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| author | Simon Rettberg | 2019-08-02 16:58:34 +0200 |
|---|---|---|
| committer | Simon Rettberg | 2019-08-02 16:58:34 +0200 |
| commit | b7af3a8c36426811762bf331e3938f9d67b7429e (patch) | |
| tree | 09ea38075824d6c0ee94e0105ee3eff191cf6691 /src/server/globals.h | |
| parent | i[SERVER] Include new pretendClient in config dump (diff) | |
| download | dnbd3-b7af3a8c36426811762bf331e3938f9d67b7429e.tar.gz dnbd3-b7af3a8c36426811762bf331e3938f9d67b7429e.tar.xz dnbd3-b7af3a8c36426811762bf331e3938f9d67b7429e.zip | |
[SERVER] Make image->users atomic and get rid of some locking
With this change it should be safe to read the users count of an image
without locking first, assuming you already have a reference on the
image or are otherwise sure it cannot be freed, i.e. in an active
uplink. Updating users, or checking whether it's 0 in order to free the
image should only be done while holding the imageListLock.
Diffstat (limited to 'src/server/globals.h')
| -rw-r--r-- | src/server/globals.h | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/src/server/globals.h b/src/server/globals.h index b248800..73eb563 100644 --- a/src/server/globals.h +++ b/src/server/globals.h @@ -117,7 +117,7 @@ struct _dnbd3_image uint32_t masterCrc32; // CRC-32 of the crc-32 list int readFd; // used to read the image. Used from multiple threads, so use atomic operations (pread et al) int completenessEstimate; // Completeness estimate in percent - int users; // clients currently using this image + atomic_int users; // clients currently using this image. XXX Lock on imageListLock when modifying and checking whether the image should be freed. Reading it elsewhere is fine without the lock. int id; // Unique ID of this image. Only unique in the context of this running instance of DNBD3-Server bool working; // true if image exists and completeness is == 100% or a working upstream proxy is connected uint16_t rid; // revision of image |