diff for duplicates of <20160616091241.GA15953@infradead.org> diff --git a/a/1.txt b/N1/1.txt index 87bcb9c..4f20719 100644 --- a/a/1.txt +++ b/N1/1.txt @@ -7,3 +7,44 @@ On Wed, Jun 15, 2016 at 03:45:37PM +0000, Trond Myklebust wrote: That is the basic defintion, but once O_DSYNC and friends come into play it gets more complicated: + +>From http://pubs.opengroup.org/onlinepubs/9699919799/functions/read.html: + + [SIO] [Option Start] If the O_DSYNC and O_RSYNC bits have been set, + read I/O operations on the file descriptor shall complete as defined + by synchronized I/O data integrity completion. If the O_SYNC and + O_RSYNC bits have been set, read I/O operations on the file descriptor + shall complete as defined by synchronized I/O file integrity completion. + [Option End] + +Which directs to: +http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html: + + 3.378 Synchronized I/O Data Integrity Completion + + For read, when the operation has been completed or diagnosed if + unsuccessful. The read is complete only when an image of the data + has been successfully transferred to the requesting process. If + there were any pending write requests affecting the data to be read + at the time that the synchronized read operation was requested, + these write requests are successfully transferred prior to reading + the data. + + For write, when the operation has been completed or diagnosed if + unsuccessful. The write is complete only when the data specified in + the write request is successfully transferred and all file system + information required to retrieve the data is successfully + transferred. + + File attributes that are not necessary for data retrieval (access + time, modification time, status change time) need not be + successfully transferred prior to returning to the calling process. + +While we'll never see O_RSYNC in the kernel glibc treats it as just +O_SYNC. Either way - I'd be much happier if we could come up with +less different ways to do read/write exclusion rather than more.. + +_______________________________________________ +xfs mailing list +xfs@oss.sgi.com +http://oss.sgi.com/mailman/listinfo/xfs diff --git a/a/content_digest b/N1/content_digest index 0ec93e3..95f90c0 100644 --- a/a/content_digest +++ b/N1/content_digest @@ -25,6 +25,47 @@ "> ???Writes can be serialized with respect to other reads and writes. If a read() of file data can be proven (by any means) to occur after a write() of the data, it must reflect that write(), even if the calls are made by different processes. A similar requirement applies to multiple write operations to the same file position. This is needed to guarantee the propagation of data from write() calls to subsequent read() calls. This requirement is particularly significant for networked file systems, where some caching schemes violate these semantics.???\n" "\n" "That is the basic defintion, but once O_DSYNC and friends come into\n" - play it gets more complicated: + "play it gets more complicated:\n" + "\n" + ">From http://pubs.opengroup.org/onlinepubs/9699919799/functions/read.html:\n" + "\n" + " [SIO] [Option Start] If the O_DSYNC and O_RSYNC bits have been set,\n" + " read I/O operations on the file descriptor shall complete as defined\n" + " by synchronized I/O data integrity completion. If the O_SYNC and\n" + " O_RSYNC bits have been set, read I/O operations on the file descriptor\n" + " shall complete as defined by synchronized I/O file integrity completion.\n" + " [Option End]\n" + "\n" + "Which directs to:\n" + "http://pubs.opengroup.org/onlinepubs/9699919799/basedefs/V1_chap03.html:\n" + "\n" + " 3.378 Synchronized I/O Data Integrity Completion\n" + "\n" + " For read, when the operation has been completed or diagnosed if\n" + " unsuccessful. The read is complete only when an image of the data\n" + " has been successfully transferred to the requesting process. If\n" + " there were any pending write requests affecting the data to be read\n" + " at the time that the synchronized read operation was requested,\n" + " these write requests are successfully transferred prior to reading\n" + " the data.\n" + "\n" + " For write, when the operation has been completed or diagnosed if\n" + " unsuccessful. The write is complete only when the data specified in\n" + " the write request is successfully transferred and all file system\n" + " information required to retrieve the data is successfully\n" + " transferred.\n" + "\n" + " File attributes that are not necessary for data retrieval (access\n" + " time, modification time, status change time) need not be\n" + " successfully transferred prior to returning to the calling process.\n" + "\n" + "While we'll never see O_RSYNC in the kernel glibc treats it as just\n" + "O_SYNC. Either way - I'd be much happier if we could come up with\n" + "less different ways to do read/write exclusion rather than more..\n" + "\n" + "_______________________________________________\n" + "xfs mailing list\n" + "xfs@oss.sgi.com\n" + http://oss.sgi.com/mailman/listinfo/xfs -29122e34e5c4af5d51c9adfeda742905f0d767fecec157378bc4f167a9439d28 +a4fbb9d28b9349f22bb4876aa20310a7b1cbfdff659c62339dc9247fa0710a12
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.