storage/posix: Implement .unlink directory

Problem: For EC volume, If a file descriptor is open and
file has been unlinked, any further write on that fd will
fail. When a write request comes, EC internally reads some
blocks using anonymous fd. This read will fail as the file
has already been unlinked.

Solution: To solve this issue, we are using .unlink directory
to keep track of unlinked file. If a file is to be unlinked
while its fd is open, move this to .unlink directory and unlink
it from .glusterfs and real path. Once all the fd will be closed,
remove this entry form .unlink directory.

Change-Id: I8344edb0d340bdb883dc46458c16edbc336916b9
BUG: 1286029
Signed-off-by: Ashish Pandey <aspandey@redhat.com>
Reviewed-on: http://review.gluster.org/12816
Reviewed-by: Krutika Dhananjay <kdhananj@redhat.com>
Reviewed-by: Xavier Hernandez <xhernandez@datalab.es>
Tested-by: NetBSD Build System <jenkins@build.gluster.org>
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Pranith Kumar Karampuri <pkarampu@redhat.com>

1 files changed, 25 insertions, 1 deletions

diff --git a/xlators/storage/posix/src/posix.h b/xlators/storage/posix/src/posix.h
index 27006ff3beb..c48a77b4f0a 100644
--- a/xlators/storage/posix/src/posix.h
+++ b/xlators/storage/posix/src/posix.h
@@ -56,6 +56,8 @@
                                                + SLEN(GF_HIDDEN_PATH) + SLEN("/") \
                                                + SLEN("00/")            \
                                                + SLEN("00/") + SLEN(UUID0_STR) + 1) /* '\0' */;
+#define GF_UNLINK_TRUE 0x0000000000000001
+#define GF_UNLINK_FALSE 0x0000000000000000
 
 /**
  * posix_fd - internal structure common to file and directory fd's
@@ -184,14 +186,36 @@ typedef struct {
         int32_t     op_errno;
 } posix_xattr_filler_t;
 
-
 #define POSIX_BASE_PATH(this) (((struct posix_private *)this->private)->base_path)
 
 #define POSIX_BASE_PATH_LEN(this) (((struct posix_private *)this->private)->base_path_length)
 
 #define POSIX_PATH_MAX(this) (((struct posix_private *)this->private)->path_max)
 
+#define POSIX_GET_FILE_UNLINK_PATH(base_path, gfid, unlink_path)                           \
+        do {                                                                               \
+                int  path_len = 0;                                                         \
+                char gfid_str[64] = {0};                                                   \
+                uuid_utoa_r (gfid, gfid_str);                                              \
+                path_len = strlen (base_path) + 1 +                                        \
+                          strlen (GF_UNLINK_PATH) + 1 +                                    \
+                          strlen (gfid_str) + 1;                                           \
+                unlink_path = alloca (path_len);                                           \
+                if (!unlink_path) {                                                        \
+                        gf_msg ("posix", GF_LOG_ERROR, ENOMEM,                             \
+                                P_MSG_UNLINK_FAILED,                                       \
+                                "Failed to get unlink_path");                              \
+                        break;                                                             \
+                }                                                                          \
+                sprintf (unlink_path, "%s/%s/%s",                                          \
+                         base_path, GF_UNLINK_PATH, gfid_str);                             \
+         } while (0)
+
+
 /* Helper functions */
+int posix_inode_ctx_get (inode_t *inode, xlator_t *this, uint64_t *ctx);
+int posix_inode_ctx_set (inode_t *inode, xlator_t *this, uint64_t ctx);
+
 int posix_gfid_set (xlator_t *this, const char *path, loc_t *loc,
                     dict_t *xattr_req);
 int posix_fdstat (xlator_t *this, int fd, struct iatt *stbuf_p);