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author | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2009-04-29 21:21:00 +0400 |
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committer | Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> | 2009-05-11 07:57:46 +0400 |
commit | 47eb6b9c8fa963c9f49967ad1d9d7ec947d15b68 (patch) | |
tree | f69916e4135bd4550b11a8faa631eacd78fddded /fs/nilfs2 | |
parent | 843382370ec614768ac13582405f93635cf3637c (diff) | |
download | linux-47eb6b9c8fa963c9f49967ad1d9d7ec947d15b68.tar.xz |
nilfs2: fix possible circular locking for get information ioctls
This is one of two patches which are to correct possible circular
locking between mm->mmap_sem and nilfs->ns_segctor_sem.
The problem was detected by lockdep check as follows:
=======================================================
[ INFO: possible circular locking dependency detected ]
2.6.30-rc3-nilfs-00002-g3552613 #6
-------------------------------------------------------
mmap/5418 is trying to acquire lock:
(&nilfs->ns_segctor_sem){++++.+}, at: [<d0d0e852>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
but task is already holding lock:
(&mm->mmap_sem){++++++}, at: [<c043700a>] do_page_fault+0x1d8/0x30a
which lock already depends on the new lock.
the existing dependency chain (in reverse order) is:
-> #1 (&mm->mmap_sem){++++++}:
[<c01470a5>] __lock_acquire+0x1066/0x13b0
[<c01474a9>] lock_acquire+0xba/0xdd
[<c01836bc>] might_fault+0x68/0x88
[<c023c730>] copy_to_user+0x2c/0xfc
[<d0d11b4f>] nilfs_ioctl_wrap_copy+0x103/0x160 [nilfs2]
[<d0d11fa9>] nilfs_ioctl+0x30a/0x3b0 [nilfs2]
[<c01a3be7>] vfs_ioctl+0x22/0x69
[<c01a408e>] do_vfs_ioctl+0x460/0x499
[<c01a4107>] sys_ioctl+0x40/0x5a
[<c01031a4>] sysenter_do_call+0x12/0x38
[<ffffffff>] 0xffffffff
-> #0 (&nilfs->ns_segctor_sem){++++.+}:
[<c0146e0b>] __lock_acquire+0xdcc/0x13b0
[<c01474a9>] lock_acquire+0xba/0xdd
[<c0433f1d>] down_read+0x2a/0x3e
[<d0d0e852>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
[<d0cfe0e5>] nilfs_page_mkwrite+0xe7/0x154 [nilfs2]
[<c0183b0b>] __do_fault+0x165/0x376
[<c01855cd>] handle_mm_fault+0x287/0x5d1
[<c043712d>] do_page_fault+0x2fb/0x30a
[<c0435462>] error_code+0x72/0x78
[<ffffffff>] 0xffffffff
other info that might help us debug this:
1 lock held by mmap/5418:
#0: (&mm->mmap_sem){++++++}, at: [<c043700a>] do_page_fault+0x1d8/0x30a
stack backtrace:
Pid: 5418, comm: mmap Not tainted 2.6.30-rc3-nilfs-00002-g3552613 #6
Call Trace:
[<c0432145>] ? printk+0xf/0x12
[<c0145c48>] print_circular_bug_tail+0xaa/0xb5
[<c0146e0b>] __lock_acquire+0xdcc/0x13b0
[<d0d10149>] ? nilfs_sufile_get_stat+0x1e/0x105 [nilfs2]
[<c013b59a>] ? up_read+0x16/0x2c
[<d0d10225>] ? nilfs_sufile_get_stat+0xfa/0x105 [nilfs2]
[<c01474a9>] lock_acquire+0xba/0xdd
[<d0d0e852>] ? nilfs_transaction_begin+0xb6/0x10c [nilfs2]
[<c0433f1d>] down_read+0x2a/0x3e
[<d0d0e852>] ? nilfs_transaction_begin+0xb6/0x10c [nilfs2]
[<d0d0e852>] nilfs_transaction_begin+0xb6/0x10c [nilfs2]
[<d0cfe0e5>] nilfs_page_mkwrite+0xe7/0x154 [nilfs2]
[<c0183b0b>] __do_fault+0x165/0x376
[<c01855cd>] handle_mm_fault+0x287/0x5d1
[<c043700a>] ? do_page_fault+0x1d8/0x30a
[<c013b54f>] ? down_read_trylock+0x39/0x43
[<c043712d>] do_page_fault+0x2fb/0x30a
[<c0436e32>] ? do_page_fault+0x0/0x30a
[<c0435462>] error_code+0x72/0x78
[<c0436e32>] ? do_page_fault+0x0/0x30a
This makes the lock granularity of nilfs->ns_segctor_sem finer than
that of the mmap semaphore for ioctl commands except
nilfs_clean_segments().
The successive patch ("nilfs2: fix lock order reversal in
nilfs_clean_segments ioctl") is required to fully resolve the problem.
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Diffstat (limited to 'fs/nilfs2')
-rw-r--r-- | fs/nilfs2/ioctl.c | 100 |
1 files changed, 38 insertions, 62 deletions
diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c index be387c6b2d46..e3c693d37d69 100644 --- a/fs/nilfs2/ioctl.c +++ b/fs/nilfs2/ioctl.c @@ -147,29 +147,12 @@ static ssize_t nilfs_ioctl_do_get_cpinfo(struct the_nilfs *nilfs, __u64 *posp, int flags, void *buf, size_t size, size_t nmembs) { - return nilfs_cpfile_get_cpinfo(nilfs->ns_cpfile, posp, flags, buf, - nmembs); -} - -static int nilfs_ioctl_get_cpinfo(struct inode *inode, struct file *filp, - unsigned int cmd, void __user *argp) -{ - struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs; - struct nilfs_argv argv; int ret; - if (copy_from_user(&argv, argp, sizeof(argv))) - return -EFAULT; - down_read(&nilfs->ns_segctor_sem); - ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd), - nilfs_ioctl_do_get_cpinfo); + ret = nilfs_cpfile_get_cpinfo(nilfs->ns_cpfile, posp, flags, buf, + nmembs); up_read(&nilfs->ns_segctor_sem); - if (ret < 0) - return ret; - - if (copy_to_user(argp, &argv, sizeof(argv))) - ret = -EFAULT; return ret; } @@ -195,28 +178,11 @@ static ssize_t nilfs_ioctl_do_get_suinfo(struct the_nilfs *nilfs, __u64 *posp, int flags, void *buf, size_t size, size_t nmembs) { - return nilfs_sufile_get_suinfo(nilfs->ns_sufile, *posp, buf, nmembs); -} - -static int nilfs_ioctl_get_suinfo(struct inode *inode, struct file *filp, - unsigned int cmd, void __user *argp) -{ - struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs; - struct nilfs_argv argv; int ret; - if (copy_from_user(&argv, argp, sizeof(argv))) - return -EFAULT; - down_read(&nilfs->ns_segctor_sem); - ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd), - nilfs_ioctl_do_get_suinfo); + ret = nilfs_sufile_get_suinfo(nilfs->ns_sufile, *posp, buf, nmembs); up_read(&nilfs->ns_segctor_sem); - if (ret < 0) - return ret; - - if (copy_to_user(argp, &argv, sizeof(argv))) - ret = -EFAULT; return ret; } @@ -242,28 +208,11 @@ static ssize_t nilfs_ioctl_do_get_vinfo(struct the_nilfs *nilfs, __u64 *posp, int flags, void *buf, size_t size, size_t nmembs) { - return nilfs_dat_get_vinfo(nilfs_dat_inode(nilfs), buf, nmembs); -} - -static int nilfs_ioctl_get_vinfo(struct inode *inode, struct file *filp, - unsigned int cmd, void __user *argp) -{ - struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs; - struct nilfs_argv argv; int ret; - if (copy_from_user(&argv, argp, sizeof(argv))) - return -EFAULT; - down_read(&nilfs->ns_segctor_sem); - ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd), - nilfs_ioctl_do_get_vinfo); + ret = nilfs_dat_get_vinfo(nilfs_dat_inode(nilfs), buf, nmembs); up_read(&nilfs->ns_segctor_sem); - if (ret < 0) - return ret; - - if (copy_to_user(argp, &argv, sizeof(argv))) - ret = -EFAULT; return ret; } @@ -276,17 +225,21 @@ nilfs_ioctl_do_get_bdescs(struct the_nilfs *nilfs, __u64 *posp, int flags, struct nilfs_bdesc *bdescs = buf; int ret, i; + down_read(&nilfs->ns_segctor_sem); for (i = 0; i < nmembs; i++) { ret = nilfs_bmap_lookup_at_level(bmap, bdescs[i].bd_offset, bdescs[i].bd_level + 1, &bdescs[i].bd_blocknr); if (ret < 0) { - if (ret != -ENOENT) + if (ret != -ENOENT) { + up_read(&nilfs->ns_segctor_sem); return ret; + } bdescs[i].bd_blocknr = 0; } } + up_read(&nilfs->ns_segctor_sem); return nmembs; } @@ -300,10 +253,8 @@ static int nilfs_ioctl_get_bdescs(struct inode *inode, struct file *filp, if (copy_from_user(&argv, argp, sizeof(argv))) return -EFAULT; - down_read(&nilfs->ns_segctor_sem); ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd), nilfs_ioctl_do_get_bdescs); - up_read(&nilfs->ns_segctor_sem); if (ret < 0) return ret; @@ -623,6 +574,29 @@ static int nilfs_ioctl_sync(struct inode *inode, struct file *filp, return 0; } +static int nilfs_ioctl_get_info(struct inode *inode, struct file *filp, + unsigned int cmd, void __user *argp, + ssize_t (*dofunc)(struct the_nilfs *, + __u64 *, int, + void *, size_t, size_t)) + +{ + struct the_nilfs *nilfs = NILFS_SB(inode->i_sb)->s_nilfs; + struct nilfs_argv argv; + int ret; + + if (copy_from_user(&argv, argp, sizeof(argv))) + return -EFAULT; + + ret = nilfs_ioctl_wrap_copy(nilfs, &argv, _IOC_DIR(cmd), dofunc); + if (ret < 0) + return ret; + + if (copy_to_user(argp, &argv, sizeof(argv))) + ret = -EFAULT; + return ret; +} + long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) { struct inode *inode = filp->f_dentry->d_inode; @@ -634,16 +608,18 @@ long nilfs_ioctl(struct file *filp, unsigned int cmd, unsigned long arg) case NILFS_IOCTL_DELETE_CHECKPOINT: return nilfs_ioctl_delete_checkpoint(inode, filp, cmd, argp); case NILFS_IOCTL_GET_CPINFO: - return nilfs_ioctl_get_cpinfo(inode, filp, cmd, argp); + return nilfs_ioctl_get_info(inode, filp, cmd, argp, + nilfs_ioctl_do_get_cpinfo); case NILFS_IOCTL_GET_CPSTAT: return nilfs_ioctl_get_cpstat(inode, filp, cmd, argp); case NILFS_IOCTL_GET_SUINFO: - return nilfs_ioctl_get_suinfo(inode, filp, cmd, argp); + return nilfs_ioctl_get_info(inode, filp, cmd, argp, + nilfs_ioctl_do_get_suinfo); case NILFS_IOCTL_GET_SUSTAT: return nilfs_ioctl_get_sustat(inode, filp, cmd, argp); case NILFS_IOCTL_GET_VINFO: - /* XXX: rename to ??? */ - return nilfs_ioctl_get_vinfo(inode, filp, cmd, argp); + return nilfs_ioctl_get_info(inode, filp, cmd, argp, + nilfs_ioctl_do_get_vinfo); case NILFS_IOCTL_GET_BDESCS: return nilfs_ioctl_get_bdescs(inode, filp, cmd, argp); case NILFS_IOCTL_CLEAN_SEGMENTS: |