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udf: Fix race between file type conversion and writeback 

udf_setsize() can race with udf_writepages() as follows:

udf_setsize()			udf_writepages()
				  if (iinfo->i_alloc_type ==
						ICBTAG_FLAG_AD_IN_ICB)
  err = udf_expand_file_adinicb(inode);
  err = udf_extend_file(inode, newsize);
				    udf_adinicb_writepages()
				      memcpy_from_file_folio() - crash
					because inode size is too big.

Fix the problem by checking the file type under folio lock in
udf_handle_page_wb() handler called from __mpage_writepages() which
properly serializes with udf_expand_file_adinicb().

Reported-by: Jianzhou Zhao <luckd0g@163.com>
Link: https://lore.kernel.org/all/f622c01.67ac.19cdbdd777d.Coremail.luckd0g@163.com
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://patch.msgid.link/20260326140635.15895-4-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara 2026-03-26 15:06:32 +01:00
parent fffca572f9
commit 102e57d56f
1 changed files with 15 additions and 18 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

33
fs/udf/inode.c
View File

@ -181,22 +181,23 @@ static void udf_write_failed(struct address_space *mapping, loff_t to)
} }
} }
static int udf_adinicb_writepages(struct address_space *mapping, static int udf_handle_page_wb(struct folio *folio,
struct writeback_control *wbc) struct writeback_control *wbc)
{ {
struct inode *inode = mapping->host; struct inode *inode = folio->mapping->host;
struct udf_inode_info *iinfo = UDF_I(inode); struct udf_inode_info *iinfo = UDF_I(inode);
struct folio *folio = NULL;
int error = 0;
while ((folio = writeback_iter(mapping, wbc, folio, &error))) { /*
BUG_ON(!folio_test_locked(folio)); * Inodes in the normal format are handled by the generic code. This
BUG_ON(folio->index != 0); * check is race-free as the folio lock protects us from inode type
memcpy_from_file_folio(iinfo->i_data + iinfo->i_lenEAttr, folio, * conversion.
*/
if (iinfo->i_alloc_type != ICBTAG_FLAG_AD_IN_ICB)
return 1;
memcpy_from_file_folio(iinfo->i_data + iinfo->i_lenEAttr, folio,
0, i_size_read(inode)); 0, i_size_read(inode));
folio_unlock(folio); folio_unlock(folio);
}
mark_inode_dirty(inode); mark_inode_dirty(inode);
return 0; return 0;
} }
@ -204,12 +205,8 @@ static int udf_adinicb_writepages(struct address_space *mapping,
static int udf_writepages(struct address_space *mapping, static int udf_writepages(struct address_space *mapping,
struct writeback_control *wbc) struct writeback_control *wbc)
{ {
struct inode *inode = mapping->host; return __mpage_writepages(mapping, wbc, udf_get_block_wb,
struct udf_inode_info *iinfo = UDF_I(inode); udf_handle_page_wb);
if (iinfo->i_alloc_type == ICBTAG_FLAG_AD_IN_ICB)
return udf_adinicb_writepages(mapping, wbc);
return mpage_writepages(mapping, wbc, udf_get_block_wb);
} }
static void udf_adinicb_read_folio(struct folio *folio) static void udf_adinicb_read_folio(struct folio *folio)