[patch v2 2/9] btrfs: Catch locking failures in {set,clear}_extent_bit
From: Jeff Mahoney <hidden>
Date: 2011-08-15 19:50:44
The *_state functions can only return 0 or -EEXIST. This patch addresses the cases where those functions return -EEXIST, representing a locking failure. It handles them by panicking with an appropriate error message. Signed-off-by: Jeff Mahoney <redacted> --- fs/btrfs/extent_io.c | 36 +++++++++++++++++++++++++----------- fs/btrfs/extent_io.h | 6 ++++++ 2 files changed, 31 insertions(+), 11 deletions(-)
--- a/fs/btrfs/extent_io.c
+++ b/fs/btrfs/extent_io.c@@ -531,7 +531,10 @@ hit_next: prealloc = alloc_extent_state_atomic(prealloc); BUG_ON(!prealloc); err = split_state(tree, state, prealloc, start); - BUG_ON(err == -EEXIST); + if (err) + btrfs_panic(tree_fs_info(tree), err, "Locking error: " + "Extent tree was modified by another " + "thread while locked."); prealloc = NULL; if (err) goto out;
@@ -553,7 +556,10 @@ hit_next: prealloc = alloc_extent_state_atomic(prealloc); BUG_ON(!prealloc); err = split_state(tree, state, prealloc, end + 1); - BUG_ON(err == -EEXIST); + if (err) + btrfs_panic(tree_fs_info(tree), err, "Locking error: " + "Extent tree was modified by another " + "thread while locked."); if (wake) wake_up(&state->wq);
@@ -736,8 +742,11 @@ again: prealloc = alloc_extent_state_atomic(prealloc); BUG_ON(!prealloc); err = insert_state(tree, prealloc, start, end, &bits); + if (err) + btrfs_panic(tree_fs_info(tree), err, "Locking error: " + "Extent tree was modified by another " + "thread while locked."); prealloc = NULL; - BUG_ON(err == -EEXIST); goto out; } state = rb_entry(node, struct extent_state, rb_node);
@@ -803,7 +812,10 @@ hit_next: prealloc = alloc_extent_state_atomic(prealloc); BUG_ON(!prealloc); err = split_state(tree, state, prealloc, start); - BUG_ON(err == -EEXIST); + if (err) + btrfs_panic(tree_fs_info(tree), err, "Locking error: " + "Extent tree was modified by another " + "thread while locked."); prealloc = NULL; if (err) goto out;
@@ -840,12 +852,11 @@ hit_next: */ err = insert_state(tree, prealloc, start, this_end, &bits); - BUG_ON(err == -EEXIST); - if (err) { - free_extent_state(prealloc); - prealloc = NULL; - goto out; - } + if (err) + btrfs_panic(tree_fs_info(tree), err, "Locking error: " + "Extent tree was modified by another " + "thread while locked."); + cache_state(prealloc, cached_state); prealloc = NULL; start = this_end + 1;
@@ -867,7 +878,10 @@ hit_next: prealloc = alloc_extent_state_atomic(prealloc); BUG_ON(!prealloc); err = split_state(tree, state, prealloc, end + 1); - BUG_ON(err == -EEXIST); + if (err) + btrfs_panic(tree_fs_info(tree), err, "Locking error: " + "Extent tree was modified by another " + "thread while locked."); set_state_bits(tree, prealloc, &bits); cache_state(prealloc, cached_state); --- a/fs/btrfs/extent_io.h +++ b/fs/btrfs/extent_io.h
@@ -159,6 +159,12 @@ static inline int extent_compress_type(u return bio_flags >> EXTENT_BIO_FLAG_SHIFT; } +static inline struct btrfs_fs_info * +tree_fs_info(struct extent_io_tree *tree) +{ + return btrfs_sb(tree->mapping->host->i_sb)->fs_info; +} + struct extent_map_tree; typedef struct extent_map *(get_extent_t)(struct inode *inode,