/* * QNX4 file system, Linux implementation. * * Version : 0.2.1 * * Using parts of the xiafs filesystem. * * History : * * 01-06-1998 by Richard Frowijn : first release. * 21-06-1998 by Frank Denis : dcache support, fixed error codes. * 04-07-1998 by Frank Denis : first step for rmdir/unlink. */ #include #include "qnx4.h" /* * check if the filename is correct. For some obscure reason, qnx writes a * new file twice in the directory entry, first with all possible options at 0 * and for a second time the way it is, they want us not to access the qnx * filesystem when whe are using linux. */ static int qnx4_match(int len, const char *name, struct buffer_head *bh, unsigned long *offset) { struct qnx4_inode_entry *de; int namelen, thislen; if (bh == NULL) { printk(KERN_WARNING "qnx4: matching unassigned buffer !\n"); return 0; } de = (struct qnx4_inode_entry *) (bh->b_data + *offset); *offset += QNX4_DIR_ENTRY_SIZE; if ((de->di_status & QNX4_FILE_LINK) != 0) { namelen = QNX4_NAME_MAX; } else { namelen = QNX4_SHORT_NAME_MAX; } thislen = strlen( de->di_fname ); if ( thislen > namelen ) thislen = namelen; if (len != thislen) { return 0; } if (strncmp(name, de->di_fname, len) == 0) { if ((de->di_status & (QNX4_FILE_USED|QNX4_FILE_LINK)) != 0) { return 1; } } return 0; } static struct buffer_head *qnx4_find_entry(int len, struct inode *dir, const char *name, struct qnx4_inode_entry **res_dir, int *ino) { unsigned long block, offset, blkofs; struct buffer_head *bh; *res_dir = NULL; bh = NULL; block = offset = blkofs = 0; while (blkofs * QNX4_BLOCK_SIZE + offset < dir->i_size) { if (!bh) { block = qnx4_block_map(dir, blkofs); if (block) bh = sb_bread(dir->i_sb, block); if (!bh) { blkofs++; continue; } } *res_dir = (struct qnx4_inode_entry *) (bh->b_data + offset); if (qnx4_match(len, name, bh, &offset)) { *ino = block * QNX4_INODES_PER_BLOCK + (offset / QNX4_DIR_ENTRY_SIZE) - 1; return bh; } if (offset < bh->b_size) { continue; } brelse(bh); bh = NULL; offset = 0; blkofs++; } brelse(bh); *res_dir = NULL; return NULL; } struct dentry * qnx4_lookup(struct inode *dir, struct dentry *dentry, unsigned int flags) { int ino; struct qnx4_inode_entry *de; struct qnx4_link_info *lnk; struct buffer_head *bh; const char *name = dentry->d_name.name; int len = dentry->d_name.len; struct inode *foundinode = NULL; if (!(bh = qnx4_find_entry(len, dir, name, &de, &ino))) goto out; /* The entry is linked, let's get the real info */ if ((de->di_status & QNX4_FILE_LINK) == QNX4_FILE_LINK) { lnk = (struct qnx4_link_info *) de; ino = (le32_to_cpu(lnk->dl_inode_blk) - 1) * QNX4_INODES_PER_BLOCK + lnk->dl_inode_ndx; } brelse(bh); foundinode = qnx4_iget(dir->i_sb, ino); if (IS_ERR(foundinode)) { QNX4DEBUG((KERN_ERR "qnx4: lookup->iget -> error %ld\n", PTR_ERR(foundinode))); return ERR_CAST(foundinode); } out: d_add(dentry, foundinode); return NULL; } 4e070bc040319aaebfec09e0144dc3341'>net/8021q/Kconfig
diff options
context:
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 /net/8021q/Kconfig
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 'net/8021q/Kconfig')