/* * Copyright (c) 1999 Al Smith * * Portions derived from work (c) 1995,1996 Christian Vogelgsang. * Portions derived from IRIX header files (c) 1988 Silicon Graphics */ #ifndef _EFS_EFS_H_ #define _EFS_EFS_H_ #ifdef pr_fmt #undef pr_fmt #endif #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include #include #define EFS_VERSION "1.0a" static const char cprt[] = "EFS: "EFS_VERSION" - (c) 1999 Al Smith "; /* 1 block is 512 bytes */ #define EFS_BLOCKSIZE_BITS 9 #define EFS_BLOCKSIZE (1 << EFS_BLOCKSIZE_BITS) typedef int32_t efs_block_t; typedef uint32_t efs_ino_t; #define EFS_DIRECTEXTENTS 12 /* * layout of an extent, in memory and on disk. 8 bytes exactly. */ typedef union extent_u { unsigned char raw[8]; struct extent_s { unsigned int ex_magic:8; /* magic # (zero) */ unsigned int ex_bn:24; /* basic block */ unsigned int ex_length:8; /* numblocks in this extent */ unsigned int ex_offset:24; /* logical offset into file */ } cooked; } efs_extent; typedef struct edevs { __be16 odev; __be32 ndev; } efs_devs; /* * extent based filesystem inode as it appears on disk. The efs inode * is exactly 128 bytes long. */ struct efs_dinode { __be16 di_mode; /* mode and type of file */ __be16 di_nlink; /* number of links to file */ __be16 di_uid; /* owner's user id */ __be16 di_gid; /* owner's group id */ __be32 di_size; /* number of bytes in file */ __be32 di_atime; /* time last accessed */ __be32 di_mtime; /* time last modified */ __be32 di_ctime; /* time created */ __be32 di_gen; /* generation number */ __be16 di_numextents; /* # of extents */ u_char di_version; /* version of inode */ u_char di_spare; /* spare - used by AFS */ union di_addr { efs_extent di_extents[EFS_DIRECTEXTENTS]; efs_devs di_dev; /* device for IFCHR/IFBLK */ } di_u; }; /* efs inode storage in memory */ struct efs_inode_info { int numextents; int lastextent; efs_extent extents[EFS_DIRECTEXTENTS]; struct inode vfs_inode; }; #include #define EFS_DIRBSIZE_BITS EFS_BLOCKSIZE_BITS #define EFS_DIRBSIZE (1 << EFS_DIRBSIZE_BITS) struct efs_dentry { __be32 inode; unsigned char namelen; char name[3]; }; #define EFS_DENTSIZE (sizeof(struct efs_dentry) - 3 + 1) #define EFS_MAXNAMELEN ((1 << (sizeof(char) * 8)) - 1) #define EFS_DIRBLK_HEADERSIZE 4 #define EFS_DIRBLK_MAGIC 0xbeef /* moo */ struct efs_dir { __be16 magic; unsigned char firstused; unsigned char slots; unsigned char space[EFS_DIRBSIZE - EFS_DIRBLK_HEADERSIZE]; }; #define EFS_MAXENTS \ ((EFS_DIRBSIZE - EFS_DIRBLK_HEADERSIZE) / \ (EFS_DENTSIZE + sizeof(char))) #define EFS_SLOTAT(dir, slot) EFS_REALOFF((dir)->space[slot]) #define EFS_REALOFF(offset) ((offset << 1)) static inline struct efs_inode_info *INODE_INFO(struct inode *inode) { return container_of(inode, struct efs_inode_info, vfs_inode); } static inline struct efs_sb_info *SUPER_INFO(struct super_block *sb) { return sb->s_fs_info; } struct statfs; struct fid; extern const struct inode_operations efs_dir_inode_operations; extern const struct file_operations efs_dir_operations; extern const struct address_space_operations efs_symlink_aops; extern struct inode *efs_iget(struct super_block *, unsigned long); extern efs_block_t efs_map_block(struct inode *, efs_block_t); extern int efs_get_block(struct inode *, sector_t, struct buffer_head *, int); extern struct dentry *efs_lookup(struct inode *, struct dentry *, unsigned int); extern struct dentry *efs_fh_to_dentry(struct super_block *sb, struct fid *fid, int fh_len, int fh_type); extern struct dentry *efs_fh_to_parent(struct super_block *sb, struct fid *fid, int fh_len, int fh_type); extern struct dentry *efs_get_parent(struct dentry *); extern int efs_bmap(struct inode *, int); #endif /* _EFS_EFS_H_ */ >space:mode:
authorDouglas Miller <dougmill@linux.vnet.ibm.com>2017-01-28 06:42:20 -0600
committerTejun Heo <tj@kernel.org>2017-01-28 07:49:42 -0500
commit966d2b04e070bc040319aaebfec09e0144dc3341 (patch)
tree4b96156e3d1dd4dfd6039b7c219c9dc4616da52d /include/xen/interface/hvm/hvm_op.h
parent1b1bc42c1692e9b62756323c675a44cb1a1f9dbd (diff)
percpu-refcount: fix reference leak during percpu-atomic transition
percpu_ref_tryget() and percpu_ref_tryget_live() should return "true" IFF they acquire a reference. But the return value from atomic_long_inc_not_zero() is a long and may have high bits set, e.g. PERCPU_COUNT_BIAS, and the return value of the tryget routines is bool so the reference may actually be acquired but the routines return "false" which results in a reference leak since the caller assumes it does not need to do a corresponding percpu_ref_put(). This was seen when performing CPU hotplug during I/O, as hangs in blk_mq_freeze_queue_wait where percpu_ref_kill (blk_mq_freeze_queue_start) raced with percpu_ref_tryget (blk_mq_timeout_work). Sample stack trace: __switch_to+0x2c0/0x450 __schedule+0x2f8/0x970 schedule+0x48/0xc0 blk_mq_freeze_queue_wait+0x94/0x120 blk_mq_queue_reinit_work+0xb8/0x180 blk_mq_queue_reinit_prepare+0x84/0xa0 cpuhp_invoke_callback+0x17c/0x600 cpuhp_up_callbacks+0x58/0x150 _cpu_up+0xf0/0x1c0 do_cpu_up+0x120/0x150 cpu_subsys_online+0x64/0xe0 device_online+0xb4/0x120 online_store+0xb4/0xc0 dev_attr_store+0x68/0xa0 sysfs_kf_write+0x80/0xb0 kernfs_fop_write+0x17c/0x250 __vfs_write+0x6c/0x1e0 vfs_write+0xd0/0x270 SyS_write+0x6c/0x110 system_call+0x38/0xe0 Examination of the queue showed a single reference (no PERCPU_COUNT_BIAS, and __PERCPU_REF_DEAD, __PERCPU_REF_ATOMIC set) and no requests. However, conditions at the time of the race are count of PERCPU_COUNT_BIAS + 0 and __PERCPU_REF_DEAD and __PERCPU_REF_ATOMIC set. The fix is to make the tryget routines use an actual boolean internally instead of the atomic long result truncated to a int. Fixes: e625305b3907 percpu-refcount: make percpu_ref based on longs instead of ints Link: https://bugzilla.kernel.org/show_bug.cgi?id=190751 Signed-off-by: Douglas Miller <dougmill@linux.vnet.ibm.com> Reviewed-by: Jens Axboe <axboe@fb.com> Signed-off-by: Tejun Heo <tj@kernel.org> Fixes: e625305b3907 ("percpu-refcount: make percpu_ref based on longs instead of ints") Cc: stable@vger.kernel.org # v3.18+
Diffstat (limited to 'include/xen/interface/hvm/hvm_op.h')