linux/include/trace/events/cachefiles.h

853 lines
23 KiB

cachefiles: notify the user daemon when looking up cookie Fscache/CacheFiles used to serve as a local cache for a remote networking fs. A new on-demand read mode will be introduced for CacheFiles, which can boost the scenario where on-demand read semantics are needed, e.g. container image distribution. The essential difference between these two modes is seen when a cache miss occurs: In the original mode, the netfs will fetch the data from the remote server and then write it to the cache file; in on-demand read mode, fetching the data and writing it into the cache is delegated to a user daemon. As the first step, notify the user daemon when looking up cookie. In this case, an anonymous fd is sent to the user daemon, through which the user daemon can write the fetched data to the cache file. Since the user daemon may move the anonymous fd around, e.g. through dup(), an object ID uniquely identifying the cache file is also attached. Also add one advisory flag (FSCACHE_ADV_WANT_CACHE_SIZE) suggesting that the cache file size shall be retrieved at runtime. This helps the scenario where one cache file contains multiple netfs files, e.g. for the purpose of deduplication. In this case, netfs itself has no idea the size of the cache file, whilst the user daemon should give the hint on it. Signed-off-by: Jeffle Xu <jefflexu@linux.alibaba.com> Link: https://lore.kernel.org/r/20220509074028.74954-3-jefflexu@linux.alibaba.com Acked-by: David Howells <dhowells@redhat.com> Signed-off-by: Gao Xiang <hsiangkao@linux.alibaba.com>
2022-04-25 20:21:24 +08:00
2022-03-11 16:02:18 +00:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00
2022-03-11 16:02:18 +00:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00
cachefiles: Implement the I/O routines Implement the I/O routines for cachefiles. There are two sets of routines here: preparation and actual I/O. Preparation for read involves looking to see whether there is data present, and how much. Netfslib tells us what it wants us to do and we have the option of adjusting shrinking and telling it whether to read from the cache, download from the server or simply clear a region. Preparation for write involves checking for space and defending against possibly running short of space, if necessary punching out a hole in the file so that we don't leave old data in the cache if we update the coherency information. Then there's a read routine and a write routine. They wait for the cookie state to move to something appropriate and then start a potentially asynchronous direct I/O operation upon it. Changes ======= ver #2: - Fix a misassigned variable[1]. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: Jeff Layton <jlayton@kernel.org> cc: linux-cachefs@redhat.com Link: https://lore.kernel.org/YaZOCk9zxApPattb@archlinux-ax161/ [1] Link: https://lore.kernel.org/r/163819647945.215744.17827962047487125939.stgit@warthog.procyon.org.uk/ # v1 Link: https://lore.kernel.org/r/163906954666.143852.1504887120569779407.stgit@warthog.procyon.org.uk/ # v2 Link: https://lore.kernel.org/r/163967163110.1823006.9206718511874339672.stgit@warthog.procyon.org.uk/ # v3 Link: https://lore.kernel.org/r/164021562168.640689.8802250542405732391.stgit@warthog.procyon.org.uk/ # v4
2021-10-21 00:19:46 +01:00