From d635711daa98be86d4c7fd01499c34f566b54ccb Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Fri, 10 Jun 2016 05:30:17 -0300 Subject: Linux-libre 4.6.2-gnu --- fs/btrfs/tree-log.c | 102 +++++++++++++++++++++++++++++++++++++++++++++------- 1 file changed, 90 insertions(+), 12 deletions(-) (limited to 'fs/btrfs/tree-log.c') diff --git a/fs/btrfs/tree-log.c b/fs/btrfs/tree-log.c index 849a30aa1..517d0ccb3 100644 --- a/fs/btrfs/tree-log.c +++ b/fs/btrfs/tree-log.c @@ -26,6 +26,7 @@ #include "print-tree.h" #include "backref.h" #include "hash.h" +#include "compression.h" /* magic values for the inode_only field in btrfs_log_inode: * @@ -1045,7 +1046,7 @@ again: /* * NOTE: we have searched root tree and checked the - * coresponding ref, it does not need to check again. + * corresponding ref, it does not need to check again. */ *search_done = 1; } @@ -4621,7 +4622,22 @@ static int btrfs_log_inode(struct btrfs_trans_handle *trans, mutex_lock(&BTRFS_I(inode)->log_mutex); - btrfs_get_logged_extents(inode, &logged_list, start, end); + /* + * Collect ordered extents only if we are logging data. This is to + * ensure a subsequent request to log this inode in LOG_INODE_ALL mode + * will process the ordered extents if they still exists at the time, + * because when we collect them we test and set for the flag + * BTRFS_ORDERED_LOGGED to prevent multiple log requests to process the + * same ordered extents. The consequence for the LOG_INODE_ALL log mode + * not processing the ordered extents is that we end up logging the + * corresponding file extent items, based on the extent maps in the + * inode's extent_map_tree's modified_list, without logging the + * respective checksums (since the may still be only attached to the + * ordered extents and have not been inserted in the csum tree by + * btrfs_finish_ordered_io() yet). + */ + if (inode_only == LOG_INODE_ALL) + btrfs_get_logged_extents(inode, &logged_list, start, end); /* * a brute force approach to making sure we get the most uptodate @@ -4908,6 +4924,42 @@ out_unlock: return err; } +/* + * Check if we must fallback to a transaction commit when logging an inode. + * This must be called after logging the inode and is used only in the context + * when fsyncing an inode requires the need to log some other inode - in which + * case we can't lock the i_mutex of each other inode we need to log as that + * can lead to deadlocks with concurrent fsync against other inodes (as we can + * log inodes up or down in the hierarchy) or rename operations for example. So + * we take the log_mutex of the inode after we have logged it and then check for + * its last_unlink_trans value - this is safe because any task setting + * last_unlink_trans must take the log_mutex and it must do this before it does + * the actual unlink operation, so if we do this check before a concurrent task + * sets last_unlink_trans it means we've logged a consistent version/state of + * all the inode items, otherwise we are not sure and must do a transaction + * commit (the concurrent task migth have only updated last_unlink_trans before + * we logged the inode or it might have also done the unlink). + */ +static bool btrfs_must_commit_transaction(struct btrfs_trans_handle *trans, + struct inode *inode) +{ + struct btrfs_fs_info *fs_info = BTRFS_I(inode)->root->fs_info; + bool ret = false; + + mutex_lock(&BTRFS_I(inode)->log_mutex); + if (BTRFS_I(inode)->last_unlink_trans > fs_info->last_trans_committed) { + /* + * Make sure any commits to the log are forced to be full + * commits. + */ + btrfs_set_log_full_commit(fs_info, trans); + ret = true; + } + mutex_unlock(&BTRFS_I(inode)->log_mutex); + + return ret; +} + /* * follow the dentry parent pointers up the chain and see if any * of the directories in it require a full commit before they can @@ -4921,7 +4973,6 @@ static noinline int check_parent_dirs_for_sync(struct btrfs_trans_handle *trans, u64 last_committed) { int ret = 0; - struct btrfs_root *root; struct dentry *old_parent = NULL; struct inode *orig_inode = inode; @@ -4953,14 +5004,7 @@ static noinline int check_parent_dirs_for_sync(struct btrfs_trans_handle *trans, BTRFS_I(inode)->logged_trans = trans->transid; smp_mb(); - if (BTRFS_I(inode)->last_unlink_trans > last_committed) { - root = BTRFS_I(inode)->root; - - /* - * make sure any commits to the log are forced - * to be full commits - */ - btrfs_set_log_full_commit(root->fs_info, trans); + if (btrfs_must_commit_transaction(trans, inode)) { ret = 1; break; } @@ -5119,6 +5163,9 @@ process_leaf: btrfs_release_path(path); ret = btrfs_log_inode(trans, root, di_inode, log_mode, 0, LLONG_MAX, ctx); + if (!ret && + btrfs_must_commit_transaction(trans, di_inode)) + ret = 1; iput(di_inode); if (ret) goto next_dir_inode; @@ -5233,6 +5280,9 @@ static int btrfs_log_all_parents(struct btrfs_trans_handle *trans, ret = btrfs_log_inode(trans, root, dir_inode, LOG_INODE_ALL, 0, LLONG_MAX, ctx); + if (!ret && + btrfs_must_commit_transaction(trans, dir_inode)) + ret = 1; iput(dir_inode); if (ret) goto out; @@ -5584,6 +5634,9 @@ error: * They revolve around files there were unlinked from the directory, and * this function updates the parent directory so that a full commit is * properly done if it is fsync'd later after the unlinks are done. + * + * Must be called before the unlink operations (updates to the subvolume tree, + * inodes, etc) are done. */ void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans, struct inode *dir, struct inode *inode, @@ -5599,8 +5652,11 @@ void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans, * into the file. When the file is logged we check it and * don't log the parents if the file is fully on disk. */ - if (S_ISREG(inode->i_mode)) + if (S_ISREG(inode->i_mode)) { + mutex_lock(&BTRFS_I(inode)->log_mutex); BTRFS_I(inode)->last_unlink_trans = trans->transid; + mutex_unlock(&BTRFS_I(inode)->log_mutex); + } /* * if this directory was already logged any new @@ -5631,7 +5687,29 @@ void btrfs_record_unlink_dir(struct btrfs_trans_handle *trans, return; record: + mutex_lock(&BTRFS_I(dir)->log_mutex); + BTRFS_I(dir)->last_unlink_trans = trans->transid; + mutex_unlock(&BTRFS_I(dir)->log_mutex); +} + +/* + * Make sure that if someone attempts to fsync the parent directory of a deleted + * snapshot, it ends up triggering a transaction commit. This is to guarantee + * that after replaying the log tree of the parent directory's root we will not + * see the snapshot anymore and at log replay time we will not see any log tree + * corresponding to the deleted snapshot's root, which could lead to replaying + * it after replaying the log tree of the parent directory (which would replay + * the snapshot delete operation). + * + * Must be called before the actual snapshot destroy operation (updates to the + * parent root and tree of tree roots trees, etc) are done. + */ +void btrfs_record_snapshot_destroy(struct btrfs_trans_handle *trans, + struct inode *dir) +{ + mutex_lock(&BTRFS_I(dir)->log_mutex); BTRFS_I(dir)->last_unlink_trans = trans->transid; + mutex_unlock(&BTRFS_I(dir)->log_mutex); } /* -- cgit v1.2.3-54-g00ecf