--- Begin Message ---
Related FS:
ReiserFS
Related Files:
fs/reiserfs/inode.c
Bug description:
Make a ReiserFS partition in USB storage HDD, create a test file with
enough size.
Write a program, do: open(O_RDONLY) - read - close. After each
operation, pause for a while, such as 3s. Between open and read, unlug the
USB wire. open returns zero-filled buffer, no error returns.
Bug analysis:
do_mpage_readpage will call FS-specific get_block to get buffer mapped
from disk. reiserfs_get_block doesn't return non-zero when I/O failure occurs.
reiserfs_get_block -> _get_block_create_0 -> search_by_position_by_key
search_by_position_by_key returns IO_ERROR, but the original code just simply
returns 0
research:
if (search_for_position_by_key (inode->i_sb, &key, &path) != POSITION_FOUND) {
pathrelse (&path);
if (p)
kunmap(bh_result->b_page) ;
// We do not return -ENOENT if there is a hole but page is uptodate, because it means
// That there is some MMAPED data associated with it that is yet to be written to disk.
if ((args & GET_BLOCK_NO_HOLE) && !PageUptodate(bh_result->b_page) ) {
return -ENOENT ;
}
return 0 ; <- 0 retuns for IO_ERROR
}
Way around:
test result of search_for_position_by_key
Signed-off-by: Qu Fuping<[email protected]>
Patch:
diff -uNp /tmp/linux-2.6.12-rc6/fs/reiserfs/inode.c /tmp/linux-2.6.12-rc6.new/fs/reiserfs/inode.c
--- /tmp/linux-2.6.12-rc6/fs/reiserfs/inode.c 2005-06-06 11:22:29.000000000 -0400
+++ /tmp/linux-2.6.12-rc6.new/fs/reiserfs/inode.c 2005-06-15 13:56:45.552564512 -0400
@@ -254,6 +254,7 @@ static int _get_block_create_0 (struct i
char * p = NULL;
int chars;
int ret ;
+ int result ;
int done = 0 ;
unsigned long offset ;
@@ -262,7 +263,8 @@ static int _get_block_create_0 (struct i
(loff_t)block * inode->i_sb->s_blocksize + 1, TYPE_ANY, 3);
research:
- if (search_for_position_by_key (inode->i_sb, &key, &path) != POSITION_FOUND) {
+ result = search_for_position_by_key (inode->i_sb, &key, &path) ;
+ if (result != POSITION_FOUND) {
pathrelse (&path);
if (p)
kunmap(bh_result->b_page) ;
@@ -270,7 +272,8 @@ research:
// That there is some MMAPED data associated with it that is yet to be written to disk.
if ((args & GET_BLOCK_NO_HOLE) && !PageUptodate(bh_result->b_page) ) {
return -ENOENT ;
- }
+ }else if (result == IO_ERROR)
+ return -EIO ;
return 0 ;
}
--- End Message ---
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