7176 Yet another hole birth issue #4981
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quick port of the recent commit by @pcd1193182 |
This is another bug in the long line of hole-birth related issues. In this particular case, it was discovered that a previous hole-birth fix (illumos bug 6513) did not cover as many cases as we thought it did. While the issue worked in the case of hole-punching (writing zeroes to a large part of a file), it did not deal with truncation, and then writing beyond the new end of the file. The problem is that dbuf_findbp will return ENOENT if the block it's trying to find is beyond the end of the file. If that happens, we assume there is no birth time, and so we lose that information when we write out new blkptrs. We should teach dbuf_findbp to look for things that are beyond the current end, but not beyond the absolute end of the file. Reviewed by: Matthew Ahrens <[email protected]> Reviewed by: George Wilson <[email protected]> Ported by: Boris Protopopov <[email protected]>
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Hm. I guess my compiler is newer. Let's re-spin. |
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dupe :) #4950 Illumos 7176 Yet another hole birth issue |
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Closing as duplicate of |
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rebased it on august 17th, thank you ! |
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This is another bug in the long line of hole-birth related issues. In
this particular case, it was discovered that a previous hole-birth fix
(illumos bug 6513) did not cover as many cases as we thought it did.
While the issue worked in the case of hole-punching (writing zeroes to a
large part of a file), it did not deal with truncation, and then writing
beyond the new end of the file.
The problem is that dbuf_findbp will return ENOENT if the block it's
trying to find is beyond the end of the file. If that happens, we assume
there is no birth time, and so we lose that information when we write out
new blkptrs. We should teach dbuf_findbp to look for things that are
beyond the current end, but not beyond the absolute end of the file.
Reviewed by: Matthew Ahrens [email protected]
Reviewed by: George Wilson [email protected]
Ported by: Boris Protopopov [email protected]