From 8ea1f4267bae6b37a4a4d474aec2692a4d211621 Mon Sep 17 00:00:00 2001

From: Fedora systemd team <systemd-maint@redhat.com>

Date: Wed, 7 Jan 2015 13:34:02 +0100

Subject: [PATCH] journald: when we detect the journal file we are about to

 write to has been deleted, rotate

https://bugzilla.redhat.com/show_bug.cgi?id=1171719

(cherry-picked from 2678031a179a9b91fc799f8ef951a548c66c4b49)

---

 src/journal/journal-file.c       | 65 ++++++++++++++++++++++++++++++----------

 src/journal/journal-file.h       |  1 +

 src/journal/journald-server.c    |  6 +++-

 src/journal/test-journal-flush.c |  3 +-

 4 files changed, 57 insertions(+), 18 deletions(-)

diff --git a/src/journal/journal-file.c b/src/journal/journal-file.c

index c5d2d19..a99265b 100644

--- a/src/journal/journal-file.c

+++ b/src/journal/journal-file.c

@@ -68,6 +68,9 @@

 /* How much to increase the journal file size at once each time we allocate something new. */

 #define FILE_SIZE_INCREASE (8ULL*1024ULL*1024ULL)              /* 8MB */

+/* Reread fstat() of the file for detecting deletions at least this often */

+#define LAST_STAT_REFRESH_USEC (5*USEC_PER_SEC)

+

 static int journal_file_set_online(JournalFile *f) {

         assert(f);

@@ -312,6 +315,22 @@ static int journal_file_verify_header(JournalFile *f) {

         return 0;

 }

+static int journal_file_fstat(JournalFile *f) {

+        assert(f);

+        assert(f->fd >= 0);

+

+        if (fstat(f->fd, &f->last_stat) < 0)

+                return -errno;

+

+        f->last_stat_usec = now(CLOCK_MONOTONIC);

+

+        /* Refuse appending to files that are already deleted */

+        if (f->last_stat.st_nlink <= 0)

+                return -EIDRM;

+

+        return 0;

+}

+

 static int journal_file_allocate(JournalFile *f, uint64_t offset, uint64_t size) {

         uint64_t old_size, new_size;

         int r;

@@ -330,8 +349,21 @@ static int journal_file_allocate(JournalFile *f, uint64_t offset, uint64_t size)

         if (new_size < le64toh(f->header->header_size))

                 new_size = le64toh(f->header->header_size);

-        if (new_size <= old_size)

-                return 0;

+        if (new_size <= old_size) {

+

+                /* We already pre-allocated enough space, but before

+                 * we write to it, let's check with fstat() if the

+                 * file got deleted, in order make sure we don't throw

+                 * away the data immediately. Don't check fstat() for

+                 * all writes though, but only once ever 10s. */

+

+                if (f->last_stat_usec + LAST_STAT_REFRESH_USEC > now(CLOCK_MONOTONIC))

+                        return 0;

+

+                return journal_file_fstat(f);

+        }

+

+        /* Allocate more space. */

         if (f->metrics.max_size > 0 && new_size > f->metrics.max_size)

                 return -E2BIG;

@@ -366,15 +398,14 @@ static int journal_file_allocate(JournalFile *f, uint64_t offset, uint64_t size)

         if (r != 0)

                 return -r;

-        if (fstat(f->fd, &f->last_stat) < 0)

-                return -errno;

-

         f->header->arena_size = htole64(new_size - le64toh(f->header->header_size));

-        return 0;

+        return journal_file_fstat(f);

 }

 static int journal_file_move_to(JournalFile *f, int context, bool keep_always, uint64_t offset, uint64_t size, void **ret) {

+        int r;

+

         assert(f);

         assert(ret);

@@ -386,8 +417,11 @@ static int journal_file_move_to(JournalFile *f, int context, bool keep_always, u

                 /* Hmm, out of range? Let's refresh the fstat() data

                  * first, before we trust that check. */

-                if (fstat(f->fd, &f->last_stat) < 0 ||

-                    offset + size > (uint64_t) f->last_stat.st_size)

+                r = journal_file_fstat(f);

+                if (r < 0)

+                        return r;

+

+                if (offset + size > (uint64_t) f->last_stat.st_size)

                         return -EADDRNOTAVAIL;

         }

@@ -2511,10 +2545,9 @@ int journal_file_open(

                 goto fail;

         }

-        if (fstat(f->fd, &f->last_stat) < 0) {

-                r = -errno;

+        r = journal_file_fstat(f);

+        if (r < 0)

                 goto fail;

-        }

         if (f->last_stat.st_size == 0 && f->writable) {

                 uint64_t crtime;

@@ -2546,10 +2579,9 @@ int journal_file_open(

                 if (r < 0)

                         goto fail;

-                if (fstat(f->fd, &f->last_stat) < 0) {

-                        r = -errno;

+                r = journal_file_fstat(f);

+                if (r < 0)

                         goto fail;

-                }

                 newly_created = true;

         }

@@ -2657,8 +2689,11 @@ int journal_file_rotate(JournalFile **f, bool compress, bool seal) {

         if (r < 0)

                 return -ENOMEM;

+        /* Try to rename the file to the archived version. If the file

+         * already was deleted, we'll get ENOENT, let's ignore that

+         * case. */

         r = rename(old_file->path, p);

-        if (r < 0)

+        if (r < 0 && errno != ENOENT)

                 return -errno;

         old_file->header->state = STATE_ARCHIVED;

diff --git a/src/journal/journal-file.h b/src/journal/journal-file.h

index 211e121..15f1301 100644

--- a/src/journal/journal-file.h

+++ b/src/journal/journal-file.h

@@ -66,6 +66,7 @@ typedef struct JournalFile {

         char *path;

         struct stat last_stat;

+        usec_t last_stat_usec;

         Header *header;

         HashItem *data_hash_table;

diff --git a/src/journal/journald-server.c b/src/journal/journald-server.c

index 80c9736..24c4d3c 100644

--- a/src/journal/journald-server.c

+++ b/src/journal/journald-server.c

@@ -315,6 +315,7 @@ static int do_rotate(Server *s, JournalFile **f, const char* name,

                                         name);

         else

                 server_fix_perms(s, *f, uid);

+

         return r;

 }

@@ -457,7 +458,8 @@ bool shall_try_append_again(JournalFile *f, int r) {

            -EPROTONOSUPPORT  Unsupported feature

            -EBADMSG          Corrupted

            -ENODATA          Truncated

-           -ESHUTDOWN        Already archived */

+           -ESHUTDOWN        Already archived

+           -EIDRM            Journal file has been deleted */

         if (r == -E2BIG || r == -EFBIG || r == -EDQUOT || r == -ENOSPC)

                 log_debug("%s: Allocation limit reached, rotating.", f->path);

@@ -469,6 +471,8 @@ bool shall_try_append_again(JournalFile *f, int r) {

                 log_info("%s: Unsupported feature, rotating.", f->path);

         else if (r == -EBADMSG || r == -ENODATA || r == ESHUTDOWN)

                 log_warning("%s: Journal file corrupted, rotating.", f->path);

+        else if (r == -EIDRM)

+                log_warning("%s: Journal file has been deleted, rotating.", f->path);

         else

                 return false;

diff --git a/src/journal/test-journal-flush.c b/src/journal/test-journal-flush.c

index 0ca24e0..40ede4a 100644

--- a/src/journal/test-journal-flush.c

+++ b/src/journal/test-journal-flush.c

@@ -39,8 +39,6 @@ int main(int argc, char *argv[]) {

         r = journal_file_open(fn, O_CREAT|O_RDWR, 0644, false, false, NULL, NULL, NULL, &new_journal);

         assert_se(r >= 0);

-        unlink(fn);

-

         r = sd_journal_open(&j, 0);

         assert_se(r >= 0);

@@ -68,6 +66,7 @@ int main(int argc, char *argv[]) {

         journal_file_close(new_journal);

+        unlink(fn);

         assert_se(rmdir(dn) == 0);

         return 0;

-- 

2.2.0