函数逻辑报告

Linux Kernel

v5.5.9

Brick Technologies Co., Ltd

Source Code:fs\d_path.c Create Date:2022-07-29 10:42:51
Last Modify:2020-03-12 14:18:49 Copyright©Brick
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函数名称：prepend_path - Prepend path string to a buffer*@path: the dentry/vfsmount to report*@root: root vfsmnt/dentry*@buffer: pointer to the end of the buffer*@buflen: pointer to buffer length* The function will first try to write out the pathname without taking

函数原型：static int prepend_path(const struct path *path, const struct path *root, char **buffer, int *buflen)

返回类型：int

参数：

类型参数名称
const struct path *path
const struct path *root
char **buffer
int *buflen
82  error等于0
83  m_seq等于0
87  _read_lock() - mark the beginning of an RCU read-side critical section* When synchronize_rcu() is invoked on one CPU while other CPUs* are within RCU read-side critical sections, then the* synchronize_rcu() is guaranteed to block until after all the other
88  restart_mnt :
89  ad_seqbegin_or_lock - begin a sequence number check or locking block*@lock: sequence lock*@seq : sequence number to be checked* First try it once optimistically without taking the lock. If that fails,* take the lock
90  seq等于0
91  _read_lock() - mark the beginning of an RCU read-side critical section* When synchronize_rcu() is invoked on one CPU while other CPUs* are within RCU read-side critical sections, then the* synchronize_rcu() is guaranteed to block until after all the other
92  restart :
93  bptr等于buffer
94  blen等于buflen
95  error等于0
96  dentry等于dentry
97  vfsmnt等于mnt
98  mnt等于real_mount(vfsmnt)
99  ad_seqbegin_or_lock - begin a sequence number check or locking block*@lock: sequence lock*@seq : sequence number to be checked* First try it once optimistically without taking the lock. If that fails,* take the lock
100  当dentry不等于dentry或vfsmnt不等于mnt循环
103  如果dentry恒等于 root of the mounted tree 或linux/include/linux/dcache.h* Dirent cache data structures* (C) Copyright 1997 Thomas Schoebel-Theuer,* with heavy changes by Linus Torvalds(dentry)则
104  parent等于READ_ONCE(mnt_parent)
106  如果dentry不等于 root of the mounted tree 则
107  bptr等于buffer
108  blen等于buflen
109  error等于3
110  退出
113  如果mnt不等于parent则
114  dentry等于READ_ONCE(mnt_mountpoint)
115  mnt等于parent
116  vfsmnt等于mnt
117  继续下一循环
119  如果is_mounted(vfsmnt)且非is_anon_ns( containing namespace )则error等于1
121  否则error等于2
123  退出
125  parent等于 parent directory
126  Prefetch instructions for Pentium III (+) and AMD Athlon (+)* It's not worth to care about 3dnow prefetches for the K6* because they are microcoded there and very slow.
127  error等于prepend_name - prepend a pathname in front of current buffer pointer*@buffer: buffer pointer*@buflen: allocated length of the buffer*@name: name string and length qstr structure* With RCU path tracing, it may race with d_move()
128  如果error则退出
131  dentry等于parent
133  如果非seq按位与1的值则_read_unlock() - marks the end of an RCU read-side critical section.* In most situations, rcu_read_unlock() is immune from deadlock.* However, in kernels built with CONFIG_RCU_BOOST, rcu_read_unlock()
135  如果need_seqretry( & rename_lock, seq)则
136  seq等于1
137  转到:restart
139  done_seqretry( & rename_lock, seq)
141  如果非m_seq按位与1的值则_read_unlock() - marks the end of an RCU read-side critical section.* In most situations, rcu_read_unlock() is immune from deadlock.* However, in kernels built with CONFIG_RCU_BOOST, rcu_read_unlock()
143  如果need_seqretry( & vfsmount lock may be taken for read to prevent changes to the* vfsmount hash, ie. during mountpoint lookups or walking back* up the tree.* It should be taken for write in all cases where the vfsmount, m_seq)则
144  m_seq等于1
145  转到:restart_mnt
147  done_seqretry( & vfsmount lock may be taken for read to prevent changes to the* vfsmount hash, ie. during mountpoint lookups or walking back* up the tree.* It should be taken for write in all cases where the vfsmount, m_seq)
149  如果error大于等于0且bptr恒等于buffer则
150  如果blen先自减小于0则error等于负ENAMETOOLONG
152  否则*bptr先自减等于'/'
155  buffer等于bptr
156  buflen等于blen
157  返回:error
调用者
名称描述
__d_path__d_path - return the path of a dentry*@path: the dentry/vfsmount to report*@root: root vfsmnt/dentry*@buf: buffer to return value in*@buflen: buffer length* Convert a dentry into an ASCII path name
d_absolute_path
path_with_deletedsame as __d_path but appends "(deleted)" for unlinked files.
SYSCALL_DEFINE2NOTE! The user-level library version returns a* character pointer