Hi Andrew,
Its been reported that ext3_getblk() is not doing the right thing
and triggering following WARN():
BUG: warning at fs/ext3/inode.c:1016/ext3_getblk()
<c01c5140> ext3_getblk+0x98/0x2a6 <c03b2806> md_wakeup_thread
+0x26/0x2a
<c01c536d> ext3_bread+0x1f/0x88 <c01cedf9> ext3_quota_read+0x136/0x1ae
<c018b683> v1_read_dqblk+0x61/0xac <c0188f32> dquot_acquire+0xf6/0x107
<c01ceaba> ext3_acquire_dquot+0x46/0x68 <c01897d4> dqget+0x155/0x1e7
<c018a97b> dquot_transfer+0x3e0/0x3e9 <c016fe52> dput+0x23/0x13e
<c01c7986> ext3_setattr+0xc3/0x240 <c0120f66> current_fs_time
+0x52/0x6a
<c017320e> notify_change+0x2bd/0x30d <c0159246> chown_common+0x9c/0xc5
<c02a222c> strncpy_from_user+0x3b/0x68 <c0167fe6> do_path_lookup
+0xdf/0x266
<c016841b> __user_walk_fd+0x44/0x5a <c01592b9> sys_chown+0x4a/0x55
<c015a43c> vfs_write+0xe7/0x13c <c01695d4> sys_mkdir+0x1f/0x23
<c0102a97> syscall_call+0x7/0xb
Looking at the code, it looks like its not handle HOLE correctly.
It ends up returning -EIO. Here is the patch to fix it.
If we really want to be paranoid, we can allow return values
0 (HOLE), 1 (we asked for one block) and return -EIO for
more than 1 block. But I really don't see a reason for
doing it - all we need is the block# here. (doesn't matter
how many blocks are mapped).
Thanks,
Badari
ext3_get_blocks_handle() returns number of blocks it mapped.
It returns 0 in case of HOLE. ext3_getblk() should handle
HOLE properly (currently its dumping warning stack and
returning -EIO).
Signed-off-by: Badari Pulavarty <pbadari@xxxxxxxxxx>
Acked-by: Mingming Cao <cmm@xxxxxxxxxx>
---
fs/ext3/inode.c | 9 +++++----
1 file changed, 5 insertions(+), 4 deletions(-)
Index: linux-2.6.18-rc5/fs/ext3/inode.c
===================================================================
--- linux-2.6.18-rc5.orig/fs/ext3/inode.c 2006-08-27 20:41:48.000000000 -0700
+++ linux-2.6.18-rc5/fs/ext3/inode.c 2006-09-05 15:32:57.000000000 -0700
@@ -1009,11 +1009,12 @@ struct buffer_head *ext3_getblk(handle_t
buffer_trace_init(&dummy.b_history);
err = ext3_get_blocks_handle(handle, inode, block, 1,
&dummy, create, 1);
- if (err == 1) {
+ /*
+ * ext3_get_blocks_handle() returns number of blocks
+ * mapped. 0 in case of a HOLE.
+ */
+ if (err > 0) {
err = 0;
- } else if (err >= 0) {
- WARN_ON(1);
- err = -EIO;
}
*errp = err;
if (!err && buffer_mapped(&dummy)) {
-
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