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udf: Fix deadlock when converting file from in-ICB one to normal one 

During BKL removal in 2.6.38, conversion of files from in-ICB format to normal
format got broken. We call ->writepage with i_data_sem held but udf_get_block()
also acquires i_data_sem thus creating A-A deadlock.

We fix the problem by dropping i_data_sem before calling ->writepage() which is
safe since i_mutex still protects us against any changes in the file. Also fix
pagelock - i_data_sem lock inversion in udf_expand_file_adinicb() by dropping
i_data_sem before calling find_or_create_page().

CC: stable@kernel.org
Reported-by: Matthias Matiak <netzpython@mail-on.us>
Tested-by: Matthias Matiak <netzpython@mail-on.us>
Reviewed-by: Namjae Jeon <linkinjeon@gmail.com>
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2011-12-10 02:30:48 +01:00
parent 7b0b0933a3
commit d2eb8c3593
2 changed files with 21 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
fs/udf/file.c
View File

@ -125,7 +125,6 @@ static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
err = udf_expand_file_adinicb(inode);
if (err) {
udf_debug("udf_expand_adinicb: err=%d\n", err);
up_write(&iinfo->i_data_sem);
return err;
}
} else {
@ -133,9 +132,10 @@ static ssize_t udf_file_aio_write(struct kiocb *iocb, const struct iovec *iov,
iinfo->i_lenAlloc = pos + count;
else
iinfo->i_lenAlloc = inode->i_size;
up_write(&iinfo->i_data_sem);
}
}
up_write(&iinfo->i_data_sem);
} else
up_write(&iinfo->i_data_sem);
retval = generic_file_aio_write(iocb, iov, nr_segs, ppos);
if (retval > 0)

21
fs/udf/inode.c
View File

@ -150,6 +150,12 @@ const struct address_space_operations udf_aops = {
.bmap = udf_bmap,
};
/*
* Expand file stored in ICB to a normal one-block-file
*
* This function requires i_data_sem for writing and releases it.
* This function requires i_mutex held
*/
int udf_expand_file_adinicb(struct inode *inode)
{
struct page *page;
@ -168,9 +174,15 @@ int udf_expand_file_adinicb(struct inode *inode)
iinfo->i_alloc_type = ICBTAG_FLAG_AD_LONG;
/* from now on we have normal address_space methods */
inode->i_data.a_ops = &udf_aops;
up_write(&iinfo->i_data_sem);
mark_inode_dirty(inode);
return 0;
}
/*
* Release i_data_sem so that we can lock a page - page lock ranks
* above i_data_sem. i_mutex still protects us against file changes.
*/
up_write(&iinfo->i_data_sem);
page = find_or_create_page(inode->i_mapping, 0, GFP_NOFS);
if (!page)
@ -186,6 +198,7 @@ int udf_expand_file_adinicb(struct inode *inode)
SetPageUptodate(page);
kunmap(page);
}
down_write(&iinfo->i_data_sem);
memset(iinfo->i_ext.i_data + iinfo->i_lenEAttr, 0x00,
iinfo->i_lenAlloc);
iinfo->i_lenAlloc = 0;
@ -195,17 +208,20 @@ int udf_expand_file_adinicb(struct inode *inode)
iinfo->i_alloc_type = ICBTAG_FLAG_AD_LONG;
/* from now on we have normal address_space methods */
inode->i_data.a_ops = &udf_aops;
up_write(&iinfo->i_data_sem);
err = inode->i_data.a_ops->writepage(page, &udf_wbc);
if (err) {
/* Restore everything back so that we don't lose data... */
lock_page(page);
kaddr = kmap(page);
down_write(&iinfo->i_data_sem);
memcpy(iinfo->i_ext.i_data + iinfo->i_lenEAttr, kaddr,
inode->i_size);
kunmap(page);
unlock_page(page);
iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB;
inode->i_data.a_ops = &udf_adinicb_aops;
up_write(&iinfo->i_data_sem);
}
page_cache_release(page);
mark_inode_dirty(inode);
@ -1105,10 +1121,9 @@ int udf_setsize(struct inode *inode, loff_t newsize)
if (bsize <
(udf_file_entry_alloc_offset(inode) + newsize)) {
err = udf_expand_file_adinicb(inode);
if (err) {
up_write(&iinfo->i_data_sem);
if (err)
return err;
}
down_write(&iinfo->i_data_sem);
} else
iinfo->i_lenAlloc = newsize;
}