From 7dd29d8d865efdb00c0542a5d2c87af8c52ea6c7 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Sun, 8 May 2011 20:42:54 +0200 Subject: [PATCH] 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 Signed-off-by: Linus Torvalds --- fs/hpfs/buffer.c | 8 ++++++++ fs/hpfs/file.c | 27 +++++++++++++++++++-------- fs/hpfs/hpfs_fn.h | 24 +++++++++++++++--------- fs/hpfs/super.c | 10 +++++++++- 4 files changed, 51 insertions(+), 18 deletions(-) diff --git a/fs/hpfs/buffer.c b/fs/hpfs/buffer.c index 793cb9d943d2..7cef5d5c3608 100644 --- a/fs/hpfs/buffer.c +++ b/fs/hpfs/buffer.c @@ -32,6 +32,8 @@ void *hpfs_map_sector(struct super_block *s, unsigned secno, struct buffer_head { struct buffer_head *bh; + hpfs_lock_assert(s); + cond_resched(); *bhp = bh = sb_bread(s, secno); @@ -50,6 +52,8 @@ void *hpfs_get_sector(struct super_block *s, unsigned secno, struct buffer_head struct buffer_head *bh; /*return hpfs_map_sector(s, secno, bhp, 0);*/ + hpfs_lock_assert(s); + cond_resched(); if ((*bhp = bh = sb_getblk(s, secno)) != NULL) { @@ -70,6 +74,8 @@ void *hpfs_map_4sectors(struct super_block *s, unsigned secno, struct quad_buffe struct buffer_head *bh; char *data; + hpfs_lock_assert(s); + cond_resched(); if (secno & 3) { @@ -125,6 +131,8 @@ void *hpfs_get_4sectors(struct super_block *s, unsigned secno, { cond_resched(); + hpfs_lock_assert(s); + if (secno & 3) { printk("HPFS: hpfs_get_4sectors: unaligned read\n"); return NULL; diff --git a/fs/hpfs/file.c b/fs/hpfs/file.c index 9b9eb6933e43..09a642f853e1 100644 --- a/fs/hpfs/file.c +++ b/fs/hpfs/file.c @@ -48,38 +48,46 @@ static secno hpfs_bmap(struct inode *inode, unsigned file_secno) static void hpfs_truncate(struct inode *i) { if (IS_IMMUTABLE(i)) return /*-EPERM*/; - hpfs_lock(i->i_sb); + hpfs_lock_assert(i->i_sb); + hpfs_i(i)->i_n_secs = 0; i->i_blocks = 1 + ((i->i_size + 511) >> 9); hpfs_i(i)->mmu_private = i->i_size; hpfs_truncate_btree(i->i_sb, i->i_ino, 1, ((i->i_size + 511) >> 9)); hpfs_write_inode(i); hpfs_i(i)->i_n_secs = 0; - hpfs_unlock(i->i_sb); } static int hpfs_get_block(struct inode *inode, sector_t iblock, struct buffer_head *bh_result, int create) { + int r; secno s; + hpfs_lock(inode->i_sb); s = hpfs_bmap(inode, iblock); if (s) { map_bh(bh_result, inode->i_sb, s); - return 0; + goto ret_0; } - if (!create) return 0; + if (!create) goto ret_0; if (iblock<<9 != hpfs_i(inode)->mmu_private) { BUG(); - return -EIO; + r = -EIO; + goto ret_r; } if ((s = hpfs_add_sector_to_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1)) == -1) { hpfs_truncate_btree(inode->i_sb, inode->i_ino, 1, inode->i_blocks - 1); - return -ENOSPC; + r = -ENOSPC; + goto ret_r; } inode->i_blocks++; hpfs_i(inode)->mmu_private += 512; set_buffer_new(bh_result); map_bh(bh_result, inode->i_sb, s); - return 0; + ret_0: + r = 0; + ret_r: + hpfs_unlock(inode->i_sb); + return r; } static int hpfs_writepage(struct page *page, struct writeback_control *wbc) @@ -130,8 +138,11 @@ static ssize_t hpfs_file_write(struct file *file, const char __user *buf, ssize_t retval; retval = do_sync_write(file, buf, count, ppos); - if (retval > 0) + if (retval > 0) { + hpfs_lock(file->f_path.dentry->d_sb); hpfs_i(file->f_path.dentry->d_inode)->i_dirty = 1; + hpfs_unlock(file->f_path.dentry->d_sb); + } return retval; } diff --git a/fs/hpfs/hpfs_fn.h b/fs/hpfs/hpfs_fn.h index c15adbca07ff..89a4714b44c7 100644 --- a/fs/hpfs/hpfs_fn.h +++ b/fs/hpfs/hpfs_fn.h @@ -63,6 +63,7 @@ struct hpfs_inode_info { }; struct hpfs_sb_info { + struct mutex hpfs_mutex; /* global hpfs lock */ ino_t sb_root; /* inode number of root dir */ unsigned sb_fs_size; /* file system size, sectors */ unsigned sb_bitmaps; /* sector number of bitmap list */ @@ -346,21 +347,26 @@ static inline time32_t gmt_to_local(struct super_block *s, time_t t) /* * Locking: * - * hpfs_lock() is a leftover from the big kernel lock. - * Right now, these functions are empty and only left - * for documentation purposes. The file system no longer - * works on SMP systems, so the lock is not needed - * any more. + * hpfs_lock() locks the whole filesystem. It must be taken + * on any method called by the VFS. * - * If someone is interested in making it work again, this - * would be the place to start by adding a per-superblock - * mutex and fixing all the bugs and performance issues - * caused by that. + * We don't do any per-file locking anymore, it is hard to + * review and HPFS is not performance-sensitive anyway. */ static inline void hpfs_lock(struct super_block *s) { + struct hpfs_sb_info *sbi = hpfs_sb(s); + mutex_lock(&sbi->hpfs_mutex); } static inline void hpfs_unlock(struct super_block *s) { + struct hpfs_sb_info *sbi = hpfs_sb(s); + mutex_unlock(&sbi->hpfs_mutex); +} + +static inline void hpfs_lock_assert(struct super_block *s) +{ + struct hpfs_sb_info *sbi = hpfs_sb(s); + WARN_ON(!mutex_is_locked(&sbi->hpfs_mutex)); } diff --git a/fs/hpfs/super.c b/fs/hpfs/super.c index 501ea86e40a4..41232c2d60dc 100644 --- a/fs/hpfs/super.c +++ b/fs/hpfs/super.c @@ -102,9 +102,12 @@ static void hpfs_put_super(struct super_block *s) { struct hpfs_sb_info *sbi = hpfs_sb(s); + hpfs_lock(s); + unmark_dirty(s); + hpfs_unlock(s); + kfree(sbi->sb_cp_table); kfree(sbi->sb_bmp_dir); - unmark_dirty(s); s->s_fs_info = NULL; kfree(sbi); } @@ -490,6 +493,9 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent) sbi->sb_bmp_dir = NULL; sbi->sb_cp_table = NULL; + mutex_init(&sbi->hpfs_mutex); + hpfs_lock(s); + mutex_init(&sbi->hpfs_creation_de); uid = current_uid(); @@ -669,6 +675,7 @@ static int hpfs_fill_super(struct super_block *s, void *options, int silent) root->i_blocks = 5; hpfs_brelse4(&qbh); } + hpfs_unlock(s); return 0; bail4: brelse(bh2); @@ -676,6 +683,7 @@ bail3: brelse(bh1); bail2: brelse(bh0); bail1: bail0: + hpfs_unlock(s); kfree(sbi->sb_bmp_dir); kfree(sbi->sb_cp_table); s->s_fs_info = NULL; -- 2.30.2