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2022-07-12xfs: replace inode fork size macros with functionsDarrick J. Wong1-14/+1
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. Wong1-3/+2
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. Wong1-1/+0
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. Wong1-2/+4
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. Wong1-6/+0
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>
2022-04-13xfs: Conditionally upgrade existing inodes to use large extent countersChandan Babu R1-0/+2
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>
2022-04-13xfs: Directory's data fork extent counter can never overflowChandan Babu R1-13/+0
The maximum file size that can be represented by the data fork extent counter in the worst case occurs when all extents are 1 block in length and each block is 1KB in size. With XFS_MAX_EXTCNT_DATA_FORK_SMALL representing maximum extent count and with 1KB sized blocks, a file can reach upto, (2^31) * 1KB = 2TB This is much larger than the theoretical maximum size of a directory i.e. XFS_DIR2_SPACE_SIZE * 3 = ~96GB. Since a directory's inode can never overflow its data fork extent counter, this commit removes all the overflow checks associated with it. xfs_dinode_verify() now performs a rough check to verify if a diretory's data fork is larger than 96GB. Reviewed-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <djwong@kernel.org> Signed-off-by: Chandan Babu R <chandan.babu@oracle.com>
2022-04-11xfs: Introduce per-inode 64-bit extent countersChandan Babu R1-0/+6
This commit introduces new fields in the on-disk inode format to support 64-bit data fork extent counters and 32-bit attribute fork extent counters. The new fields will be used only when an inode has XFS_DIFLAG2_NREXT64 flag set. Otherwise we continue to use the regular 32-bit data fork extent counters and 16-bit attribute fork 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> Suggested-by: Dave Chinner <dchinner@redhat.com>
2022-04-11xfs: Introduce macros to represent new maximum extent counts for data/attr forksChandan Babu R1-4/+17
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 R1-1/+1
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 R1-0/+32
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: Introduce xfs_iext_max_nextents() helperChandan Babu R1-0/+8
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. Wong1-1/+1
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>
2021-04-15xfs: remove XFS_IFEXTENTSChristoph Hellwig1-6/+6
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 Hellwig1-1/+0
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>
2021-04-07xfs: move the di_forkoff field to struct xfs_inodeChristoph Hellwig1-2/+2
In preparation of removing the historic icinode struct, move the forkoff 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 Chinner1-0/+2
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>
2021-01-22xfs: Check for extent overflow when swapping extentsChandan Babu R1-0/+7
Removing an initial range of source/donor file's extent and adding a new extent (from donor/source file) in its place will cause extent count to increase by 1. Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> 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: Check for extent overflow when moving extent from cow to data forkChandan Babu R1-0/+9
Moving an extent to data fork can cause a sub-interval of an existing extent to be unmapped. This will increase extent count by 1. Mapping in the new extent can increase the extent count by 1 again i.e. | Old extent | New extent | Old extent | Hence number of extents increases by 2. 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: Check for extent overflow when writing to unwritten extentChandan Babu R1-0/+9
A write to a sub-interval of an existing unwritten extent causes the original extent to be split into 3 extents i.e. | Unwritten | Real | Unwritten | Hence extent count can increase by 2. 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: Check for extent overflow when adding/removing xattrsChandan Babu R1-0/+10
Adding/removing an xattr can cause XFS_DA_NODE_MAXDEPTH extents to be added. One extra extent for dabtree in case a local attr is large enough to cause a double split. It can also cause extent count to increase proportional to the size of a remote xattr's value. 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: Check for extent overflow when adding dir entriesChandan Babu R1-0/+13
Directory entry addition can cause the following, 1. Data block can be added/removed. A new extent can cause extent count to increase by 1. 2. Free disk block can be added/removed. Same behaviour as described above for Data block. 3. Dabtree blocks. XFS_DA_NODE_MAXDEPTH blocks can be added. Each of these can be new extents. Hence extent count can increase by XFS_DA_NODE_MAXDEPTH. Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2021-01-22xfs: Check for extent overflow when punching a holeChandan Babu R1-0/+7
The extent mapping the file offset at which a hole has to be inserted will be split into two extents causing extent count to increase by 1. 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: Check for extent overflow when trivally adding a new extentChandan Babu R1-0/+6
When adding a new data extent (without modifying an inode's existing extents) the extent count increases only by 1. This commit checks for extent count overflow in such cases. 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/+2
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>
2020-05-19xfs: cleanup xfs_idestroy_forkChristoph Hellwig1-1/+1
Move freeing the dynamically allocated attr and COW fork, as well as zeroing the pointers where actually needed into the callers, and just pass the xfs_ifork structure to xfs_idestroy_fork. Also simplify the kmem_free calls by not checking for NULL first. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-19xfs: move the fork format fields into struct xfs_iforkChristoph Hellwig1-15/+13
Both the data and attr fork have a format that is stored in the legacy idinode. Move it into the xfs_ifork structure instead, where it uses up padding. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-19xfs: move the per-fork nextents fields into struct xfs_iforkChristoph Hellwig1-12/+8
There are there are three extents counters per inode, one for each of the forks. Two are in the legacy icdinode and one is directly in struct xfs_inode. Switch to a single counter in the xfs_ifork structure where it uses up padding at the end of the structure. This simplifies various bits of code that just wants the number of extents counter and can now directly dereference it. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-19xfs: refactor xfs_inode_verify_forksChristoph Hellwig1-2/+2
The split between xfs_inode_verify_forks and the two helpers implementing the actual functionality is a little strange. Reshuffle it so that xfs_inode_verify_forks verifies if the data and attr forks are actually in local format and only call the low-level helpers if that is the case. Handle the actual error reporting in the low-level handlers to streamline the caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-05-19xfs: remove xfs_ifork_opsChristoph Hellwig1-13/+2
xfs_ifork_ops add up to two indirect calls per inode read and flush, despite just having a single instance in the kernel. In xfsprogs phase6 in xfs_repair overrides the verify_dir method to deal with inodes that do not have a valid parent, but that can be fixed pretty easily by ensuring they always have a valid looking parent. 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>
2020-05-19xfs: split xfs_iformat_forkChristoph Hellwig1-1/+2
xfs_iformat_fork is a weird catchall. Split it into one helper for the data fork and one for the attr fork, and then call both helper as well as the COW fork initialization from xfs_inode_from_disk. Order the COW fork initialization after the attr fork initialization given that it can't fail to simplify the error handling. Note that the newly split helpers are moved down the file in xfs_inode_fork.c to avoid the need for forward declarations. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2020-03-19xfs: only check the superblock version for dinode size calculationChristoph Hellwig1-7/+2
The size of the dinode structure is only dependent on the file system version, so instead of checking the individual inode version just use the newly added xfs_sb_version_has_large_dinode helper, and simplify various calling conventions. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-11-10xfs: refactor "does this fork map blocks" predicateDarrick J. Wong1-0/+4
Replace the open-coded checks for whether or not an inode fork maps blocks with a macro that will implant the code for us. This helps us declutter the bmap code a bit. Note that I had to use a macro instead of a static inline function because of C header dependency problems between xfs_inode.h and xfs_inode_fork.h. Conversion was performed with the following Coccinelle script: @@ expression ip, w; @@ - XFS_IFORK_FORMAT(ip, w) == XFS_DINODE_FMT_EXTENTS || XFS_IFORK_FORMAT(ip, w) == XFS_DINODE_FMT_BTREE + xfs_ifork_has_extents(ip, w) @@ expression ip, w; @@ - XFS_IFORK_FORMAT(ip, w) != XFS_DINODE_FMT_EXTENTS && XFS_IFORK_FORMAT(ip, w) != XFS_DINODE_FMT_BTREE + !xfs_ifork_has_extents(ip, w) @@ expression ip, w; @@ - XFS_IFORK_FORMAT(ip, w) == XFS_DINODE_FMT_BTREE || XFS_IFORK_FORMAT(ip, w) == XFS_DINODE_FMT_EXTENTS + xfs_ifork_has_extents(ip, w) @@ expression ip, w; @@ - XFS_IFORK_FORMAT(ip, w) != XFS_DINODE_FMT_BTREE && XFS_IFORK_FORMAT(ip, w) != XFS_DINODE_FMT_EXTENTS + !xfs_ifork_has_extents(ip, w) @@ expression ip, w; @@ - (xfs_ifork_has_extents(ip, w)) + xfs_ifork_has_extents(ip, w) @@ expression ip, w; @@ - (!xfs_ifork_has_extents(ip, w)) + !xfs_ifork_has_extents(ip, w) Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Christoph Hellwig <hch@lst.de>
2019-10-21xfs: fix inode fork extent count overflowDave Chinner1-6/+8
[commit message is verbose for discussion purposes - will trim it down later. Some questions about implementation details at the end.] Zorro Lang recently ran a new test to stress single inode extent counts now that they are no longer limited by memory allocation. The test was simply: # xfs_io -f -c "falloc 0 40t" /mnt/scratch/big-file # ~/src/xfstests-dev/punch-alternating /mnt/scratch/big-file This test uncovered a problem where the hole punching operation appeared to finish with no error, but apparently only created 268M extents instead of the 10 billion it was supposed to. Further, trying to punch out extents that should have been present resulted in success, but no change in the extent count. It looked like a silent failure. While running the test and observing the behaviour in real time, I observed the extent coutn growing at ~2M extents/minute, and saw this after about an hour: # xfs_io -f -c "stat" /mnt/scratch/big-file |grep next ; \ > sleep 60 ; \ > xfs_io -f -c "stat" /mnt/scratch/big-file |grep next fsxattr.nextents = 127657993 fsxattr.nextents = 129683339 # And a few minutes later this: # xfs_io -f -c "stat" /mnt/scratch/big-file |grep next fsxattr.nextents = 4177861124 # Ah, what? Where did that 4 billion extra extents suddenly come from? Stop the workload, unmount, mount: # xfs_io -f -c "stat" /mnt/scratch/big-file |grep next fsxattr.nextents = 166044375 # And it's back at the expected number. i.e. the extent count is correct on disk, but it's screwed up in memory. I loaded up the extent list, and immediately: # xfs_io -f -c "stat" /mnt/scratch/big-file |grep next fsxattr.nextents = 4192576215 # It's bad again. So, where does that number come from? xfs_fill_fsxattr(): if (ip->i_df.if_flags & XFS_IFEXTENTS) fa->fsx_nextents = xfs_iext_count(&ip->i_df); else fa->fsx_nextents = ip->i_d.di_nextents; And that's the behaviour I just saw in a nutshell. The on disk count is correct, but once the tree is loaded into memory, it goes whacky. Clearly there's something wrong with xfs_iext_count(): inline xfs_extnum_t xfs_iext_count(struct xfs_ifork *ifp) { return ifp->if_bytes / sizeof(struct xfs_iext_rec); } Simple enough, but 134M extents is 2**27, and that's right about where things went wrong. A struct xfs_iext_rec is 16 bytes in size, which means 2**27 * 2**4 = 2**31 and we're right on target for an integer overflow. And, sure enough: struct xfs_ifork { int if_bytes; /* bytes in if_u1 */ .... Once we get 2**27 extents in a file, we overflow if_bytes and the in-core extent count goes wrong. And when we reach 2**28 extents, if_bytes wraps back to zero and things really start to go wrong there. This is where the silent failure comes from - only the first 2**28 extents can be looked up directly due to the overflow, all the extents above this index wrap back to somewhere in the first 2**28 extents. Hence with a regular pattern, trying to punch a hole in the range that didn't have holes mapped to a hole in the first 2**28 extents and so "succeeded" without changing anything. Hence "silent failure"... Fix this by converting if_bytes to a int64_t and converting all the index variables and size calculations to use int64_t types to avoid overflows in future. Signed integers are still used to enable easy detection of extent count underflows. This enables scalability of extent counts to the limits of the on-disk format - MAXEXTNUM (2**31) extents. Current testing is at over 500M extents and still going: fsxattr.nextents = 517310478 Reported-by: Zorro Lang <zlang@redhat.com> Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2019-02-11xfs: update fork seq counter on data fork changesBrian Foster1-1/+1
The sequence counter in the xfs_ifork structure is only updated on COW forks. This is because the counter is currently only used to optimize out repetitive COW fork checks at writeback time. Tweak the extent code to update the seq counter regardless of the fork type in preparation for using this counter on data forks as well. Signed-off-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Allison Henderson <allison.henderson@oracle.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-31xfs: maintain a sequence count for inode fork manipulationsChristoph Hellwig1-0/+1
Add a simple 32-bit unsigned integer as the sequence count for modifications to the extent list in the inode fork. This will be used to optimize away extent list lookups in the writeback code. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Carlos Maiolino <cmaiolino@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-07-30xfs: remove the xfs_ifork_t typedefChristoph Hellwig1-2/+2
We only have a few more callers left, so seize the opportunity and kill it off. 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>
2018-07-30xfs: remove if_real_bytesChristoph Hellwig1-1/+0
The field is only used for asserts, and to track if we really need to do realloc when growing the inode fork data. But the krealloc function already performs this check internally, so there is no need to keep track of the real allocation size. This will free space in the inode fork for keeping a sequence counter of changes to the extent list. 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>
2018-06-06xfs: convert to SPDX license tagsDave Chinner1-13/+1
Remove the verbose license text from XFS files and replace them with SPDX tags. This does not change the license of any of the code, merely refers to the common, up-to-date license files in LICENSES/ This change was mostly scripted. fs/xfs/Makefile and fs/xfs/libxfs/xfs_fs.h were modified by hand, the rest were detected and modified by the following command: for f in `git grep -l "GNU General" fs/xfs/` ; do echo $f cat $f | awk -f hdr.awk > $f.new mv -f $f.new $f done And the hdr.awk script that did the modification (including detecting the difference between GPL-2.0 and GPL-2.0+ licenses) is as follows: $ cat hdr.awk BEGIN { hdr = 1.0 tag = "GPL-2.0" str = "" } /^ \* This program is free software/ { hdr = 2.0; next } /any later version./ { tag = "GPL-2.0+" next } /^ \*\// { if (hdr > 0.0) { print "// SPDX-License-Identifier: " tag print str print $0 str="" hdr = 0.0 next } print $0 next } /^ \* / { if (hdr > 1.0) next if (hdr > 0.0) { if (str != "") str = str "\n" str = str $0 next } print $0 next } /^ \*/ { if (hdr > 0.0) next print $0 next } // { if (hdr > 0.0) { if (str != "") str = str "\n" str = str $0 next } print $0 } END { } $ Signed-off-by: Dave Chinner <dchinner@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2018-01-08xfs: provide a centralized method for verifying inline fork dataDarrick J. Wong1-0/+14
Replace the current haphazard dir2 shortform verifier callsites with a centralized verifier function that can be called either with the default verifier functions or with a custom set. This helps us strengthen integrity checking while providing us with flexibility for repair tools. xfs_repair wants this to be able to supply its own verifier functions when trying to fix possibly corrupt metadata. Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com> Reviewed-by: Dave Chinner <dchinner@redhat.com>
2017-11-06xfs: remove the nr_extents argument to xfs_iext_removeChristoph Hellwig1-1/+1
We only have two places that remove 2 extents at the same time, so unroll the loop there. 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>
2017-11-06xfs: remove the nr_extents argument to xfs_iext_insertChristoph Hellwig1-1/+1
We only have two places that insert 2 extents at the same time, so unroll the loop there. 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>
2017-11-06xfs: use a b+tree for the in-core extent listChristoph Hellwig1-77/+7
Replace the current linear list and the indirection array for the in-core extent list with a b+tree to avoid the need for larger memory allocations for the indirection array when lots of extents are present. The current extent list implementations leads to heavy pressure on the memory allocator when modifying files with a high extent count, and can lead to high latencies because of that. The replacement is a b+tree with a few quirks. The leaf nodes directly store the extent record in two u64 values. The encoding is a little bit different from the existing in-core extent records so that the start offset and length which are required for lookups can be retreived with simple mask operations. The inner nodes store a 64-bit key containing the start offset in the first half of the node, and the pointers to the next lower level in the second half. In either case we walk the node from the beginninig to the end and do a linear search, as that is more efficient for the low number of cache lines touched during a search (2 for the inner nodes, 4 for the leaf nodes) than a binary search. We store termination markers (zero length for the leaf nodes, an otherwise impossible high bit for the inner nodes) to terminate the key list / records instead of storing a count to use the available cache lines as efficiently as possible. One quirk of the algorithm is that while we normally split a node half and half like usual btree implementations we just spill over entries added at the very end of the list to a new node on its own. This means we get a 100% fill grade for the common cases of bulk insertion when reading an inode into memory, and when only sequentially appending to a file. The downside is a slightly higher chance of splits on the first random insertions. Both insert and removal manually recurse into the lower levels, but the bulk deletion of the whole tree is still implemented as a recursive function call, although one limited by the overall depth and with very little stack usage in every iteration. For the first few extents we dynamically grow the list from a single extent to the next powers of two until we have a first full leaf block and that building the actual tree. The code started out based on the generic lib/btree.c code from Joern Engel based on earlier work from Peter Zijlstra, but has since been rewritten beyond recognition. 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>
2017-11-06xfs: remove support for inlining data/extents into the inode forkChristoph Hellwig1-11/+0
Supporting a small bit of data inside the inode fork blows up the fork size a lot, removing the 32 bytes of inline data halves the effective size of the inode fork (and it still has a lot of unused padding left), and the performance of a single kmalloc doesn't show up compared to the size to read an inode or create one. It also simplifies the fork management code a lot. 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>
2017-11-06xfs: introduce the xfs_iext_cursor abstractionChristoph Hellwig1-8/+79
Add a new xfs_iext_cursor structure to hide the direct extent map index manipulations. In addition to the existing lookup/get/insert/ remove and update routines new primitives to get the first and last extent cursor, as well as moving up and down by one extent are provided. Also new are convenience to increment/decrement the cursor and retreive the new extent, as well as to peek into the previous/next extent without updating the cursor and last but not least a macro to iterate over all extents in a fork. [darrick: rename for_each_iext to for_each_xfs_iext] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Brian Foster <bfoster@redhat.com> Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com> Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
2017-10-26xfs: add a new xfs_iext_lookup_extent_before helperChristoph Hellwig1-0/+4
This helper looks up the last extent the covers space before the passed in block number. This is useful for truncate and similar operations that operate backwards over the extent list. For xfs_bunmapi it also is a slight optimization as we can return early if there are not extents at or below the end of the to be truncated range. 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>
2017-10-26xfs: remove if_rdevChristoph Hellwig1-1/+0
We can simply use the i_rdev field in the Linux inode and just convert to and from the XFS dev_t when reading or logging/writing the inode. 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>
2017-10-26xfs: remove the never fully implemented UUID fork formatChristoph Hellwig1-1/+0
Remove the dead code dealing with the UUID fork format that was never implemented in Linux (and neither in IRIX as far as I know). 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>