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authorRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2010-08-13 12:42:24 +0900
committerRyusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>2010-08-16 11:08:36 +0900
commitaf4e36318edb848fcc0a8d5f75000ca00cdc7595 (patch)
treec23ce8d1839f31ec4c472da184f16542a59752dd /fs/nilfs2
parentda5cabf80e2433131bf0ed8993abc0f7ea618c73 (diff)
nilfs2: fix list corruption after ifile creation failure
If nilfs_attach_checkpoint() gets a memory allocation failure during creation of ifile, it will return without removing nilfs_sb_info struct from ns_supers list. When a concurrently mounted snapshot is unmounted or another new snapshot is mounted after that, this causes kernel oops as below: > BUG: unable to handle kernel NULL pointer dereference at (null) > IP: [<f83662ff>] nilfs_find_sbinfo+0x74/0xa4 [nilfs2] > *pde = 00000000 > Oops: 0000 [#1] SMP <snip> > Call Trace: > [<f835dc29>] ? nilfs_get_sb+0x165/0x532 [nilfs2] > [<c1173c87>] ? ida_get_new_above+0x16d/0x187 > [<c109a7f8>] ? alloc_vfsmnt+0x7e/0x10a > [<c1070790>] ? kstrdup+0x2c/0x40 > [<c1089041>] ? vfs_kern_mount+0x96/0x14e > [<c108913d>] ? do_kern_mount+0x32/0xbd > [<c109b331>] ? do_mount+0x642/0x6a1 > [<c101a415>] ? do_page_fault+0x0/0x2d1 > [<c1099c00>] ? copy_mount_options+0x80/0xe2 > [<c10705d8>] ? strndup_user+0x48/0x67 > [<c109b3f1>] ? sys_mount+0x61/0x90 > [<c10027cc>] ? sysenter_do_call+0x12/0x22 This fixes the problem. Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Tested-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp> Cc: stable@kernel.org
Diffstat (limited to 'fs/nilfs2')
-rw-r--r--fs/nilfs2/super.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/fs/nilfs2/super.c b/fs/nilfs2/super.c
index 1fa86b9df73b..bee60c04109a 100644
--- a/fs/nilfs2/super.c
+++ b/fs/nilfs2/super.c
@@ -400,9 +400,10 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
list_add(&sbi->s_list, &nilfs->ns_supers);
up_write(&nilfs->ns_super_sem);
+ err = -ENOMEM;
sbi->s_ifile = nilfs_ifile_new(sbi, nilfs->ns_inode_size);
if (!sbi->s_ifile)
- return -ENOMEM;
+ goto delist;
down_read(&nilfs->ns_segctor_sem);
err = nilfs_cpfile_get_checkpoint(nilfs->ns_cpfile, cno, 0, &raw_cp,
@@ -433,6 +434,7 @@ int nilfs_attach_checkpoint(struct nilfs_sb_info *sbi, __u64 cno)
nilfs_mdt_destroy(sbi->s_ifile);
sbi->s_ifile = NULL;
+ delist:
down_write(&nilfs->ns_super_sem);
list_del_init(&sbi->s_list);
up_write(&nilfs->ns_super_sem);