fs/ext4/file.c

   1 /*
   2  *  linux/fs/ext4/file.c
   3  *
   4  * Copyright (C) 1992, 1993, 1994, 1995
   5  * Remy Card (card@masi.ibp.fr)
   6  * Laboratoire MASI - Institut Blaise Pascal
   7  * Universite Pierre et Marie Curie (Paris VI)
   8  *
   9  *  from
  10  *
  11  *  linux/fs/minix/file.c
  12  *
  13  *  Copyright (C) 1991, 1992  Linus Torvalds
  14  *
  15  *  ext4 fs regular file handling primitives
  16  *
  17  *  64-bit file support on 64-bit platforms by Jakub Jelinek
  18  *      (jj@sunsite.ms.mff.cuni.cz)
  19  */
  20
  21 #include <linux/time.h>
  22 #include <linux/fs.h>
  23 #include <linux/jbd2.h>
  24 #include <linux/mount.h>
  25 #include <linux/path.h>
  26 #include <linux/quotaops.h>
  27 #include "ext4.h"
  28 #include "ext4_jbd2.h"
  29 #include "xattr.h"
  30 #include "acl.h"
  31
  32 /*
  33  * Called when an inode is released. Note that this is different
  34  * from ext4_file_open: open gets called at every open, but release
  35  * gets called only when /all/ the files are closed.
  36  */
  37 static int ext4_release_file(struct inode *inode, struct file *filp)
  38 {
  39         if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
  40                 ext4_alloc_da_blocks(inode);
  41                 ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
  42         }
  43         /* if we are the last writer on the inode, drop the block reservation */
  44         if ((filp->f_mode & FMODE_WRITE) &&
  45                         (atomic_read(&inode->i_writecount) == 1) &&
  46                         !EXT4_I(inode)->i_reserved_data_blocks)
  47         {
  48                 down_write(&EXT4_I(inode)->i_data_sem);
  49                 ext4_discard_preallocations(inode);
  50                 up_write(&EXT4_I(inode)->i_data_sem);
  51         }
  52         if (is_dx(inode) && filp->private_data)
  53                 ext4_htree_free_dir_info(filp->private_data);
  54
  55         return 0;
  56 }
  57
  58 static ssize_t
  59 ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
  60                 unsigned long nr_segs, loff_t pos)
  61 {
  62         struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
  63
  64         /*
  65          * If we have encountered a bitmap-format file, the size limit
  66          * is smaller than s_maxbytes, which is for extent-mapped files.
  67          */
  68
  69         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
  70                 struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
  71                 size_t length = iov_length(iov, nr_segs);
  72
  73                 if ((pos > sbi->s_bitmap_maxbytes ||
  74                     (pos == sbi->s_bitmap_maxbytes && length > 0)))
  75                         return -EFBIG;
  76
  77                 if (pos + length > sbi->s_bitmap_maxbytes) {
  78                         nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
  79                                               sbi->s_bitmap_maxbytes - pos);
  80                 }
  81         }
  82
  83         return generic_file_aio_write(iocb, iov, nr_segs, pos);
  84 }
  85
  86 static const struct vm_operations_struct ext4_file_vm_ops = {
  87         .fault          = filemap_fault,
  88         .page_mkwrite   = ext4_page_mkwrite,
  89 };
  90
  91 static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
  92 {
  93         struct address_space *mapping = file->f_mapping;
  94
  95         if (!mapping->a_ops->readpage)
  96                 return -ENOEXEC;
  97         file_accessed(file);
  98         vma->vm_ops = &ext4_file_vm_ops;
  99         vma->vm_flags |= VM_CAN_NONLINEAR;
 100         return 0;
 101 }
 102
 103 static int ext4_file_open(struct inode * inode, struct file * filp)
 104 {
 105         struct super_block *sb = inode->i_sb;
 106         struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
 107         struct ext4_inode_info *ei = EXT4_I(inode);
 108         struct vfsmount *mnt = filp->f_path.mnt;
 109         struct path path;
 110         char buf[64], *cp;
 111
 112         if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
 113                      !(sb->s_flags & MS_RDONLY))) {
 114                 sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
 115                 /*
 116                  * Sample where the filesystem has been mounted and
 117                  * store it in the superblock for sysadmin convenience
 118                  * when trying to sort through large numbers of block
 119                  * devices or filesystem images.
 120                  */
 121                 memset(buf, 0, sizeof(buf));
 122                 path.mnt = mnt;
 123                 path.dentry = mnt->mnt_root;
 124                 cp = d_path(&path, buf, sizeof(buf));
 125                 if (!IS_ERR(cp)) {
 126                         memcpy(sbi->s_es->s_last_mounted, cp,
 127                                sizeof(sbi->s_es->s_last_mounted));
 128                         ext4_mark_super_dirty(sb);
 129                 }
 130         }
 131         /*
 132          * Set up the jbd2_inode if we are opening the inode for
 133          * writing and the journal is present
 134          */
 135         if (sbi->s_journal && !ei->jinode && (filp->f_mode & FMODE_WRITE)) {
 136                 struct jbd2_inode *jinode = jbd2_alloc_inode(GFP_KERNEL);
 137
 138                 spin_lock(&inode->i_lock);
 139                 if (!ei->jinode) {
 140                         if (!jinode) {
 141                                 spin_unlock(&inode->i_lock);
 142                                 return -ENOMEM;
 143                         }
 144                         ei->jinode = jinode;
 145                         jbd2_journal_init_jbd_inode(ei->jinode, inode);
 146                         jinode = NULL;
 147                 }
 148                 spin_unlock(&inode->i_lock);
 149                 if (unlikely(jinode != NULL))
 150                         jbd2_free_inode(jinode);
 151         }
 152         return dquot_file_open(inode, filp);
 153 }
 154
 155 /*
 156  * ext4_llseek() copied from generic_file_llseek() to handle both
 157  * block-mapped and extent-mapped maxbytes values. This should
 158  * otherwise be identical with generic_file_llseek().
 159  */
 160 loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
 161 {
 162         struct inode *inode = file->f_mapping->host;
 163         loff_t maxbytes;
 164
 165         if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
 166                 maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
 167         else
 168                 maxbytes = inode->i_sb->s_maxbytes;
 169         mutex_lock(&inode->i_mutex);
 170         switch (origin) {
 171         case SEEK_END:
 172                 offset += inode->i_size;
 173                 break;
 174         case SEEK_CUR:
 175                 if (offset == 0) {
 176                         mutex_unlock(&inode->i_mutex);
 177                         return file->f_pos;
 178                 }
 179                 offset += file->f_pos;
 180                 break;
 181         }
 182
 183         if (offset < 0 || offset > maxbytes) {
 184                 mutex_unlock(&inode->i_mutex);
 185                 return -EINVAL;
 186         }
 187
 188         if (offset != file->f_pos) {
 189                 file->f_pos = offset;
 190                 file->f_version = 0;
 191         }
 192         mutex_unlock(&inode->i_mutex);
 193
 194         return offset;
 195 }
 196
 197 const struct file_operations ext4_file_operations = {
 198         .llseek         = ext4_llseek,
 199         .read           = do_sync_read,
 200         .write          = do_sync_write,
 201         .aio_read       = generic_file_aio_read,
 202         .aio_write      = ext4_file_write,
 203         .unlocked_ioctl = ext4_ioctl,
 204 #ifdef CONFIG_COMPAT
 205         .compat_ioctl   = ext4_compat_ioctl,
 206 #endif
 207         .mmap           = ext4_file_mmap,
 208         .open           = ext4_file_open,
 209         .release        = ext4_release_file,
 210         .fsync          = ext4_sync_file,
 211         .splice_read    = generic_file_splice_read,
 212         .splice_write   = generic_file_splice_write,
 213         .fallocate      = ext4_fallocate,
 214 };
 215
 216 const struct inode_operations ext4_file_inode_operations = {
 217         .truncate       = ext4_truncate,
 218         .setattr        = ext4_setattr,
 219         .getattr        = ext4_getattr,
 220 #ifdef CONFIG_EXT4_FS_XATTR
 221         .setxattr       = generic_setxattr,
 222         .getxattr       = generic_getxattr,
 223         .listxattr      = ext4_listxattr,
 224         .removexattr    = generic_removexattr,
 225 #endif
 226         .check_acl      = ext4_check_acl,
 227         .fiemap         = ext4_fiemap,
 228 };
 229