[PATCH] Kprobes: Fix deadlock in function-return probes

[linux-2.6/linux-acpi-2.6/ibm-acpi-2.6.git] / fs / cifs / dir.c

/*
 *   fs/cifs/dir.c
 *
 *   vfs operations that deal with dentries
 * 
 *   Copyright (C) International Business Machines  Corp., 2002,2005
 *   Author(s): Steve French (sfrench@us.ibm.com)
 *
 *   This library is free software; you can redistribute it and/or modify
 *   it under the terms of the GNU Lesser General Public License as published
 *   by the Free Software Foundation; either version 2.1 of the License, or
 *   (at your option) any later version.
 *
 *   This library is distributed in the hope that it will be useful,
 *   but WITHOUT ANY WARRANTY; without even the implied warranty of
 *   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See
 *   the GNU Lesser General Public License for more details.
 *
 *   You should have received a copy of the GNU Lesser General Public License
 *   along with this library; if not, write to the Free Software
 *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
 */
#include <linux/fs.h>
#include <linux/stat.h>
#include <linux/slab.h>
#include <linux/namei.h>
#include "cifsfs.h"
#include "cifspdu.h"
#include "cifsglob.h"
#include "cifsproto.h"
#include "cifs_debug.h"
#include "cifs_fs_sb.h"

void
renew_parental_timestamps(struct dentry *direntry)
{
        /* BB check if there is a way to get the kernel to do this or if we really need this */
        do {
                direntry->d_time = jiffies;
                direntry = direntry->d_parent;
        } while (!IS_ROOT(direntry));   
}

/* Note: caller must free return buffer */
char *
build_path_from_dentry(struct dentry *direntry)
{
        struct dentry *temp;
        int namelen = 0;
        char *full_path;
        char dirsep = CIFS_DIR_SEP(CIFS_SB(direntry->d_sb));

        if(direntry == NULL)
                return NULL;  /* not much we can do if dentry is freed and
                we need to reopen the file after it was closed implicitly
                when the server crashed */

cifs_bp_rename_retry:
        for (temp = direntry; !IS_ROOT(temp);) {
                namelen += (1 + temp->d_name.len);
                temp = temp->d_parent;
                if(temp == NULL) {
                        cERROR(1,("corrupt dentry"));
                        return NULL;
                }
        }

        full_path = kmalloc(namelen+1, GFP_KERNEL);
        if(full_path == NULL)
                return full_path;
        full_path[namelen] = 0; /* trailing null */

        for (temp = direntry; !IS_ROOT(temp);) {
                namelen -= 1 + temp->d_name.len;
                if (namelen < 0) {
                        break;
                } else {
                        full_path[namelen] = dirsep;
                        strncpy(full_path + namelen + 1, temp->d_name.name,
                                temp->d_name.len);
                        cFYI(0, (" name: %s ", full_path + namelen));
                }
                temp = temp->d_parent;
                if(temp == NULL) {
                        cERROR(1,("corrupt dentry"));
                        kfree(full_path);
                        return NULL;
                }
        }
        if (namelen != 0) {
                cERROR(1,
                       ("We did not end path lookup where we expected namelen is %d",
                        namelen));
                /* presumably this is only possible if we were racing with a rename 
                of one of the parent directories  (we can not lock the dentries
                above us to prevent this, but retrying should be harmless) */
                kfree(full_path);
                namelen = 0;
                goto cifs_bp_rename_retry;
        }

        return full_path;
}

/* char * build_wildcard_path_from_dentry(struct dentry *direntry)
{
        if(full_path == NULL)
                return full_path;

        full_path[namelen] = '\\';
        full_path[namelen+1] = '*';
        full_path[namelen+2] = 0;
BB remove above eight lines BB */

/* Inode operations in similar order to how they appear in the Linux file fs.h */

int
cifs_create(struct inode *inode, struct dentry *direntry, int mode,
                struct nameidata *nd)
{
        int rc = -ENOENT;
        int xid;
        int oplock = 0;
        int desiredAccess = GENERIC_READ | GENERIC_WRITE;
        __u16 fileHandle;
        struct cifs_sb_info *cifs_sb;
        struct cifsTconInfo *pTcon;
        char *full_path = NULL;
        FILE_ALL_INFO * buf = NULL;
        struct inode *newinode = NULL;
        struct cifsFileInfo * pCifsFile = NULL;
        struct cifsInodeInfo * pCifsInode;
        int disposition = FILE_OVERWRITE_IF;
        int write_only = FALSE;

        xid = GetXid();

        cifs_sb = CIFS_SB(inode->i_sb);
        pTcon = cifs_sb->tcon;

        down(&direntry->d_sb->s_vfs_rename_sem);
        full_path = build_path_from_dentry(direntry);
        up(&direntry->d_sb->s_vfs_rename_sem);
        if(full_path == NULL) {
                FreeXid(xid);
                return -ENOMEM;
        }

        if(nd && (nd->flags & LOOKUP_OPEN)) {
                int oflags = nd->intent.open.flags;

                desiredAccess = 0;
                if (oflags & FMODE_READ)
                        desiredAccess |= GENERIC_READ;
                if (oflags & FMODE_WRITE) {
                        desiredAccess |= GENERIC_WRITE;
                        if (!(oflags & FMODE_READ))
                                write_only = TRUE;
                }

                if((oflags & (O_CREAT | O_EXCL)) == (O_CREAT | O_EXCL))
                        disposition = FILE_CREATE;
                else if((oflags & (O_CREAT | O_TRUNC)) == (O_CREAT | O_TRUNC))
                        disposition = FILE_OVERWRITE_IF;
                else if((oflags & O_CREAT) == O_CREAT)
                        disposition = FILE_OPEN_IF;
                else {
                        cFYI(1,("Create flag not set in create function"));
                }
        }

        /* BB add processing to set equivalent of mode - e.g. via CreateX with ACLs */
        if (oplockEnabled)
                oplock = REQ_OPLOCK;

        buf = kmalloc(sizeof(FILE_ALL_INFO),GFP_KERNEL);
        if(buf == NULL) {
                kfree(full_path);
                FreeXid(xid);
                return -ENOMEM;
        }

        rc = CIFSSMBOpen(xid, pTcon, full_path, disposition,
                         desiredAccess, CREATE_NOT_DIR,
                         &fileHandle, &oplock, buf, cifs_sb->local_nls,
                         cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
        if(rc == -EIO) {
                /* old server, retry the open legacy style */
                rc = SMBLegacyOpen(xid, pTcon, full_path, disposition,
                        desiredAccess, CREATE_NOT_DIR,
                        &fileHandle, &oplock, buf, cifs_sb->local_nls,
                        cifs_sb->mnt_cifs_flags & CIFS_MOUNT_MAP_SPECIAL_CHR);
        } 
        if (rc) {
                cFYI(1, ("cifs_create returned 0x%x ", rc));
        } else {
                /* If Open reported that we actually created a file
                then we now have to set the mode if possible */
                if ((cifs_sb->tcon->ses->capabilities & CAP_UNIX) &&
                        (oplock & CIFS_CREATE_ACTION))
                        if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
                                CIFSSMBUnixSetPerms(xid, pTcon, full_path, mode,
                                        (__u64)current->fsuid,
                                        (__u64)current->fsgid,
                                        0 /* dev */,
                                        cifs_sb->local_nls, 
                                        cifs_sb->mnt_cifs_flags & 
                                                CIFS_MOUNT_MAP_SPECIAL_CHR);
                        } else {
                                CIFSSMBUnixSetPerms(xid, pTcon, full_path, mode,
                                        (__u64)-1,
                                        (__u64)-1,
                                        0 /* dev */,
                                        cifs_sb->local_nls,
                                        cifs_sb->mnt_cifs_flags & 
                                                CIFS_MOUNT_MAP_SPECIAL_CHR);
                        }
                else {
                        /* BB implement mode setting via Windows security descriptors */
                        /* eg CIFSSMBWinSetPerms(xid,pTcon,full_path,mode,-1,-1,local_nls);*/
                        /* could set r/o dos attribute if mode & 0222 == 0 */
                }

        /* BB server might mask mode so we have to query for Unix case*/
                if (pTcon->ses->capabilities & CAP_UNIX)
                        rc = cifs_get_inode_info_unix(&newinode, full_path,
                                                 inode->i_sb,xid);
                else {
                        rc = cifs_get_inode_info(&newinode, full_path,
                                                 buf, inode->i_sb,xid);
                        if(newinode) {
                                newinode->i_mode = mode;
                                if((oplock & CIFS_CREATE_ACTION) &&
                                  (cifs_sb->mnt_cifs_flags & 
                                     CIFS_MOUNT_SET_UID)) {
                                        newinode->i_uid = current->fsuid;
                                        newinode->i_gid = current->fsgid;
                                }
                        }
                }

                if (rc != 0) {
                        cFYI(1,
                             ("Create worked but get_inode_info failed rc = %d",
                              rc));
                } else {
                        if (pTcon->nocase)
                                direntry->d_op = &cifs_ci_dentry_ops;
                        else
                                direntry->d_op = &cifs_dentry_ops;
                        d_instantiate(direntry, newinode);
                }
                if((nd->flags & LOOKUP_OPEN) == FALSE) {
                        /* mknod case - do not leave file open */
                        CIFSSMBClose(xid, pTcon, fileHandle);
                } else if(newinode) {
                        pCifsFile =
                           kmalloc(sizeof (struct cifsFileInfo), GFP_KERNEL);
                        
                        if(pCifsFile == NULL)
                                goto cifs_create_out;
                        memset((char *)pCifsFile, 0,
                               sizeof (struct cifsFileInfo));
                        pCifsFile->netfid = fileHandle;
                        pCifsFile->pid = current->tgid;
                        pCifsFile->pInode = newinode;
                        pCifsFile->invalidHandle = FALSE;
                        pCifsFile->closePend     = FALSE;
                        init_MUTEX(&pCifsFile->fh_sem);
                        /* set the following in open now 
                                pCifsFile->pfile = file; */
                        write_lock(&GlobalSMBSeslock);
                        list_add(&pCifsFile->tlist,&pTcon->openFileList);
                        pCifsInode = CIFS_I(newinode);
                        if(pCifsInode) {
                                /* if readable file instance put first in list*/
                                if (write_only == TRUE) {
                                        list_add_tail(&pCifsFile->flist,
                                                &pCifsInode->openFileList);
                                } else {
                                        list_add(&pCifsFile->flist,
                                                &pCifsInode->openFileList);
                                }
                                if((oplock & 0xF) == OPLOCK_EXCLUSIVE) {
                                        pCifsInode->clientCanCacheAll = TRUE;
                                        pCifsInode->clientCanCacheRead = TRUE;
                                        cFYI(1,("Exclusive Oplock for inode %p",
                                                newinode));
                                } else if((oplock & 0xF) == OPLOCK_READ)
                                        pCifsInode->clientCanCacheRead = TRUE;
                        }
                        write_unlock(&GlobalSMBSeslock);
                }
        } 
cifs_create_out:
        kfree(buf);
        kfree(full_path);
        FreeXid(xid);
        return rc;
}

int cifs_mknod(struct inode *inode, struct dentry *direntry, int mode, 
                dev_t device_number) 
{
        int rc = -EPERM;
        int xid;
        struct cifs_sb_info *cifs_sb;
        struct cifsTconInfo *pTcon;
        char *full_path = NULL;
        struct inode * newinode = NULL;

        if (!old_valid_dev(device_number))
                return -EINVAL;

        xid = GetXid();

        cifs_sb = CIFS_SB(inode->i_sb);
        pTcon = cifs_sb->tcon;

        down(&direntry->d_sb->s_vfs_rename_sem);
        full_path = build_path_from_dentry(direntry);
        up(&direntry->d_sb->s_vfs_rename_sem);
        if(full_path == NULL)
                rc = -ENOMEM;
        else if (pTcon->ses->capabilities & CAP_UNIX) {
                if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_SET_UID) {
                        rc = CIFSSMBUnixSetPerms(xid, pTcon, full_path,
                                mode,(__u64)current->fsuid,(__u64)current->fsgid,
                                device_number, cifs_sb->local_nls,
                                cifs_sb->mnt_cifs_flags & 
                                        CIFS_MOUNT_MAP_SPECIAL_CHR);
                } else {
                        rc = CIFSSMBUnixSetPerms(xid, pTcon,
                                full_path, mode, (__u64)-1, (__u64)-1,
                                device_number, cifs_sb->local_nls,
                                cifs_sb->mnt_cifs_flags & 
                                        CIFS_MOUNT_MAP_SPECIAL_CHR);
                }

                if(!rc) {
                        rc = cifs_get_inode_info_unix(&newinode, full_path,
                                                inode->i_sb,xid);
                        if (pTcon->nocase)
                                direntry->d_op = &cifs_ci_dentry_ops;
                        else
                                direntry->d_op = &cifs_dentry_ops;
                        if(rc == 0)
                                d_instantiate(direntry, newinode);
                }
        } else {
                if(cifs_sb->mnt_cifs_flags & CIFS_MOUNT_UNX_EMUL) {
                        int oplock = 0;
                        u16 fileHandle;
                        FILE_ALL_INFO * buf;

                        cFYI(1,("sfu compat create special file"));

                        buf = kmalloc(sizeof(FILE_ALL_INFO),GFP_KERNEL);
                        if(buf == NULL) {
                                kfree(full_path);
                                FreeXid(xid);
                                return -ENOMEM;
                        }

                        rc = CIFSSMBOpen(xid, pTcon, full_path,
                                         FILE_CREATE, /* fail if exists */
                                         GENERIC_WRITE /* BB would 
                                          WRITE_OWNER | WRITE_DAC be better? */,
                                         /* Create a file and set the
                                            file attribute to SYSTEM */
                                         CREATE_NOT_DIR | CREATE_OPTION_SPECIAL,
                                         &fileHandle, &oplock, buf,
                                         cifs_sb->local_nls,
                                         cifs_sb->mnt_cifs_flags & 
                                            CIFS_MOUNT_MAP_SPECIAL_CHR);

                        if(!rc) {
                                /* BB Do not bother to decode buf since no
                                   local inode yet to put timestamps in,
                                   but we can reuse it safely */
                                int bytes_written;
                                struct win_dev *pdev;
                                pdev = (struct win_dev *)buf;
                                if(S_ISCHR(mode)) {
                                        memcpy(pdev->type, "IntxCHR", 8);
                                        pdev->major =
                                              cpu_to_le64(MAJOR(device_number));
                                        pdev->minor = 
                                              cpu_to_le64(MINOR(device_number));
                                        rc = CIFSSMBWrite(xid, pTcon,
                                                fileHandle,
                                                sizeof(struct win_dev),
                                                0, &bytes_written, (char *)pdev,
                                                NULL, 0);
                                } else if(S_ISBLK(mode)) {
                                        memcpy(pdev->type, "IntxBLK", 8);
                                        pdev->major =
                                              cpu_to_le64(MAJOR(device_number));
                                        pdev->minor =
                                              cpu_to_le64(MINOR(device_number));
                                        rc = CIFSSMBWrite(xid, pTcon,
                                                fileHandle,
                                                sizeof(struct win_dev),
                                                0, &bytes_written, (char *)pdev,
                                                NULL, 0);
                                } /* else if(S_ISFIFO */
                                CIFSSMBClose(xid, pTcon, fileHandle);
                                d_drop(direntry);
                        }
                        kfree(buf);
                        /* add code here to set EAs */
                }
        }

        kfree(full_path);
        FreeXid(xid);
        return rc;
}


struct dentry *
cifs_lookup(struct inode *parent_dir_inode, struct dentry *direntry, struct nameidata *nd)
{
        int xid;
        int rc = 0; /* to get around spurious gcc warning, set to zero here */
        struct cifs_sb_info *cifs_sb;
        struct cifsTconInfo *pTcon;
        struct inode *newInode = NULL;
        char *full_path = NULL;

        xid = GetXid();

        cFYI(1,
             (" parent inode = 0x%p name is: %s and dentry = 0x%p",
              parent_dir_inode, direntry->d_name.name, direntry));

        /* BB Add check of incoming data - e.g. frame not longer than maximum SMB - let server check the namelen BB */

        /* check whether path exists */

        cifs_sb = CIFS_SB(parent_dir_inode->i_sb);
        pTcon = cifs_sb->tcon;

        /* can not grab the rename sem here since it would
        deadlock in the cases (beginning of sys_rename itself)
        in which we already have the sb rename sem */
        full_path = build_path_from_dentry(direntry);
        if(full_path == NULL) {
                FreeXid(xid);
                return ERR_PTR(-ENOMEM);
        }

        if (direntry->d_inode != NULL) {
                cFYI(1, (" non-NULL inode in lookup"));
        } else {
                cFYI(1, (" NULL inode in lookup"));
        }
        cFYI(1,
             (" Full path: %s inode = 0x%p", full_path, direntry->d_inode));

        if (pTcon->ses->capabilities & CAP_UNIX)
                rc = cifs_get_inode_info_unix(&newInode, full_path,
                                              parent_dir_inode->i_sb,xid);
        else
                rc = cifs_get_inode_info(&newInode, full_path, NULL,
                                         parent_dir_inode->i_sb,xid);

        if ((rc == 0) && (newInode != NULL)) {
                if (pTcon->nocase)
                        direntry->d_op = &cifs_ci_dentry_ops;
                else
                        direntry->d_op = &cifs_dentry_ops;
                d_add(direntry, newInode);

                /* since paths are not looked up by component - the parent 
                   directories are presumed to be good here */
                renew_parental_timestamps(direntry);

        } else if (rc == -ENOENT) {
                rc = 0;
                direntry->d_time = jiffies;
                if (pTcon->nocase)
                        direntry->d_op = &cifs_ci_dentry_ops;
                else
                        direntry->d_op = &cifs_dentry_ops;
                d_add(direntry, NULL);
        /*      if it was once a directory (but how can we tell?) we could do  
                        shrink_dcache_parent(direntry); */
        } else {
                cERROR(1,("Error 0x%x on cifs_get_inode_info in lookup of %s",
                           rc,full_path));
                /* BB special case check for Access Denied - watch security 
                exposure of returning dir info implicitly via different rc 
                if file exists or not but no access BB */
        }

        kfree(full_path);
        FreeXid(xid);
        return ERR_PTR(rc);
}

static int
cifs_d_revalidate(struct dentry *direntry, struct nameidata *nd)
{
        int isValid = 1;

        if (direntry->d_inode) {
                if (cifs_revalidate(direntry)) {
                        return 0;
                }
        } else {
                cFYI(1, ("neg dentry 0x%p name = %s",
                         direntry, direntry->d_name.name));
                if(time_after(jiffies, direntry->d_time + HZ) || 
                        !lookupCacheEnabled) {
                        d_drop(direntry);
                        isValid = 0;
                } 
        }

        return isValid;
}

/* static int cifs_d_delete(struct dentry *direntry)
{
        int rc = 0;

        cFYI(1, ("In cifs d_delete, name = %s", direntry->d_name.name));

        return rc;
}     */

struct dentry_operations cifs_dentry_ops = {
        .d_revalidate = cifs_d_revalidate,
/* d_delete:       cifs_d_delete,       *//* not needed except for debugging */
        /* no need for d_hash, d_compare, d_release, d_iput ... yet. BB confirm this BB */
};

static int cifs_ci_hash(struct dentry *dentry, struct qstr *q)
{
        struct nls_table *codepage = CIFS_SB(dentry->d_inode->i_sb)->local_nls;
        unsigned long hash;
        int i;

        hash = init_name_hash();
        for (i = 0; i < q->len; i++)
                hash = partial_name_hash(nls_tolower(codepage, q->name[i]),
                                         hash);
        q->hash = end_name_hash(hash);

        return 0;
}

static int cifs_ci_compare(struct dentry *dentry, struct qstr *a,
                           struct qstr *b)
{
        struct nls_table *codepage = CIFS_SB(dentry->d_inode->i_sb)->local_nls;

        if ((a->len == b->len) &&
            (nls_strnicmp(codepage, a->name, b->name, a->len) == 0)) {
                /*
                 * To preserve case, don't let an existing negative dentry's
                 * case take precedence.  If a is not a negative dentry, this
                 * should have no side effects
                 */
                memcpy((unsigned char *)a->name, b->name, a->len);
                return 0;
        }
        return 1;
}

struct dentry_operations cifs_ci_dentry_ops = {
        .d_revalidate = cifs_d_revalidate,
        .d_hash = cifs_ci_hash,
        .d_compare = cifs_ci_compare,
};