diff options
Diffstat (limited to 'mm/filemap.c')
| -rw-r--r-- | mm/filemap.c | 33 |
1 files changed, 32 insertions, 1 deletions
diff --git a/mm/filemap.c b/mm/filemap.c index dc83baab85a1..fa18e71f9c88 100644 --- a/mm/filemap.c +++ b/mm/filemap.c @@ -1966,8 +1966,19 @@ no_page: if (err == -EEXIST) goto repeat; - if (err) + if (err) { + /* + * When NOWAIT I/O fails to allocate folios this could + * be due to a nonblocking memory allocation and not + * because the system actually is out of memory. + * Return -EAGAIN so that there caller retries in a + * blocking fashion instead of propagating -ENOMEM + * to the application. + */ + if ((fgp_flags & FGP_NOWAIT) && err == -ENOMEM) + err = -EAGAIN; return ERR_PTR(err); + } /* * filemap_add_folio locks the page, and for mmap * we expect an unlocked page. @@ -2211,6 +2222,7 @@ unsigned filemap_get_folios_contig(struct address_space *mapping, *start = folio->index + nr; goto out; } + xas_advance(&xas, folio_next_index(folio) - 1); continue; put_folio: folio_put(folio); @@ -4384,6 +4396,20 @@ resched: } /* + * See mincore: reveal pagecache information only for files + * that the calling process has write access to, or could (if + * tried) open for writing. + */ +static inline bool can_do_cachestat(struct file *f) +{ + if (f->f_mode & FMODE_WRITE) + return true; + if (inode_owner_or_capable(file_mnt_idmap(f), file_inode(f))) + return true; + return file_permission(f, MAY_WRITE) == 0; +} + +/* * The cachestat(2) system call. * * cachestat() returns the page cache statistics of a file in the @@ -4442,6 +4468,11 @@ SYSCALL_DEFINE4(cachestat, unsigned int, fd, return -EOPNOTSUPP; } + if (!can_do_cachestat(fd_file(f))) { + fdput(f); + return -EPERM; + } + if (flags != 0) { fdput(f); return -EINVAL; |