cluster/ec: OpenFD heal implementation for EC

Existing EC code doesn't try to heal the OpenFD to
avoid unnecessary healing of the data later.

Fix implements the healing of open FDs before
carrying out file operations on them by making an
attempt to open the FDs on required up nodes.

BUG: 1431955
Change-Id: Ib696f59c41ffd8d5678a484b23a00bb02764ed15
Signed-off-by: Sunil Kumar Acharya <sheggodu@redhat.com>

1 files changed, 99 insertions, 78 deletions

diff --git a/xlators/cluster/ec/src/ec-types.h b/xlators/cluster/ec/src/ec-types.h
index 7b2b7b8247d..23dc434bc42 100644
--- a/xlators/cluster/ec/src/ec-types.h
+++ b/xlators/cluster/ec/src/ec-types.h
@@ -145,6 +145,13 @@ enum _ec_stripe_part {
         EC_STRIPE_TAIL
 };
 
+/* Enumartions to indicate FD status. */
+typedef enum {
+    EC_FD_NOT_OPENED,
+    EC_FD_OPENED,
+    EC_FD_OPENING
+} ec_fd_status_t;
+
 struct _ec_config {
     uint32_t version;
     uint8_t  algorithm;
@@ -158,6 +165,7 @@ struct _ec_fd {
     loc_t     loc;
     uintptr_t open;
     int32_t   flags;
+    ec_fd_status_t fd_status[0];
 };
 
 struct _ec_stripe {
@@ -309,75 +317,82 @@ struct _ec_fragment_range {
                        the bricks (offset on brick) */
 };
 
+/* EC xlator data structure to collect all the data required to perform
+ * the file operation.*/
 struct _ec_fop_data {
-    int32_t              id;
-    int32_t              refs;
-    int32_t              state;
-    int32_t              minimum;
-    int32_t              expected;
-    int32_t              winds;
-    int32_t              jobs;
-    int32_t              error;
-    ec_fop_data_t       *parent;
-    xlator_t            *xl;
-    call_frame_t        *req_frame;    /* frame of the calling xlator */
-    call_frame_t        *frame;        /* frame used by this fop */
-    struct list_head     cbk_list;     /* sorted list of groups of answers */
-    struct list_head     answer_list;  /* list of answers */
-    struct list_head     pending_list; /* member of ec_t.pending_fops */
-    ec_cbk_data_t       *answer;       /* accepted answer */
-    int32_t              lock_count;
-    int32_t              locked;
-    ec_lock_link_t       locks[2];
-    int32_t              first_lock;
-    gf_lock_t            lock;
-
-    uint32_t             flags;
-    uint32_t             first;
-    uintptr_t            mask;
-    uintptr_t            healing; /*Dispatch is done but call is successful
-                                    only if fop->minimum number of subvolumes
-                                    succeed which are not healing*/
-    uintptr_t            remaining;
-    uintptr_t            received; /* Mask of responses */
-    uintptr_t            good;
-
-    uid_t                uid;
-    gid_t                gid;
-
-    ec_wind_f            wind;
-    ec_handler_f         handler;
-    ec_resume_f          resume;
-    ec_cbk_t             cbks;
-    void                *data;
-    ec_heal_t           *heal;
-    struct list_head     healer;
-
-    uint64_t             user_size;
-    uint32_t             head;
-
-    int32_t              use_fd;
-
-    dict_t              *xdata;
-    dict_t              *dict;
-    int32_t              int32;
-    uint32_t             uint32;
-    uint64_t             size;
-    off_t                offset;
-    mode_t               mode[2];
-    entrylk_cmd          entrylk_cmd;
-    entrylk_type         entrylk_type;
-    gf_xattrop_flags_t   xattrop_flags;
-    dev_t                dev;
-    inode_t             *inode;
-    fd_t                *fd;
-    struct iatt          iatt;
-    char                *str[2];
-    loc_t                loc[2];
-    struct gf_flock      flock;
-    struct iovec        *vector;
-    struct iobref       *buffers;
-    gf_seek_what_t       seek;
+    int32_t            id;           /* ID of the file operation */
+    int32_t            refs;
+    int32_t            state;
+    int32_t            minimum;      /* Mininum number of successful
+                                        operation required to conclude a
+                                        fop as successful */
+    int32_t            expected;
+    int32_t            winds;
+    int32_t            jobs;
+    int32_t            error;
+    ec_fop_data_t     *parent;
+    xlator_t          *xl;           /* points to EC xlator */
+    call_frame_t      *req_frame;    /* frame of the calling xlator */
+    call_frame_t      *frame;        /* frame used by this fop */
+    struct list_head   cbk_list;     /* sorted list of groups of answers */
+    struct list_head   answer_list;  /* list of answers */
+    struct list_head   pending_list; /* member of ec_t.pending_fops */
+    ec_cbk_data_t     *answer;       /* accepted answer */
+    int32_t            lock_count;
+    int32_t            locked;
+    ec_lock_link_t     locks[2];
+    int32_t            first_lock;
+    gf_lock_t          lock;
+
+    uint32_t           flags;
+    uint32_t           first;
+    uintptr_t          mask;
+    uintptr_t          healing; /*Dispatch is done but call is successful only
+                                  if fop->minimum number of subvolumes succeed
+                                  which are not healing*/
+    uintptr_t          remaining;
+    uintptr_t          received; /* Mask of responses */
+    uintptr_t          good;
+
+    uid_t              uid;
+    gid_t              gid;
+
+    ec_wind_f          wind;          /* Function to wind to */
+    ec_handler_f       handler;       /* FOP manager function */
+    ec_resume_f        resume;
+    ec_cbk_t           cbks;          /* Callback function for this FOP */
+    void              *data;
+    ec_heal_t         *heal;
+    struct list_head   healer;
+
+    uint64_t           user_size;
+    uint32_t           head;
+
+    int32_t            use_fd;        /* Indicates whether this FOP uses FD or
+                                         not */
+
+    dict_t            *xdata;
+    dict_t            *dict;
+    int32_t            int32;
+    uint32_t           uint32;
+    uint64_t           size;
+    off_t              offset;
+    mode_t             mode[2];
+    entrylk_cmd        entrylk_cmd;
+    entrylk_type       entrylk_type;
+    gf_xattrop_flags_t xattrop_flags;
+    dev_t              dev;
+    inode_t           *inode;
+    fd_t              *fd;              /* FD of the file on which FOP is
+                                           being carried upon */
+    struct iatt        iatt;
+    char              *str[2];
+    loc_t              loc[2];          /* Holds the location details for
+                                           the file */
+    struct gf_flock    flock;
+    struct iovec      *vector;
+    struct iobref     *buffers;
+    gf_seek_what_t     seek;
     ec_fragment_range_t  frag_range; /* This will hold the range of stripes
                                          affected by the fop. */
 };
@@ -623,18 +638,24 @@ struct _ec {
     xlator_t          *xl;
     int32_t            healers;
     int32_t            heal_waiters;
-    int32_t            nodes;
+    int32_t            nodes;                /* Total number of bricks(n) */
     int32_t            bits_for_nodes;
-    int32_t            fragments;
-    int32_t            redundancy;
-    uint32_t           fragment_size;
-    uint32_t           stripe_size;
-    int32_t            up;
+    int32_t            fragments;            /* Data bricks(k) */
+    int32_t            redundancy;           /* Redundant bricks(m) */
+    uint32_t           fragment_size;        /* Size of fragment/chunk on a
+                                                brick. */
+    uint32_t           stripe_size;          /* (fragment_size * fragments)
+                                                maximum size of user data
+                                                stored in one stripe. */
+    int32_t            up;                   /* Represents whether EC volume is
+                                                up or not. */
     uint32_t           idx;
-    uint32_t           xl_up_count;
-    uintptr_t          xl_up;
-    uint32_t           xl_notify_count;
-    uintptr_t          xl_notify;
+    uint32_t           xl_up_count;          /* Number of UP bricks. */
+    uintptr_t          xl_up;                /* Bit flag representing UP
+                                                bricks */
+    uint32_t           xl_notify_count;      /* Number of notifications. */
+    uintptr_t          xl_notify;            /* Bit flag representing
+                                                notification for bricks. */
     uintptr_t          node_mask;
     xlator_t         **xl_list;
     gf_lock_t          lock;