mirror of https://gitee.com/openkylin/linux.git
339 lines
9.3 KiB
C
339 lines
9.3 KiB
C
/*
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* linux/fs/ext4/file.c
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*
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* Copyright (C) 1992, 1993, 1994, 1995
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* Remy Card (card@masi.ibp.fr)
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* Laboratoire MASI - Institut Blaise Pascal
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* Universite Pierre et Marie Curie (Paris VI)
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*
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* from
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*
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* linux/fs/minix/file.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*
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* ext4 fs regular file handling primitives
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*
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* 64-bit file support on 64-bit platforms by Jakub Jelinek
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* (jj@sunsite.ms.mff.cuni.cz)
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*/
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#include <linux/time.h>
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#include <linux/fs.h>
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#include <linux/jbd2.h>
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#include <linux/mount.h>
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#include <linux/path.h>
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#include <linux/quotaops.h>
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#include "ext4.h"
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#include "ext4_jbd2.h"
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#include "xattr.h"
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#include "acl.h"
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/*
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* Called when an inode is released. Note that this is different
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* from ext4_file_open: open gets called at every open, but release
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* gets called only when /all/ the files are closed.
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*/
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static int ext4_release_file(struct inode *inode, struct file *filp)
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{
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if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) {
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ext4_alloc_da_blocks(inode);
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ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE);
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}
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/* if we are the last writer on the inode, drop the block reservation */
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if ((filp->f_mode & FMODE_WRITE) &&
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(atomic_read(&inode->i_writecount) == 1) &&
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!EXT4_I(inode)->i_reserved_data_blocks)
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{
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down_write(&EXT4_I(inode)->i_data_sem);
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ext4_discard_preallocations(inode);
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up_write(&EXT4_I(inode)->i_data_sem);
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}
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if (is_dx(inode) && filp->private_data)
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ext4_htree_free_dir_info(filp->private_data);
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return 0;
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}
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void ext4_unwritten_wait(struct inode *inode)
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{
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wait_queue_head_t *wq = ext4_ioend_wq(inode);
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wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0));
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}
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/*
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* This tests whether the IO in question is block-aligned or not.
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* Ext4 utilizes unwritten extents when hole-filling during direct IO, and they
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* are converted to written only after the IO is complete. Until they are
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* mapped, these blocks appear as holes, so dio_zero_block() will assume that
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* it needs to zero out portions of the start and/or end block. If 2 AIO
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* threads are at work on the same unwritten block, they must be synchronized
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* or one thread will zero the other's data, causing corruption.
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*/
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static int
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ext4_unaligned_aio(struct inode *inode, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos)
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{
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struct super_block *sb = inode->i_sb;
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int blockmask = sb->s_blocksize - 1;
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size_t count = iov_length(iov, nr_segs);
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loff_t final_size = pos + count;
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if (pos >= inode->i_size)
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return 0;
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if ((pos & blockmask) || (final_size & blockmask))
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return 1;
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return 0;
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}
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static ssize_t
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ext4_file_dio_write(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos)
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{
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struct file *file = iocb->ki_filp;
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struct inode *inode = file->f_mapping->host;
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struct blk_plug plug;
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int unaligned_aio = 0;
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ssize_t ret;
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int overwrite = 0;
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size_t length = iov_length(iov, nr_segs);
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if (ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) &&
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!is_sync_kiocb(iocb))
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unaligned_aio = ext4_unaligned_aio(inode, iov, nr_segs, pos);
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/* Unaligned direct AIO must be serialized; see comment above */
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if (unaligned_aio) {
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static unsigned long unaligned_warn_time;
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/* Warn about this once per day */
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if (printk_timed_ratelimit(&unaligned_warn_time, 60*60*24*HZ))
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ext4_msg(inode->i_sb, KERN_WARNING,
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"Unaligned AIO/DIO on inode %ld by %s; "
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"performance will be poor.",
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inode->i_ino, current->comm);
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mutex_lock(ext4_aio_mutex(inode));
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ext4_unwritten_wait(inode);
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}
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BUG_ON(iocb->ki_pos != pos);
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mutex_lock(&inode->i_mutex);
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blk_start_plug(&plug);
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iocb->private = &overwrite;
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/* check whether we do a DIO overwrite or not */
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if (ext4_should_dioread_nolock(inode) && !unaligned_aio &&
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!file->f_mapping->nrpages && pos + length <= i_size_read(inode)) {
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struct ext4_map_blocks map;
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unsigned int blkbits = inode->i_blkbits;
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int err, len;
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map.m_lblk = pos >> blkbits;
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map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits)
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- map.m_lblk;
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len = map.m_len;
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err = ext4_map_blocks(NULL, inode, &map, 0);
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/*
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* 'err==len' means that all of blocks has been preallocated no
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* matter they are initialized or not. For excluding
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* uninitialized extents, we need to check m_flags. There are
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* two conditions that indicate for initialized extents.
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* 1) If we hit extent cache, EXT4_MAP_MAPPED flag is returned;
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* 2) If we do a real lookup, non-flags are returned.
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* So we should check these two conditions.
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*/
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if (err == len && (map.m_flags & EXT4_MAP_MAPPED))
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overwrite = 1;
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}
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ret = __generic_file_aio_write(iocb, iov, nr_segs, &iocb->ki_pos);
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mutex_unlock(&inode->i_mutex);
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if (ret > 0 || ret == -EIOCBQUEUED) {
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ssize_t err;
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err = generic_write_sync(file, pos, ret);
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if (err < 0 && ret > 0)
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ret = err;
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}
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blk_finish_plug(&plug);
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if (unaligned_aio)
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mutex_unlock(ext4_aio_mutex(inode));
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return ret;
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}
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static ssize_t
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ext4_file_write(struct kiocb *iocb, const struct iovec *iov,
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unsigned long nr_segs, loff_t pos)
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{
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struct inode *inode = iocb->ki_filp->f_path.dentry->d_inode;
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ssize_t ret;
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/*
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* If we have encountered a bitmap-format file, the size limit
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* is smaller than s_maxbytes, which is for extent-mapped files.
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*/
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if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) {
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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size_t length = iov_length(iov, nr_segs);
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if ((pos > sbi->s_bitmap_maxbytes ||
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(pos == sbi->s_bitmap_maxbytes && length > 0)))
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return -EFBIG;
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if (pos + length > sbi->s_bitmap_maxbytes) {
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nr_segs = iov_shorten((struct iovec *)iov, nr_segs,
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sbi->s_bitmap_maxbytes - pos);
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}
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}
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if (unlikely(iocb->ki_filp->f_flags & O_DIRECT))
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ret = ext4_file_dio_write(iocb, iov, nr_segs, pos);
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else
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ret = generic_file_aio_write(iocb, iov, nr_segs, pos);
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return ret;
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}
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static const struct vm_operations_struct ext4_file_vm_ops = {
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.fault = filemap_fault,
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.page_mkwrite = ext4_page_mkwrite,
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.remap_pages = generic_file_remap_pages,
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};
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static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma)
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{
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struct address_space *mapping = file->f_mapping;
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if (!mapping->a_ops->readpage)
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return -ENOEXEC;
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file_accessed(file);
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vma->vm_ops = &ext4_file_vm_ops;
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return 0;
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}
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static int ext4_file_open(struct inode * inode, struct file * filp)
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{
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struct super_block *sb = inode->i_sb;
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struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb);
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struct ext4_inode_info *ei = EXT4_I(inode);
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struct vfsmount *mnt = filp->f_path.mnt;
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struct path path;
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char buf[64], *cp;
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if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) &&
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!(sb->s_flags & MS_RDONLY))) {
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sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED;
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/*
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* Sample where the filesystem has been mounted and
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* store it in the superblock for sysadmin convenience
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* when trying to sort through large numbers of block
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* devices or filesystem images.
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*/
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memset(buf, 0, sizeof(buf));
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path.mnt = mnt;
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path.dentry = mnt->mnt_root;
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cp = d_path(&path, buf, sizeof(buf));
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if (!IS_ERR(cp)) {
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handle_t *handle;
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int err;
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handle = ext4_journal_start_sb(sb, 1);
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if (IS_ERR(handle))
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return PTR_ERR(handle);
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err = ext4_journal_get_write_access(handle, sbi->s_sbh);
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if (err) {
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ext4_journal_stop(handle);
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return err;
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}
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strlcpy(sbi->s_es->s_last_mounted, cp,
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sizeof(sbi->s_es->s_last_mounted));
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ext4_handle_dirty_super(handle, sb);
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ext4_journal_stop(handle);
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}
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}
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/*
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* Set up the jbd2_inode if we are opening the inode for
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* writing and the journal is present
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*/
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if (sbi->s_journal && !ei->jinode && (filp->f_mode & FMODE_WRITE)) {
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struct jbd2_inode *jinode = jbd2_alloc_inode(GFP_KERNEL);
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spin_lock(&inode->i_lock);
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if (!ei->jinode) {
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if (!jinode) {
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spin_unlock(&inode->i_lock);
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return -ENOMEM;
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}
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ei->jinode = jinode;
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jbd2_journal_init_jbd_inode(ei->jinode, inode);
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jinode = NULL;
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}
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spin_unlock(&inode->i_lock);
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if (unlikely(jinode != NULL))
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jbd2_free_inode(jinode);
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}
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return dquot_file_open(inode, filp);
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}
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/*
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* ext4_llseek() handles both block-mapped and extent-mapped maxbytes values
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* by calling generic_file_llseek_size() with the appropriate maxbytes
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* value for each.
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*/
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loff_t ext4_llseek(struct file *file, loff_t offset, int origin)
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{
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struct inode *inode = file->f_mapping->host;
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loff_t maxbytes;
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if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS)))
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maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes;
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else
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maxbytes = inode->i_sb->s_maxbytes;
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return generic_file_llseek_size(file, offset, origin,
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maxbytes, i_size_read(inode));
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}
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const struct file_operations ext4_file_operations = {
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.llseek = ext4_llseek,
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.read = do_sync_read,
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.write = do_sync_write,
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.aio_read = generic_file_aio_read,
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.aio_write = ext4_file_write,
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.unlocked_ioctl = ext4_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = ext4_compat_ioctl,
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#endif
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.mmap = ext4_file_mmap,
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.open = ext4_file_open,
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.release = ext4_release_file,
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.fsync = ext4_sync_file,
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.splice_read = generic_file_splice_read,
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.splice_write = generic_file_splice_write,
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.fallocate = ext4_fallocate,
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};
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const struct inode_operations ext4_file_inode_operations = {
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.setattr = ext4_setattr,
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.getattr = ext4_getattr,
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#ifdef CONFIG_EXT4_FS_XATTR
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.setxattr = generic_setxattr,
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.getxattr = generic_getxattr,
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.listxattr = ext4_listxattr,
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.removexattr = generic_removexattr,
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#endif
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.get_acl = ext4_get_acl,
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.fiemap = ext4_fiemap,
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};
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