fs/udf/file.c

0001 /*
0002  * file.c
0003  *
0004  * PURPOSE
0005  *  File handling routines for the OSTA-UDF(tm) filesystem.
0006  *
0007  * COPYRIGHT
0008  *  This file is distributed under the terms of the GNU General Public
0009  *  License (GPL). Copies of the GPL can be obtained from:
0010  *    ftp://prep.ai.mit.edu/pub/gnu/GPL
0011  *  Each contributing author retains all rights to their own work.
0012  *
0013  *  (C) 1998-1999 Dave Boynton
0014  *  (C) 1998-2004 Ben Fennema
0015  *  (C) 1999-2000 Stelias Computing Inc
0016  *
0017  * HISTORY
0018  *
0019  *  10/02/98 dgb  Attempt to integrate into udf.o
0020  *  10/07/98      Switched to using generic_readpage, etc., like isofs
0021  *                And it works!
0022  *  12/06/98 blf  Added udf_file_read. uses generic_file_read for all cases but
0023  *                ICBTAG_FLAG_AD_IN_ICB.
0024  *  04/06/99      64 bit file handling on 32 bit systems taken from ext2 file.c
0025  *  05/12/99      Preliminary file write support
0026  */
0027
0028 #include "udfdecl.h"
0029 #include <linux/fs.h>
0030 #include <linux/uaccess.h>
0031 #include <linux/kernel.h>
0032 #include <linux/string.h> /* memset */
0033 #include <linux/capability.h>
0034 #include <linux/errno.h>
0035 #include <linux/pagemap.h>
0036 #include <linux/uio.h>
0037
0038 #include "udf_i.h"
0039 #include "udf_sb.h"
0040
0041 static void __udf_adinicb_readpage(struct page *page)
0042 {
0043     struct inode *inode = page->mapping->host;
0044     char *kaddr;
0045     struct udf_inode_info *iinfo = UDF_I(inode);
0046     loff_t isize = i_size_read(inode);
0047
0048     /*
0049      * We have to be careful here as truncate can change i_size under us.
0050      * So just sample it once and use the same value everywhere.
0051      */
0052     kaddr = kmap_atomic(page);
0053     memcpy(kaddr, iinfo->i_data + iinfo->i_lenEAttr, isize);
0054     memset(kaddr + isize, 0, PAGE_SIZE - isize);
0055     flush_dcache_page(page);
0056     SetPageUptodate(page);
0057     kunmap_atomic(kaddr);
0058 }
0059
0060 static int udf_adinicb_read_folio(struct file *file, struct folio *folio)
0061 {
0062     BUG_ON(!folio_test_locked(folio));
0063     __udf_adinicb_readpage(&folio->page);
0064     folio_unlock(folio);
0065
0066     return 0;
0067 }
0068
0069 static int udf_adinicb_writepage(struct page *page,
0070                  struct writeback_control *wbc)
0071 {
0072     struct inode *inode = page->mapping->host;
0073     char *kaddr;
0074     struct udf_inode_info *iinfo = UDF_I(inode);
0075
0076     BUG_ON(!PageLocked(page));
0077
0078     kaddr = kmap_atomic(page);
0079     memcpy(iinfo->i_data + iinfo->i_lenEAttr, kaddr, i_size_read(inode));
0080     SetPageUptodate(page);
0081     kunmap_atomic(kaddr);
0082     mark_inode_dirty(inode);
0083     unlock_page(page);
0084
0085     return 0;
0086 }
0087
0088 static int udf_adinicb_write_begin(struct file *file,
0089             struct address_space *mapping, loff_t pos,
0090             unsigned len, struct page **pagep,
0091             void **fsdata)
0092 {
0093     struct page *page;
0094
0095     if (WARN_ON_ONCE(pos >= PAGE_SIZE))
0096         return -EIO;
0097     page = grab_cache_page_write_begin(mapping, 0);
0098     if (!page)
0099         return -ENOMEM;
0100     *pagep = page;
0101
0102     if (!PageUptodate(page))
0103         __udf_adinicb_readpage(page);
0104     return 0;
0105 }
0106
0107 static ssize_t udf_adinicb_direct_IO(struct kiocb *iocb, struct iov_iter *iter)
0108 {
0109     /* Fallback to buffered I/O. */
0110     return 0;
0111 }
0112
0113 static int udf_adinicb_write_end(struct file *file, struct address_space *mapping,
0114                  loff_t pos, unsigned len, unsigned copied,
0115                  struct page *page, void *fsdata)
0116 {
0117     struct inode *inode = page->mapping->host;
0118     loff_t last_pos = pos + copied;
0119     if (last_pos > inode->i_size)
0120         i_size_write(inode, last_pos);
0121     set_page_dirty(page);
0122     unlock_page(page);
0123     put_page(page);
0124     return copied;
0125 }
0126
0127 const struct address_space_operations udf_adinicb_aops = {
0128     .dirty_folio    = block_dirty_folio,
0129     .invalidate_folio = block_invalidate_folio,
0130     .read_folio = udf_adinicb_read_folio,
0131     .writepage  = udf_adinicb_writepage,
0132     .write_begin    = udf_adinicb_write_begin,
0133     .write_end  = udf_adinicb_write_end,
0134     .direct_IO  = udf_adinicb_direct_IO,
0135 };
0136
0137 static ssize_t udf_file_write_iter(struct kiocb *iocb, struct iov_iter *from)
0138 {
0139     ssize_t retval;
0140     struct file *file = iocb->ki_filp;
0141     struct inode *inode = file_inode(file);
0142     struct udf_inode_info *iinfo = UDF_I(inode);
0143     int err;
0144
0145     inode_lock(inode);
0146
0147     retval = generic_write_checks(iocb, from);
0148     if (retval <= 0)
0149         goto out;
0150
0151     down_write(&iinfo->i_data_sem);
0152     if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB) {
0153         loff_t end = iocb->ki_pos + iov_iter_count(from);
0154
0155         if (inode->i_sb->s_blocksize <
0156                 (udf_file_entry_alloc_offset(inode) + end)) {
0157             err = udf_expand_file_adinicb(inode);
0158             if (err) {
0159                 inode_unlock(inode);
0160                 udf_debug("udf_expand_adinicb: err=%d\n", err);
0161                 return err;
0162             }
0163         } else {
0164             iinfo->i_lenAlloc = max(end, inode->i_size);
0165             up_write(&iinfo->i_data_sem);
0166         }
0167     } else
0168         up_write(&iinfo->i_data_sem);
0169
0170     retval = __generic_file_write_iter(iocb, from);
0171 out:
0172     inode_unlock(inode);
0173
0174     if (retval > 0) {
0175         mark_inode_dirty(inode);
0176         retval = generic_write_sync(iocb, retval);
0177     }
0178
0179     return retval;
0180 }
0181
0182 long udf_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
0183 {
0184     struct inode *inode = file_inode(filp);
0185     long old_block, new_block;
0186     int result;
0187
0188     if (file_permission(filp, MAY_READ) != 0) {
0189         udf_debug("no permission to access inode %lu\n", inode->i_ino);
0190         return -EPERM;
0191     }
0192
0193     if (!arg && ((cmd == UDF_GETVOLIDENT) || (cmd == UDF_GETEASIZE) ||
0194              (cmd == UDF_RELOCATE_BLOCKS) || (cmd == UDF_GETEABLOCK))) {
0195         udf_debug("invalid argument to udf_ioctl\n");
0196         return -EINVAL;
0197     }
0198
0199     switch (cmd) {
0200     case UDF_GETVOLIDENT:
0201         if (copy_to_user((char __user *)arg,
0202                  UDF_SB(inode->i_sb)->s_volume_ident, 32))
0203             return -EFAULT;
0204         return 0;
0205     case UDF_RELOCATE_BLOCKS:
0206         if (!capable(CAP_SYS_ADMIN))
0207             return -EPERM;
0208         if (get_user(old_block, (long __user *)arg))
0209             return -EFAULT;
0210         result = udf_relocate_blocks(inode->i_sb,
0211                         old_block, &new_block);
0212         if (result == 0)
0213             result = put_user(new_block, (long __user *)arg);
0214         return result;
0215     case UDF_GETEASIZE:
0216         return put_user(UDF_I(inode)->i_lenEAttr, (int __user *)arg);
0217     case UDF_GETEABLOCK:
0218         return copy_to_user((char __user *)arg,
0219                     UDF_I(inode)->i_data,
0220                     UDF_I(inode)->i_lenEAttr) ? -EFAULT : 0;
0221     default:
0222         return -ENOIOCTLCMD;
0223     }
0224
0225     return 0;
0226 }
0227
0228 static int udf_release_file(struct inode *inode, struct file *filp)
0229 {
0230     if (filp->f_mode & FMODE_WRITE &&
0231         atomic_read(&inode->i_writecount) == 1) {
0232         /*
0233          * Grab i_mutex to avoid races with writes changing i_size
0234          * while we are running.
0235          */
0236         inode_lock(inode);
0237         down_write(&UDF_I(inode)->i_data_sem);
0238         udf_discard_prealloc(inode);
0239         udf_truncate_tail_extent(inode);
0240         up_write(&UDF_I(inode)->i_data_sem);
0241         inode_unlock(inode);
0242     }
0243     return 0;
0244 }
0245
0246 const struct file_operations udf_file_operations = {
0247     .read_iter      = generic_file_read_iter,
0248     .unlocked_ioctl     = udf_ioctl,
0249     .open           = generic_file_open,
0250     .mmap           = generic_file_mmap,
0251     .write_iter     = udf_file_write_iter,
0252     .release        = udf_release_file,
0253     .fsync          = generic_file_fsync,
0254     .splice_read        = generic_file_splice_read,
0255     .llseek         = generic_file_llseek,
0256 };
0257
0258 static int udf_setattr(struct user_namespace *mnt_userns, struct dentry *dentry,
0259                struct iattr *attr)
0260 {
0261     struct inode *inode = d_inode(dentry);
0262     struct super_block *sb = inode->i_sb;
0263     int error;
0264
0265     error = setattr_prepare(&init_user_ns, dentry, attr);
0266     if (error)
0267         return error;
0268
0269     if ((attr->ia_valid & ATTR_UID) &&
0270         UDF_QUERY_FLAG(sb, UDF_FLAG_UID_SET) &&
0271         !uid_eq(attr->ia_uid, UDF_SB(sb)->s_uid))
0272         return -EPERM;
0273     if ((attr->ia_valid & ATTR_GID) &&
0274         UDF_QUERY_FLAG(sb, UDF_FLAG_GID_SET) &&
0275         !gid_eq(attr->ia_gid, UDF_SB(sb)->s_gid))
0276         return -EPERM;
0277
0278     if ((attr->ia_valid & ATTR_SIZE) &&
0279         attr->ia_size != i_size_read(inode)) {
0280         error = udf_setsize(inode, attr->ia_size);
0281         if (error)
0282             return error;
0283     }
0284
0285     if (attr->ia_valid & ATTR_MODE)
0286         udf_update_extra_perms(inode, attr->ia_mode);
0287
0288     setattr_copy(&init_user_ns, inode, attr);
0289     mark_inode_dirty(inode);
0290     return 0;
0291 }
0292
0293 const struct inode_operations udf_file_inode_operations = {
0294     .setattr        = udf_setattr,
0295 };