KERNEL in pure transaction contextsDave Chinner1-4/+4
When running in a transaction context, memory allocations are scoped to GFP_NOFS. Hence we don't need to use GFP_NOFS contexts in pure transaction context allocations - GFP_KERNEL will automatically get converted to GFP_NOFS as appropriate. Go through the code and convert all the obvious GFP_NOFS allocations in transaction context to use GFP_KERNEL. This further reduces the explicit use of GFP_NOFS in XFS. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: use __GFP_NOLOCKDEP instead of GFP_NOFSDave Chinner1-3/+5
In the past we've had problems with lockdep false positives stemming from inode locking occurring in memory reclaim contexts (e.g. from superblock shrinkers). Lockdep doesn't know that inodes access from above memory reclaim cannot be accessed from below memory reclaim (and vice versa) but there has never been a good solution to solving this problem with lockdep annotations. This situation isn't unique to inode locks - buffers are also locked above and below memory reclaim, and we have to maintain lock ordering for them - and against inodes - appropriately. IOWs, the same code paths and locks are taken both above and below memory reclaim and so we always need to make sure the lock orders are consistent. We are spared the lockdep problems this might cause by the fact that semaphores and bit locks aren't covered by lockdep. In general, this sort of lockdep false positive detection is cause by code that runs GFP_KERNEL memory allocation with an actively referenced inode locked. When it is run from a transaction, memory allocation is automatically GFP_NOFS, so we don't have reclaim recursion issues. So in the places where we do memory allocation with inodes locked outside of a transaction, we have explicitly set them to use GFP_NOFS allocations to prevent lockdep false positives from being reported if the allocation dips into direct memory reclaim. More recently, __GFP_NOLOCKDEP was added to the memory allocation flags to tell lockdep not to track that particular allocation for the purposes of reclaim recursion detection. This is a much better way of preventing false positives - it allows us to use GFP_KERNEL context outside of transactions, and allows direct memory reclaim to proceed normally without throwing out false positive deadlock warnings. The obvious places that lock inodes and do memory allocation are the lookup paths and inode extent list initialisation. These occur in non-transactional GFP_KERNEL contexts, and so can run direct reclaim and lock inodes. This patch makes a first path through all the explicit GFP_NOFS allocations in XFS and converts the obvious ones to GFP_KERNEL | __GFP_NOLOCKDEP as a first step towards removing explicit GFP_NOFS allocations from the XFS code. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: convert remaining kmem_free() to kfree()Dave Chinner1-3/+3
The remaining callers of kmem_free() are freeing heap memory, so we can convert them directly to kfree() and get rid of kmem_free() altogether. This conversion was done with: $ for f in `git grep -l kmem_free fs/xfs`; do > sed -i s/kmem_free/kfree/ $f > done $ Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2024-02-13xfs: convert kmem_alloc() to kmalloc()Dave Chinner1-7/+8
kmem_alloc() is just a thin wrapper around kmalloc() these days. Convert everything to use kmalloc() so we can get rid of the wrapper. Note: the transaction region allocation in xlog_add_to_transaction() can be a high order allocation. Converting it to use kmalloc(__GFP_NOFAIL) results in warnings in the page allocation code being triggered because the mm subsystem does not want us to use __GFP_NOFAIL with high order allocations like we've been doing with the kmem_alloc() wrapper for a couple of decades. Hence this specific case gets converted to xlog_kvmalloc() rather than kmalloc() to avoid this issue. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2023-12-29xfs: remove struct xfs_attr_shortformChristoph Hellwig1-3/+2
sparse complains about struct xfs_attr_shortform because it embeds a structure with a variable sized array in a variable sized array. Given that xfs_attr_shortform is not a very useful structure, and the dir2 equivalent has been removed a long time ago, remove it as well. Provide a xfs_attr_sf_firstentry helper that returns the first xfs_attr_sf_entry behind a xfs_attr_sf_hdr to replace the structure dereference. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2023-12-29xfs: return if_data from xfs_idata_reallocChristoph Hellwig1-12/+8
Many of the xfs_idata_realloc callers need to set a local pointer to the just reallocated if_data memory. Return the pointer to simplify them a bit and use the opportunity to re-use krealloc for freeing if_data if the size hits 0. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2023-12-29xfs: make if_data a void pointerChristoph Hellwig1-29/+24
The xfs_ifork structure currently has a union of the if_root void pointer and the if_data char pointer. In either case it is an opaque pointer that depends on the fork format. Replace the union with a single if_data void pointer as that is what almost all callers want. Only the symlink NULL termination code in xfs_init_local_fork actually needs a new local variable now. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: "Darrick J. Wong" <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandanbabu@kernel.org>
2023-12-15xfs: repair inode fork block mapping data structuresDarrick J. Wong1-0/+1
Use the reverse-mapping btree information to rebuild an inode block map. Update the btree bulk loading code as necessary to support inode rooted btrees and fix some bitrot problems. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-12-15xfs: zap broken inode forksDarrick J. Wong1-7/+26
Determine if inode fork damage is responsible for the inode being unable to pass the ifork verifiers in xfs_iget and zap the fork contents if this is true. Once this is done the fork will be empty but we'll be able to construct an in-core inode, and a subsequent call to the inode fork repair ioctl will search the rmapbt to rebuild the records that were in the fork. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2023-04-14Merge tag 'btree-complain-bad-records-6.4_2023-04-11' of ↵Dave Chinner1-1/+2
git://git.kernel.org/pub/scm/linux/kernel/git/djwong/xfs-linux into guilt/xfs-for-next xfs: standardize btree record checking code [v24.5] While I was cleaning things up for 6.1, I noticed that the btree _query_range and _query_all functions don't perform the same checking that the _get_rec functions perform. In fact, they don't perform /any/ sanity checking, which means that callers aren't warned about impossible records. Therefore, hoist the record validation and complaint logging code into separate functions, and call them from any place where we convert an ondisk record into an incore record. For online scrub, we can replace checking code with a call to the record checking functions in libxfs, thereby reducing the size of the codebase. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Dave Chinner <david@fromorbit.com>
2023-04-12xfs: _{attr,data}_map_shared should take ILOCK_EXCL until iread_extents is ↵Darrick J. Wong1-1/+15
completely done While fuzzing the data fork extent count on a btree-format directory with xfs/375, I observed the following (excerpted) splat: XFS: Assertion failed: xfs_isilocked(ip, XFS_ILOCK_EXCL), file: fs/xfs/libxfs/xfs_bmap.c, line: 1208 ------------[ cut here ]------------ WARNING: CPU: 0 PID: 43192 at fs/xfs/xfs_message.c:104 assfail+0x46/0x4a [xfs] Call Trace: <TASK> xfs_iread_extents+0x1af/0x210 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] xchk_dir_walk+0xb8/0x190 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] xchk_parent_count_parent_dentries+0x41/0x80 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] xchk_parent_validate+0x199/0x2e0 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] xchk_parent+0xdf/0x130 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] xfs_scrub_metadata+0x2b8/0x730 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] xfs_scrubv_metadata+0x38b/0x4d0 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] xfs_ioc_scrubv_metadata+0x111/0x160 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] xfs_file_ioctl+0x367/0xf50 [xfs 09f66509ece4938760fac7de64732a0cbd3e39cd] __x64_sys_ioctl+0x82/0xa0 do_syscall_64+0x2b/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 The cause of this is a race condition in xfs_ilock_data_map_shared, which performs an unlocked access to the data fork to guess which lock mode it needs: Thread 0 Thread 1 xfs_need_iread_extents <observe no iext tree> xfs_ilock(..., ILOCK_EXCL) xfs_iread_extents <observe no iext tree> <check ILOCK_EXCL> <load bmbt extents into iext> <notice iext size doesn't match nextents> xfs_need_iread_extents <observe iext tree> xfs_ilock(..., ILOCK_SHARED) <tear down iext tree> xfs_iunlock(..., ILOCK_EXCL) xfs_iread_extents <observe no iext tree> <check ILOCK_EXCL> *BOOM* Fix this race by adding a flag to the xfs_ifork structure to indicate that we have not yet read in the extent records and changing the predicate to look at the flag state, not if_height. The memory barrier ensures that the flag will not be set until the very end of the function. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2023-04-11xfs: complain about bad file mapping records in the ondisk bmbtDarrick J. Wong1-1/+2
Similar to what we've just done for the other btrees, create a function to log corrupt bmbt records and call it whenever we encounter a bad record in the ondisk btree. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-09-19xfs: clean up "%Ld/%Lu" which doesn't meet C standardZeng Heng1-2/+2
The "%Ld" specifier, which represents long long unsigned, doesn't meet C language standard, and even more, it makes people easily mistake with "%ld", which represent long unsigned. So replace "%Ld" with "lld". Do the same with "%Lu". Signed-off-by: Zeng Heng <zengheng4@huawei.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-07-20xfs: don't leak memory when attr fork loading failsDarrick J. Wong1-4/+1
I observed the following evidence of a memory leak while running xfs/399 from the xfs fsck test suite (edited for brevity): XFS (sde): Metadata corruption detected at xfs_attr_shortform_verify_struct.part.0+0x7b/0xb0 [xfs], inode 0x1172 attr fork XFS: Assertion failed: ip->i_af.if_u1.if_data == NULL, file: fs/xfs/libxfs/xfs_inode_fork.c, line: 315 ------------[ cut here ]------------ WARNING: CPU: 2 PID: 91635 at fs/xfs/xfs_message.c:104 assfail+0x46/0x4a [xfs] CPU: 2 PID: 91635 Comm: xfs_scrub Tainted: G W 5.19.0-rc7-xfsx #rc7 6e6475eb29fd9dda3181f81b7ca7ff961d277a40 Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.15.0-1 04/01/2014 RIP: 0010:assfail+0x46/0x4a [xfs] Call Trace: <TASK> xfs_ifork_zap_attr+0x7c/0xb0 xfs_iformat_attr_fork+0x86/0x110 xfs_inode_from_disk+0x41d/0x480 xfs_iget+0x389/0xd70 xfs_bulkstat_one_int+0x5b/0x540 xfs_bulkstat_iwalk+0x1e/0x30 xfs_iwalk_ag_recs+0xd1/0x160 xfs_iwalk_run_callbacks+0xb9/0x180 xfs_iwalk_ag+0x1d8/0x2e0 xfs_iwalk+0x141/0x220 xfs_bulkstat+0x105/0x180 xfs_ioc_bulkstat.constprop.0.isra.0+0xc5/0x130 xfs_file_ioctl+0xa5f/0xef0 __x64_sys_ioctl+0x82/0xa0 do_syscall_64+0x2b/0x80 entry_SYSCALL_64_after_hwframe+0x46/0xb0 This newly-added assertion checks that there aren't any incore data structures hanging off the incore fork when we're trying to reset its contents. From the call trace, it is evident that iget was trying to construct an incore inode from the ondisk inode, but the attr fork verifier failed and we were trying to undo all the memory allocations that we had done earlier. The three assertions in xfs_ifork_zap_attr check that the caller has already called xfs_idestroy_fork, which clearly has not been done here. As the zap function then zeroes the pointers, we've effectively leaked the memory. The shortest change would have been to insert an extra call to xfs_idestroy_fork, but it makes more sense to bundle the _idestroy_fork call into _zap_attr, since all other callsites call _idestroy_fork immediately prior to calling _zap_attr. IOWs, it eliminates one way to fail. Note: This change only applies cleanly to 2ed5b09b3e8f, since we just reworked the attr fork lifetime. However, I think this memory leak has existed since 0f45a1b20cd8, since the chain xfs_iformat_attr_fork -> xfs_iformat_local -> xfs_init_local_fork will allocate ifp->if_u1.if_data, but if xfs_ifork_verify_local_attr fails, xfs_iformat_attr_fork will free i_afp without freeing any of the stuff hanging off i_afp. The solution for older kernels I think is to add the missing call to xfs_idestroy_fork just prior to calling kmem_cache_free. Found by fuzzing a.sfattr.hdr.totsize = lastbit in xfs/399. Fixes: 2ed5b09b3e8f ("xfs: make inode attribute forks a permanent part of struct xfs_inode") Probably-Fixes: 0f45a1b20cd8 ("xfs: improve local fork verification") Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-07-20xfs: delete unnecessary NULL checksDan Carpenter1-2/+1
These NULL check are no long needed after commit 2ed5b09b3e8f ("xfs: make inode attribute forks a permanent part of struct xfs_inode"). Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2022-07-12xfs: replace inode fork size macros with functionsDarrick J. Wong1-5/+5
Replace the shouty macros here with typechecked helper functions. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-07-12xfs: replace XFS_IFORK_Q with a proper predicate functionDarrick J. Wong1-1/+1
Replace this shouty macro with a real C function that has a more descriptive name. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-07-09xfs: use XFS_IFORK_Q to determine the presence of an xattr forkDarrick J. Wong1-6/+1
Modify xfs_ifork_ptr to return a NULL pointer if the caller asks for the attribute fork but i_forkoff is zero. This eliminates the ambiguity between i_forkoff and i_af.if_present, which should make it easier to understand the lifetime of attr forks. While we're at it, remove the if_present checks around calls to xfs_idestroy_fork and xfs_ifork_zap_attr since they can both handle attr forks that have already been torn down. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-07-09xfs: make inode attribute forks a permanent part of struct xfs_inodeDarrick J. Wong1-16/+28
Syzkaller reported a UAF bug a while back: ================================================================== BUG: KASAN: use-after-free in xfs_ilock_attr_map_shared+0xe3/0xf6 fs/xfs/xfs_inode.c:127 Read of size 4 at addr ffff88802cec919c by task syz-executor262/2958 CPU: 2 PID: 2958 Comm: syz-executor262 Not tainted 5.15.0-0.30.3-20220406_1406 #3 Hardware name: Red Hat KVM, BIOS 1.13.0-2.module+el8.3.0+7860+a7792d29 04/01/2014 Call Trace: <TASK> __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x82/0xa9 lib/dump_stack.c:106 print_address_description.constprop.9+0x21/0x2d5 mm/kasan/report.c:256 __kasan_report mm/kasan/report.c:442 [inline] kasan_report.cold.14+0x7f/0x11b mm/kasan/report.c:459 xfs_ilock_attr_map_shared+0xe3/0xf6 fs/xfs/xfs_inode.c:127 xfs_attr_get+0x378/0x4c2 fs/xfs/libxfs/xfs_attr.c:159 xfs_xattr_get+0xe3/0x150 fs/xfs/xfs_xattr.c:36 __vfs_getxattr+0xdf/0x13d fs/xattr.c:399 cap_inode_need_killpriv+0x41/0x5d security/commoncap.c:300 security_inode_need_killpriv+0x4c/0x97 security/security.c:1408 dentry_needs_remove_privs.part.28+0x21/0x63 fs/inode.c:1912 dentry_needs_remove_privs+0x80/0x9e fs/inode.c:1908 do_truncate+0xc3/0x1e0 fs/open.c:56 handle_truncate fs/namei.c:3084 [inline] do_open fs/namei.c:3432 [inline] path_openat+0x30ab/0x396d fs/namei.c:3561 do_filp_open+0x1c4/0x290 fs/namei.c:3588 do_sys_openat2+0x60d/0x98c fs/open.c:1212 do_sys_open+0xcf/0x13c fs/open.c:1228 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0x0 RIP: 0033:0x7f7ef4bb753d Code: 00 c3 66 2e 0f 1f 84 00 00 00 00 00 90 f3 0f 1e fa 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 8b 0d 1b 79 2c 00 f7 d8 64 89 01 48 RSP: 002b:00007f7ef52c2ed8 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 0000000000404148 RCX: 00007f7ef4bb753d RDX: 00007f7ef4bb753d RSI: 0000000000000000 RDI: 0000000020004fc0 RBP: 0000000000404140 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0030656c69662f2e R13: 00007ffd794db37f R14: 00007ffd794db470 R15: 00007f7ef52c2fc0 </TASK> Allocated by task 2953: kasan_save_stack+0x19/0x38 mm/kasan/common.c:38 kasan_set_track mm/kasan/common.c:46 [inline] set_alloc_info mm/kasan/common.c:434 [inline] __kasan_slab_alloc+0x68/0x7c mm/kasan/common.c:467 kasan_slab_alloc include/linux/kasan.h:254 [inline] slab_post_alloc_hook mm/slab.h:519 [inline] slab_alloc_node mm/slub.c:3213 [inline] slab_alloc mm/slub.c:3221 [inline] kmem_cache_alloc+0x11b/0x3eb mm/slub.c:3226 kmem_cache_zalloc include/linux/slab.h:711 [inline] xfs_ifork_alloc+0x25/0xa2 fs/xfs/libxfs/xfs_inode_fork.c:287 xfs_bmap_add_attrfork+0x3f2/0x9b1 fs/xfs/libxfs/xfs_bmap.c:1098 xfs_attr_set+0xe38/0x12a7 fs/xfs/libxfs/xfs_attr.c:746 xfs_xattr_set+0xeb/0x1a9 fs/xfs/xfs_xattr.c:59 __vfs_setxattr+0x11b/0x177 fs/xattr.c:180 __vfs_setxattr_noperm+0x128/0x5e0 fs/xattr.c:214 __vfs_setxattr_locked+0x1d4/0x258 fs/xattr.c:275 vfs_setxattr+0x154/0x33d fs/xattr.c:301 setxattr+0x216/0x29f fs/xattr.c:575 __do_sys_fsetxattr fs/xattr.c:632 [inline] __se_sys_fsetxattr fs/xattr.c:621 [inline] __x64_sys_fsetxattr+0x243/0x2fe fs/xattr.c:621 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0x0 Freed by task 2949: kasan_save_stack+0x19/0x38 mm/kasan/common.c:38 kasan_set_track+0x1c/0x21 mm/kasan/common.c:46 kasan_set_free_info+0x20/0x30 mm/kasan/generic.c:360 ____kasan_slab_free mm/kasan/common.c:366 [inline] ____kasan_slab_free mm/kasan/common.c:328 [inline] __kasan_slab_free+0xe2/0x10e mm/kasan/common.c:374 kasan_slab_free include/linux/kasan.h:230 [inline] slab_free_hook mm/slub.c:1700 [inline] slab_free_freelist_hook mm/slub.c:1726 [inline] slab_free mm/slub.c:3492 [inline] kmem_cache_free+0xdc/0x3ce mm/slub.c:3508 xfs_attr_fork_remove+0x8d/0x132 fs/xfs/libxfs/xfs_attr_leaf.c:773 xfs_attr_sf_removename+0x5dd/0x6cb fs/xfs/libxfs/xfs_attr_leaf.c:822 xfs_attr_remove_iter+0x68c/0x805 fs/xfs/libxfs/xfs_attr.c:1413 xfs_attr_remove_args+0xb1/0x10d fs/xfs/libxfs/xfs_attr.c:684 xfs_attr_set+0xf1e/0x12a7 fs/xfs/libxfs/xfs_attr.c:802 xfs_xattr_set+0xeb/0x1a9 fs/xfs/xfs_xattr.c:59 __vfs_removexattr+0x106/0x16a fs/xattr.c:468 cap_inode_killpriv+0x24/0x47 security/commoncap.c:324 security_inode_killpriv+0x54/0xa1 security/security.c:1414 setattr_prepare+0x1a6/0x897 fs/attr.c:146 xfs_vn_change_ok+0x111/0x15e fs/xfs/xfs_iops.c:682 xfs_vn_setattr_size+0x5f/0x15a fs/xfs/xfs_iops.c:1065 xfs_vn_setattr+0x125/0x2ad fs/xfs/xfs_iops.c:1093 notify_change+0xae5/0x10a1 fs/attr.c:410 do_truncate+0x134/0x1e0 fs/open.c:64 handle_truncate fs/namei.c:3084 [inline] do_open fs/namei.c:3432 [inline] path_openat+0x30ab/0x396d fs/namei.c:3561 do_filp_open+0x1c4/0x290 fs/namei.c:3588 do_sys_openat2+0x60d/0x98c fs/open.c:1212 do_sys_open+0xcf/0x13c fs/open.c:1228 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x3a/0x7e arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x44/0x0 The buggy address belongs to the object at ffff88802cec9188 which belongs to the cache xfs_ifork of size 40 The buggy address is located 20 bytes inside of 40-byte region [ffff88802cec9188, ffff88802cec91b0) The buggy address belongs to the page: page:00000000c3af36a1 refcount:1 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x2cec9 flags: 0xfffffc0000200(slab|node=0|zone=1|lastcpupid=0x1fffff) raw: 000fffffc0000200 ffffea00009d2580 0000000600000006 ffff88801a9ffc80 raw: 0000000000000000 0000000080490049 00000001ffffffff 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff88802cec9080: fb fb fb fc fc fa fb fb fb fb fc fc fb fb fb fb ffff88802cec9100: fb fc fc fb fb fb fb fb fc fc fb fb fb fb fb fc >ffff88802cec9180: fc fa fb fb fb fb fc fc fa fb fb fb fb fc fc fb ^ ffff88802cec9200: fb fb fb fb fc fc fb fb fb fb fb fc fc fb fb fb ffff88802cec9280: fb fb fc fc fa fb fb fb fb fc fc fa fb fb fb fb ================================================================== The root cause of this bug is the unlocked access to xfs_inode.i_afp from the getxattr code paths while trying to determine which ILOCK mode to use to stabilize the xattr data. Unfortunately, the VFS does not acquire i_rwsem when vfs_getxattr (or listxattr) call into the filesystem, which means that getxattr can race with a removexattr that's tearing down the attr fork and crash: xfs_attr_set: xfs_attr_get: xfs_attr_fork_remove: xfs_ilock_attr_map_shared: xfs_idestroy_fork(ip->i_afp); kmem_cache_free(xfs_ifork_cache, ip->i_afp); if (ip->i_afp && ip->i_afp = NULL; xfs_need_iread_extents(ip->i_afp)) <KABOOM> ip->i_forkoff = 0; Regrettably, the VFS is much more lax about i_rwsem and getxattr than is immediately obvious -- not only does it not guarantee that we hold i_rwsem, it actually doesn't guarantee that we *don't* hold it either. The getxattr system call won't acquire the lock before calling XFS, but the file capabilities code calls getxattr with and without i_rwsem held to determine if the "security.capabilities" xattr is set on the file. Fixing the VFS locking requires a treewide investigation into every code path that could touch an xattr and what i_rwsem state it expects or sets up. That could take years or even prove impossible; fortunately, we can fix this UAF problem inside XFS. An earlier version of this patch used smp_wmb in xfs_attr_fork_remove to ensure that i_forkoff is always zeroed before i_afp is set to null and changed the read paths to use smp_rmb before accessing i_forkoff and i_afp, which avoided these UAF problems. However, the patch author was too busy dealing with other problems in the meantime, and by the time he came back to this issue, the situation had changed a bit. On a modern system with selinux, each inode will always have at least one xattr for the selinux label, so it doesn't make much sense to keep incurring the extra pointer dereference. Furthermore, Allison's upcoming parent pointer patchset will also cause nearly every inode in the filesystem to have extended attributes. Therefore, make the inode attribute fork structure part of struct xfs_inode, at a cost of 40 more bytes. This patch adds a clunky if_present field where necessary to maintain the existing logic of xattr fork null pointer testing in the existing codebase. The next patch switches the logic over to XFS_IFORK_Q and it all goes away. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-07-09xfs: convert XFS_IFORK_PTR to a static inline helperDarrick J. Wong1-8/+8
We're about to make this logic do a bit more, so convert the macro to a static inline function for better typechecking and fewer shouty macros. No functional changes here. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2022-05-04xfs: hide log iovec alignment constraintsDave Chinner1-16/+4
Callers currently have to round out the size of buffers to match the aligment constraints of log iovecs and xlog_write(). They should not need to know this detail, so introduce a new function to calculate the iovec length (for use in ->iop_size implementations). Also modify xlog_finish_iovec() to round up the length to the correct alignment so the callers don't need to do this, either. Convert the only user - inode forks - of this alignment rounding to use the new interface. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-05-04xfs: zero inode fork buffer at allocationDave Chinner1-3/+9
When we first allocate or resize an inline inode fork, we round up the allocation to 4 byte alingment to make journal alignment constraints. We don't clear the unused bytes, so we can copy up to three uninitialised bytes into the journal. Zero those bytes so we only ever copy zeros into the journal. Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Signed-off-by: Dave Chinner <david@fromorbit.com>
2022-04-13xfs: Conditionally upgrade existing inodes to use large extent countersChandan Babu R1-0/+24
This commit enables upgrading existing inodes to use large extent counters provided that underlying filesystem's superblock has large extent counter feature enabled. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
2022-04-11xfs: Introduce macros to represent new maximum extent counts for data/attr forksChandan Babu R1-1/+2
This commit defines new macros to represent maximum extent counts allowed by filesystems which have support for large per-inode extent counters. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
2022-04-11xfs: Promote xfs_extnum_t and xfs_aextnum_t to 64 and 32-bits respectivelyChandan Babu R1-2/+2
A future commit will introduce a 64-bit on-disk data extent counter and a 32-bit on-disk attr extent counter. This commit promotes xfs_extnum_t and xfs_aextnum_t to 64 and 32-bits in order to correctly handle in-core versions of these quantities. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
2022-04-11xfs: Introduce xfs_dfork_nextents() helperChandan Babu R1-4/+4
This commit replaces the macro XFS_DFORK_NEXTENTS() with the helper function xfs_dfork_nextents(). As of this commit, xfs_dfork_nextents() returns the same value as XFS_DFORK_NEXTENTS(). A future commit which extends inode's extent counter fields will add more logic to this helper. This commit also replaces direct accesses to xfs_dinode->di_[a]nextents with calls to xfs_dfork_nextents(). No functional changes have been made. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
2022-04-11xfs: Use xfs_extnum_t instead of basic data typesChandan Babu R1-1/+1
xfs_extnum_t is the type to use to declare variables which have values obtained from xfs_dinode->di_[a]nextents. This commit replaces basic types (e.g. uint32_t) with xfs_extnum_t for such variables. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
2022-04-11xfs: Introduce xfs_iext_max_nextents() helperChandan Babu R1-1/+1
xfs_iext_max_nextents() returns the maximum number of extents possible for one of data, cow or attribute fork. This helper will be extended further in a future commit when maximum extent counts associated with data/attribute forks are increased. Reviewed-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Dave Chinner <dchinner@redhat.com> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
2021-10-22xfs: rename _zone variables to _cacheDarrick J. Wong1-4/+4
Now that we've gotten rid of the kmem_zone_t typedef, rename the variables to _cache since that's what they are. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
2021-10-22xfs: remove kmem_zone typedefDarrick J. Wong1-1/+1
Remove these typedefs by referencing kmem_cache directly. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Chandan Babu R <chandan.babu@oracle.com>
2021-10-14xfs: remove the xfs_dinode_t typedefChristoph Hellwig1-8/+8
Remove the few leftover instances of the xfs_dinode_t typedef. 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>
2021-04-15xfs: remove XFS_IFEXTENTSChristoph Hellwig1-6/+0
The in-memory XFS_IFEXTENTS is now only used to check if an inode with extents still needs the extents to be read into memory before doing operations that need the extent map. Add a new xfs_need_iread_extents helper that returns true for btree format forks that do not have any entries in the in-memory extent btree, and use that instead of checking the XFS_IFEXTENTS flag. 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>
2021-04-15xfs: remove XFS_IFINLINEChristoph Hellwig1-1/+0
Just check for an inline format fork instead of the using the equivalent in-memory XFS_IFINLINE flag. 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>
2021-04-15xfs: remove XFS_IFBROOTChristoph Hellwig1-3/+1
Just check for a btree format fork instead of the using the equivalent in-memory XFS_IFBROOT flag. 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>
2021-04-15xfs: only look at the fork format in xfs_idestroy_forkChristoph Hellwig1-7/+6
Stop using the XFS_IFEXTENTS flag, and instead switch on the fork format in xfs_idestroy_fork to decide how to cleanup. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org>
2021-04-07xfs: move the di_nblocks field to struct xfs_inodeChristoph Hellwig1-1/+1
In preparation of removing the historic icinode struct, move the nblocks field into the containing xfs_inode structure. 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>
2021-04-07xfs: move the di_size field to struct xfs_inodeChristoph Hellwig1-1/+1
In preparation of removing the historic icinode struct, move the on-disk size field into the containing xfs_inode structure. 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>
2021-03-25xfs: initialise attr fork on inode createDave Chinner1-5/+15
When we allocate a new inode, we often need to add an attribute to the inode as part of the create. This can happen as a result of needing to add default ACLs or security labels before the inode is made visible to userspace. This is highly inefficient right now. We do the create transaction to allocate the inode, then we do an "add attr fork" transaction to modify the just created empty inode to set the inode fork offset to allow attributes to be stored, then we go and do the attribute creation. This means 3 transactions instead of 1 to allocate an inode, and this greatly increases the load on the CIL commit code, resulting in excessive contention on the CIL spin locks and performance degradation: 18.99% [kernel] [k] __pv_queued_spin_lock_slowpath 3.57% [kernel] [k] do_raw_spin_lock 2.51% [kernel] [k] __raw_callee_save___pv_queued_spin_unlock 2.48% [kernel] [k] memcpy 2.34% [kernel] [k] xfs_log_commit_cil The typical profile resulting from running fsmark on a selinux enabled filesytem is adds this overhead to the create path: - 15.30% xfs_init_security - 15.23% security_inode_init_security - 13.05% xfs_initxattrs - 12.94% xfs_attr_set - 6.75% xfs_bmap_add_attrfork - 5.51% xfs_trans_commit - 5.48% __xfs_trans_commit - 5.35% xfs_log_commit_cil - 3.86% _raw_spin_lock - do_raw_spin_lock __pv_queued_spin_lock_slowpath - 0.70% xfs_trans_alloc 0.52% xfs_trans_reserve - 5.41% xfs_attr_set_args - 5.39% xfs_attr_set_shortform.constprop.0 - 4.46% xfs_trans_commit - 4.46% __xfs_trans_commit - 4.33% xfs_log_commit_cil - 2.74% _raw_spin_lock - do_raw_spin_lock __pv_queued_spin_lock_slowpath 0.60% xfs_inode_item_format 0.90% xfs_attr_try_sf_addname - 1.99% selinux_inode_init_security - 1.02% security_sid_to_context_force - 1.00% security_sid_to_context_core - 0.92% sidtab_entry_to_string - 0.90% sidtab_sid2str_get 0.59% sidtab_sid2str_put.part.0 - 0.82% selinux_determine_inode_label - 0.77% security_transition_sid 0.70% security_compute_sid.part.0 And fsmark creation rate performance drops by ~25%. The key point to note here is that half the additional overhead comes from adding the attribute fork to the newly created inode. That's crazy, considering we can do this same thing at inode create time with a couple of lines of code and no extra overhead. So, if we know we are going to add an attribute immediately after creating the inode, let's just initialise the attribute fork inside the create transaction and chop that whole chunk of code out of the create fast path. This completely removes the performance drop caused by enabling SELinux, and the profile looks like: - 8.99% xfs_init_security - 9.00% security_inode_init_security - 6.43% xfs_initxattrs - 6.37% xfs_attr_set - 5.45% xfs_attr_set_args - 5.42% xfs_attr_set_shortform.constprop.0 - 4.51% xfs_trans_commit - 4.54% __xfs_trans_commit - 4.59% xfs_log_commit_cil - 2.67% _raw_spin_lock - 3.28% do_raw_spin_lock 3.08% __pv_queued_spin_lock_slowpath 0.66% xfs_inode_item_format - 0.90% xfs_attr_try_sf_addname - 0.60% xfs_trans_alloc - 2.35% selinux_inode_init_security - 1.25% security_sid_to_context_force - 1.21% security_sid_to_context_core - 1.19% sidtab_entry_to_string - 1.20% sidtab_sid2str_get - 0.86% sidtab_sid2str_put.part.0 - 0.62% _raw_spin_lock_irqsave - 0.77% do_raw_spin_lock __pv_queued_spin_lock_slowpath - 0.84% selinux_determine_inode_label - 0.83% security_transition_sid 0.86% security_compute_sid.part.0 Which indicates the XFS overhead of creating the selinux xattr has been halved. This doesn't fix the CIL lock contention problem, just means it's not a limiting factor for this workload. Lock contention in the security subsystems is going to be an issue soon, though... Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> [djwong: fix compilation error when CONFIG_SECURITY=n] Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Gao Xiang <hsiangkao@redhat.com>
2021-03-25xfs: validate ag btree levels using the precomputed valuesDarrick J. Wong1-1/+1
Use the AG btree height limits that we precomputed into the xfs_mount to validate the AG headers instead of using XFS_BTREE_MAXLEVELS. Signed-off-by: Darrick J. Wong <djwong@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de>
2021-01-22xfs: Introduce error injection to reduce maximum inode fork extent countChandan Babu R1-0/+4
This commit adds XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag which enables userspace programs to test "Inode fork extent count overflow detection" by reducing maximum possible inode fork extent count to 10. Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2021-01-22xfs: Add helper for checking per-inode extent count overflowChandan Babu R1-0/+23
XFS does not check for possible overflow of per-inode extent counter fields when adding extents to either data or attr fork. For e.g. 1. Insert 5 million xattrs (each having a value size of 255 bytes) and then delete 50% of them in an alternating manner. 2. On a 4k block sized XFS filesystem instance, the above causes 98511 extents to be created in the attr fork of the inode. xfsaild/loop0 2008 [003] 1475.127209: probe:xfs_inode_to_disk: (ffffffffa43fb6b0) if_nextents=98511 i_ino=131 3. The incore inode fork extent counter is a signed 32-bit quantity. However the on-disk extent counter is an unsigned 16-bit quantity and hence cannot hold 98511 extents. 4. The following incorrect value is stored in the attr extent counter, # xfs_db -f -c 'inode 131' -c 'print core.naextents' /dev/loop0 core.naextents = -32561 This commit adds a new helper function (i.e. xfs_iext_count_may_overflow()) to check for overflow of the per-inode data and xattr extent counters. Future patches will use this function to make sure that an FS operation won't cause the extent counter to overflow. Suggested-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-09-06xfs: remove kmem_realloc()Carlos Maiolino1-4/+4
Remove kmem_realloc() function and convert its users to use MM API directly (krealloc()) Signed-off-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-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>