From 15440319767942a363f282d6585303d3d75088ba Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Thu, 8 Jan 2009 14:00:00 -0500 Subject: [XFS] truncate readdir offsets to signed 32 bit values John Stanley reported EOVERFLOW errors in readdir from his self-build glibc. I traced this down to glibc enabling d_off overflow checks in one of the about five million different getdents implementations. In 2.6.28 Dave Woodhouse moved our readdir double buffering required for NFS4 readdirplus into nfsd and at that point we lost the capping of the directory offsets to 32 bit signed values. Johns glibc used getdents64 to even implement readdir for normal 32 bit offset dirents, and failed with EOVERFLOW only if this happens on the first dirent in a getdents call. I managed to come up with a testcase that uses raw getdents and does the EOVERFLOW check manually. We always hit it with our last entry due to the special end of directory marker. The patch below is a dumb version of just putting back the masking, to make sure we have the same behavior as in 2.6.27 and earlier. I will work on a better and cleaner fix for 2.6.30. Reported-by: John Stanley Tested-by: John Stanley Signed-off-by: Christoph Hellwig Reviewed-by: Dave Chinner Signed-off-by: Lachlan McIlroy --- fs/xfs/xfs_dir2_block.c | 7 ++++--- fs/xfs/xfs_dir2_leaf.c | 6 +++--- fs/xfs/xfs_dir2_sf.c | 15 ++++++++------- 3 files changed, 15 insertions(+), 13 deletions(-) diff --git a/fs/xfs/xfs_dir2_block.c b/fs/xfs/xfs_dir2_block.c index e2fa0a1d8e9..e1f0a06aaf0 100644 --- a/fs/xfs/xfs_dir2_block.c +++ b/fs/xfs/xfs_dir2_block.c @@ -517,9 +517,9 @@ xfs_dir2_block_getdents( /* * If it didn't fit, set the final offset to here & return. */ - if (filldir(dirent, dep->name, dep->namelen, cook, + if (filldir(dirent, dep->name, dep->namelen, cook & 0x7fffffff, ino, DT_UNKNOWN)) { - *offset = cook; + *offset = cook & 0x7fffffff; xfs_da_brelse(NULL, bp); return 0; } @@ -529,7 +529,8 @@ xfs_dir2_block_getdents( * Reached the end of the block. * Set the offset to a non-existent block 1 and return. */ - *offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0); + *offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0) & + 0x7fffffff; xfs_da_brelse(NULL, bp); return 0; } diff --git a/fs/xfs/xfs_dir2_leaf.c b/fs/xfs/xfs_dir2_leaf.c index 93535992cb6..ef805a374ee 100644 --- a/fs/xfs/xfs_dir2_leaf.c +++ b/fs/xfs/xfs_dir2_leaf.c @@ -1092,7 +1092,7 @@ xfs_dir2_leaf_getdents( * Won't fit. Return to caller. */ if (filldir(dirent, dep->name, dep->namelen, - xfs_dir2_byte_to_dataptr(mp, curoff), + xfs_dir2_byte_to_dataptr(mp, curoff) & 0x7fffffff, ino, DT_UNKNOWN)) break; @@ -1108,9 +1108,9 @@ xfs_dir2_leaf_getdents( * All done. Set output offset value to current offset. */ if (curoff > xfs_dir2_dataptr_to_byte(mp, XFS_DIR2_MAX_DATAPTR)) - *offset = XFS_DIR2_MAX_DATAPTR; + *offset = XFS_DIR2_MAX_DATAPTR & 0x7fffffff; else - *offset = xfs_dir2_byte_to_dataptr(mp, curoff); + *offset = xfs_dir2_byte_to_dataptr(mp, curoff) & 0x7fffffff; kmem_free(map); if (bp) xfs_da_brelse(NULL, bp); diff --git a/fs/xfs/xfs_dir2_sf.c b/fs/xfs/xfs_dir2_sf.c index b46af0013ec..a8a8a6efad5 100644 --- a/fs/xfs/xfs_dir2_sf.c +++ b/fs/xfs/xfs_dir2_sf.c @@ -752,8 +752,8 @@ xfs_dir2_sf_getdents( #if XFS_BIG_INUMS ino += mp->m_inoadd; #endif - if (filldir(dirent, ".", 1, dot_offset, ino, DT_DIR)) { - *offset = dot_offset; + if (filldir(dirent, ".", 1, dot_offset & 0x7fffffff, ino, DT_DIR)) { + *offset = dot_offset & 0x7fffffff; return 0; } } @@ -766,8 +766,8 @@ xfs_dir2_sf_getdents( #if XFS_BIG_INUMS ino += mp->m_inoadd; #endif - if (filldir(dirent, "..", 2, dotdot_offset, ino, DT_DIR)) { - *offset = dotdot_offset; + if (filldir(dirent, "..", 2, dotdot_offset & 0x7fffffff, ino, DT_DIR)) { + *offset = dotdot_offset & 0x7fffffff; return 0; } } @@ -791,14 +791,15 @@ xfs_dir2_sf_getdents( #endif if (filldir(dirent, sfep->name, sfep->namelen, - off, ino, DT_UNKNOWN)) { - *offset = off; + off & 0x7fffffff, ino, DT_UNKNOWN)) { + *offset = off & 0x7fffffff; return 0; } sfep = xfs_dir2_sf_nextentry(sfp, sfep); } - *offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0); + *offset = xfs_dir2_db_off_to_dataptr(mp, mp->m_dirdatablk + 1, 0) & + 0x7fffffff; return 0; } -- cgit v1.2.3-70-g09d2