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[PATCH] Fix IO error reporting on fsync()
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When IO error happens on metadata buffer, buffer is freed from memory and
later fsync() is called, filesystems like ext2 fail to report EIO.  We

solve the problem by introducing a pointer to associated address space into
the buffer_head.  When a buffer is removed from a list of metadata buffers
associated with an address space, IO error is transferred from the buffer to
the address space, so that fsync can later report it.

Signed-off-by: Jan Kara <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
jankara authored and Linus Torvalds committed Oct 17, 2006
1 parent d343fce commit 58ff407
Showing 2 changed files with 11 additions and 2 deletions.
11 changes: 9 additions & 2 deletions fs/buffer.c
Original file line number Diff line number Diff line change
@@ -452,6 +452,7 @@ static void end_buffer_async_write(struct buffer_head *bh, int uptodate)
bdevname(bh->b_bdev, b));
}
set_bit(AS_EIO, &page->mapping->flags);
set_buffer_write_io_error(bh);
clear_buffer_uptodate(bh);
SetPageError(page);
}
@@ -571,6 +572,10 @@ EXPORT_SYMBOL(mark_buffer_async_write);
static inline void __remove_assoc_queue(struct buffer_head *bh)
{
list_del_init(&bh->b_assoc_buffers);
WARN_ON(!bh->b_assoc_map);
if (buffer_write_io_error(bh))
set_bit(AS_EIO, &bh->b_assoc_map->flags);
bh->b_assoc_map = NULL;
}

int inode_has_buffers(struct inode *inode)
@@ -669,6 +674,7 @@ void mark_buffer_dirty_inode(struct buffer_head *bh, struct inode *inode)
spin_lock(&buffer_mapping->private_lock);
list_move_tail(&bh->b_assoc_buffers,
&mapping->private_list);
bh->b_assoc_map = mapping;
spin_unlock(&buffer_mapping->private_lock);
}
}
@@ -765,7 +771,7 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)
spin_lock(lock);
while (!list_empty(list)) {
bh = BH_ENTRY(list->next);
list_del_init(&bh->b_assoc_buffers);
__remove_assoc_queue(bh);
if (buffer_dirty(bh) || buffer_locked(bh)) {
list_add(&bh->b_assoc_buffers, &tmp);
if (buffer_dirty(bh)) {
@@ -786,7 +792,7 @@ static int fsync_buffers_list(spinlock_t *lock, struct list_head *list)

while (!list_empty(&tmp)) {
bh = BH_ENTRY(tmp.prev);
__remove_assoc_queue(bh);
list_del_init(&bh->b_assoc_buffers);
get_bh(bh);
spin_unlock(lock);
wait_on_buffer(bh);
@@ -1167,6 +1173,7 @@ void __bforget(struct buffer_head *bh)

spin_lock(&buffer_mapping->private_lock);
list_del_init(&bh->b_assoc_buffers);
bh->b_assoc_map = NULL;
spin_unlock(&buffer_mapping->private_lock);
}
__brelse(bh);
2 changes: 2 additions & 0 deletions include/linux/buffer_head.h
Original file line number Diff line number Diff line change
@@ -69,6 +69,8 @@ struct buffer_head {
bh_end_io_t *b_end_io; /* I/O completion */
void *b_private; /* reserved for b_end_io */
struct list_head b_assoc_buffers; /* associated with another mapping */
struct address_space *b_assoc_map; /* mapping this buffer is
associated with */
atomic_t b_count; /* users using this buffer_head */
};

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