kernel/linux.git/include/linux/nfs_page.h, branch v6.12.80

NFS: Fix a race when updating an existing write

2025-08-28T14:31:05+00:00

commit 76d2e3890fb169168c73f2e4f8375c7cc24a765e upstream. After nfs_lock_and_join_requests() tests for whether the request is still attached to the mapping, nothing prevents a call to nfs_inode_remove_request() from succeeding until we actually lock the page group. The reason is that whoever called nfs_inode_remove_request() doesn't necessarily have a lock on the page group head. So in order to avoid races, let's take the page group lock earlier in nfs_lock_and_join_requests(), and hold it across the removal of the request in nfs_inode_remove_request(). Reported-by: Jeff Layton Tested-by: Joe Quanaim Tested-by: Andrew Steffen Reviewed-by: Jeff Layton Fixes: bd37d6fce184 ("NFSv4: Convert nfs_lock_and_join_requests() to use nfs_page_find_head_request()") Cc: stable@vger.kernel.org Signed-off-by: Trond Myklebust Signed-off-by: Greg Kroah-Hartman

nfs: move nfs_wait_on_request to write.c

2024-07-08T17:47:51+00:00

nfs_wait_on_request is now only used in write.c. Move it there and mark it static. Signed-off-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Signed-off-by: Anna Schumaker

nfs: fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests

2024-07-08T17:47:51+00:00

Fold nfs_page_group_lock_subrequests into nfs_lock_and_join_requests to prepare for future changes to this code, and move the helpers to write.c as well. Signed-off-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Signed-off-by: Anna Schumaker

nfs: simplify nfs_folio_find_and_lock_request

2024-07-08T17:47:51+00:00

nfs_folio_find_and_lock_request and the nfs_page_group_lock_head helper called by it spend quite some effort to deal with head vs subrequests. But given that only the head request can be stashed in the folio private data, non of that is required. Fold the locking logic from nfs_page_group_lock_head into nfs_folio_find_and_lock_request and simplify the result based on the invariant that we always find the head request in the folio private data. Signed-off-by: Christoph Hellwig Signed-off-by: Anna Schumaker

nfs: remove dead code for the old swap over NFS implementation

2024-07-08T17:47:51+00:00

Remove the code testing folio_test_swapcache either explicitly or implicitly in pagemap.h headers, as is now handled using the direct I/O path and not the buffered I/O path that these helpers are located in. Signed-off-by: Christoph Hellwig Reviewed-by: Sagi Grimberg Signed-off-by: Anna Schumaker

NFS: Use the correct commit info in nfs_join_page_group()

2023-09-13T15:51:11+00:00

Ensure that nfs_clear_request_commit() updates the correct counters when it removes them from the commit list. Fixes: ed5d588fe47f ("NFS: Try to join page groups before an O_DIRECT retransmission") Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker

NFS: Convert buffered read paths to use netfs when fscache is enabled

2023-04-11T17:08:26+00:00

Convert the NFS buffered read code paths to corresponding netfs APIs, but only when fscache is configured and enabled. The netfs API defines struct netfs_request_ops which must be filled in by the network filesystem. For NFS, we only need to define 5 of the functions, the main one being the issue_read() function. The issue_read() function is called by the netfs layer when a read cannot be fulfilled locally, and must be sent to the server (either the cache is not active, or it is active but the data is not available). Once the read from the server is complete, netfs requires a call to netfs_subreq_terminated() which conveys either how many bytes were read successfully, or an error. Note that issue_read() is called with a structure, netfs_io_subrequest, which defines the IO requested, and contains a start and a length (both in bytes), and assumes the underlying netfs will return a either an error on the whole region, or the number of bytes successfully read. The NFS IO path is page based and the main APIs are the pgio APIs defined in pagelist.c. For the pgio APIs, there is no way for the caller to know how many RPCs will be sent and how the pages will be broken up into underlying RPCs, each of which will have their own completion and return code. In contrast, netfs is subrequest based, a single subrequest may contain multiple pages, and a single subrequest is initiated with issue_read() and terminated with netfs_subreq_terminated(). Thus, to utilze the netfs APIs, NFS needs some way to accommodate the netfs API requirement on the single response to the whole subrequest, while also minimizing disruptive changes to the NFS pgio layer. The approach taken with this patch is to allocate a small structure for each nfs_netfs_issue_read() call, store the final error and number of bytes successfully transferred in the structure, and update these values as each RPC completes. The refcount on the structure is used as a marker for the last RPC completion, is incremented in nfs_netfs_read_initiate(), and decremented inside nfs_netfs_read_completion(), when a nfs_pgio_header contains a valid pointer to the data. On the final put (which signals the final outstanding RPC is complete) in nfs_netfs_read_completion(), call netfs_subreq_terminated() with either the final error value (if one or more READs complete with an error) or the number of bytes successfully transferred (if all RPCs complete successfully). Note that when all RPCs complete successfully, the number of bytes transferred is capped to the length of the subrequest. Capping the transferred length to the subrequest length prevents "Subreq overread" warnings from netfs. This is due to the "aligned_len" in nfs_pageio_add_page(), and the corner case where NFS requests a full page at the end of the file, even when i_size reflects only a partial page (NFS overread). Signed-off-by: Dave Wysochanski Tested-by: Daire Byrne Signed-off-by: Anna Schumaker

NFS: Clean up O_DIRECT request allocation

2023-02-14T19:22:33+00:00

Rather than adjusting the index+offset after the call to nfs_create_request(), add a function nfs_page_create_from_page() that takes an offset. Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker

NFS: Convert buffered reads to use folios

2023-02-14T19:22:32+00:00

Perform a largely mechanical conversion of references to struct page and page-specific functions to use the folio equivalents. Note that the fscache functionality remains untouched. Instead we just pass in the folio page. This should be OK, as long as we use order 0 folios together with fscache. Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker

NFS: Add a helper to convert a struct nfs_page into an inode

2023-02-14T19:22:32+00:00

Replace all the open coded calls to page_file_mapping(req->wb_page)->host. Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker