From: "Darrick J. Wong" darrick.wong@oracle.com
commit e8db2aafcedb7d88320ab83f1000f1606b26d4d7 upstream.
[Replaced XFS_IS_CORRUPT() calls with ASSERT() for 5.4.y backport]
While running generic/103, I observed what looks like memory corruption and (with slub debugging turned on) a slub redzone warning on i386 when inactivating an inode with a 64k remote attr value.
On a v5 filesystem, maximally sized remote attr values require one block more than 64k worth of space to hold both the remote attribute value header (64 bytes). On a 4k block filesystem this results in a 68k buffer; on a 64k block filesystem, this would be a 128k buffer. Note that even though we'll never use more than 65,600 bytes of this buffer, XFS_MAX_BLOCKSIZE is 64k.
This is a problem because the definition of struct xfs_buf_log_format allows for XFS_MAX_BLOCKSIZE worth of dirty bitmap (64k). On i386 when we invalidate a remote attribute, xfs_trans_binval zeroes all 68k worth of the dirty map, writing right off the end of the log item and corrupting memory. We've gotten away with this on x86_64 for years because the compiler inserts a u32 padding on the end of struct xfs_buf_log_format.
Fortunately for us, remote attribute values are written to disk with xfs_bwrite(), which is to say that they are not logged. Fix the problem by removing all places where we could end up creating a buffer log item for a remote attribute value and leave a note explaining why. Next, replace the open-coded buffer invalidation with a call to the helper we created in the previous patch that does better checking for bad metadata before marking the buffer stale.
Signed-off-by: Darrick J. Wong darrick.wong@oracle.com Reviewed-by: Christoph Hellwig hch@lst.de Acked-by: Darrick J. Wong djwong@kernel.org Signed-off-by: Chandan Babu R chandan.babu@oracle.com --- fs/xfs/libxfs/xfs_attr_remote.c | 37 +++++++++++++++++++++----- fs/xfs/xfs_attr_inactive.c | 47 +++++++++------------------------ 2 files changed, 44 insertions(+), 40 deletions(-)
diff --git a/fs/xfs/libxfs/xfs_attr_remote.c b/fs/xfs/libxfs/xfs_attr_remote.c index 4e5579edcf8c..de9096b8a47c 100644 --- a/fs/xfs/libxfs/xfs_attr_remote.c +++ b/fs/xfs/libxfs/xfs_attr_remote.c @@ -24,6 +24,23 @@
#define ATTR_RMTVALUE_MAPSIZE 1 /* # of map entries at once */
+/* + * Remote Attribute Values + * ======================= + * + * Remote extended attribute values are conceptually simple -- they're written + * to data blocks mapped by an inode's attribute fork, and they have an upper + * size limit of 64k. Setting a value does not involve the XFS log. + * + * However, on a v5 filesystem, maximally sized remote attr values require one + * block more than 64k worth of space to hold both the remote attribute value + * header (64 bytes). On a 4k block filesystem this results in a 68k buffer; + * on a 64k block filesystem, this would be a 128k buffer. Note that the log + * format can only handle a dirty buffer of XFS_MAX_BLOCKSIZE length (64k). + * Therefore, we /must/ ensure that remote attribute value buffers never touch + * the logging system and therefore never have a log item. + */ + /* * Each contiguous block has a header, so it is not just a simple attribute * length to FSB conversion. @@ -400,17 +417,25 @@ xfs_attr_rmtval_get( (map[i].br_startblock != HOLESTARTBLOCK)); dblkno = XFS_FSB_TO_DADDR(mp, map[i].br_startblock); dblkcnt = XFS_FSB_TO_BB(mp, map[i].br_blockcount); - error = xfs_trans_read_buf(mp, args->trans, - mp->m_ddev_targp, - dblkno, dblkcnt, 0, &bp, - &xfs_attr3_rmt_buf_ops); - if (error) + bp = xfs_buf_read(mp->m_ddev_targp, dblkno, dblkcnt, 0, + &xfs_attr3_rmt_buf_ops); + if (!bp) + return -ENOMEM; + error = bp->b_error; + if (error) { + xfs_buf_ioerror_alert(bp, __func__); + xfs_buf_relse(bp); + + /* bad CRC means corrupted metadata */ + if (error == -EFSBADCRC) + error = -EFSCORRUPTED; return error; + }
error = xfs_attr_rmtval_copyout(mp, bp, args->dp->i_ino, &offset, &valuelen, &dst); - xfs_trans_brelse(args->trans, bp); + xfs_buf_relse(bp); if (error) return error;
diff --git a/fs/xfs/xfs_attr_inactive.c b/fs/xfs/xfs_attr_inactive.c index 766b1386402a..9d5c27db1239 100644 --- a/fs/xfs/xfs_attr_inactive.c +++ b/fs/xfs/xfs_attr_inactive.c @@ -25,22 +25,20 @@ #include "xfs_error.h"
/* - * Look at all the extents for this logical region, - * invalidate any buffers that are incore/in transactions. + * Invalidate any incore buffers associated with this remote attribute value + * extent. We never log remote attribute value buffers, which means that they + * won't be attached to a transaction and are therefore safe to mark stale. + * The actual bunmapi will be taken care of later. */ STATIC int -xfs_attr3_leaf_freextent( - struct xfs_trans **trans, +xfs_attr3_rmt_stale( struct xfs_inode *dp, xfs_dablk_t blkno, int blkcnt) { struct xfs_bmbt_irec map; - struct xfs_buf *bp; xfs_dablk_t tblkno; - xfs_daddr_t dblkno; int tblkcnt; - int dblkcnt; int nmap; int error;
@@ -57,35 +55,18 @@ xfs_attr3_leaf_freextent( nmap = 1; error = xfs_bmapi_read(dp, (xfs_fileoff_t)tblkno, tblkcnt, &map, &nmap, XFS_BMAPI_ATTRFORK); - if (error) { + if (error) return error; - } ASSERT(nmap == 1); - ASSERT(map.br_startblock != DELAYSTARTBLOCK);
/* - * If it's a hole, these are already unmapped - * so there's nothing to invalidate. + * Mark any incore buffers for the remote value as stale. We + * never log remote attr value buffers, so the buffer should be + * easy to kill. */ - if (map.br_startblock != HOLESTARTBLOCK) { - - dblkno = XFS_FSB_TO_DADDR(dp->i_mount, - map.br_startblock); - dblkcnt = XFS_FSB_TO_BB(dp->i_mount, - map.br_blockcount); - bp = xfs_trans_get_buf(*trans, - dp->i_mount->m_ddev_targp, - dblkno, dblkcnt, 0); - if (!bp) - return -ENOMEM; - xfs_trans_binval(*trans, bp); - /* - * Roll to next transaction. - */ - error = xfs_trans_roll_inode(trans, dp); - if (error) - return error; - } + error = xfs_attr_rmtval_stale(dp, &map, 0); + if (error) + return error;
tblkno += map.br_blockcount; tblkcnt -= map.br_blockcount; @@ -174,9 +155,7 @@ xfs_attr3_leaf_inactive( */ error = 0; for (lp = list, i = 0; i < count; i++, lp++) { - tmp = xfs_attr3_leaf_freextent(trans, dp, - lp->valueblk, lp->valuelen); - + tmp = xfs_attr3_rmt_stale(dp, lp->valueblk, lp->valuelen); if (error == 0) error = tmp; /* save only the 1st errno */ }