From: Shuning Zhang sunny.s.zhang@oracle.com Subject: ocfs2: protect extent tree in ocfs2_prepare_inode_for_write()

When the extent tree is modified, it should be protected by inode cluster lock and ip_alloc_sem.

The extent tree is accessed and modified in the ocfs2_prepare_inode_for_write, but isn't protected by ip_alloc_sem.

The following is a case. The function ocfs2_fiemap is accessing the extent tree, which is modified at the same time.

[47145.974472] kernel BUG at fs/ocfs2/extent_map.c:475! [47145.974480] invalid opcode: 0000 [#1] SMP [47145.974489] Modules linked in: tun ocfs2 ocfs2_nodemanager configfs ocfs2_stackglue xen_netback xen_blkback xen_gntalloc xen_gntdev xen_evtchn xenfs xen_privcmd vfat fat bnx2fc fcoe libfcoe libfc scsi_transport_fc sunrpc bridge 8021q mrp garp stp llc ib_iser rdma_cm ib_cm iw_cm ib_sa ib_mad ib_core ib_addr dm_round_robin dm_multipath sg pcspkr raid1 shpchp ipmi_devintf ipmi_msghandler ext4 jbd2 mbcache2 sd_mod nvme nvme_core bnxt_en xhci_pci xhci_hcd crc32c_intel be2iscsi bnx2i cnic uio cxgb4i cxgb4 cxgb3i libcxgbi ipv6 cxgb3 mdio qla4xxx wmi dm_mirror dm_region_hash dm_log dm_mod iscsi_tcp libiscsi_tcp libiscsi scsi_transport_iscsi iscsi_ibft iscsi_boot_sysfs [47145.974636] CPU: 16 PID: 14047 Comm: o2info Not tainted 4.1.12-124.23.1.el6uek.x86_64 #2 [47145.974646] Hardware name: Oracle Corporation ORACLE SERVER X7-2L/ASM, MB MECH, X7-2L, BIOS 42040600 10/19/2018 [47145.974658] task: ffff88019487e200 ti: ffff88003daa4000 task.ti: ffff88003daa4000 [47145.974667] RIP: e030:[<ffffffffa05e4840>] [<ffffffffa05e4840>] ocfs2_get_clusters_nocache.isra.11+0x390/0x550 [ocfs2] [47145.974708] RSP: e02b:ffff88003daa7d88 EFLAGS: 00010287 [47145.974713] RAX: 00000000000000de RBX: ffff8801d1104030 RCX: ffff8801d1104e10 [47145.974719] RDX: 00000000000000de RSI: 000000000009ec40 RDI: ffff8801d1104e24 [47145.974725] RBP: ffff88003daa7df8 R08: ffff88003daa7e38 R09: 0000000000000000 [47145.974732] R10: 000000000009ec3f R11: 0000000000000246 R12: 000000000009ec3f [47145.974739] R13: ffff88004c419000 R14: 0000000000000002 R15: ffff88003daa7e28 [47145.974754] FS: 00007fdbccc92720(0000) GS:ffff880358800000(0000) knlGS:ffff880358800000 [47145.974764] CS: e033 DS: 0000 ES: 0000 CR0: 0000000080050033 [47145.974772] CR2: 00007fd5dfcd8350 CR3: 0000000208677000 CR4: 0000000000042660 [47145.974785] Stack: [47145.974790] ffff88003daa7df8 00002000a05e249b ffff8801d1104000 ffff88003daa7e2c [47145.974802] ffff88003daa7e38 ffff88000cc484c0 ffff880145f5b478 0000000000000000 [47145.974811] 0000000000002000 ffff88000cc484c0 ffff88003daa7ea0 0000000000000000 [47145.974820] Call Trace: [47145.974837] [<ffffffffa05e53e3>] ocfs2_fiemap+0x1e3/0x430 [ocfs2] [47145.974848] [<ffffffff816f644f>] ? xen_hypervisor_callback+0x7f/0x120 [47145.974855] [<ffffffff816f6448>] ? xen_hypervisor_callback+0x78/0x120 [47145.974861] [<ffffffff816f64a3>] ? xen_hypervisor_callback+0xd3/0x120 [47145.974872] [<ffffffff81220905>] do_vfs_ioctl+0x155/0x510 [47145.974878] [<ffffffff81220d41>] SyS_ioctl+0x81/0xa0 [47145.974885] [<ffffffff816f1b9f>] ? system_call_after_swapgs+0xe9/0x190 [47145.974891] [<ffffffff816f1b98>] ? system_call_after_swapgs+0xe2/0x190 [47145.974899] [<ffffffff816f1b91>] ? system_call_after_swapgs+0xdb/0x190 [47145.974905] [<ffffffff816f1c5e>] system_call_fastpath+0x18/0xd8 [47145.974910] Code: 18 48 c7 c6 60 7f 65 a0 31 c0 bb e2 ff ff ff 48 8b 4a 40 48 8b 7a 28 48 c7 c2 78 2d 66 a0 e8 38 4f 05 00 e9 28 fe ff ff 0f 1f 00 <0f> 0b 66 0f 1f 44 00 00 bb 86 ff ff ff e9 13 fe ff ff 66 0f 1f [47145.975000] RIP [<ffffffffa05e4840>] ocfs2_get_clusters_nocache.isra.11+0x390/0x550 [ocfs2] [47145.975018] RSP <ffff88003daa7d88> [47145.989999] ---[ end trace c8aa0c8180e869dc ]--- [47146.087579] Kernel panic - not syncing: Fatal exception [47146.087691] Kernel Offset: disabled

This issue can be reproduced every week in a production environment.

This issue is related to the usage mode. If others use ocfs2 in this mode, the kernel will panic frequently.

[akpm@linux-foundation.org: coding style fixes] Link: http://lkml.kernel.org/r/1568772175-2906-2-git-send-email-sunny.s.zhang@orac... Signed-off-by: Shuning Zhang sunny.s.zhang@oracle.com Reviewed-by: Junxiao Bi junxiao.bi@oracle.com Reviewed-by: Gang He ghe@suse.com Cc: Mark Fasheh mark@fasheh.com Cc: Joel Becker jlbec@evilplan.org Cc: Joseph Qi jiangqi903@gmail.com Cc: Changwei Ge gechangwei@live.cn Cc: Jun Piao piaojun@huawei.com Cc: stable@vger.kernel.org Signed-off-by: Andrew Morton akpm@linux-foundation.org ---

fs/ocfs2/file.c | 125 ++++++++++++++++++++++++++++++++++++---------- 1 file changed, 99 insertions(+), 26 deletions(-)

--- a/fs/ocfs2/file.c~ocfs2-protect-extent-tree-in-the-ocfs2_prepare_inode_for_write +++ a/fs/ocfs2/file.c @@ -2125,26 +2125,89 @@ out: return ret; }

+static int ocfs2_inode_lock_for_extent_tree(struct inode *inode, + struct buffer_head **di_bh, + int meta_level, + int overwrite_io, + int write_sem, + int wait) +{ + int ret = 0; + + if (wait) + ret = ocfs2_inode_lock(inode, NULL, meta_level); + else + ret = ocfs2_try_inode_lock(inode, + overwrite_io ? NULL : di_bh, meta_level); + if (ret < 0) + goto out; + + if (wait) { + if (write_sem) + down_write(&OCFS2_I(inode)->ip_alloc_sem); + else + down_read(&OCFS2_I(inode)->ip_alloc_sem); + } else { + if (write_sem) + ret = down_write_trylock(&OCFS2_I(inode)->ip_alloc_sem); + else + ret = down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem); + + if (!ret) { + ret = -EAGAIN; + goto out_unlock; + } + } + + return ret; + +out_unlock: + brelse(*di_bh); + ocfs2_inode_unlock(inode, meta_level); +out: + return ret; +} + +static void ocfs2_inode_unlock_for_extent_tree(struct inode *inode, + struct buffer_head **di_bh, + int meta_level, + int write_sem) +{ + if (write_sem) + up_write(&OCFS2_I(inode)->ip_alloc_sem); + else + up_read(&OCFS2_I(inode)->ip_alloc_sem); + + brelse(*di_bh); + *di_bh = NULL; + + if (meta_level >= 0) + ocfs2_inode_unlock(inode, meta_level); +} + static int ocfs2_prepare_inode_for_write(struct file *file, loff_t pos, size_t count, int wait) { int ret = 0, meta_level = 0, overwrite_io = 0; + int write_sem = 0; struct dentry *dentry = file->f_path.dentry; struct inode *inode = d_inode(dentry); struct buffer_head *di_bh = NULL; + u32 cpos; + u32 clusters;

/* * We start with a read level meta lock and only jump to an ex * if we need to make modifications here. */ for(;;) { - if (wait) - ret = ocfs2_inode_lock(inode, NULL, meta_level); - else - ret = ocfs2_try_inode_lock(inode, - overwrite_io ? NULL : &di_bh, meta_level); + ret = ocfs2_inode_lock_for_extent_tree(inode, + &di_bh, + meta_level, + overwrite_io, + write_sem, + wait); if (ret < 0) { - meta_level = -1; if (ret != -EAGAIN) mlog_errno(ret); goto out; @@ -2156,15 +2219,8 @@ static int ocfs2_prepare_inode_for_write */ if (!wait && !overwrite_io) { overwrite_io = 1; - if (!down_read_trylock(&OCFS2_I(inode)->ip_alloc_sem)) { - ret = -EAGAIN; - goto out_unlock; - }

ret = ocfs2_overwrite_io(inode, di_bh, pos, count); - brelse(di_bh); - di_bh = NULL; - up_read(&OCFS2_I(inode)->ip_alloc_sem); if (ret < 0) { if (ret != -EAGAIN) mlog_errno(ret); @@ -2183,7 +2239,10 @@ static int ocfs2_prepare_inode_for_write * set inode->i_size at the end of a write. */ if (should_remove_suid(dentry)) { if (meta_level == 0) { - ocfs2_inode_unlock(inode, meta_level); + ocfs2_inode_unlock_for_extent_tree(inode, + &di_bh, + meta_level, + write_sem); meta_level = 1; continue; } @@ -2197,18 +2256,32 @@ static int ocfs2_prepare_inode_for_write

ret = ocfs2_check_range_for_refcount(inode, pos, count); if (ret == 1) { - ocfs2_inode_unlock(inode, meta_level); - meta_level = -1; + ocfs2_inode_unlock_for_extent_tree(inode, + &di_bh, + meta_level, + write_sem); + ret = ocfs2_inode_lock_for_extent_tree(inode, + &di_bh, + meta_level, + overwrite_io, + 1, + wait); + write_sem = 1; + if (ret < 0) { + if (ret != -EAGAIN) + mlog_errno(ret); + goto out; + }

- ret = ocfs2_prepare_inode_for_refcount(inode, - file, - pos, - count, - &meta_level); + cpos = pos >> OCFS2_SB(inode->i_sb)->s_clustersize_bits; + clusters = + ocfs2_clusters_for_bytes(inode->i_sb, pos + count) - cpos; + ret = ocfs2_refcount_cow(inode, di_bh, cpos, clusters, UINT_MAX); }

if (ret < 0) { - mlog_errno(ret); + if (ret != -EAGAIN) + mlog_errno(ret); goto out_unlock; }

@@ -2219,10 +2292,10 @@ out_unlock: trace_ocfs2_prepare_inode_for_write(OCFS2_I(inode)->ip_blkno, pos, count, wait);

- brelse(di_bh); - - if (meta_level >= 0) - ocfs2_inode_unlock(inode, meta_level); + ocfs2_inode_unlock_for_extent_tree(inode, + &di_bh, + meta_level, + write_sem);

out: return ret; _