xfs: overflow in xfs_iomap_eof_align_last_fsb
PATCH 1/1 xfs: overflow in xfs_iomap_eof_align_last_fsb
Someone else may have run into this already, if not please take a look.
Peter
If extsize is set and new_last_fsb is larger than 32 bits, the roundup to extsize will overflow the align variable. Instead, combine alignments by rounding extsize hint up to stripe size.
--- fs/xfs/xfs_iomap.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-)
fs/xfs/xfs_iomap.c +10 -9
@@ -52,7 +52,7 @@ xfs_iomap_eof_align_last_fsb(xfs_extlen_t extsize, xfs_fileoff_t *last_fsb) { - xfs_fileoff_t new_last_fsb = 0; + xfs_fileoff_t new_last_fsb;xfs_extlen_t align =0 ;int eof, error;
@@ -70,23 +70,24 @@ xfs_iomap_eof_align_last_fsb(else if (mp->m_dalign) align = mp->m_dalign; -if (align &&XFS_ISIZE (ip) >=XFS_FSB_TO_B (mp, align)) - new_last_fsb =roundup_64 (*last_fsb, align); +if (align &&XFS_ISIZE (ip) <XFS_FSB_TO_B (mp, align)) + align =0 ; }/* -* Always round up the allocation request to an extent boundary -* (when file on a real-time subvolume or has di_extsize hint). +* Round up the allocation request to an extent boundary. If +* already aligned to a stripe, round extsize up to a stripe +* boundary. */ if (extsize) { -if (new_last_fsb) - align =roundup_64 (new_last_fsb, extsize); +if (align) + align =roundup_64 (extsize, align);else align = extsize; - new_last_fsb =roundup_64 (*last_fsb, align); } -if (new_last_fsb) { +if (align) { + new_last_fsb =roundup_64 (*last_fsb, align); error =xfs_bmap_eof (ip, new_last_fsb,XFS_DATA_FORK , &eof);if (error)return error;
Signature · 6 lines
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Quoted 5 lines · Peter Watkins
Someone else may have run into this already, if not please take a look.
Peter
Quoted 7 lines
If extsize is set and
new_last_fsbis larger than 32 bits, the roundup to extsize will overflow the align variable. Instead, combine alignments by rounding extsize hint up to stripe size.Signed-off-by Peter Watkins <[email protected]>Reviewed-by Nathaniel W. Turner <[email protected]>---
So we basically assign a file offset value to an extent length variable. Nice spot...
Quoted 28 lines
fs/xfs/xfs_iomap.c | 19 ++++++++++--------- 1 file changed, 10 insertions(+), 9 deletions(-)fs/xfs/xfs_iomap.c +3
-4@@ -52,7 +52,7 @@ xfs_iomap_eof_align_last_fsb(xfs_extlen_t extsize, xfs_fileoff_t *last_fsb) { - xfs_fileoff_t new_last_fsb = 0; + xfs_fileoff_t new_last_fsb;xfs_extlen_t align =0 ;int eof, error;@@ -70,23 +70,24 @@ xfs_iomap_eof_align_last_fsb(else if (mp->m_dalign) align = mp->m_dalign; -if (align &&XFS_ISIZE (ip) >=XFS_FSB_TO_B (mp, align)) - new_last_fsb =roundup_64 (*last_fsb, align); +if (align &&XFS_ISIZE (ip) <XFS_FSB_TO_B (mp, align)) + align =0 ; }/* -* Always round up the allocation request to an extent boundary
fs/xfs/xfs_iomap.c xfs_iomap_eof_align_last_fsb( · line 84
Quoted 10 lines
fs/xfs/xfs_iomap.c +5
-3-* (when file on a real-time subvolume or has di_extsize hint). +* Round up the allocation request to an extent boundary. If +* already aligned to a stripe, round extsize up to a stripe +* boundary. */ if (extsize) { -if (new_last_fsb) - align =roundup_64 (new_last_fsb, extsize); +if (align) + align =roundup_64 (extsize, align);
I think the previous behavior would swap this around and round up the alignment to the extsize. Because we aligned from the actual fsb, we'd effectively use the stripe alignment as a min. alloc and always align to the hint. Here we simply round up extsize to the stripe alignment. IOW, the alignment was previously always to the hint, even if smaller than the stripe alignment, and now we align to the larger of the hint or stripe.
That said, it's kind of a weird scenario and it's not clear to me whether it's important or even intended. If not, the patch seems Ok to me...
Brian
Quoted 18 lines
fs/xfs/xfs_iomap.c +2
-2else align = extsize; - new_last_fsb =roundup_64 (*last_fsb, align); } -if (new_last_fsb) { +if (align) { + new_last_fsb =roundup_64 (*last_fsb, align); error =xfs_bmap_eof (ip, new_last_fsb,XFS_DATA_FORK , &eof);if (error)return error;Signature · 6 lines
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Quoted 8 lines · Peter Watkins
Someone else may have run into this already, if not please take a look.
Peter
If extsize is set and
new_last_fsbis larger than 32 bits, the roundup to extsize will overflow the align variable. Instead, combine alignments by rounding extsize hint up to stripe size.
Change of allocator behaviour that will cause significant problems for applications that depend on deterministic behaviour from the extent size hint.
i.e. The extsize hint is supposed to override all other alignments that are made - extent size hints are effectively a "unit of allocation". Hence we round up to stripe unit/width, then apply the extent size hint alignment so that extent sizes are always aligned to the extent size hint....
....
fs/xfs/xfs_iomap.c xfs_iomap_eof_align_last_fsb( · line 55
Quoted 6 lines
fs/xfs/xfs_iomap.c +1
-1@@ -52,7 +52,7 @@ xfs_iomap_eof_align_last_fsb(xfs_extlen_t extsize, xfs_fileoff_t *last_fsb) { - xfs_fileoff_t new_last_fsb = 0; + xfs_fileoff_t new_last_fsb;
That can be declared in the context that uses it now.
Quoted 10 lines
fs/xfs/xfs_iomap.c +1
-2xfs_extlen_t align =0 ;int eof, error;@@ -70,23 +70,24 @@ xfs_iomap_eof_align_last_fsb(else if (mp->m_dalign) align = mp->m_dalign; -if (align &&XFS_ISIZE (ip) >=XFS_FSB_TO_B (mp, align)) - new_last_fsb =roundup_64 (*last_fsb, align); +if (align &&XFS_ISIZE (ip) <XFS_FSB_TO_B (mp, align))
fs/xfs/xfs_iomap.c xfs_iomap_eof_align_last_fsb( · line 81
Quoted 10 lines
fs/xfs/xfs_iomap.c +4
-2+ align =0 ; }/* -* Always round up the allocation request to an extent boundary -* (when file on a real-time subvolume or has di_extsize hint). +* Round up the allocation request to an extent boundary. If +* already aligned to a stripe, round extsize up to a stripe +* boundary. */
Drop the comment change...
fs/xfs/xfs_iomap.c xfs_iomap_eof_align_last_fsb( · line 84
Quoted 5 lines
fs/xfs/xfs_iomap.c +2
-2if (extsize) { -if (new_last_fsb) - align =roundup_64 (new_last_fsb, extsize); +if (align) + align =roundup_64 (extsize, align);
align = roundup(align, extsize);
fs/xfs/xfs_iomap.c xfs_iomap_eof_align_last_fsb( · line 90
Quoted 8 lines
fs/xfs/xfs_iomap.c +2
-2else align = extsize; - new_last_fsb =roundup_64 (*last_fsb, align); } -if (new_last_fsb) { +if (align) { + new_last_fsb =roundup_64 (*last_fsb, align);
xfs_fileoff_t new_last_fsb = roundup_64(*last_fsb, align);
fs/xfs/xfs_iomap.c xfs_iomap_eof_align_last_fsb( · line 93
Quoted 3 lines
fs/xfs/xfs_iomap.c +0
-0error =xfs_bmap_eof (ip, new_last_fsb,XFS_DATA_FORK , &eof);if (error)return error;
Cheers,
Dave.
Signature · 7 lines
Dave Chinner [email protected] _______________________________________________ xfs mailing list [email protected] http://oss.sgi.com/mailman/listinfo/xfs
PATCH v2 1/1 xfs: overflow in xfs_iomap_eof_align_last_fsb
In reply to Peter WatkinsIf extsize is set and new_last_fsb is larger than 32 bits, the roundup to extsize will overflow the align variable. Instead, combine alignments by rounding stripe size up to extsize.
--- fs/xfs/xfs_iomap.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)
fs/xfs/xfs_iomap.c +6 -7
@@ -52,7 +52,6 @@ xfs_iomap_eof_align_last_fsb(xfs_extlen_t extsize, xfs_fileoff_t *last_fsb) { - xfs_fileoff_t new_last_fsb = 0; xfs_extlen_t align = 0;int eof, error;
@@ -70,8 +69,8 @@ xfs_iomap_eof_align_last_fsb(else if (mp->m_dalign) align = mp->m_dalign; -if (align &&XFS_ISIZE (ip) >=XFS_FSB_TO_B (mp, align)) - new_last_fsb =roundup_64 (*last_fsb, align); +if (align &&XFS_ISIZE (ip) <XFS_FSB_TO_B (mp, align)) + align =0 ; }/*
@@ -79,14 +78,14 @@ xfs_iomap_eof_align_last_fsb(* (when file on a real-time subvolume or has di_extsize hint). */ if (extsize) { -if (new_last_fsb) - align =roundup_64 (new_last_fsb, extsize); +if (align) + align =roundup_64 (align, extsize);else align = extsize; - new_last_fsb =roundup_64 (*last_fsb, align); } -if (new_last_fsb) { +if (align) { +xfs_fileoff_t new_last_fsb =roundup_64 (*last_fsb, align); error =xfs_bmap_eof (ip, new_last_fsb,XFS_DATA_FORK , &eof);if (error)return error;
Signature · 6 lines
1.7.9.5 _______________________________________________ xfs mailing list [email protected] http://oss.sgi.com/mailman/listinfo/xfs
Quoted 7 lines · Peter Watkins
If extsize is set and
new_last_fsbis larger than 32 bits, the roundup to extsize will overflow the align variable. Instead, combine alignments by rounding stripe size up to extsize.Signed-off-by Peter Watkins <[email protected]>Reviewed-by Nathaniel W. Turner <[email protected]>---
Looks fine to me:
Quoted 52 lines
fs/xfs/xfs_iomap.c | 13 ++++++------- 1 file changed, 6 insertions(+), 7 deletions(-)fs/xfs/xfs_iomap.c +6
-7@@ -52,7 +52,6 @@ xfs_iomap_eof_align_last_fsb(xfs_extlen_t extsize, xfs_fileoff_t *last_fsb) { - xfs_fileoff_t new_last_fsb = 0; xfs_extlen_t align = 0;int eof, error;@@ -70,8 +69,8 @@ xfs_iomap_eof_align_last_fsb(else if (mp->m_dalign) align = mp->m_dalign; -if (align &&XFS_ISIZE (ip) >=XFS_FSB_TO_B (mp, align)) - new_last_fsb =roundup_64 (*last_fsb, align); +if (align &&XFS_ISIZE (ip) <XFS_FSB_TO_B (mp, align)) + align =0 ; }/* @@ -79,14 +78,14 @@ xfs_iomap_eof_align_last_fsb(* (when file on a real-time subvolume or has di_extsize hint). */ if (extsize) { -if (new_last_fsb) - align =roundup_64 (new_last_fsb, extsize); +if (align) + align =roundup_64 (align, extsize);else align = extsize; - new_last_fsb =roundup_64 (*last_fsb, align); } -if (new_last_fsb) { +if (align) { +xfs_fileoff_t new_last_fsb =roundup_64 (*last_fsb, align); error =xfs_bmap_eof (ip, new_last_fsb,XFS_DATA_FORK , &eof);if (error)return error;Signature · 6 lines
1.7.9.5 _______________________________________________ xfs mailing list [email protected] http://oss.sgi.com/mailman/listinfo/xfs
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