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udf: Fix data loss when converting inline inodes to out of line

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When udf_expand_file_adinicb() converts file from inline format to out
of line, we use filemap_fdatawrite() to writeout the data to the new
blocks. However since 36580ed087 ("udf: Do not allocate blocks on page
writeback") the writeback actually doesn't allocate the new block and
the folio dirty bit is just silently cleared. Thus unless the file is
written to after the conversion (as it can easily happen in case of
truncate up), the data is just lost. Fix the problem by explicitely
allocating the block underlying the data before starting writeback.

Fixes: 36580ed087 ("udf: Do not allocate blocks on page writeback")
CC: stable@vger.kernel.org
Link: https://patch.msgid.link/20260730104232.4086759-4-jack@suse.cz
Signed-off-by: Jan Kara <jack@suse.cz>
This commit is contained in:
Jan Kara
2026-07-30 12:42:29 +02:00
parent 97e9d759a4
commit 62333e480d
1 changed files with 13 additions and 2 deletions
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15
fs/udf/inode.c
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@@ -405,6 +405,10 @@ int udf_expand_file_adinicb(struct inode *inode)
{
struct folio *folio;
struct udf_inode_info *iinfo = UDF_I(inode);
struct udf_map_rq map = {
.lblk = 0,
.iflags = UDF_MAP_CREATE,
};
int err;
WARN_ON_ONCE(!inode_is_locked(inode));
@@ -434,20 +438,27 @@ int udf_expand_file_adinicb(struct inode *inode)
iinfo->i_alloc_type = ICBTAG_FLAG_AD_SHORT;
else
iinfo->i_alloc_type = ICBTAG_FLAG_AD_LONG;
up_write(&iinfo->i_data_sem);
/* Allocate the block underlying the data */
err = udf_map_block(inode, &map);
if (err < 0)
goto restore;
folio_mark_dirty(folio);
folio_unlock(folio);
up_write(&iinfo->i_data_sem);
err = filemap_fdatawrite(inode->i_mapping);
if (err) {
/* Restore everything back so that we don't lose data... */
folio_lock(folio);
restore:
down_write(&iinfo->i_data_sem);
memcpy_from_folio(iinfo->i_data + iinfo->i_lenEAttr,
folio, 0, inode->i_size);
folio_unlock(folio);
iinfo->i_alloc_type = ICBTAG_FLAG_AD_IN_ICB;
iinfo->i_lenAlloc = inode->i_size;
up_write(&iinfo->i_data_sem);
folio_unlock(folio);
}
folio_put(folio);
mark_inode_dirty(inode);