From: J. Bruce Fields Date: Wed, 18 Apr 2012 19:16:33 +0000 (-0400) Subject: vfs: pull ext4's double-i_mutex-locking into common code X-Git-Url: http://drtracing.org/?a=commitdiff_plain;h=375e289ea85166c5241c570940e7e7e966c63a9f;p=deliverable%2Flinux.git vfs: pull ext4's double-i_mutex-locking into common code We want to do this elsewhere as well. Also catch any attempts to use it for directories (where this ordering would conflict with ancestor-first directory ordering in lock_rename). Cc: Andreas Dilger Cc: Dave Chinner Acked-by: Jeff Layton Acked-by: "Theodore Ts'o" Signed-off-by: J. Bruce Fields Signed-off-by: Al Viro --- diff --git a/fs/ext4/ext4.h b/fs/ext4/ext4.h index af815ea9d7cc..d01d62315f7e 100644 --- a/fs/ext4/ext4.h +++ b/fs/ext4/ext4.h @@ -2734,8 +2734,6 @@ extern void ext4_double_down_write_data_sem(struct inode *first, struct inode *second); extern void ext4_double_up_write_data_sem(struct inode *orig_inode, struct inode *donor_inode); -void ext4_inode_double_lock(struct inode *inode1, struct inode *inode2); -void ext4_inode_double_unlock(struct inode *inode1, struct inode *inode2); extern int ext4_move_extents(struct file *o_filp, struct file *d_filp, __u64 start_orig, __u64 start_donor, __u64 len, __u64 *moved_len); diff --git a/fs/ext4/ioctl.c b/fs/ext4/ioctl.c index a569d335f804..60589b60e9b0 100644 --- a/fs/ext4/ioctl.c +++ b/fs/ext4/ioctl.c @@ -130,7 +130,7 @@ static long swap_inode_boot_loader(struct super_block *sb, /* Protect orig inodes against a truncate and make sure, * that only 1 swap_inode_boot_loader is running. */ - ext4_inode_double_lock(inode, inode_bl); + lock_two_nondirectories(inode, inode_bl); truncate_inode_pages(&inode->i_data, 0); truncate_inode_pages(&inode_bl->i_data, 0); @@ -205,7 +205,7 @@ static long swap_inode_boot_loader(struct super_block *sb, ext4_inode_resume_unlocked_dio(inode); ext4_inode_resume_unlocked_dio(inode_bl); - ext4_inode_double_unlock(inode, inode_bl); + unlock_two_nondirectories(inode, inode_bl); iput(inode_bl); diff --git a/fs/ext4/move_extent.c b/fs/ext4/move_extent.c index 7fa4d855dbd5..773b503bd18c 100644 --- a/fs/ext4/move_extent.c +++ b/fs/ext4/move_extent.c @@ -1202,42 +1202,6 @@ mext_check_arguments(struct inode *orig_inode, return 0; } -/** - * ext4_inode_double_lock - Lock i_mutex on both @inode1 and @inode2 - * - * @inode1: the inode structure - * @inode2: the inode structure - * - * Lock two inodes' i_mutex - */ -void -ext4_inode_double_lock(struct inode *inode1, struct inode *inode2) -{ - BUG_ON(inode1 == inode2); - if (inode1 < inode2) { - mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT); - mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD); - } else { - mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT); - mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD); - } -} - -/** - * ext4_inode_double_unlock - Release i_mutex on both @inode1 and @inode2 - * - * @inode1: the inode that is released first - * @inode2: the inode that is released second - * - */ - -void -ext4_inode_double_unlock(struct inode *inode1, struct inode *inode2) -{ - mutex_unlock(&inode1->i_mutex); - mutex_unlock(&inode2->i_mutex); -} - /** * ext4_move_extents - Exchange the specified range of a file * @@ -1327,7 +1291,7 @@ ext4_move_extents(struct file *o_filp, struct file *d_filp, return -EINVAL; } /* Protect orig and donor inodes against a truncate */ - ext4_inode_double_lock(orig_inode, donor_inode); + lock_two_nondirectories(orig_inode, donor_inode); /* Wait for all existing dio workers */ ext4_inode_block_unlocked_dio(orig_inode); @@ -1535,7 +1499,7 @@ out: ext4_double_up_write_data_sem(orig_inode, donor_inode); ext4_inode_resume_unlocked_dio(orig_inode); ext4_inode_resume_unlocked_dio(donor_inode); - ext4_inode_double_unlock(orig_inode, donor_inode); + unlock_two_nondirectories(orig_inode, donor_inode); return ret; } diff --git a/fs/inode.c b/fs/inode.c index bf7a8b3ab937..ef25afdf3906 100644 --- a/fs/inode.c +++ b/fs/inode.c @@ -942,6 +942,42 @@ void unlock_new_inode(struct inode *inode) } EXPORT_SYMBOL(unlock_new_inode); +/** + * lock_two_nondirectories - take two i_mutexes on non-directory objects + * @inode1: first inode to lock + * @inode2: second inode to lock + */ +void lock_two_nondirectories(struct inode *inode1, struct inode *inode2) +{ + WARN_ON_ONCE(S_ISDIR(inode1->i_mode)); + if (inode1 == inode2 || !inode2) { + mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT); + return; + } + WARN_ON_ONCE(S_ISDIR(inode2->i_mode)); + if (inode1 < inode2) { + mutex_lock_nested(&inode1->i_mutex, I_MUTEX_PARENT); + mutex_lock_nested(&inode2->i_mutex, I_MUTEX_CHILD); + } else { + mutex_lock_nested(&inode2->i_mutex, I_MUTEX_PARENT); + mutex_lock_nested(&inode1->i_mutex, I_MUTEX_CHILD); + } +} +EXPORT_SYMBOL(lock_two_nondirectories); + +/** + * unlock_two_nondirectories - release locks from lock_two_nondirectories() + * @inode1: first inode to unlock + * @inode2: second inode to unlock + */ +void unlock_two_nondirectories(struct inode *inode1, struct inode *inode2) +{ + mutex_unlock(&inode1->i_mutex); + if (inode2 && inode2 != inode1) + mutex_unlock(&inode2->i_mutex); +} +EXPORT_SYMBOL(unlock_two_nondirectories); + /** * iget5_locked - obtain an inode from a mounted file system * @sb: super block of file system diff --git a/include/linux/fs.h b/include/linux/fs.h index 5e44b0893db8..4e1a0b41f966 100644 --- a/include/linux/fs.h +++ b/include/linux/fs.h @@ -637,6 +637,9 @@ enum inode_i_mutex_lock_class I_MUTEX_QUOTA }; +void lock_two_nondirectories(struct inode *, struct inode*); +void unlock_two_nondirectories(struct inode *, struct inode*); + /* * NOTE: in a 32bit arch with a preemptable kernel and * an UP compile the i_size_read/write must be atomic