I noticed a series of hung_task notifications in dmesg, so I went poking at it. Process is 'dropbox', and it's stuck trying to llseek it's library.zip file.
strace of dropbox: ... stat("/home/x/.dropbox-dist/library.zip", {st_mode=S_IFREG|0755, st_size=11575179, ...}) = 0 open("/home/x/.dropbox-dist/library.zip", O_RDONLY) = 3 fstat(3, {st_mode=S_IFREG|0755, st_size=11575179, ...}) = 0 mmap(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0x7fa766ea8000 fstat(3, {st_mode=S_IFREG|0755, st_size=11575179, ...}) = 0 lseek(3, 11571200, SEEK_SET SEEK_SET is less than st_size strace of dd if=library.zip of=/dev/null bs=1 seek=11571200: open("library.zip", O_RDONLY) = 3 dup2(3, 0) = 0 close(3) = 0 lseek(0, 0, SEEK_CUR [72960.716080] INFO: task dropbox:1348 blocked for more than 120 seconds. [72960.716084] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. [72960.716087] dropbox D ffff8800762d8a78 0 1348 1 0x00000004 [72960.716092] ffff880069cede18 0000000000000086 0000000000096000 0000000000000000 [72960.716097] ffff880069cec000 00000000000119c0 ffff8800762d8700 00000000000119c0 [72960.716101] ffff880069cedfd8 0000000000004000 ffff880069cedfd8 00000000000119c0 [72960.716106] Call Trace: [72960.716113] [<ffffffff81331f9e>] ? trace_hardirqs_on_thunk+0x3a/0x3c [72960.716119] [<ffffffff8155710a>] ? retint_restore_args+0xe/0xe [72960.716124] [<ffffffff810e8ef1>] ? noop_llseek+0xa/0xa [72960.716129] [<ffffffff810340ff>] ? mutex_spin_on_owner+0x1c/0x45 [72960.716133] [<ffffffff81555be0>] __mutex_lock_slowpath+0xd2/0x116 [72960.716137] [<ffffffff81559edd>] ? do_page_fault+0x374/0x3e6 [72960.716140] [<ffffffff81555a87>] mutex_lock+0x16/0x27 [72960.716146] [<ffffffff812c8ad7>] btrfs_file_llseek+0x38/0x297 [72960.716150] [<ffffffff81331fda>] ? trace_hardirqs_off_thunk+0x3a/0x6c [72960.716153] [<ffffffff810e8f2c>] vfs_llseek+0x2e/0x30 [72960.716155] [<ffffffff810e9311>] sys_lseek+0x3e/0x5d [72960.716159] [<ffffffff8155d4fb>] system_call_fastpath+0x16/0x1b Oddly enough, it's just llseek. I can copy/read the file sequentially just fine, but llseek fails on a copy as well. Once I get physically to the system I'll recompile to an unmodified kernel and try again. Other files of the same approximate age llseek correctly. Kernel is 3.1-rc1 with the fglrx module from AMD and the following patch: (I was playing with cross-subvolume reflinking, but not on this file) diff --git a/fs/btrfs/ioctl.c b/fs/btrfs/ioctl.c index 7cf0133..a13b5e2 100644 --- a/fs/btrfs/ioctl.c +++ b/fs/btrfs/ioctl.c @@ -2182,7 +2182,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, goto out_fput; ret = -EXDEV; - if (src->i_sb != inode->i_sb || BTRFS_I(src)->root != root) + if (src->i_sb != inode->i_sb) goto out_fput; ret = -ENOMEM; @@ -2246,13 +2246,13 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, * note the key will change type as we walk through the * tree. */ - ret = btrfs_search_slot(NULL, root, &key, path, 0, 0); + ret = btrfs_search_slot(NULL, BTRFS_I(src)->root, &key, path, 0, 0); if (ret < 0) goto out; nritems = btrfs_header_nritems(path->nodes[0]); if (path->slots[0] >= nritems) { - ret = btrfs_next_leaf(root, path); + ret = btrfs_next_leaf(BTRFS_I(src)->root, path); if (ret < 0) goto out; if (ret > 0) @@ -2313,7 +2313,7 @@ static noinline long btrfs_ioctl_clone(struct file *file, unsigned long srcfd, else new_key.offset = destoff; - trans = btrfs_start_transaction(root, 1); + trans = btrfs_start_transaction(root, 3); if (IS_ERR(trans)) { ret = PTR_ERR(trans); goto out; -- To unsubscribe from this list: send the line "unsubscribe linux-btrfs" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html