HPFS: Introduce a global mutex and lock it on every callback from VFS.
Introduce a global mutex and lock it on every callback from VFS. Performance doesn't matter, reviewing the whole code for locking correctness would be too complicated, so simply lock it all. Signed-off-by: Mikulas Patocka <mikulas@artax.karlin.mff.cuni.cz> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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@ -32,6 +32,8 @@ void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head
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{
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struct buffer_head *bh;
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hpfs_lock_assert(s);
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cond_resched();
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*bhp = bh = sb_bread(s, secno);
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@ -50,6 +52,8 @@ void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head
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struct buffer_head *bh;
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/*return hpfs_map_sector(s, secno, bhp, 0);*/
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hpfs_lock_assert(s);
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cond_resched();
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if ((*bhp = bh = sb_getblk(s, secno)) != NULL) {
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@ -70,6 +74,8 @@ void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffe
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struct buffer_head *bh;
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char *data;
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hpfs_lock_assert(s);
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cond_resched();
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if (secno & 3) {
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@ -125,6 +131,8 @@ void *hpfs_get_4sectors(struct super_block *s, unsigned secno,
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{
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cond_resched();
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hpfs_lock_assert(s);
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if (secno & 3) {
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printk("HPFS: hpfs_get_4sectors: unaligned read\n");
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return NULL;
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@ -48,38 +48,46 @@ static secno hpfs_bmap(struct inode *inode, unsigned file_secno)
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static void hpfs_truncate(struct inode *i)
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{
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if (IS_IMMUTABLE(i)) return /*-EPERM*/;
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hpfs_lock(i->i_sb);
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hpfs_lock_assert(i->i_sb);
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hpfs_i(i)->i_n_secs = 0;
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i->i_blocks = 1 + ((i->i_size + 511) >> 9);
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hpfs_i(i)->mmu_private = i->i_size;
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hpfs_truncate_btree(i->i_sb, i->i_ino, 1, ((i->i_size + 511) >> 9));
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hpfs_write_inode(i);
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hpfs_i(i)->i_n_secs = 0;
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hpfs_unlock(i->i_sb);
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}
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static int hpfs_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create)
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{
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int r;
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secno s;
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hpfs_lock(inode->i_sb);
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s = hpfs_bmap(inode, iblock);
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if (s) {
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map_bh(bh_result, inode->i_sb, s);
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return 0;
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goto ret_0;
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}
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if (!create) return 0;
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if (!create) goto ret_0;
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if (iblock<<9 != hpfs_i(inode)->mmu_private) {
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BUG();
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return -EIO;
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r = -EIO;
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goto ret_r;
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}
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if ((s = hpfs_add_sector_to_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1)) == -1) {
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hpfs_truncate_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1);
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return -ENOSPC;
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r = -ENOSPC;
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goto ret_r;
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}
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inode->i_blocks++;
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hpfs_i(inode)->mmu_private += 512;
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set_buffer_new(bh_result);
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map_bh(bh_result, inode->i_sb, s);
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return 0;
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ret_0:
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r = 0;
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ret_r:
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hpfs_unlock(inode->i_sb);
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return r;
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}
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static int hpfs_writepage(struct page *page, struct writeback_control *wbc)
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@ -130,8 +138,11 @@ static ssize_t hpfs_file_write(struct file *file, const char __user *buf,
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ssize_t retval;
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retval = do_sync_write(file, buf, count, ppos);
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if (retval > 0)
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if (retval > 0) {
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hpfs_lock(file->f_path.dentry->d_sb);
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hpfs_i(file->f_path.dentry->d_inode)->i_dirty = 1;
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hpfs_unlock(file->f_path.dentry->d_sb);
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}
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return retval;
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}
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@ -63,6 +63,7 @@ struct hpfs_inode_info {
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};
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struct hpfs_sb_info {
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struct mutex hpfs_mutex; /* global hpfs lock */
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ino_t sb_root; /* inode number of root dir */
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unsigned sb_fs_size; /* file system size, sectors */
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unsigned sb_bitmaps; /* sector number of bitmap list */
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@ -346,21 +347,26 @@ static inline time32_t gmt_to_local(struct super_block *s, time_t t)
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/*
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* Locking:
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*
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* hpfs_lock() is a leftover from the big kernel lock.
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* Right now, these functions are empty and only left
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* for documentation purposes. The file system no longer
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* works on SMP systems, so the lock is not needed
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* any more.
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* hpfs_lock() locks the whole filesystem. It must be taken
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* on any method called by the VFS.
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*
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* If someone is interested in making it work again, this
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* would be the place to start by adding a per-superblock
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* mutex and fixing all the bugs and performance issues
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* caused by that.
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* We don't do any per-file locking anymore, it is hard to
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* review and HPFS is not performance-sensitive anyway.
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*/
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static inline void hpfs_lock(struct super_block *s)
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{
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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mutex_lock(&sbi->hpfs_mutex);
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}
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static inline void hpfs_unlock(struct super_block *s)
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{
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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mutex_unlock(&sbi->hpfs_mutex);
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}
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static inline void hpfs_lock_assert(struct super_block *s)
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{
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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WARN_ON(!mutex_is_locked(&sbi->hpfs_mutex));
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}
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@ -102,9 +102,12 @@ static void hpfs_put_super(struct super_block *s)
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{
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struct hpfs_sb_info *sbi = hpfs_sb(s);
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hpfs_lock(s);
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unmark_dirty(s);
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hpfs_unlock(s);
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kfree(sbi->sb_cp_table);
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kfree(sbi->sb_bmp_dir);
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unmark_dirty(s);
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s->s_fs_info = NULL;
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kfree(sbi);
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}
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@ -490,6 +493,9 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
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sbi->sb_bmp_dir = NULL;
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sbi->sb_cp_table = NULL;
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mutex_init(&sbi->hpfs_mutex);
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hpfs_lock(s);
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mutex_init(&sbi->hpfs_creation_de);
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uid = current_uid();
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@ -669,6 +675,7 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent)
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root->i_blocks = 5;
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hpfs_brelse4(&qbh);
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}
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hpfs_unlock(s);
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return 0;
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bail4: brelse(bh2);
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@ -676,6 +683,7 @@ bail3: brelse(bh1);
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bail2: brelse(bh0);
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bail1:
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bail0:
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hpfs_unlock(s);
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kfree(sbi->sb_bmp_dir);
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kfree(sbi->sb_cp_table);
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s->s_fs_info = NULL;
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