diff options
Diffstat (limited to 'kernel/fs/ext4/file.c')
| -rw-r--r-- | kernel/fs/ext4/file.c | 651 |
1 files changed, 651 insertions, 0 deletions
diff --git a/kernel/fs/ext4/file.c b/kernel/fs/ext4/file.c new file mode 100644 index 000000000..0613c256c --- /dev/null +++ b/kernel/fs/ext4/file.c @@ -0,0 +1,651 @@ +/* + * linux/fs/ext4/file.c + * + * Copyright (C) 1992, 1993, 1994, 1995 + * Remy Card (card@masi.ibp.fr) + * Laboratoire MASI - Institut Blaise Pascal + * Universite Pierre et Marie Curie (Paris VI) + * + * from + * + * linux/fs/minix/file.c + * + * Copyright (C) 1991, 1992 Linus Torvalds + * + * ext4 fs regular file handling primitives + * + * 64-bit file support on 64-bit platforms by Jakub Jelinek + * (jj@sunsite.ms.mff.cuni.cz) + */ + +#include <linux/time.h> +#include <linux/fs.h> +#include <linux/mount.h> +#include <linux/path.h> +#include <linux/quotaops.h> +#include <linux/pagevec.h> +#include <linux/uio.h> +#include "ext4.h" +#include "ext4_jbd2.h" +#include "xattr.h" +#include "acl.h" + +/* + * Called when an inode is released. Note that this is different + * from ext4_file_open: open gets called at every open, but release + * gets called only when /all/ the files are closed. + */ +static int ext4_release_file(struct inode *inode, struct file *filp) +{ + if (ext4_test_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE)) { + ext4_alloc_da_blocks(inode); + ext4_clear_inode_state(inode, EXT4_STATE_DA_ALLOC_CLOSE); + } + /* if we are the last writer on the inode, drop the block reservation */ + if ((filp->f_mode & FMODE_WRITE) && + (atomic_read(&inode->i_writecount) == 1) && + !EXT4_I(inode)->i_reserved_data_blocks) + { + down_write(&EXT4_I(inode)->i_data_sem); + ext4_discard_preallocations(inode); + up_write(&EXT4_I(inode)->i_data_sem); + } + if (is_dx(inode) && filp->private_data) + ext4_htree_free_dir_info(filp->private_data); + + return 0; +} + +static void ext4_unwritten_wait(struct inode *inode) +{ + wait_queue_head_t *wq = ext4_ioend_wq(inode); + + wait_event(*wq, (atomic_read(&EXT4_I(inode)->i_unwritten) == 0)); +} + +/* + * This tests whether the IO in question is block-aligned or not. + * Ext4 utilizes unwritten extents when hole-filling during direct IO, and they + * are converted to written only after the IO is complete. Until they are + * mapped, these blocks appear as holes, so dio_zero_block() will assume that + * it needs to zero out portions of the start and/or end block. If 2 AIO + * threads are at work on the same unwritten block, they must be synchronized + * or one thread will zero the other's data, causing corruption. + */ +static int +ext4_unaligned_aio(struct inode *inode, struct iov_iter *from, loff_t pos) +{ + struct super_block *sb = inode->i_sb; + int blockmask = sb->s_blocksize - 1; + + if (pos >= i_size_read(inode)) + return 0; + + if ((pos | iov_iter_alignment(from)) & blockmask) + return 1; + + return 0; +} + +static ssize_t +ext4_file_write_iter(struct kiocb *iocb, struct iov_iter *from) +{ + struct file *file = iocb->ki_filp; + struct inode *inode = file_inode(iocb->ki_filp); + struct mutex *aio_mutex = NULL; + struct blk_plug plug; + int o_direct = iocb->ki_flags & IOCB_DIRECT; + int overwrite = 0; + ssize_t ret; + + /* + * Unaligned direct AIO must be serialized; see comment above + * In the case of O_APPEND, assume that we must always serialize + */ + if (o_direct && + ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS) && + !is_sync_kiocb(iocb) && + (iocb->ki_flags & IOCB_APPEND || + ext4_unaligned_aio(inode, from, iocb->ki_pos))) { + aio_mutex = ext4_aio_mutex(inode); + mutex_lock(aio_mutex); + ext4_unwritten_wait(inode); + } + + mutex_lock(&inode->i_mutex); + ret = generic_write_checks(iocb, from); + if (ret <= 0) + goto out; + + /* + * If we have encountered a bitmap-format file, the size limit + * is smaller than s_maxbytes, which is for extent-mapped files. + */ + if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) { + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + + if (iocb->ki_pos >= sbi->s_bitmap_maxbytes) { + ret = -EFBIG; + goto out; + } + iov_iter_truncate(from, sbi->s_bitmap_maxbytes - iocb->ki_pos); + } + + iocb->private = &overwrite; + if (o_direct) { + size_t length = iov_iter_count(from); + loff_t pos = iocb->ki_pos; + blk_start_plug(&plug); + + /* check whether we do a DIO overwrite or not */ + if (ext4_should_dioread_nolock(inode) && !aio_mutex && + !file->f_mapping->nrpages && pos + length <= i_size_read(inode)) { + struct ext4_map_blocks map; + unsigned int blkbits = inode->i_blkbits; + int err, len; + + map.m_lblk = pos >> blkbits; + map.m_len = (EXT4_BLOCK_ALIGN(pos + length, blkbits) >> blkbits) + - map.m_lblk; + len = map.m_len; + + err = ext4_map_blocks(NULL, inode, &map, 0); + /* + * 'err==len' means that all of blocks has + * been preallocated no matter they are + * initialized or not. For excluding + * unwritten extents, we need to check + * m_flags. There are two conditions that + * indicate for initialized extents. 1) If we + * hit extent cache, EXT4_MAP_MAPPED flag is + * returned; 2) If we do a real lookup, + * non-flags are returned. So we should check + * these two conditions. + */ + if (err == len && (map.m_flags & EXT4_MAP_MAPPED)) + overwrite = 1; + } + } + + ret = __generic_file_write_iter(iocb, from); + mutex_unlock(&inode->i_mutex); + + if (ret > 0) { + ssize_t err; + + err = generic_write_sync(file, iocb->ki_pos - ret, ret); + if (err < 0) + ret = err; + } + if (o_direct) + blk_finish_plug(&plug); + + if (aio_mutex) + mutex_unlock(aio_mutex); + return ret; + +out: + mutex_unlock(&inode->i_mutex); + if (aio_mutex) + mutex_unlock(aio_mutex); + return ret; +} + +#ifdef CONFIG_FS_DAX +static int ext4_dax_fault(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + return dax_fault(vma, vmf, ext4_get_block); + /* Is this the right get_block? */ +} + +static int ext4_dax_mkwrite(struct vm_area_struct *vma, struct vm_fault *vmf) +{ + return dax_mkwrite(vma, vmf, ext4_get_block); +} + +static const struct vm_operations_struct ext4_dax_vm_ops = { + .fault = ext4_dax_fault, + .page_mkwrite = ext4_dax_mkwrite, + .pfn_mkwrite = dax_pfn_mkwrite, +}; +#else +#define ext4_dax_vm_ops ext4_file_vm_ops +#endif + +static const struct vm_operations_struct ext4_file_vm_ops = { + .fault = filemap_fault, + .map_pages = filemap_map_pages, + .page_mkwrite = ext4_page_mkwrite, +}; + +static int ext4_file_mmap(struct file *file, struct vm_area_struct *vma) +{ + struct inode *inode = file->f_mapping->host; + + if (ext4_encrypted_inode(inode)) { + int err = ext4_generate_encryption_key(inode); + if (err) + return 0; + } + file_accessed(file); + if (IS_DAX(file_inode(file))) { + vma->vm_ops = &ext4_dax_vm_ops; + vma->vm_flags |= VM_MIXEDMAP; + } else { + vma->vm_ops = &ext4_file_vm_ops; + } + return 0; +} + +static int ext4_file_open(struct inode * inode, struct file * filp) +{ + struct super_block *sb = inode->i_sb; + struct ext4_sb_info *sbi = EXT4_SB(inode->i_sb); + struct vfsmount *mnt = filp->f_path.mnt; + struct path path; + char buf[64], *cp; + int ret; + + if (unlikely(!(sbi->s_mount_flags & EXT4_MF_MNTDIR_SAMPLED) && + !(sb->s_flags & MS_RDONLY))) { + sbi->s_mount_flags |= EXT4_MF_MNTDIR_SAMPLED; + /* + * Sample where the filesystem has been mounted and + * store it in the superblock for sysadmin convenience + * when trying to sort through large numbers of block + * devices or filesystem images. + */ + memset(buf, 0, sizeof(buf)); + path.mnt = mnt; + path.dentry = mnt->mnt_root; + cp = d_path(&path, buf, sizeof(buf)); + if (!IS_ERR(cp)) { + handle_t *handle; + int err; + + handle = ext4_journal_start_sb(sb, EXT4_HT_MISC, 1); + if (IS_ERR(handle)) + return PTR_ERR(handle); + BUFFER_TRACE(sbi->s_sbh, "get_write_access"); + err = ext4_journal_get_write_access(handle, sbi->s_sbh); + if (err) { + ext4_journal_stop(handle); + return err; + } + strlcpy(sbi->s_es->s_last_mounted, cp, + sizeof(sbi->s_es->s_last_mounted)); + ext4_handle_dirty_super(handle, sb); + ext4_journal_stop(handle); + } + } + /* + * Set up the jbd2_inode if we are opening the inode for + * writing and the journal is present + */ + if (filp->f_mode & FMODE_WRITE) { + ret = ext4_inode_attach_jinode(inode); + if (ret < 0) + return ret; + } + ret = dquot_file_open(inode, filp); + if (!ret && ext4_encrypted_inode(inode)) { + ret = ext4_generate_encryption_key(inode); + if (ret) + ret = -EACCES; + } + return ret; +} + +/* + * Here we use ext4_map_blocks() to get a block mapping for a extent-based + * file rather than ext4_ext_walk_space() because we can introduce + * SEEK_DATA/SEEK_HOLE for block-mapped and extent-mapped file at the same + * function. When extent status tree has been fully implemented, it will + * track all extent status for a file and we can directly use it to + * retrieve the offset for SEEK_DATA/SEEK_HOLE. + */ + +/* + * When we retrieve the offset for SEEK_DATA/SEEK_HOLE, we would need to + * lookup page cache to check whether or not there has some data between + * [startoff, endoff] because, if this range contains an unwritten extent, + * we determine this extent as a data or a hole according to whether the + * page cache has data or not. + */ +static int ext4_find_unwritten_pgoff(struct inode *inode, + int whence, + struct ext4_map_blocks *map, + loff_t *offset) +{ + struct pagevec pvec; + unsigned int blkbits; + pgoff_t index; + pgoff_t end; + loff_t endoff; + loff_t startoff; + loff_t lastoff; + int found = 0; + + blkbits = inode->i_sb->s_blocksize_bits; + startoff = *offset; + lastoff = startoff; + endoff = (loff_t)(map->m_lblk + map->m_len) << blkbits; + + index = startoff >> PAGE_CACHE_SHIFT; + end = endoff >> PAGE_CACHE_SHIFT; + + pagevec_init(&pvec, 0); + do { + int i, num; + unsigned long nr_pages; + + num = min_t(pgoff_t, end - index, PAGEVEC_SIZE); + nr_pages = pagevec_lookup(&pvec, inode->i_mapping, index, + (pgoff_t)num); + if (nr_pages == 0) { + if (whence == SEEK_DATA) + break; + + BUG_ON(whence != SEEK_HOLE); + /* + * If this is the first time to go into the loop and + * offset is not beyond the end offset, it will be a + * hole at this offset + */ + if (lastoff == startoff || lastoff < endoff) + found = 1; + break; + } + + /* + * If this is the first time to go into the loop and + * offset is smaller than the first page offset, it will be a + * hole at this offset. + */ + if (lastoff == startoff && whence == SEEK_HOLE && + lastoff < page_offset(pvec.pages[0])) { + found = 1; + break; + } + + for (i = 0; i < nr_pages; i++) { + struct page *page = pvec.pages[i]; + struct buffer_head *bh, *head; + + /* + * If the current offset is not beyond the end of given + * range, it will be a hole. + */ + if (lastoff < endoff && whence == SEEK_HOLE && + page->index > end) { + found = 1; + *offset = lastoff; + goto out; + } + + lock_page(page); + + if (unlikely(page->mapping != inode->i_mapping)) { + unlock_page(page); + continue; + } + + if (!page_has_buffers(page)) { + unlock_page(page); + continue; + } + + if (page_has_buffers(page)) { + lastoff = page_offset(page); + bh = head = page_buffers(page); + do { + if (buffer_uptodate(bh) || + buffer_unwritten(bh)) { + if (whence == SEEK_DATA) + found = 1; + } else { + if (whence == SEEK_HOLE) + found = 1; + } + if (found) { + *offset = max_t(loff_t, + startoff, lastoff); + unlock_page(page); + goto out; + } + lastoff += bh->b_size; + bh = bh->b_this_page; + } while (bh != head); + } + + lastoff = page_offset(page) + PAGE_SIZE; + unlock_page(page); + } + + /* + * The no. of pages is less than our desired, that would be a + * hole in there. + */ + if (nr_pages < num && whence == SEEK_HOLE) { + found = 1; + *offset = lastoff; + break; + } + + index = pvec.pages[i - 1]->index + 1; + pagevec_release(&pvec); + } while (index <= end); + +out: + pagevec_release(&pvec); + return found; +} + +/* + * ext4_seek_data() retrieves the offset for SEEK_DATA. + */ +static loff_t ext4_seek_data(struct file *file, loff_t offset, loff_t maxsize) +{ + struct inode *inode = file->f_mapping->host; + struct ext4_map_blocks map; + struct extent_status es; + ext4_lblk_t start, last, end; + loff_t dataoff, isize; + int blkbits; + int ret = 0; + + mutex_lock(&inode->i_mutex); + + isize = i_size_read(inode); + if (offset >= isize) { + mutex_unlock(&inode->i_mutex); + return -ENXIO; + } + + blkbits = inode->i_sb->s_blocksize_bits; + start = offset >> blkbits; + last = start; + end = isize >> blkbits; + dataoff = offset; + + do { + map.m_lblk = last; + map.m_len = end - last + 1; + ret = ext4_map_blocks(NULL, inode, &map, 0); + if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) { + if (last != start) + dataoff = (loff_t)last << blkbits; + break; + } + + /* + * If there is a delay extent at this offset, + * it will be as a data. + */ + ext4_es_find_delayed_extent_range(inode, last, last, &es); + if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) { + if (last != start) + dataoff = (loff_t)last << blkbits; + break; + } + + /* + * If there is a unwritten extent at this offset, + * it will be as a data or a hole according to page + * cache that has data or not. + */ + if (map.m_flags & EXT4_MAP_UNWRITTEN) { + int unwritten; + unwritten = ext4_find_unwritten_pgoff(inode, SEEK_DATA, + &map, &dataoff); + if (unwritten) + break; + } + + last++; + dataoff = (loff_t)last << blkbits; + } while (last <= end); + + mutex_unlock(&inode->i_mutex); + + if (dataoff > isize) + return -ENXIO; + + return vfs_setpos(file, dataoff, maxsize); +} + +/* + * ext4_seek_hole() retrieves the offset for SEEK_HOLE. + */ +static loff_t ext4_seek_hole(struct file *file, loff_t offset, loff_t maxsize) +{ + struct inode *inode = file->f_mapping->host; + struct ext4_map_blocks map; + struct extent_status es; + ext4_lblk_t start, last, end; + loff_t holeoff, isize; + int blkbits; + int ret = 0; + + mutex_lock(&inode->i_mutex); + + isize = i_size_read(inode); + if (offset >= isize) { + mutex_unlock(&inode->i_mutex); + return -ENXIO; + } + + blkbits = inode->i_sb->s_blocksize_bits; + start = offset >> blkbits; + last = start; + end = isize >> blkbits; + holeoff = offset; + + do { + map.m_lblk = last; + map.m_len = end - last + 1; + ret = ext4_map_blocks(NULL, inode, &map, 0); + if (ret > 0 && !(map.m_flags & EXT4_MAP_UNWRITTEN)) { + last += ret; + holeoff = (loff_t)last << blkbits; + continue; + } + + /* + * If there is a delay extent at this offset, + * we will skip this extent. + */ + ext4_es_find_delayed_extent_range(inode, last, last, &es); + if (es.es_len != 0 && in_range(last, es.es_lblk, es.es_len)) { + last = es.es_lblk + es.es_len; + holeoff = (loff_t)last << blkbits; + continue; + } + + /* + * If there is a unwritten extent at this offset, + * it will be as a data or a hole according to page + * cache that has data or not. + */ + if (map.m_flags & EXT4_MAP_UNWRITTEN) { + int unwritten; + unwritten = ext4_find_unwritten_pgoff(inode, SEEK_HOLE, + &map, &holeoff); + if (!unwritten) { + last += ret; + holeoff = (loff_t)last << blkbits; + continue; + } + } + + /* find a hole */ + break; + } while (last <= end); + + mutex_unlock(&inode->i_mutex); + + if (holeoff > isize) + holeoff = isize; + + return vfs_setpos(file, holeoff, maxsize); +} + +/* + * ext4_llseek() handles both block-mapped and extent-mapped maxbytes values + * by calling generic_file_llseek_size() with the appropriate maxbytes + * value for each. + */ +loff_t ext4_llseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_mapping->host; + loff_t maxbytes; + + if (!(ext4_test_inode_flag(inode, EXT4_INODE_EXTENTS))) + maxbytes = EXT4_SB(inode->i_sb)->s_bitmap_maxbytes; + else + maxbytes = inode->i_sb->s_maxbytes; + + switch (whence) { + case SEEK_SET: + case SEEK_CUR: + case SEEK_END: + return generic_file_llseek_size(file, offset, whence, + maxbytes, i_size_read(inode)); + case SEEK_DATA: + return ext4_seek_data(file, offset, maxbytes); + case SEEK_HOLE: + return ext4_seek_hole(file, offset, maxbytes); + } + + return -EINVAL; +} + +const struct file_operations ext4_file_operations = { + .llseek = ext4_llseek, + .read_iter = generic_file_read_iter, + .write_iter = ext4_file_write_iter, + .unlocked_ioctl = ext4_ioctl, +#ifdef CONFIG_COMPAT + .compat_ioctl = ext4_compat_ioctl, +#endif + .mmap = ext4_file_mmap, + .open = ext4_file_open, + .release = ext4_release_file, + .fsync = ext4_sync_file, + .splice_read = generic_file_splice_read, + .splice_write = iter_file_splice_write, + .fallocate = ext4_fallocate, +}; + +const struct inode_operations ext4_file_inode_operations = { + .setattr = ext4_setattr, + .getattr = ext4_getattr, + .setxattr = generic_setxattr, + .getxattr = generic_getxattr, + .listxattr = ext4_listxattr, + .removexattr = generic_removexattr, + .get_acl = ext4_get_acl, + .set_acl = ext4_set_acl, + .fiemap = ext4_fiemap, +}; + |