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![Josef Bacik](/assets/img/avatar_default.png)
Btrfs needs to be able to control how filemap_write_and_wait_range() is called in fsync to make it less of a painful operation, so push down taking i_mutex and the calling of filemap_write_and_wait() down into the ->fsync() handlers. Some file systems can drop taking the i_mutex altogether it seems, like ext3 and ocfs2. For correctness sake I just pushed everything down in all cases to make sure that we keep the current behavior the same for everybody, and then each individual fs maintainer can make up their mind about what to do from there. Thanks, Acked-by: Jan Kara <jack@suse.cz> Signed-off-by: Josef Bacik <josef@redhat.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
319 lines
9.1 KiB
C
319 lines
9.1 KiB
C
/*
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* Copyright 2000 by Hans Reiser, licensing governed by reiserfs/README
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*/
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#include <linux/string.h>
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#include <linux/errno.h>
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#include <linux/fs.h>
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#include <linux/reiserfs_fs.h>
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#include <linux/stat.h>
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#include <linux/buffer_head.h>
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#include <linux/slab.h>
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#include <asm/uaccess.h>
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extern const struct reiserfs_key MIN_KEY;
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static int reiserfs_readdir(struct file *, void *, filldir_t);
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static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
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int datasync);
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const struct file_operations reiserfs_dir_operations = {
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.llseek = generic_file_llseek,
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.read = generic_read_dir,
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.readdir = reiserfs_readdir,
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.fsync = reiserfs_dir_fsync,
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.unlocked_ioctl = reiserfs_ioctl,
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#ifdef CONFIG_COMPAT
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.compat_ioctl = reiserfs_compat_ioctl,
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#endif
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};
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static int reiserfs_dir_fsync(struct file *filp, loff_t start, loff_t end,
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int datasync)
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{
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struct inode *inode = filp->f_mapping->host;
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int err;
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err = filemap_write_and_wait_range(inode->i_mapping, start, end);
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if (err)
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return err;
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mutex_lock(&inode->i_mutex);
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reiserfs_write_lock(inode->i_sb);
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err = reiserfs_commit_for_inode(inode);
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reiserfs_write_unlock(inode->i_sb);
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mutex_unlock(&inode->i_mutex);
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if (err < 0)
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return err;
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return 0;
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}
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#define store_ih(where,what) copy_item_head (where, what)
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static inline bool is_privroot_deh(struct dentry *dir,
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struct reiserfs_de_head *deh)
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{
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struct dentry *privroot = REISERFS_SB(dir->d_sb)->priv_root;
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return (dir == dir->d_parent && privroot->d_inode &&
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deh->deh_objectid == INODE_PKEY(privroot->d_inode)->k_objectid);
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}
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int reiserfs_readdir_dentry(struct dentry *dentry, void *dirent,
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filldir_t filldir, loff_t *pos)
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{
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struct inode *inode = dentry->d_inode;
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struct cpu_key pos_key; /* key of current position in the directory (key of directory entry) */
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INITIALIZE_PATH(path_to_entry);
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struct buffer_head *bh;
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int item_num, entry_num;
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const struct reiserfs_key *rkey;
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struct item_head *ih, tmp_ih;
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int search_res;
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char *local_buf;
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loff_t next_pos;
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char small_buf[32]; /* avoid kmalloc if we can */
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struct reiserfs_dir_entry de;
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int ret = 0;
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reiserfs_write_lock(inode->i_sb);
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reiserfs_check_lock_depth(inode->i_sb, "readdir");
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/* form key for search the next directory entry using f_pos field of
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file structure */
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make_cpu_key(&pos_key, inode, *pos ?: DOT_OFFSET, TYPE_DIRENTRY, 3);
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next_pos = cpu_key_k_offset(&pos_key);
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path_to_entry.reada = PATH_READA;
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while (1) {
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research:
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/* search the directory item, containing entry with specified key */
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search_res =
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search_by_entry_key(inode->i_sb, &pos_key, &path_to_entry,
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&de);
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if (search_res == IO_ERROR) {
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// FIXME: we could just skip part of directory which could
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// not be read
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ret = -EIO;
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goto out;
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}
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entry_num = de.de_entry_num;
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bh = de.de_bh;
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item_num = de.de_item_num;
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ih = de.de_ih;
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store_ih(&tmp_ih, ih);
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/* we must have found item, that is item of this directory, */
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RFALSE(COMP_SHORT_KEYS(&(ih->ih_key), &pos_key),
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"vs-9000: found item %h does not match to dir we readdir %K",
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ih, &pos_key);
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RFALSE(item_num > B_NR_ITEMS(bh) - 1,
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"vs-9005 item_num == %d, item amount == %d",
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item_num, B_NR_ITEMS(bh));
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/* and entry must be not more than number of entries in the item */
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RFALSE(I_ENTRY_COUNT(ih) < entry_num,
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"vs-9010: entry number is too big %d (%d)",
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entry_num, I_ENTRY_COUNT(ih));
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if (search_res == POSITION_FOUND
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|| entry_num < I_ENTRY_COUNT(ih)) {
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/* go through all entries in the directory item beginning from the entry, that has been found */
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struct reiserfs_de_head *deh =
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B_I_DEH(bh, ih) + entry_num;
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for (; entry_num < I_ENTRY_COUNT(ih);
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entry_num++, deh++) {
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int d_reclen;
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char *d_name;
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off_t d_off;
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ino_t d_ino;
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if (!de_visible(deh))
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/* it is hidden entry */
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continue;
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d_reclen = entry_length(bh, ih, entry_num);
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d_name = B_I_DEH_ENTRY_FILE_NAME(bh, ih, deh);
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if (d_reclen <= 0 ||
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d_name + d_reclen > bh->b_data + bh->b_size) {
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/* There is corrupted data in entry,
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* We'd better stop here */
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pathrelse(&path_to_entry);
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ret = -EIO;
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goto out;
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}
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if (!d_name[d_reclen - 1])
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d_reclen = strlen(d_name);
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if (d_reclen >
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REISERFS_MAX_NAME(inode->i_sb->
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s_blocksize)) {
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/* too big to send back to VFS */
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continue;
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}
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/* Ignore the .reiserfs_priv entry */
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if (is_privroot_deh(dentry, deh))
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continue;
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d_off = deh_offset(deh);
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*pos = d_off;
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d_ino = deh_objectid(deh);
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if (d_reclen <= 32) {
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local_buf = small_buf;
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} else {
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local_buf = kmalloc(d_reclen,
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GFP_NOFS);
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if (!local_buf) {
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pathrelse(&path_to_entry);
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ret = -ENOMEM;
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goto out;
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}
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if (item_moved(&tmp_ih, &path_to_entry)) {
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kfree(local_buf);
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goto research;
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}
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}
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// Note, that we copy name to user space via temporary
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// buffer (local_buf) because filldir will block if
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// user space buffer is swapped out. At that time
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// entry can move to somewhere else
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memcpy(local_buf, d_name, d_reclen);
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/*
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* Since filldir might sleep, we can release
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* the write lock here for other waiters
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*/
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reiserfs_write_unlock(inode->i_sb);
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if (filldir
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(dirent, local_buf, d_reclen, d_off, d_ino,
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DT_UNKNOWN) < 0) {
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reiserfs_write_lock(inode->i_sb);
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if (local_buf != small_buf) {
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kfree(local_buf);
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}
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goto end;
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}
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reiserfs_write_lock(inode->i_sb);
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if (local_buf != small_buf) {
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kfree(local_buf);
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}
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// next entry should be looked for with such offset
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next_pos = deh_offset(deh) + 1;
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if (item_moved(&tmp_ih, &path_to_entry)) {
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goto research;
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}
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} /* for */
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}
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if (item_num != B_NR_ITEMS(bh) - 1)
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// end of directory has been reached
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goto end;
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/* item we went through is last item of node. Using right
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delimiting key check is it directory end */
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rkey = get_rkey(&path_to_entry, inode->i_sb);
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if (!comp_le_keys(rkey, &MIN_KEY)) {
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/* set pos_key to key, that is the smallest and greater
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that key of the last entry in the item */
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set_cpu_key_k_offset(&pos_key, next_pos);
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continue;
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}
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if (COMP_SHORT_KEYS(rkey, &pos_key)) {
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// end of directory has been reached
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goto end;
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}
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/* directory continues in the right neighboring block */
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set_cpu_key_k_offset(&pos_key,
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le_key_k_offset(KEY_FORMAT_3_5, rkey));
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} /* while */
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end:
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*pos = next_pos;
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pathrelse(&path_to_entry);
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reiserfs_check_path(&path_to_entry);
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out:
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reiserfs_write_unlock(inode->i_sb);
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return ret;
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}
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static int reiserfs_readdir(struct file *file, void *dirent, filldir_t filldir)
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{
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struct dentry *dentry = file->f_path.dentry;
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return reiserfs_readdir_dentry(dentry, dirent, filldir, &file->f_pos);
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}
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/* compose directory item containing "." and ".." entries (entries are
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not aligned to 4 byte boundary) */
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/* the last four params are LE */
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void make_empty_dir_item_v1(char *body, __le32 dirid, __le32 objid,
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__le32 par_dirid, __le32 par_objid)
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{
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struct reiserfs_de_head *deh;
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memset(body, 0, EMPTY_DIR_SIZE_V1);
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deh = (struct reiserfs_de_head *)body;
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/* direntry header of "." */
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put_deh_offset(&(deh[0]), DOT_OFFSET);
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/* these two are from make_le_item_head, and are are LE */
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deh[0].deh_dir_id = dirid;
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deh[0].deh_objectid = objid;
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deh[0].deh_state = 0; /* Endian safe if 0 */
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put_deh_location(&(deh[0]), EMPTY_DIR_SIZE_V1 - strlen("."));
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mark_de_visible(&(deh[0]));
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/* direntry header of ".." */
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put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
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/* key of ".." for the root directory */
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/* these two are from the inode, and are are LE */
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deh[1].deh_dir_id = par_dirid;
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deh[1].deh_objectid = par_objid;
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deh[1].deh_state = 0; /* Endian safe if 0 */
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put_deh_location(&(deh[1]), deh_location(&(deh[0])) - strlen(".."));
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mark_de_visible(&(deh[1]));
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/* copy ".." and "." */
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memcpy(body + deh_location(&(deh[0])), ".", 1);
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memcpy(body + deh_location(&(deh[1])), "..", 2);
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}
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/* compose directory item containing "." and ".." entries */
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void make_empty_dir_item(char *body, __le32 dirid, __le32 objid,
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__le32 par_dirid, __le32 par_objid)
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{
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struct reiserfs_de_head *deh;
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memset(body, 0, EMPTY_DIR_SIZE);
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deh = (struct reiserfs_de_head *)body;
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/* direntry header of "." */
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put_deh_offset(&(deh[0]), DOT_OFFSET);
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/* these two are from make_le_item_head, and are are LE */
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deh[0].deh_dir_id = dirid;
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deh[0].deh_objectid = objid;
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deh[0].deh_state = 0; /* Endian safe if 0 */
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put_deh_location(&(deh[0]), EMPTY_DIR_SIZE - ROUND_UP(strlen(".")));
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mark_de_visible(&(deh[0]));
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/* direntry header of ".." */
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put_deh_offset(&(deh[1]), DOT_DOT_OFFSET);
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/* key of ".." for the root directory */
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/* these two are from the inode, and are are LE */
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deh[1].deh_dir_id = par_dirid;
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deh[1].deh_objectid = par_objid;
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deh[1].deh_state = 0; /* Endian safe if 0 */
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put_deh_location(&(deh[1]),
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deh_location(&(deh[0])) - ROUND_UP(strlen("..")));
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mark_de_visible(&(deh[1]));
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/* copy ".." and "." */
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memcpy(body + deh_location(&(deh[0])), ".", 1);
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memcpy(body + deh_location(&(deh[1])), "..", 2);
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}
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