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593 lines
14 KiB
593 lines
14 KiB
// SPDX-License-Identifier: GPL-2.0 |
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|
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/* |
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* Directory operations for Coda filesystem |
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* Original version: (C) 1996 P. Braam and M. Callahan |
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* Rewritten for Linux 2.1. (C) 1997 Carnegie Mellon University |
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* |
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* Carnegie Mellon encourages users to contribute improvements to |
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* the Coda project. Contact Peter Braam ([email protected]). |
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*/ |
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|
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#include <linux/types.h> |
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#include <linux/kernel.h> |
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#include <linux/time.h> |
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#include <linux/fs.h> |
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#include <linux/slab.h> |
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#include <linux/file.h> |
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#include <linux/stat.h> |
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#include <linux/errno.h> |
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#include <linux/string.h> |
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#include <linux/spinlock.h> |
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#include <linux/namei.h> |
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#include <linux/uaccess.h> |
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#include <linux/coda.h> |
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#include "coda_psdev.h" |
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#include "coda_linux.h" |
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#include "coda_cache.h" |
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#include "coda_int.h" |
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|
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/* same as fs/bad_inode.c */ |
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static int coda_return_EIO(void) |
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{ |
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return -EIO; |
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} |
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#define CODA_EIO_ERROR ((void *) (coda_return_EIO)) |
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|
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/* inode operations for directories */ |
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/* access routines: lookup, readlink, permission */ |
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static struct dentry *coda_lookup(struct inode *dir, struct dentry *entry, unsigned int flags) |
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{ |
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struct super_block *sb = dir->i_sb; |
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const char *name = entry->d_name.name; |
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size_t length = entry->d_name.len; |
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struct inode *inode; |
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int type = 0; |
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|
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if (length > CODA_MAXNAMLEN) { |
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pr_err("name too long: lookup, %s %zu\n", |
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coda_i2s(dir), length); |
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return ERR_PTR(-ENAMETOOLONG); |
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} |
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|
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/* control object, create inode on the fly */ |
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if (is_root_inode(dir) && coda_iscontrol(name, length)) { |
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inode = coda_cnode_makectl(sb); |
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type = CODA_NOCACHE; |
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} else { |
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struct CodaFid fid = { { 0, } }; |
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int error = venus_lookup(sb, coda_i2f(dir), name, length, |
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&type, &fid); |
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inode = !error ? coda_cnode_make(&fid, sb) : ERR_PTR(error); |
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} |
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if (!IS_ERR(inode) && (type & CODA_NOCACHE)) |
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coda_flag_inode(inode, C_VATTR | C_PURGE); |
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if (inode == ERR_PTR(-ENOENT)) |
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inode = NULL; |
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return d_splice_alias(inode, entry); |
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} |
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int coda_permission(struct user_namespace *mnt_userns, struct inode *inode, |
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int mask) |
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{ |
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int error; |
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if (mask & MAY_NOT_BLOCK) |
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return -ECHILD; |
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mask &= MAY_READ | MAY_WRITE | MAY_EXEC; |
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if (!mask) |
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return 0; |
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if ((mask & MAY_EXEC) && !execute_ok(inode)) |
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return -EACCES; |
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if (coda_cache_check(inode, mask)) |
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return 0; |
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error = venus_access(inode->i_sb, coda_i2f(inode), mask); |
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if (!error) |
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coda_cache_enter(inode, mask); |
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return error; |
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} |
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static inline void coda_dir_update_mtime(struct inode *dir) |
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{ |
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#ifdef REQUERY_VENUS_FOR_MTIME |
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/* invalidate the directory cnode's attributes so we refetch the |
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* attributes from venus next time the inode is referenced */ |
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coda_flag_inode(dir, C_VATTR); |
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#else |
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/* optimistically we can also act as if our nose bleeds. The |
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* granularity of the mtime is coarse anyways so we might actually be |
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* right most of the time. Note: we only do this for directories. */ |
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dir->i_mtime = dir->i_ctime = current_time(dir); |
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#endif |
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} |
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/* we have to wrap inc_nlink/drop_nlink because sometimes userspace uses a |
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* trick to fool GNU find's optimizations. If we can't be sure of the link |
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* (because of volume mount points) we set i_nlink to 1 which forces find |
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* to consider every child as a possible directory. We should also never |
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* see an increment or decrement for deleted directories where i_nlink == 0 */ |
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static inline void coda_dir_inc_nlink(struct inode *dir) |
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{ |
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if (dir->i_nlink >= 2) |
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inc_nlink(dir); |
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} |
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static inline void coda_dir_drop_nlink(struct inode *dir) |
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{ |
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if (dir->i_nlink > 2) |
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drop_nlink(dir); |
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} |
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/* creation routines: create, mknod, mkdir, link, symlink */ |
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static int coda_create(struct user_namespace *mnt_userns, struct inode *dir, |
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struct dentry *de, umode_t mode, bool excl) |
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{ |
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int error; |
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const char *name=de->d_name.name; |
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int length=de->d_name.len; |
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struct inode *inode; |
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struct CodaFid newfid; |
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struct coda_vattr attrs; |
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if (is_root_inode(dir) && coda_iscontrol(name, length)) |
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return -EPERM; |
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error = venus_create(dir->i_sb, coda_i2f(dir), name, length, |
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0, mode, &newfid, &attrs); |
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if (error) |
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goto err_out; |
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inode = coda_iget(dir->i_sb, &newfid, &attrs); |
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if (IS_ERR(inode)) { |
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error = PTR_ERR(inode); |
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goto err_out; |
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} |
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/* invalidate the directory cnode's attributes */ |
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coda_dir_update_mtime(dir); |
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d_instantiate(de, inode); |
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return 0; |
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err_out: |
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d_drop(de); |
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return error; |
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} |
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static int coda_mkdir(struct user_namespace *mnt_userns, struct inode *dir, |
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struct dentry *de, umode_t mode) |
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{ |
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struct inode *inode; |
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struct coda_vattr attrs; |
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const char *name = de->d_name.name; |
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int len = de->d_name.len; |
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int error; |
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struct CodaFid newfid; |
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if (is_root_inode(dir) && coda_iscontrol(name, len)) |
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return -EPERM; |
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attrs.va_mode = mode; |
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error = venus_mkdir(dir->i_sb, coda_i2f(dir), |
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name, len, &newfid, &attrs); |
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if (error) |
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goto err_out; |
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inode = coda_iget(dir->i_sb, &newfid, &attrs); |
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if (IS_ERR(inode)) { |
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error = PTR_ERR(inode); |
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goto err_out; |
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} |
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/* invalidate the directory cnode's attributes */ |
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coda_dir_inc_nlink(dir); |
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coda_dir_update_mtime(dir); |
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d_instantiate(de, inode); |
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return 0; |
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err_out: |
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d_drop(de); |
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return error; |
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} |
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/* try to make de an entry in dir_inodde linked to source_de */ |
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static int coda_link(struct dentry *source_de, struct inode *dir_inode, |
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struct dentry *de) |
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{ |
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struct inode *inode = d_inode(source_de); |
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const char * name = de->d_name.name; |
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int len = de->d_name.len; |
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int error; |
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if (is_root_inode(dir_inode) && coda_iscontrol(name, len)) |
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return -EPERM; |
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error = venus_link(dir_inode->i_sb, coda_i2f(inode), |
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coda_i2f(dir_inode), (const char *)name, len); |
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if (error) { |
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d_drop(de); |
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return error; |
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} |
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coda_dir_update_mtime(dir_inode); |
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ihold(inode); |
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d_instantiate(de, inode); |
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inc_nlink(inode); |
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return 0; |
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} |
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static int coda_symlink(struct user_namespace *mnt_userns, |
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struct inode *dir_inode, struct dentry *de, |
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const char *symname) |
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{ |
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const char *name = de->d_name.name; |
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int len = de->d_name.len; |
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int symlen; |
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int error; |
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if (is_root_inode(dir_inode) && coda_iscontrol(name, len)) |
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return -EPERM; |
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symlen = strlen(symname); |
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if (symlen > CODA_MAXPATHLEN) |
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return -ENAMETOOLONG; |
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/* |
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* This entry is now negative. Since we do not create |
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* an inode for the entry we have to drop it. |
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*/ |
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d_drop(de); |
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error = venus_symlink(dir_inode->i_sb, coda_i2f(dir_inode), name, len, |
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symname, symlen); |
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/* mtime is no good anymore */ |
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if (!error) |
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coda_dir_update_mtime(dir_inode); |
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return error; |
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} |
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/* destruction routines: unlink, rmdir */ |
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static int coda_unlink(struct inode *dir, struct dentry *de) |
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{ |
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int error; |
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const char *name = de->d_name.name; |
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int len = de->d_name.len; |
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error = venus_remove(dir->i_sb, coda_i2f(dir), name, len); |
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if (error) |
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return error; |
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coda_dir_update_mtime(dir); |
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drop_nlink(d_inode(de)); |
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return 0; |
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} |
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static int coda_rmdir(struct inode *dir, struct dentry *de) |
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{ |
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const char *name = de->d_name.name; |
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int len = de->d_name.len; |
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int error; |
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error = venus_rmdir(dir->i_sb, coda_i2f(dir), name, len); |
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if (!error) { |
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/* VFS may delete the child */ |
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if (d_really_is_positive(de)) |
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clear_nlink(d_inode(de)); |
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/* fix the link count of the parent */ |
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coda_dir_drop_nlink(dir); |
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coda_dir_update_mtime(dir); |
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} |
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return error; |
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} |
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/* rename */ |
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static int coda_rename(struct user_namespace *mnt_userns, struct inode *old_dir, |
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struct dentry *old_dentry, struct inode *new_dir, |
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struct dentry *new_dentry, unsigned int flags) |
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{ |
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const char *old_name = old_dentry->d_name.name; |
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const char *new_name = new_dentry->d_name.name; |
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int old_length = old_dentry->d_name.len; |
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int new_length = new_dentry->d_name.len; |
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int error; |
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if (flags) |
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return -EINVAL; |
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error = venus_rename(old_dir->i_sb, coda_i2f(old_dir), |
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coda_i2f(new_dir), old_length, new_length, |
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(const char *) old_name, (const char *)new_name); |
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if (!error) { |
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if (d_really_is_positive(new_dentry)) { |
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if (d_is_dir(new_dentry)) { |
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coda_dir_drop_nlink(old_dir); |
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coda_dir_inc_nlink(new_dir); |
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} |
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coda_dir_update_mtime(old_dir); |
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coda_dir_update_mtime(new_dir); |
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coda_flag_inode(d_inode(new_dentry), C_VATTR); |
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} else { |
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coda_flag_inode(old_dir, C_VATTR); |
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coda_flag_inode(new_dir, C_VATTR); |
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} |
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} |
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return error; |
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} |
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static inline unsigned int CDT2DT(unsigned char cdt) |
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{ |
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unsigned int dt; |
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switch(cdt) { |
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case CDT_UNKNOWN: dt = DT_UNKNOWN; break; |
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case CDT_FIFO: dt = DT_FIFO; break; |
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case CDT_CHR: dt = DT_CHR; break; |
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case CDT_DIR: dt = DT_DIR; break; |
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case CDT_BLK: dt = DT_BLK; break; |
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case CDT_REG: dt = DT_REG; break; |
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case CDT_LNK: dt = DT_LNK; break; |
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case CDT_SOCK: dt = DT_SOCK; break; |
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case CDT_WHT: dt = DT_WHT; break; |
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default: dt = DT_UNKNOWN; break; |
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} |
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return dt; |
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} |
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/* support routines */ |
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static int coda_venus_readdir(struct file *coda_file, struct dir_context *ctx) |
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{ |
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struct coda_file_info *cfi; |
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struct coda_inode_info *cii; |
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struct file *host_file; |
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struct venus_dirent *vdir; |
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unsigned long vdir_size = offsetof(struct venus_dirent, d_name); |
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unsigned int type; |
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struct qstr name; |
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ino_t ino; |
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int ret; |
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cfi = coda_ftoc(coda_file); |
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host_file = cfi->cfi_container; |
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cii = ITOC(file_inode(coda_file)); |
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vdir = kmalloc(sizeof(*vdir), GFP_KERNEL); |
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if (!vdir) return -ENOMEM; |
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if (!dir_emit_dots(coda_file, ctx)) |
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goto out; |
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while (1) { |
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loff_t pos = ctx->pos - 2; |
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/* read entries from the directory file */ |
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ret = kernel_read(host_file, vdir, sizeof(*vdir), &pos); |
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if (ret < 0) { |
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pr_err("%s: read dir %s failed %d\n", |
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__func__, coda_f2s(&cii->c_fid), ret); |
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break; |
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} |
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if (ret == 0) break; /* end of directory file reached */ |
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/* catch truncated reads */ |
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if (ret < vdir_size || ret < vdir_size + vdir->d_namlen) { |
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pr_err("%s: short read on %s\n", |
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__func__, coda_f2s(&cii->c_fid)); |
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ret = -EBADF; |
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break; |
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} |
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/* validate whether the directory file actually makes sense */ |
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if (vdir->d_reclen < vdir_size + vdir->d_namlen) { |
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pr_err("%s: invalid dir %s\n", |
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__func__, coda_f2s(&cii->c_fid)); |
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ret = -EBADF; |
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break; |
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} |
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name.len = vdir->d_namlen; |
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name.name = vdir->d_name; |
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/* Make sure we skip '.' and '..', we already got those */ |
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if (name.name[0] == '.' && (name.len == 1 || |
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(name.name[1] == '.' && name.len == 2))) |
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vdir->d_fileno = name.len = 0; |
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/* skip null entries */ |
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if (vdir->d_fileno && name.len) { |
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ino = vdir->d_fileno; |
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type = CDT2DT(vdir->d_type); |
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if (!dir_emit(ctx, name.name, name.len, ino, type)) |
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break; |
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} |
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/* we'll always have progress because d_reclen is unsigned and |
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* we've already established it is non-zero. */ |
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ctx->pos += vdir->d_reclen; |
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} |
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out: |
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kfree(vdir); |
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return 0; |
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} |
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/* file operations for directories */ |
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static int coda_readdir(struct file *coda_file, struct dir_context *ctx) |
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{ |
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struct coda_file_info *cfi; |
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struct file *host_file; |
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int ret; |
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cfi = coda_ftoc(coda_file); |
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host_file = cfi->cfi_container; |
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if (host_file->f_op->iterate || host_file->f_op->iterate_shared) { |
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struct inode *host_inode = file_inode(host_file); |
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ret = -ENOENT; |
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if (!IS_DEADDIR(host_inode)) { |
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if (host_file->f_op->iterate_shared) { |
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inode_lock_shared(host_inode); |
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ret = host_file->f_op->iterate_shared(host_file, ctx); |
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file_accessed(host_file); |
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inode_unlock_shared(host_inode); |
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} else { |
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inode_lock(host_inode); |
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ret = host_file->f_op->iterate(host_file, ctx); |
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file_accessed(host_file); |
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inode_unlock(host_inode); |
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} |
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} |
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return ret; |
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} |
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/* Venus: we must read Venus dirents from a file */ |
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return coda_venus_readdir(coda_file, ctx); |
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} |
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/* called when a cache lookup succeeds */ |
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static int coda_dentry_revalidate(struct dentry *de, unsigned int flags) |
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{ |
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struct inode *inode; |
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struct coda_inode_info *cii; |
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if (flags & LOOKUP_RCU) |
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return -ECHILD; |
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inode = d_inode(de); |
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if (!inode || is_root_inode(inode)) |
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goto out; |
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if (is_bad_inode(inode)) |
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goto bad; |
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cii = ITOC(d_inode(de)); |
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if (!(cii->c_flags & (C_PURGE | C_FLUSH))) |
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goto out; |
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shrink_dcache_parent(de); |
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|
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/* propagate for a flush */ |
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if (cii->c_flags & C_FLUSH) |
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coda_flag_inode_children(inode, C_FLUSH); |
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if (d_count(de) > 1) |
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/* pretend it's valid, but don't change the flags */ |
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goto out; |
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|
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/* clear the flags. */ |
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spin_lock(&cii->c_lock); |
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cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH); |
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spin_unlock(&cii->c_lock); |
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bad: |
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return 0; |
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out: |
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return 1; |
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} |
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|
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/* |
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* This is the callback from dput() when d_count is going to 0. |
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* We use this to unhash dentries with bad inodes. |
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*/ |
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static int coda_dentry_delete(const struct dentry * dentry) |
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{ |
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int flags; |
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|
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if (d_really_is_negative(dentry)) |
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return 0; |
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flags = (ITOC(d_inode(dentry))->c_flags) & C_PURGE; |
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if (is_bad_inode(d_inode(dentry)) || flags) { |
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return 1; |
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} |
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return 0; |
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} |
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|
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/* |
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* This is called when we want to check if the inode has |
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* changed on the server. Coda makes this easy since the |
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* cache manager Venus issues a downcall to the kernel when this |
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* happens |
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*/ |
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int coda_revalidate_inode(struct inode *inode) |
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{ |
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struct coda_vattr attr; |
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int error; |
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int old_mode; |
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ino_t old_ino; |
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struct coda_inode_info *cii = ITOC(inode); |
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|
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if (!cii->c_flags) |
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return 0; |
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if (cii->c_flags & (C_VATTR | C_PURGE | C_FLUSH)) { |
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error = venus_getattr(inode->i_sb, &(cii->c_fid), &attr); |
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if (error) |
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return -EIO; |
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|
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/* this inode may be lost if: |
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- it's ino changed |
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- type changes must be permitted for repair and |
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missing mount points. |
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*/ |
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old_mode = inode->i_mode; |
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old_ino = inode->i_ino; |
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coda_vattr_to_iattr(inode, &attr); |
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|
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if ((old_mode & S_IFMT) != (inode->i_mode & S_IFMT)) { |
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pr_warn("inode %ld, fid %s changed type!\n", |
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inode->i_ino, coda_f2s(&(cii->c_fid))); |
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} |
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|
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/* the following can happen when a local fid is replaced |
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with a global one, here we lose and declare the inode bad */ |
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if (inode->i_ino != old_ino) |
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return -EIO; |
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|
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coda_flag_inode_children(inode, C_FLUSH); |
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|
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spin_lock(&cii->c_lock); |
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cii->c_flags &= ~(C_VATTR | C_PURGE | C_FLUSH); |
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spin_unlock(&cii->c_lock); |
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} |
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return 0; |
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} |
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|
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const struct dentry_operations coda_dentry_operations = { |
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.d_revalidate = coda_dentry_revalidate, |
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.d_delete = coda_dentry_delete, |
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}; |
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const struct inode_operations coda_dir_inode_operations = { |
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.create = coda_create, |
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.lookup = coda_lookup, |
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.link = coda_link, |
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.unlink = coda_unlink, |
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.symlink = coda_symlink, |
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.mkdir = coda_mkdir, |
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.rmdir = coda_rmdir, |
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.mknod = CODA_EIO_ERROR, |
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.rename = coda_rename, |
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.permission = coda_permission, |
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.getattr = coda_getattr, |
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.setattr = coda_setattr, |
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}; |
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const struct file_operations coda_dir_operations = { |
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.llseek = generic_file_llseek, |
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.read = generic_read_dir, |
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.iterate = coda_readdir, |
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.open = coda_open, |
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.release = coda_release, |
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.fsync = coda_fsync, |
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};
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