netfs: clear post-EOF pagecache when extending a file via write

{
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                    "vendor": "Linux",
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                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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                        "fs/netfs/buffered_write.c",
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                        "include/linux/netfs.h"
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{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
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                        "fs/netfs/buffered_write.c",
                        "fs/netfs/direct_write.c",
                        "fs/netfs/internal.h",
                        "fs/netfs/misc.c",
                        "include/linux/netfs.h"
                    ],
                    "versions": [
                        {
                            "version": "6.8",
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                        },
                        {
                            "version": "0",
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                            "version": "7.3",
                            "lessThanOrEqual": "*",
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                            "versionType": "original_commit_for_fix"
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                    ]
                }