• Linus Torvalds's avatar
    Merge tag 'afs-next-20200604' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs · 9daa0a27
    Linus Torvalds authored
    Pull AFS updates from David Howells:
     "There's some core VFS changes which affect a couple of filesystems:
    
       - Make the inode hash table RCU safe and providing some RCU-safe
         accessor functions. The search can then be done without taking the
         inode_hash_lock. Care must be taken because the object may be being
         deleted and no wait is made.
    
       - Allow iunique() to avoid taking the inode_hash_lock.
    
       - Allow AFS's callback processing to avoid taking the inode_hash_lock
         when using the inode table to find an inode to notify.
    
       - Improve Ext4's time updating. Konstantin Khlebnikov said "For now,
         I've plugged this issue with try-lock in ext4 lazy time update.
         This solution is much better."
    
      Then there's a set of changes to make a number of improvements to the
      AFS driver:
    
       - Improve callback (ie. third party change notification) processing
         by:
    
          (a) Relying more on the fact we're doing this under RCU and by
              using fewer locks. This makes use of the RCU-based inode
              searching outlined above.
    
          (b) Moving to keeping volumes in a tree indexed by volume ID
              rather than a flat list.
    
          (c) Making the server and volume records logically part of the
              cell. This means that a server record now points directly at
              the cell and the tree of volumes is there. This removes an N:M
              mapping table, simplifying things.
    
       - Improve keeping NAT or firewall channels open for the server
         callbacks to reach the client by actively polling the fileserver on
         a timed basis, instead of only doing it when we have an operation
         to process.
    
       - Improving detection of delayed or lost callbacks by including the
         parent directory in the list of file IDs to be queried when doing a
         bulk status fetch from lookup. We can then check to see if our copy
         of the directory has changed under us without us getting notified.
    
       - Determine aliasing of cells (such as a cell that is pointed to be a
         DNS alias). This allows us to avoid having ambiguity due to
         apparently different cells using the same volume and file servers.
    
       - Improve the fileserver rotation to do more probing when it detects
         that all of the addresses to a server are listed as non-responsive.
         It's possible that an address that previously stopped responding
         has become responsive again.
    
      Beyond that, lay some foundations for making some calls asynchronous:
    
       - Turn the fileserver cursor struct into a general operation struct
         and hang the parameters off of that rather than keeping them in
         local variables and hang results off of that rather than the call
         struct.
    
       - Implement some general operation handling code and simplify the
         callers of operations that affect a volume or a volume component
         (such as a file). Most of the operation is now done by core code.
    
       - Operations are supplied with a table of operations to issue
         different variants of RPCs and to manage the completion, where all
         the required data is held in the operation object, thereby allowing
         these to be called from a workqueue.
    
       - Put the standard "if (begin), while(select), call op, end" sequence
         into a canned function that just emulates the current behaviour for
         now.
    
      There are also some fixes interspersed:
    
       - Don't let the EACCES from ICMP6 mapping reach the user as such,
         since it's confusing as to whether it's a filesystem error. Convert
         it to EHOSTUNREACH.
    
       - Don't use the epoch value acquired through probing a server. If we
         have two servers with the same UUID but in different cells, it's
         hard to draw conclusions from them having different epoch values.
    
       - Don't interpret the argument to the CB.ProbeUuid RPC as a
         fileserver UUID and look up a fileserver from it.
    
       - Deal with servers in different cells having the same UUIDs. In the
         event that a CB.InitCallBackState3 RPC is received, we have to
         break the callback promises for every server record matching that
         UUID.
    
       - Don't let afs_statfs return values that go below 0.
    
       - Don't use running fileserver probe state to make server selection
         and address selection decisions on. Only make decisions on final
         state as the running state is cleared at the start of probing"
    
    Acked-by: Al Viro <viro@zeniv.linux.org.uk> (fs/inode.c part)
    
    * tag 'afs-next-20200604' of git://git.kernel.org/pub/scm/linux/kernel/git/dhowells/linux-fs: (27 commits)
      afs: Adjust the fileserver rotation algorithm to reprobe/retry more quickly
      afs: Show more a bit more server state in /proc/net/afs/servers
      afs: Don't use probe running state to make decisions outside probe code
      afs: Fix afs_statfs() to not let the values go below zero
      afs: Fix the by-UUID server tree to allow servers with the same UUID
      afs: Reorganise volume and server trees to be rooted on the cell
      afs: Add a tracepoint to track the lifetime of the afs_volume struct
      afs: Detect cell aliases 3 - YFS Cells with a canonical cell name op
      afs: Detect cell aliases 2 - Cells with no root volumes
      afs: Detect cell aliases 1 - Cells with root volumes
      afs: Implement client support for the YFSVL.GetCellName RPC op
      afs: Retain more of the VLDB record for alias detection
      afs: Fix handling of CB.ProbeUuid cache manager op
      afs: Don't get epoch from a server because it may be ambiguous
      afs: Build an abstraction around an "operation" concept
      afs: Rename struct afs_fs_cursor to afs_operation
      afs: Remove the error argument from afs_protocol_error()
      afs: Set error flag rather than return error from file status decode
      afs: Make callback processing more efficient.
      afs: Show more information in /proc/net/afs/servers
      ...
    9daa0a27
inode.c 63 KB