[LU-14366] "lfs mkdir" on existing directory returns "Operation not supported/already in progress" Created: 26/Jan/21 Updated: 23/Feb/22 Resolved: 15/Apr/21 |
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| Status: | Resolved |
| Project: | Lustre |
| Component/s: | None |
| Affects Version/s: | Lustre 2.14.0 |
| Fix Version/s: | Lustre 2.15.0 |
| Type: | Bug | Priority: | Minor |
| Reporter: | Andreas Dilger | Assignee: | Lai Siyao |
| Resolution: | Fixed | Votes: | 0 |
| Labels: | dne3 | ||
| Issue Links: |
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| Severity: | 3 | ||||||||||||||||
| Rank (Obsolete): | 9223372036854775807 | ||||||||||||||||
| Description |
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Running "[{lfs mkdir /path/to/existing/directory}}" prints an error message "Operation not permitted" (-EPERM) for a directory that already exists, rather than the more expected "File already exists" (-EEXIST). It turns out that this is because "lfs mkdir" will now restriping a directory in the background, if it already exists, to match the new layout given by "lfs mkdir". This fails with "Operation not permitted" if mdt.*.enable_dir_restripe=0. If "mdt.*.enable_dir_restripe=1" then the background restripe fails with "Operation already in progress" (-EALREADY). I think it is confusing from a user perspective if "lfs mkdir" is trying to migrate the directory when it already exists. This is happening because "lfs mkdir" is internally just an alias for "lfs setdirstripe", but I still think it is confusing, and wonder if we need to treat these commands slightly differently in this case (e.g. add a flag to "lfs mkdir" to prevent it from doing the silent migration? It should return -EEXIST in that case. My understanding is that the difference between "lfs setdirstripe" and "lfs migrate -m" is that setdirstripe will only move the entries to the new MDT(s), while "migrate -m" will also move the inodes to the new MDT(s)? I definitely like the idea of being able to restripe a directory and only move the entries, but I wonder if the entry-only restripe would be more clear if it was an option for "lfs migrate -m"? |
| Comments |
| Comment by Lai Siyao [ 26/Jan/21 ] |
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I'll add a flag for this later. The main difference between 'lfs setdirstripe' and 'lfs migrate -m' is: for directory restripe, the existing master object and shards will be kept(If it's a plain directory, the original directory object will become the first shard), while 'lfs migrate -m' will always create new master object and shards. Once "mdt.*.dir_restripe_nsonly" is set to "0", directory restripe will move inodes too. |
| Comment by Gerrit Updater [ 15/Apr/21 ] |
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Oleg Drokin (green@whamcloud.com) merged in patch https://review.whamcloud.com/41329/ |
| Comment by Peter Jones [ 15/Apr/21 ] |
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Landed for 2.15 |