| Message ID | 149162063502.22901.11947139521251833946.stgit@birch.djwong.org (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
On Fri, Apr 07, 2017 at 08:03:55PM -0700, Darrick J. Wong wrote: > From: Darrick J. Wong <darrick.wong@oracle.com> > > The function block_to_bt plays an integral role in determining the btree > geometry of a block that we want to manipulate with the debugger. > Normally we use the block magic to find the geometry profile, but if the > magic is bad we'll never find it and return NULL. The callers of this > function do not check for NULL and crash. > > Therefore, if we can't find a geometry profile matching the magic > number, use the iocursor type to guess the profile and scowl about that > to stdout. This makes it so that even with a corrupt magic we can try > to print the fields instead of crashing the debugger. .... > +#define M(a,b) (!xfs_sb_version_hascrc(&mp->m_sb) ? (a) : (b)) > + switch (iocur_top->typ->typnm) { > + case TYP_BMAPBTA: > + case TYP_BMAPBTD: > + magic = M(XFS_BMAP_MAGIC, XFS_BMAP_CRC_MAGIC); > + break; That's really quite special, Darrick. :P This: (!xfs_sb_version_hascrc(&mp->m_sb) ? (a) : (b)) Could written more simply as: (xfs_sb_version_hascrc(&mp->m_sb) ? (b) : (a)) or you could swap the macro args so you only need to drop the negation. Even better, though, would be to use a local variable to only evaluate the CRC status once and kill the macro altogether: has_crc = xfs_sb_version_hascrc(&mp->m_sb); switch (iocur_top->typ->typnm) { case TYP_BMAPBTA: case TYP_BMAPBTD: magic = has_crc ? XFS_ABTB_CRC_MAGIC : XFS_ABTB_MAGIC; break; ..... -Dave.
On Sun, Apr 09, 2017 at 09:19:53AM +1000, Dave Chinner wrote: > On Fri, Apr 07, 2017 at 08:03:55PM -0700, Darrick J. Wong wrote: > > From: Darrick J. Wong <darrick.wong@oracle.com> > > > > The function block_to_bt plays an integral role in determining the btree > > geometry of a block that we want to manipulate with the debugger. > > Normally we use the block magic to find the geometry profile, but if the > > magic is bad we'll never find it and return NULL. The callers of this > > function do not check for NULL and crash. > > > > Therefore, if we can't find a geometry profile matching the magic > > number, use the iocursor type to guess the profile and scowl about that > > to stdout. This makes it so that even with a corrupt magic we can try > > to print the fields instead of crashing the debugger. > > .... > > > +#define M(a,b) (!xfs_sb_version_hascrc(&mp->m_sb) ? (a) : (b)) > > + switch (iocur_top->typ->typnm) { > > + case TYP_BMAPBTA: > > + case TYP_BMAPBTD: > > + magic = M(XFS_BMAP_MAGIC, XFS_BMAP_CRC_MAGIC); > > + break; > > That's really quite special, Darrick. :P > > This: > > (!xfs_sb_version_hascrc(&mp->m_sb) ? (a) : (b)) > > Could written more simply as: > > (xfs_sb_version_hascrc(&mp->m_sb) ? (b) : (a)) > > or you could swap the macro args so you only need to drop the > negation. > > Even better, though, would be to use a local variable to only > evaluate the CRC status once and kill the macro altogether: > > has_crc = xfs_sb_version_hascrc(&mp->m_sb); > switch (iocur_top->typ->typnm) { > case TYP_BMAPBTA: > case TYP_BMAPBTD: > magic = has_crc ? XFS_ABTB_CRC_MAGIC : XFS_ABTB_MAGIC; > break; > ..... Ok, done. --D > > -Dave. > -- > Dave Chinner > david@fromorbit.com -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/db/btblock.c b/db/btblock.c index 835a5f0..ba81645 100644 --- a/db/btblock.c +++ b/db/btblock.c @@ -25,6 +25,8 @@ #include "print.h" #include "bit.h" #include "init.h" +#include "io.h" +#include "output.h" /* * Definition of the possible btree block layouts. @@ -122,13 +124,49 @@ static struct xfs_db_btree * block_to_bt( struct xfs_btree_block *bb) { - struct xfs_db_btree *btp = &btrees[0]; + struct xfs_db_btree *btp; + uint32_t magic; + + magic = be32_to_cpu((bb)->bb_magic); + for (btp = &btrees[0]; btp->magic != 0; btp++) + if (magic == btp->magic) + return btp; - do { - if (be32_to_cpu((bb)->bb_magic) == btp->magic) +#define M(a,b) (!xfs_sb_version_hascrc(&mp->m_sb) ? (a) : (b)) + switch (iocur_top->typ->typnm) { + case TYP_BMAPBTA: + case TYP_BMAPBTD: + magic = M(XFS_BMAP_MAGIC, XFS_BMAP_CRC_MAGIC); + break; + case TYP_BNOBT: + magic = M(XFS_ABTB_MAGIC, XFS_ABTB_CRC_MAGIC); + break; + case TYP_CNTBT: + magic = M(XFS_ABTC_MAGIC, XFS_ABTC_CRC_MAGIC); + break; + case TYP_INOBT: + magic = M(XFS_IBT_MAGIC, XFS_IBT_CRC_MAGIC); + break; + case TYP_FINOBT: + magic = M(XFS_FIBT_MAGIC, XFS_FIBT_CRC_MAGIC); + break; + case TYP_RMAPBT: + magic = M(0, XFS_RMAP_CRC_MAGIC); + break; + case TYP_REFCBT: + magic = M(0, XFS_REFC_CRC_MAGIC); + break; + default: + ASSERT(0); + } +#undef M + dbprintf(_("Bad btree magic 0x%x; coercing to %s.\n"), + be32_to_cpu((bb)->bb_magic), + iocur_top->typ->name); + + for (btp = &btrees[0]; btp->magic != 0; btp++) + if (magic == btp->magic) return btp; - btp++; - } while (btp->magic != 0); return NULL; } @@ -193,7 +231,6 @@ btblock_key_offset( int offset; ASSERT(startoff == 0); - ASSERT(block->bb_level != 0); offset = bt->block_len + (idx - 1) * bt->key_len; return bitize(offset); @@ -214,7 +251,6 @@ btblock_ptr_offset( int maxrecs; ASSERT(startoff == 0); - ASSERT(block->bb_level != 0); maxrecs = btblock_maxrecs(bt, mp->m_sb.sb_blocksize); offset = bt->block_len + @@ -238,7 +274,6 @@ btblock_rec_offset( int offset; ASSERT(startoff == 0); - ASSERT(block->bb_level == 0); offset = bt->block_len + (idx - 1) * bt->rec_len; return bitize(offset);