| Message ID | 20200918094759.2727564-11-chandanrlinux@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | Bail out if transaction can cause extent count to overflow | expand |
On Fri, Sep 18, 2020 at 03:17:59PM +0530, Chandan Babu R wrote: > This commit adds XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag which enables > userspace programs to test "Inode fork extent count overflow detection" > by reducing maximum possible inode fork extent count to > 10 (i.e. MAXERRTAGEXTNUM). > > This commit makes the following additional changes to enable writing > deterministic userspace tests for checking inode extent count overflow, > 1. xfs_bmap_add_extent_hole_real() > File & disk offsets at which extents are allocated by Directory, > Xattr and Realtime code cannot be controlled explicitly from > userspace. When XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag is enabled, > xfs_bmap_add_extent_hole_real() prevents extents from being merged > even though the new extent might be contiguous and have the same > state as its neighbours. That sounds like fs corruption to me, since btree records are supposed to be maximally sized. > 2. xfs_growfs_rt_alloc() > This function allocates as large an extent as possible to fit in the > additional bitmap/summary blocks. We now force allocation of block > sized extents when XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag is > enabled. Ah, so your goal is to dramatically cut the MAX?EXTNUM and then force the allocator to fragment the fs, so that it will quickly hit that maximum. /me suspects that "maximally fragment" ought to be a separate error injector that teaches the alloctor to satisfy the minimum required allocation, and to look only in the short end of the cntbt. > Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com> > --- > fs/xfs/libxfs/xfs_bmap.c | 9 +++++++-- > fs/xfs/libxfs/xfs_errortag.h | 4 +++- > fs/xfs/libxfs/xfs_inode_fork.c | 4 ++++ > fs/xfs/libxfs/xfs_types.h | 1 + > fs/xfs/xfs_error.c | 3 +++ > fs/xfs/xfs_rtalloc.c | 16 ++++++++++++++-- > 6 files changed, 32 insertions(+), 5 deletions(-) > > diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c > index 9c665e379dfc..287f0c4f6d33 100644 > --- a/fs/xfs/libxfs/xfs_bmap.c > +++ b/fs/xfs/libxfs/xfs_bmap.c > @@ -2729,11 +2729,14 @@ xfs_bmap_add_extent_hole_real( > int rval=0; /* return value (logging flags) */ > int state = xfs_bmap_fork_to_state(whichfork); > struct xfs_bmbt_irec old; > + int test_iext_overflow; > > ASSERT(!isnullstartblock(new->br_startblock)); > ASSERT(!cur || !(cur->bc_ino.flags & XFS_BTCUR_BMBT_WASDEL)); > > XFS_STATS_INC(mp, xs_add_exlist); > + test_iext_overflow = XFS_TEST_ERROR(false, ip->i_mount, > + XFS_ERRTAG_REDUCE_MAX_IEXTENTS); > > /* > * Check and set flags if this segment has a left neighbor. > @@ -2762,7 +2765,8 @@ xfs_bmap_add_extent_hole_real( > left.br_startoff + left.br_blockcount == new->br_startoff && > left.br_startblock + left.br_blockcount == new->br_startblock && > left.br_state == new->br_state && > - left.br_blockcount + new->br_blockcount <= MAXEXTLEN) > + left.br_blockcount + new->br_blockcount <= MAXEXTLEN && > + !test_iext_overflow) > state |= BMAP_LEFT_CONTIG; > > if ((state & BMAP_RIGHT_VALID) && !(state & BMAP_RIGHT_DELAY) && > @@ -2772,7 +2776,8 @@ xfs_bmap_add_extent_hole_real( > new->br_blockcount + right.br_blockcount <= MAXEXTLEN && > (!(state & BMAP_LEFT_CONTIG) || > left.br_blockcount + new->br_blockcount + > - right.br_blockcount <= MAXEXTLEN)) > + right.br_blockcount <= MAXEXTLEN) && > + !test_iext_overflow) > state |= BMAP_RIGHT_CONTIG; > > error = 0; > diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h > index 53b305dea381..1c56fcceeea6 100644 > --- a/fs/xfs/libxfs/xfs_errortag.h > +++ b/fs/xfs/libxfs/xfs_errortag.h > @@ -56,7 +56,8 @@ > #define XFS_ERRTAG_FORCE_SUMMARY_RECALC 33 > #define XFS_ERRTAG_IUNLINK_FALLBACK 34 > #define XFS_ERRTAG_BUF_IOERROR 35 > -#define XFS_ERRTAG_MAX 36 > +#define XFS_ERRTAG_REDUCE_MAX_IEXTENTS 36 > +#define XFS_ERRTAG_MAX 37 > > /* > * Random factors for above tags, 1 means always, 2 means 1/2 time, etc. > @@ -97,5 +98,6 @@ > #define XFS_RANDOM_FORCE_SUMMARY_RECALC 1 > #define XFS_RANDOM_IUNLINK_FALLBACK (XFS_RANDOM_DEFAULT/10) > #define XFS_RANDOM_BUF_IOERROR XFS_RANDOM_DEFAULT > +#define XFS_RANDOM_REDUCE_MAX_IEXTENTS 1 > > #endif /* __XFS_ERRORTAG_H_ */ > diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c > index 8d48716547e5..14389d10c597 100644 > --- a/fs/xfs/libxfs/xfs_inode_fork.c > +++ b/fs/xfs/libxfs/xfs_inode_fork.c > @@ -24,6 +24,7 @@ > #include "xfs_dir2_priv.h" > #include "xfs_attr_leaf.h" > #include "xfs_types.h" > +#include "xfs_errortag.h" > > kmem_zone_t *xfs_ifork_zone; > > @@ -745,6 +746,9 @@ xfs_iext_count_may_overflow( > > max_exts = (whichfork == XFS_ATTR_FORK) ? MAXAEXTNUM : MAXEXTNUM; > > + if (XFS_TEST_ERROR(false, ip->i_mount, XFS_ERRTAG_REDUCE_MAX_IEXTENTS)) > + max_exts = MAXERRTAGEXTNUM; > + > nr_exts = ifp->if_nextents + nr_to_add; > if (nr_exts < ifp->if_nextents || nr_exts > max_exts) > return -EFBIG; > diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h > index 397d94775440..f2d6736b72e0 100644 > --- a/fs/xfs/libxfs/xfs_types.h > +++ b/fs/xfs/libxfs/xfs_types.h > @@ -61,6 +61,7 @@ typedef void * xfs_failaddr_t; > #define MAXEXTLEN ((xfs_extlen_t)0x001fffff) /* 21 bits */ > #define MAXEXTNUM ((xfs_extnum_t)0x7fffffff) /* signed int */ > #define MAXAEXTNUM ((xfs_aextnum_t)0x7fff) /* signed short */ > +#define MAXERRTAGEXTNUM ((xfs_extnum_t)0xa) FWIW you could probably just hardcode this in _count_may_overflow. --D > > /* > * Minimum and maximum blocksize and sectorsize. > diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c > index 7f6e20899473..3780b118cc47 100644 > --- a/fs/xfs/xfs_error.c > +++ b/fs/xfs/xfs_error.c > @@ -54,6 +54,7 @@ static unsigned int xfs_errortag_random_default[] = { > XFS_RANDOM_FORCE_SUMMARY_RECALC, > XFS_RANDOM_IUNLINK_FALLBACK, > XFS_RANDOM_BUF_IOERROR, > + XFS_RANDOM_REDUCE_MAX_IEXTENTS, > }; > > struct xfs_errortag_attr { > @@ -164,6 +165,7 @@ XFS_ERRORTAG_ATTR_RW(force_repair, XFS_ERRTAG_FORCE_SCRUB_REPAIR); > XFS_ERRORTAG_ATTR_RW(bad_summary, XFS_ERRTAG_FORCE_SUMMARY_RECALC); > XFS_ERRORTAG_ATTR_RW(iunlink_fallback, XFS_ERRTAG_IUNLINK_FALLBACK); > XFS_ERRORTAG_ATTR_RW(buf_ioerror, XFS_ERRTAG_BUF_IOERROR); > +XFS_ERRORTAG_ATTR_RW(reduce_max_iextents, XFS_ERRTAG_REDUCE_MAX_IEXTENTS); > > static struct attribute *xfs_errortag_attrs[] = { > XFS_ERRORTAG_ATTR_LIST(noerror), > @@ -202,6 +204,7 @@ static struct attribute *xfs_errortag_attrs[] = { > XFS_ERRORTAG_ATTR_LIST(bad_summary), > XFS_ERRORTAG_ATTR_LIST(iunlink_fallback), > XFS_ERRORTAG_ATTR_LIST(buf_ioerror), > + XFS_ERRORTAG_ATTR_LIST(reduce_max_iextents), > NULL, > }; > > diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c > index 3e841a75f272..29a519fc30fb 100644 > --- a/fs/xfs/xfs_rtalloc.c > +++ b/fs/xfs/xfs_rtalloc.c > @@ -18,6 +18,8 @@ > #include "xfs_trans_space.h" > #include "xfs_icache.h" > #include "xfs_rtalloc.h" > +#include "xfs_error.h" > +#include "xfs_errortag.h" > > > /* > @@ -780,17 +782,27 @@ xfs_growfs_rt_alloc( > int resblks; /* space reservation */ > enum xfs_blft buf_type; > struct xfs_trans *tp; > + xfs_extlen_t nr_blks_alloc; > + int test_iext_overflow; > > if (ip == mp->m_rsumip) > buf_type = XFS_BLFT_RTSUMMARY_BUF; > else > buf_type = XFS_BLFT_RTBITMAP_BUF; > > + test_iext_overflow = XFS_TEST_ERROR(false, ip->i_mount, > + XFS_ERRTAG_REDUCE_MAX_IEXTENTS); > + > /* > * Allocate space to the file, as necessary. > */ > while (oblocks < nblocks) { > - resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks); > + if (likely(!test_iext_overflow)) > + nr_blks_alloc = nblocks - oblocks; > + else > + nr_blks_alloc = 1; > + > + resblks = XFS_GROWFSRT_SPACE_RES(mp, nr_blks_alloc); > /* > * Reserve space & log for one extent added to the file. > */ > @@ -813,7 +825,7 @@ xfs_growfs_rt_alloc( > * Allocate blocks to the bitmap file. > */ > nmap = 1; > - error = xfs_bmapi_write(tp, ip, oblocks, nblocks - oblocks, > + error = xfs_bmapi_write(tp, ip, oblocks, nr_blks_alloc, > XFS_BMAPI_METADATA, 0, &map, &nmap); > if (!error && nmap < 1) > error = -ENOSPC; > -- > 2.28.0 >
On Friday 18 September 2020 9:09:30 PM IST Darrick J. Wong wrote: > On Fri, Sep 18, 2020 at 03:17:59PM +0530, Chandan Babu R wrote: > > This commit adds XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag which enables > > userspace programs to test "Inode fork extent count overflow detection" > > by reducing maximum possible inode fork extent count to > > 10 (i.e. MAXERRTAGEXTNUM). > > > > This commit makes the following additional changes to enable writing > > deterministic userspace tests for checking inode extent count overflow, > > 1. xfs_bmap_add_extent_hole_real() > > File & disk offsets at which extents are allocated by Directory, > > Xattr and Realtime code cannot be controlled explicitly from > > userspace. When XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag is enabled, > > xfs_bmap_add_extent_hole_real() prevents extents from being merged > > even though the new extent might be contiguous and have the same > > state as its neighbours. > > That sounds like fs corruption to me, since btree records are supposed > to be maximally sized. > > > 2. xfs_growfs_rt_alloc() > > This function allocates as large an extent as possible to fit in the > > additional bitmap/summary blocks. We now force allocation of block > > sized extents when XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag is > > enabled. > > Ah, so your goal is to dramatically cut the MAX?EXTNUM and then force > the allocator to fragment the fs, so that it will quickly hit that > maximum. > > /me suspects that "maximally fragment" ought to be a separate error > injector that teaches the alloctor to satisfy the minimum required > allocation, and to look only in the short end of the cntbt. This looks like a perfect fit for my requirements. I will take a shot at implementing this. Thanks for the suggestion.
diff --git a/fs/xfs/libxfs/xfs_bmap.c b/fs/xfs/libxfs/xfs_bmap.c index 9c665e379dfc..287f0c4f6d33 100644 --- a/fs/xfs/libxfs/xfs_bmap.c +++ b/fs/xfs/libxfs/xfs_bmap.c @@ -2729,11 +2729,14 @@ xfs_bmap_add_extent_hole_real( int rval=0; /* return value (logging flags) */ int state = xfs_bmap_fork_to_state(whichfork); struct xfs_bmbt_irec old; + int test_iext_overflow; ASSERT(!isnullstartblock(new->br_startblock)); ASSERT(!cur || !(cur->bc_ino.flags & XFS_BTCUR_BMBT_WASDEL)); XFS_STATS_INC(mp, xs_add_exlist); + test_iext_overflow = XFS_TEST_ERROR(false, ip->i_mount, + XFS_ERRTAG_REDUCE_MAX_IEXTENTS); /* * Check and set flags if this segment has a left neighbor. @@ -2762,7 +2765,8 @@ xfs_bmap_add_extent_hole_real( left.br_startoff + left.br_blockcount == new->br_startoff && left.br_startblock + left.br_blockcount == new->br_startblock && left.br_state == new->br_state && - left.br_blockcount + new->br_blockcount <= MAXEXTLEN) + left.br_blockcount + new->br_blockcount <= MAXEXTLEN && + !test_iext_overflow) state |= BMAP_LEFT_CONTIG; if ((state & BMAP_RIGHT_VALID) && !(state & BMAP_RIGHT_DELAY) && @@ -2772,7 +2776,8 @@ xfs_bmap_add_extent_hole_real( new->br_blockcount + right.br_blockcount <= MAXEXTLEN && (!(state & BMAP_LEFT_CONTIG) || left.br_blockcount + new->br_blockcount + - right.br_blockcount <= MAXEXTLEN)) + right.br_blockcount <= MAXEXTLEN) && + !test_iext_overflow) state |= BMAP_RIGHT_CONTIG; error = 0; diff --git a/fs/xfs/libxfs/xfs_errortag.h b/fs/xfs/libxfs/xfs_errortag.h index 53b305dea381..1c56fcceeea6 100644 --- a/fs/xfs/libxfs/xfs_errortag.h +++ b/fs/xfs/libxfs/xfs_errortag.h @@ -56,7 +56,8 @@ #define XFS_ERRTAG_FORCE_SUMMARY_RECALC 33 #define XFS_ERRTAG_IUNLINK_FALLBACK 34 #define XFS_ERRTAG_BUF_IOERROR 35 -#define XFS_ERRTAG_MAX 36 +#define XFS_ERRTAG_REDUCE_MAX_IEXTENTS 36 +#define XFS_ERRTAG_MAX 37 /* * Random factors for above tags, 1 means always, 2 means 1/2 time, etc. @@ -97,5 +98,6 @@ #define XFS_RANDOM_FORCE_SUMMARY_RECALC 1 #define XFS_RANDOM_IUNLINK_FALLBACK (XFS_RANDOM_DEFAULT/10) #define XFS_RANDOM_BUF_IOERROR XFS_RANDOM_DEFAULT +#define XFS_RANDOM_REDUCE_MAX_IEXTENTS 1 #endif /* __XFS_ERRORTAG_H_ */ diff --git a/fs/xfs/libxfs/xfs_inode_fork.c b/fs/xfs/libxfs/xfs_inode_fork.c index 8d48716547e5..14389d10c597 100644 --- a/fs/xfs/libxfs/xfs_inode_fork.c +++ b/fs/xfs/libxfs/xfs_inode_fork.c @@ -24,6 +24,7 @@ #include "xfs_dir2_priv.h" #include "xfs_attr_leaf.h" #include "xfs_types.h" +#include "xfs_errortag.h" kmem_zone_t *xfs_ifork_zone; @@ -745,6 +746,9 @@ xfs_iext_count_may_overflow( max_exts = (whichfork == XFS_ATTR_FORK) ? MAXAEXTNUM : MAXEXTNUM; + if (XFS_TEST_ERROR(false, ip->i_mount, XFS_ERRTAG_REDUCE_MAX_IEXTENTS)) + max_exts = MAXERRTAGEXTNUM; + nr_exts = ifp->if_nextents + nr_to_add; if (nr_exts < ifp->if_nextents || nr_exts > max_exts) return -EFBIG; diff --git a/fs/xfs/libxfs/xfs_types.h b/fs/xfs/libxfs/xfs_types.h index 397d94775440..f2d6736b72e0 100644 --- a/fs/xfs/libxfs/xfs_types.h +++ b/fs/xfs/libxfs/xfs_types.h @@ -61,6 +61,7 @@ typedef void * xfs_failaddr_t; #define MAXEXTLEN ((xfs_extlen_t)0x001fffff) /* 21 bits */ #define MAXEXTNUM ((xfs_extnum_t)0x7fffffff) /* signed int */ #define MAXAEXTNUM ((xfs_aextnum_t)0x7fff) /* signed short */ +#define MAXERRTAGEXTNUM ((xfs_extnum_t)0xa) /* * Minimum and maximum blocksize and sectorsize. diff --git a/fs/xfs/xfs_error.c b/fs/xfs/xfs_error.c index 7f6e20899473..3780b118cc47 100644 --- a/fs/xfs/xfs_error.c +++ b/fs/xfs/xfs_error.c @@ -54,6 +54,7 @@ static unsigned int xfs_errortag_random_default[] = { XFS_RANDOM_FORCE_SUMMARY_RECALC, XFS_RANDOM_IUNLINK_FALLBACK, XFS_RANDOM_BUF_IOERROR, + XFS_RANDOM_REDUCE_MAX_IEXTENTS, }; struct xfs_errortag_attr { @@ -164,6 +165,7 @@ XFS_ERRORTAG_ATTR_RW(force_repair, XFS_ERRTAG_FORCE_SCRUB_REPAIR); XFS_ERRORTAG_ATTR_RW(bad_summary, XFS_ERRTAG_FORCE_SUMMARY_RECALC); XFS_ERRORTAG_ATTR_RW(iunlink_fallback, XFS_ERRTAG_IUNLINK_FALLBACK); XFS_ERRORTAG_ATTR_RW(buf_ioerror, XFS_ERRTAG_BUF_IOERROR); +XFS_ERRORTAG_ATTR_RW(reduce_max_iextents, XFS_ERRTAG_REDUCE_MAX_IEXTENTS); static struct attribute *xfs_errortag_attrs[] = { XFS_ERRORTAG_ATTR_LIST(noerror), @@ -202,6 +204,7 @@ static struct attribute *xfs_errortag_attrs[] = { XFS_ERRORTAG_ATTR_LIST(bad_summary), XFS_ERRORTAG_ATTR_LIST(iunlink_fallback), XFS_ERRORTAG_ATTR_LIST(buf_ioerror), + XFS_ERRORTAG_ATTR_LIST(reduce_max_iextents), NULL, }; diff --git a/fs/xfs/xfs_rtalloc.c b/fs/xfs/xfs_rtalloc.c index 3e841a75f272..29a519fc30fb 100644 --- a/fs/xfs/xfs_rtalloc.c +++ b/fs/xfs/xfs_rtalloc.c @@ -18,6 +18,8 @@ #include "xfs_trans_space.h" #include "xfs_icache.h" #include "xfs_rtalloc.h" +#include "xfs_error.h" +#include "xfs_errortag.h" /* @@ -780,17 +782,27 @@ xfs_growfs_rt_alloc( int resblks; /* space reservation */ enum xfs_blft buf_type; struct xfs_trans *tp; + xfs_extlen_t nr_blks_alloc; + int test_iext_overflow; if (ip == mp->m_rsumip) buf_type = XFS_BLFT_RTSUMMARY_BUF; else buf_type = XFS_BLFT_RTBITMAP_BUF; + test_iext_overflow = XFS_TEST_ERROR(false, ip->i_mount, + XFS_ERRTAG_REDUCE_MAX_IEXTENTS); + /* * Allocate space to the file, as necessary. */ while (oblocks < nblocks) { - resblks = XFS_GROWFSRT_SPACE_RES(mp, nblocks - oblocks); + if (likely(!test_iext_overflow)) + nr_blks_alloc = nblocks - oblocks; + else + nr_blks_alloc = 1; + + resblks = XFS_GROWFSRT_SPACE_RES(mp, nr_blks_alloc); /* * Reserve space & log for one extent added to the file. */ @@ -813,7 +825,7 @@ xfs_growfs_rt_alloc( * Allocate blocks to the bitmap file. */ nmap = 1; - error = xfs_bmapi_write(tp, ip, oblocks, nblocks - oblocks, + error = xfs_bmapi_write(tp, ip, oblocks, nr_blks_alloc, XFS_BMAPI_METADATA, 0, &map, &nmap); if (!error && nmap < 1) error = -ENOSPC;
This commit adds XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag which enables userspace programs to test "Inode fork extent count overflow detection" by reducing maximum possible inode fork extent count to 10 (i.e. MAXERRTAGEXTNUM). This commit makes the following additional changes to enable writing deterministic userspace tests for checking inode extent count overflow, 1. xfs_bmap_add_extent_hole_real() File & disk offsets at which extents are allocated by Directory, Xattr and Realtime code cannot be controlled explicitly from userspace. When XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag is enabled, xfs_bmap_add_extent_hole_real() prevents extents from being merged even though the new extent might be contiguous and have the same state as its neighbours. 2. xfs_growfs_rt_alloc() This function allocates as large an extent as possible to fit in the additional bitmap/summary blocks. We now force allocation of block sized extents when XFS_ERRTAG_REDUCE_MAX_IEXTENTS error tag is enabled. Signed-off-by: Chandan Babu R <chandanrlinux@gmail.com> --- fs/xfs/libxfs/xfs_bmap.c | 9 +++++++-- fs/xfs/libxfs/xfs_errortag.h | 4 +++- fs/xfs/libxfs/xfs_inode_fork.c | 4 ++++ fs/xfs/libxfs/xfs_types.h | 1 + fs/xfs/xfs_error.c | 3 +++ fs/xfs/xfs_rtalloc.c | 16 ++++++++++++++-- 6 files changed, 32 insertions(+), 5 deletions(-)