230 lines
8.8 KiB
C
230 lines
8.8 KiB
C
/* SPDX-License-Identifier: GPL-2.0 */
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#ifndef _LINUX_NAMEI_H
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#define _LINUX_NAMEI_H
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#include <linux/fs.h>
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#include <linux/kernel.h>
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#include <linux/path.h>
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#include <linux/fcntl.h>
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#include <linux/errno.h>
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#include <linux/fs_struct.h>
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enum { MAX_NESTED_LINKS = 8 };
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#define MAXSYMLINKS 40
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/*
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* Type of the last component on LOOKUP_PARENT
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*/
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enum {LAST_NORM, LAST_ROOT, LAST_DOT, LAST_DOTDOT};
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/* pathwalk mode */
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#define LOOKUP_FOLLOW BIT(0) /* follow links at the end */
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#define LOOKUP_DIRECTORY BIT(1) /* require a directory */
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#define LOOKUP_AUTOMOUNT BIT(2) /* force terminal automount */
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#define LOOKUP_EMPTY BIT(3) /* accept empty path [user_... only] */
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#define LOOKUP_LINKAT_EMPTY BIT(4) /* Linkat request with empty path. */
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#define LOOKUP_DOWN BIT(5) /* follow mounts in the starting point */
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#define LOOKUP_MOUNTPOINT BIT(6) /* follow mounts in the end */
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#define LOOKUP_REVAL BIT(7) /* tell ->d_revalidate() to trust no cache */
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#define LOOKUP_RCU BIT(8) /* RCU pathwalk mode; semi-internal */
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#define LOOKUP_CACHED BIT(9) /* Only do cached lookup */
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#define LOOKUP_PARENT BIT(10) /* Looking up final parent in path */
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/* 5 spare bits for pathwalk */
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/* These tell filesystem methods that we are dealing with the final component... */
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#define LOOKUP_OPEN BIT(16) /* ... in open */
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#define LOOKUP_CREATE BIT(17) /* ... in object creation */
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#define LOOKUP_EXCL BIT(18) /* ... in target must not exist */
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#define LOOKUP_RENAME_TARGET BIT(19) /* ... in destination of rename() */
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/* 4 spare bits for intent */
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/* Scoping flags for lookup. */
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#define LOOKUP_NO_SYMLINKS BIT(24) /* No symlink crossing. */
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#define LOOKUP_NO_MAGICLINKS BIT(25) /* No nd_jump_link() crossing. */
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#define LOOKUP_NO_XDEV BIT(26) /* No mountpoint crossing. */
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#define LOOKUP_BENEATH BIT(27) /* No escaping from starting point. */
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#define LOOKUP_IN_ROOT BIT(28) /* Treat dirfd as fs root. */
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/* LOOKUP_* flags which do scope-related checks based on the dirfd. */
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#define LOOKUP_IS_SCOPED (LOOKUP_BENEATH | LOOKUP_IN_ROOT)
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/* 3 spare bits for scoping */
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extern int path_pts(struct path *path);
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extern int user_path_at(int, const char __user *, unsigned, struct path *);
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struct dentry *lookup_one_qstr_excl(const struct qstr *name,
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struct dentry *base,
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unsigned int flags);
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extern int kern_path(const char *, unsigned, struct path *);
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struct dentry *kern_path_parent(const char *name, struct path *parent);
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extern struct dentry *start_creating_path(int, const char *, struct path *, unsigned int);
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extern struct dentry *start_creating_user_path(int, const char __user *, struct path *, unsigned int);
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extern void end_creating_path(const struct path *, struct dentry *);
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extern struct dentry *start_removing_path(const char *, struct path *);
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extern struct dentry *start_removing_user_path_at(int , const char __user *, struct path *);
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static inline void end_removing_path(const struct path *path , struct dentry *dentry)
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{
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end_creating_path(path, dentry);
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}
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int vfs_path_parent_lookup(struct filename *filename, unsigned int flags,
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struct path *parent, struct qstr *last, int *type,
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const struct path *root);
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int vfs_path_lookup(struct dentry *, struct vfsmount *, const char *,
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unsigned int, struct path *);
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extern struct dentry *try_lookup_noperm(struct qstr *, struct dentry *);
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extern struct dentry *lookup_noperm(struct qstr *, struct dentry *);
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extern struct dentry *lookup_noperm_unlocked(struct qstr *, struct dentry *);
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extern struct dentry *lookup_noperm_positive_unlocked(struct qstr *, struct dentry *);
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struct dentry *lookup_one(struct mnt_idmap *, struct qstr *, struct dentry *);
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struct dentry *lookup_one_unlocked(struct mnt_idmap *idmap,
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struct qstr *name, struct dentry *base);
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struct dentry *lookup_one_positive_unlocked(struct mnt_idmap *idmap,
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struct qstr *name,
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struct dentry *base);
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struct dentry *lookup_one_positive_killable(struct mnt_idmap *idmap,
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struct qstr *name,
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struct dentry *base);
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struct dentry *start_creating(struct mnt_idmap *idmap, struct dentry *parent,
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struct qstr *name);
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struct dentry *start_removing(struct mnt_idmap *idmap, struct dentry *parent,
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struct qstr *name);
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struct dentry *start_creating_killable(struct mnt_idmap *idmap,
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struct dentry *parent,
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struct qstr *name);
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struct dentry *start_removing_killable(struct mnt_idmap *idmap,
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struct dentry *parent,
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struct qstr *name);
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struct dentry *start_creating_noperm(struct dentry *parent, struct qstr *name);
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struct dentry *start_removing_noperm(struct dentry *parent, struct qstr *name);
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struct dentry *start_creating_dentry(struct dentry *parent,
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struct dentry *child);
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struct dentry *start_removing_dentry(struct dentry *parent,
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struct dentry *child);
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/* end_creating - finish action started with start_creating
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* @child: dentry returned by start_creating() or vfs_mkdir()
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*
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* Unlock and release the child. This can be called after
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* start_creating() whether that function succeeded or not,
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* but it is not needed on failure.
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*
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* If vfs_mkdir() was called then the value returned from that function
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* should be given for @child rather than the original dentry, as vfs_mkdir()
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* may have provided a new dentry.
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*
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*
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* If vfs_mkdir() was not called, then @child will be a valid dentry and
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* @parent will be ignored.
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*/
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static inline void end_creating(struct dentry *child)
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{
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end_dirop(child);
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}
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/* end_creating_keep - finish action started with start_creating() and return result
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* @child: dentry returned by start_creating() or vfs_mkdir()
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*
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* Unlock and return the child. This can be called after
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* start_creating() whether that function succeeded or not,
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* but it is not needed on failure.
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*
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* If vfs_mkdir() was called then the value returned from that function
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* should be given for @child rather than the original dentry, as vfs_mkdir()
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* may have provided a new dentry.
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*
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* Returns: @child, which may be a dentry or an error.
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*
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*/
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static inline struct dentry *end_creating_keep(struct dentry *child)
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{
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if (!IS_ERR(child))
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dget(child);
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end_dirop(child);
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return child;
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}
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/**
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* end_removing - finish action started with start_removing
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* @child: dentry returned by start_removing()
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* @parent: dentry given to start_removing()
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*
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* Unlock and release the child.
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*
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* This is identical to end_dirop(). It can be passed the result of
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* start_removing() whether that was successful or not, but it not needed
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* if start_removing() failed.
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*/
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static inline void end_removing(struct dentry *child)
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{
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end_dirop(child);
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}
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extern int follow_down_one(struct path *);
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extern int follow_down(struct path *path, unsigned int flags);
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extern int follow_up(struct path *);
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extern struct dentry *lock_rename(struct dentry *, struct dentry *);
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extern struct dentry *lock_rename_child(struct dentry *, struct dentry *);
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extern void unlock_rename(struct dentry *, struct dentry *);
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int start_renaming(struct renamedata *rd, int lookup_flags,
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struct qstr *old_last, struct qstr *new_last);
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int start_renaming_dentry(struct renamedata *rd, int lookup_flags,
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struct dentry *old_dentry, struct qstr *new_last);
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int start_renaming_two_dentries(struct renamedata *rd,
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struct dentry *old_dentry, struct dentry *new_dentry);
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void end_renaming(struct renamedata *rd);
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/**
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* mode_strip_umask - handle vfs umask stripping
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* @dir: parent directory of the new inode
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* @mode: mode of the new inode to be created in @dir
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*
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* In most filesystems, umask stripping depends on whether or not the
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* filesystem supports POSIX ACLs. If the filesystem doesn't support it umask
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* stripping is done directly in here. If the filesystem does support POSIX
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* ACLs umask stripping is deferred until the filesystem calls
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* posix_acl_create().
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*
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* Some filesystems (like NFSv4) also want to avoid umask stripping by the
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* VFS, but don't support POSIX ACLs. Those filesystems can set SB_I_NOUMASK
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* to get this effect without declaring that they support POSIX ACLs.
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*
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* Returns: mode
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*/
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static inline umode_t __must_check mode_strip_umask(const struct inode *dir, umode_t mode)
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{
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if (!IS_POSIXACL(dir) && !(dir->i_sb->s_iflags & SB_I_NOUMASK))
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mode &= ~current_umask();
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return mode;
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}
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extern int __must_check nd_jump_link(const struct path *path);
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static inline void nd_terminate_link(void *name, size_t len, size_t maxlen)
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{
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((char *) name)[min(len, maxlen)] = '\0';
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}
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/**
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* retry_estale - determine whether the caller should retry an operation
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* @error: the error that would currently be returned
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* @flags: flags being used for next lookup attempt
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*
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* Check to see if the error code was -ESTALE, and then determine whether
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* to retry the call based on whether "flags" already has LOOKUP_REVAL set.
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*
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* Returns true if the caller should try the operation again.
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*/
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static inline bool
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retry_estale(const long error, const unsigned int flags)
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{
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return unlikely(error == -ESTALE && !(flags & LOOKUP_REVAL));
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}
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#endif /* _LINUX_NAMEI_H */
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